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{{About|the chemical compounds alkaloids|the [[pharmaceutical company]] in the [[Republic of Macedonia]]|Alkaloid (company)}}
{{no footnotes|date=January 2013}}
{{Infobox Italian comune
| name                    = Abano Terme
| official_name          = Comune di Abano Terme
| native_name            =
| image_skyline          =
| imagesize              =
| image_alt              =
| image_caption          =
| image_shield            = Abano Terme-Stemma.png
| shield_alt              =
| image_map              =
| map_alt                =
| map_caption            =
| pushpin_label_position  =
| pushpin_map_alt        =
| latd  = 45 |latm  = 21 |lats  = 37 |latNS  = N
| longd = 11 |longm = 47 |longs =  24 |longEW = E
| coordinates_type        = region:IT_type:city(19062)
| coordinates_display    = title
| coordinates_footnotes  =
| region                  = [[Veneto]]
| province                = [[Province of Padua|Padua]] (PD)
| frazioni                = Feriole, Giarre, Monterosso, Monteortone
| mayor_party            =
| mayor                  = Luca Claudio
| area_footnotes          =
| area_total_km2          = 21
| population_footnotes    =
| population_total        = 19062
| population_as_of        = 2006
| pop_density_footnotes  =
| population_demonym      = Aponensi or Abanesi
| elevation_footnotes    =
| elevation_m            = 14
| twin1                  =
| twin1_country          =
| saint                  = St. Lawrence
| day                    = August 10
| postal_code            = 35031
| area_code              = 049
| website                = {{official website|http://www.comune.abanoterme.pd.it/}}
| footnotes              =
}}
[[Image:AbanoCampanile.jpg|thumb|left|250px|Tower of St. Lorenzo Cathedral]]
'''Abano Terme''' (known as ''Abano Bagni'' until 1924) is a town and ''[[comune]]'' in the [[province of Padua]], in the [[Veneto]] region, [[Italy]], on the eastern slope of the [[Colli Euganei]]; it is 10 kilometers southwest by rail from [[Padua]]. Abano Terme's population is 19,062 (2001) (in 1901 it was only 4,556).


[[File:Papaver somniferum 01.jpg|thumb|250px|The first individual alkaloid, [[morphine]], was isolated in 1804 from [[opium poppies|poppy]] (''Papaver somniferum'').<ref>{{cite book|url=http://books.google.com/?id=MtOiLVWBn8cC&pg=PA20|page=20|title=Molecular, clinical and environmental toxicology|author=Andreas Luch|publisher=Springer|year=2009|isbn=3-7643-8335-6}}</ref>]]
The town's hot springs and mud baths are the main economic resource. The waters have a temperature of some 80°C.


'''Alkaloids''' are a group of naturally occurring [[chemical compound]]s that contain mostly [[base (chemistry)|basic]] [[nitrogen]] atoms. This group also includes some related compounds with neutral<ref name="goldbook.iupac.org">[http://goldbook.iupac.org/A00220.html IUPAC. Compendium of Chemical Terminology], 2nd ed. (The "Gold Book"). Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997) ISBN 0-9678550-9-8 {{doi|10.1351/goldbook}}</ref> and even weakly [[acid]]ic properties.<ref>R. H. F. Manske. ''The Alkaloids. Chemistry and Physiology''. Volume VIII. – New York: [[Academic Press]], 1965, p. 673</ref> Some synthetic compounds of similar structure are also attributed to alkaloids.<ref>Robert Alan Lewis. [http://books.google.com/books?id=caTqdbD7j4AC&pg=PA51 ''Lewis' dictionary of toxicology'']. CRC Press, 1998, p. 51 ISBN 1-56670-223-2</ref> In addition to [[carbon]], [[hydrogen]] and [[nitrogen]], alkaloids may also contain [[oxygen]], [[sulfur]] and more rarely other elements such as [[chlorine]], [[bromine]], and [[phosphorus]].<ref name="XimE: alkaloidy">[http://www.xumuk.ru/encyklopedia/119.html Chemical Encyclopedia: alkaloids]. xumuk.ru</ref>
==History==
The baths were known to the Romans as ''[[Aponus|Aponi]] fons'' or ''Aquae Patavinae''. A description of them is given in a letter of [[Theodoric the Great|Theodoric]], the king of the [[Ostrogoths]]. Some remains of the ancient baths have been discovered (S. Mandruzzato, ''Trattato dei Bagni d'Abano,'' Padua, 1789). An oracle of [[Geryon]] lay near, and the so-called ''sortes Praenestinae'' (C.I.L. i., Berlin, 1863; 1438–1454), small bronze cylinders inscribed, and used as oracles, were perhaps found here in the 16th century.


Alkaloids are produced by a large variety of organisms, including [[bacteria]], [[fungus|fungi]], [[plant]]s, and [[animal]]s, and are part of the group of [[natural product]]s (also called [[secondary metabolite]]s). Many alkaloids can be purified from crude extracts by [[acid-base extraction]]. Many alkaloids are [[toxicity|toxic]] to other organisms. They often have [[pharmacology|pharmacological]] effects and are used as [[medication]]s, as [[recreational drug]]s, or in [[entheogenic]] rituals. Examples are the [[local anesthetic]] and [[stimulant]] [[cocaine]], the psychedelic [[psilocin]], the stimulant [[caffeine]], [[nicotine]],<ref>{{cite web|title=Alkaloid|url=http://science.howstuffworks.com/alkaloid-info.htm}}</ref> the [[analgesic]] [[morphine]], the antibacterial [[berberine]], the anticancer compound [[vincristine]], the antihypertension agent [[reserpine]], the cholinomimeric [[galantamine]], the spasmolysis agent [[atropine]], the vasodilator [[vincamine]], the anti-arrhythmia compound [[quinidine]], the anti-asthma therapeutic [[ephedrine]], and the [[antimalarial drug]] [[quinine]].
The baths were destroyed by the Lombards in the 6th century, but they were rebuilt and enlarged when Abano became an autonomous [[medieval commune|comune]] in the 12th century and, again, in the late 14th century. The city was under the [[Republic of Venice]] from 1405 to 1797.
Although alkaloids act on a diversity of metabolic systems in humans and other animals, they almost uniformly invoke a [[Bitter (taste)#Bitterness|bitter taste]].<ref name=Rhoades1979>{{cite book|year=1979 |author=Rhoades, David F |chapter=Evolution of Plant Chemical Defense against Herbivores |editor=Rosenthal, Gerald A., and Janzen, Daniel H|title=Herbivores: Their Interaction with Secondary Plant Metabolites |place=New York |publisher=Academic Press |page=41 |isbn=0-12-597180-X}}</ref>


The boundary between alkaloids and other nitrogen-containing natural compounds is not clear-cut.<ref name="Meyers">Robert A. Meyers ''Encyclopedia of Physical Science and Technology'' – Alkaloids, 3rd edition. ISBN 0-12-227411-3</ref> Compounds like [[amino acid]] [[peptide]]s, [[protein]]s, [[nucleotide]]s, [[nucleic acid]], [[amine]]s, and [[antibiotics]] are usually not called alkaloids.<ref name="goldbook.iupac.org"/> Natural compounds containing nitrogen in the [[Alicyclic compound|exocyclic]] position ([[mescaline]], [[serotonin]], [[dopamine]], etc.) are usually attributed to [[amine]]s rather than alkaloids.<ref>Leland J. Cseke [http://books.google.com/books?id=wV2T41nGFc4C&pg=PA30 Natural Products from Plants] Second Edition. – CRC, 2006, p. 30 ISBN 0-8493-2976-0</ref> Some authors, however, consider alkaloids a special case of amines.<ref>A. William Johnson [http://books.google.com/books?id=0X4cQus2gz8C&pg=PA433 Invitation to Organic Chemistry], Jones and Bartlett, 1999, p. 433 ISBN 0-7637-0432-6</ref><ref>Raj K Bansal [http://books.google.com/books?id=1B6ijcTkD5EC&pg=PA644 A Text Book of Organic Chemistry]. 4th Edition, New Age International, 2004, p. 644 ISBN 81-224-1459-1</ref><ref name="Aniszewski 110">[[#Aniszewski|Aniszewski]], p. 110</ref>
==Main sights==
*[[Abano Cathedral]], or the cathedral (''[[duomo]]'') of St. Lawrence. The current edifice was erected in 1780 over a pre-existing church which was allegedly destroyed by [[Cangrande della Scala]]. The bell tower has parts from the 9th/10th and 14th centuries.
*The Montirone Gallery, housing works of [[Il Moretto]], [[Palma the Younger]], [[Guido Reni]], [[Giandomenico Tiepolo]] and others.
*The Sanctuary of the ''Madonna della Salute'' or of Monteortone (built from 1428). It lies on the site where the Madonna appeared to Pietro Falco, healing his wounds. The church is on the Latin cross plan, with a nave and two aisles with three apses decorated by a frieze. It has with a Baroque portal (1667), a noteworthy bell tower, presbytery frescoes portraying the ''Histories of St. Peter'' and ''Virgin'' by [[Jacopo da Montagnana]] (1495) and [[Palma il Giovane|Palma the Younger]]'s altarpiece depicting ''Christ Crucifixed Between St. Augustine and St. Jerome''.


==Naming==
Just outside the city is San Daniele Abbey (11th century). 6&nbsp;km from the city is also Praglia Abbey, founded in the 11th century by Benedictine monks and rebuilt in 1496–1550. The church of the Assumption, with a marble portal from 1548, has a Renaissance style interior. Noteworthy is the four cloister complex.
[[File:Meissner alkalod definition article 1819.png|thumb|160px|The article that introduced the concept of "alkaloid".]]


The name "alkaloids" ({{lang-de|Alkaloide}}) was introduced in 1819 by the German chemist [[:de:Carl Friedrich Wilhelm Meißner|Carl Friedrich Wilhelm Meißner]], and is derived from late Latin root ''{{lang-la|alkali}}'' (which, in turn, comes from the Arabic ''al-qalwī'' – "ashes of plants") and the suffix ''{{lang-el|-οειδής}}'' – "like".<ref group="nb">In the penultimate sentence of his article – W. Meissner (1819) "Über Pflanzenalkalien: II. Über ein neues Pflanzenalkali (Alkaloid)" (On plant alkalis: II. On a new plant alkali (alkaloid)), ''Journal für Chemie und Physik'', '''25''' : 379–381 ; available on-line at:  [http://babel.hathitrust.org/cgi/pt?id=nyp.33433069069056;view=1up;seq=415 Hathi Trust] – Meissner wrote:  "''Überhaupt scheint es mir auch angemessen, die bis jetzt bekannten Pflanzenstoffe nicht mit dem Namen Alkalien, sondern Alkaloide zu belegen, da sie doch in manchen Eigenschaften von den Alkalien sehr abweichen, sie würden daher in dem Abschnitt der Pflanzenchemie vor den Pflanzensäuren ihre Stelle finden''." (In general, it seems appropriate to me to impose on the currently known plant substances not the name "alkalis" but "alkaloids", since they differ greatly in some properties from the alkalis; among the chapters of plant chemistry, they would therefore find their place before plant acids [since "Alkaloid" would precede "Säure" (acid)].)</ref> However, the term came into wide use only after the publication of a review article by Oscar Jacobsen in the chemical dictionary of [[Albert Ladenburg]] in the 1880s.<ref>[[#Hesse|Hesse]], pp. 1–3</ref><ref>Oscar Jacobsen, "Alkaloide" in:  Ladenburg, ''Handwörterbuch der Chemie'' (Breslau, Germany:  Eduard Trewendt, 1882), vol. 1, [http://books.google.com/books?id=-9fUAAAAMAAJ&pg=PA213 pp. 213–422].</ref>
==Notable people==
* [[Peter of Abano]] (c.1257 – 1316), physician and philosopher


There is no unique method of naming alkaloids.<ref name="Hesse 5">[[#Hesse|Hesse]], p. 5</ref> Many individual names are formed by adding the suffix "ine" to the species or genus name.<ref>The suffix "ine" is a Greek feminine patronymic suffix and means "daughter of"; hence, for example, "atropine" means "daughter of Atropa (belladonna)": [https://webspace.yale.edu/chem125/125/history99/5Valence/Nomenclature/alkanenames.html Development of Systematic Names for the Simple Alkanes]. yale.edu</ref> For example, [[atropine]] is isolated from the plant [[Atropa belladonna]], [[strychnine]] is obtained from the seed of [[Strychnine tree]]  (''Strychnos nux-vomica'' L.).<ref name="XimE: alkaloidy"/> If several alkaloids are extracted from one plant then their names often contain suffixes "idine", "anine", "aline", "inine", etc. There are also at least 86 alkaloids containing the root "vin" (extracted from the [[Vinca]] plant).<ref>[[#Hesse|Hesse]], p. 7</ref>
==References==
*''L'Italia da scoprire'', Giorgio Mondadori, 2006.


== History ==
==External links==
[[File:Friedrich Wilhelm Adam Sertuerner.jpg|thumb|left|[[Friedrich Sertürner]], the German chemist who first isolated [[morphine]] from [[opium]].]]
*{{Wikisource-inline|list=
Alkaloid-containing plants have been used by humans since ancient times for therapeutic and recreational purposes. For example, medicinal plants have been known in the [[Mesopotamia]] at least around 2000 BC.<ref name="Aniszewski 182">[[#Aniszewski|Aniszewski]], p. 182</ref> The ''[[Odyssey]]'' of [[Homer]] referred to a gift given to Helen by the Egyptian queen, a drug bringing oblivion. It is believed that the gift was an opium-containing drug.<ref>[[#Hesse|Hesse]], p. 338</ref> A Chinese book on houseplants written in 1st–3rd centuries BC mentioned a medical use of [[Ephedra]] and [[Opium poppy|opium poppies]].<ref>[[#Hesse|Hesse]], p. 304</ref> Also, [[coca]] leaves have been used by [[South America]]n Indians since ancient times.<ref>[[#Hesse|Hesse]], p. 350</ref>
**{{Cite EB1911|wstitle=Abano Bagni |short=x |noicon=x}}
**{{Cite Collier's|Abano Bagni|noicon=x}}
}}
** [http://www.abano.it/en/Default.aspx Abano.it Touristic informations web site]
{{Province of Padua}}


[[Extracts]] from plants containing toxic alkaloids, such as [[aconitine]] and [[tubocurarine]], were used since antiquity for poisoning arrows.<ref name="Aniszewski 182"/>
[[Category:Cities and towns in Veneto]]
 
[[Category:Spa towns in Italy]]
Studies of alkaloids began in the 19th century. In 1804, the German chemist [[Friedrich Sertürner]] isolated from opium a "soporific principle" ({{lang-la|principium somniferum}}), which he called "morphium" in honor of [[Morpheus (mythology)|Morpheus]], the [[Ancient Greece|Greek]] god of dreams; in German and some other Central-European languages, this is still the name of the drug. The term "morphine", used in English and French, was given by the French physicist [[Joseph Louis Gay-Lussac]].
 
A significant contribution to the chemistry of alkaloids in the early years of its development was made by the French researchers [[Pierre Joseph Pelletier]] and [[Joseph Bienaimé Caventou]], who discovered [[quinine]] (1820) and [[strychnine]] (1818). Several other alkaloids were discovered around that time, including [[xanthine]] (1817), [[atropine]] (1819), [[caffeine]] (1820), [[coniine]] (1827), [[nicotine]] (1828), [[colchicine]] (1833), [[sparteine]] (1851), and [[cocaine]] (1860).<ref>[[#Hesse|Hesse]], pp. 313–316</ref>
 
The first complete synthesis of an alkaloid was achieved in 1886 by the German chemist [[Albert Ladenburg]]. He produced [[coniine]] by reacting 2-methylpyridine with [[acetaldehyde]] and reducing the resulting 2-propenyl pyridine with [[sodium]].<ref name="BSE: koniin">[http://slovari.yandex.ru/dict/bse/article/00036/77600.htm Кониин]. [[Great Soviet Encyclopedia]] (1969–1978)</ref><ref>[[#Hesse|Hesse]], p. 204</ref> The development of the chemistry of alkaloids was accelerated by the emergence of [[spectroscopy|spectroscopic]] and [[Chromatography|chromatographic]] methods in the 20th century, so that by 2008 more than 12,000 alkaloids had been identified.<ref>[[#Begley|Begley]], Natural Products in Plants</ref>
 
[[File:Bufotenin.svg|thumb|160px|[[Bufotenin]], an alkaloid from some toads, contains an [[indole]] core and is produced in living organisms from the amino acid [[tryptophan]].]]
 
== Classification ==
[[File:Nicotine.svg|thumb|160px|The [[nicotine]] molecule contains both [[pyridine]] (left) and [[pyrrolidine]] rings (right).]]
 
Compared with most other classes of natural compounds, alkaloids are characterized by a great structural diversity and there is no uniform classification of alkaloids.<ref name="ref15">[[#Hesse|Hesse]], p. 11</ref> First classification methods have historically combined alkaloids by the common natural source, e.g., a certain type of plants. This classification was justified by the lack of knowledge about the chemical structure of alkaloids and is now considered obsolete.<ref name="XimE: alkaloidy"/><ref>[[#Orekhov|Orekhov]], p. 6</ref>
 
More recent classifications are based on similarity of the carbon skeleton (e.g., [[indole]]-, [[isoquinoline]]-, and [[pyridine]]-like) or biogenetic precursor ([[ornithine]], [[lysine]], [[tyrosine]], [[tryptophan]], etc.).<ref name="XimE: alkaloidy"/> However, they require compromises in borderline cases;<ref name="ref15" /> for example, [[nicotine]] contains a pyridine fragment from [[nicotinamide]] and [[pyrrolidine]] part from ornithine<ref>[[#Aniszewski|Aniszewski]], p. 109</ref> and therefore can be assigned to both classes.<ref name="ref19">[[#Dewick|Dewick]], p. 307</ref>
 
Alkaloids are often divided into the following major groups:<ref>[[#Hesse|Hesse]], p. 12</ref>
 
# "True alkaloids", which contain [[nitrogen]] in the [[heterocycle]] and originate from [[amino acid]]s.<ref name="ref21">[[#Plemenkov|Plemenkov]], p. 223</ref> Their characteristic examples are [[atropine]], [[nicotine]], and [[morphine]]. This group also includes some alkaloids that besides nitrogen heterocycle contain [[terpene]] (e.g., [[evonine]]<ref>[[#Aniszewski|Aniszewski]], p. 108</ref>) or peptide fragments (e.g. [[ergotamine]]<ref name="ref23">[[#Hesse|Hesse]], p. 84</ref>). This group also includes piperidine alkaloids [[coniine]] and [[coniceine]]<ref name="ref24">[[#Hesse|Hesse]], p. 31</ref> although they do not originate from amino acids.<ref name="ref25">[[#Dewick|Dewick]], p. 381</ref>
# "Protoalkaloids", which contain [[nitrogen]] and also originate from amino acids.<ref name="ref21" /> Examples include [[mescaline]], [[adrenaline]] and [[ephedrine]].
# Polyamine alkaloids – derivatives of [[putrescine]], [[spermidine]], and [[spermine]].
# Peptide and cyclopeptide alkaloids.<ref name="ref27">{{cite journal|author = Dimitris C. Gournelif, Gregory G. Laskarisb and Robert Verpoorte|title = Cyclopeptide alkaloids|doi = 10.1039/NP9971400075|journal = Nat. Prod. Rep.|year = 1997|volume = 14|pages = 75–82|pmid = 9121730|issue = 1}}</ref>
# Pseudalkaloids – alkaloid-like compounds that do not originate from amino acids.<ref>[[#Aniszewski|Aniszewski]], p. 11</ref> This group includes, [[terpene]]-like and [[steroid]]-like alkaloids,<ref>[[#Plemenkov|Plemenkov]], p. 246</ref> as well as [[purine]]-like alkaloids such as [[caffeine]], [[theobromine]], [[theacrine]] and [[theophylline]].<ref name="ref30">[[#Aniszewski|Aniszewski]], p. 12</ref> Some authors classify as pseudoalkaloids such compounds such as [[ephedrine]] and [[cathinone]]. Those originate from the amino acid [[phenylalanine]], but acquire their nitrogen atom not from the amino acid but through [[transamination]].<ref name="ref30" /><ref name="ref31">[[#Dewick|Dewick]], p. 382</ref>
 
Some alkaloids do not have the carbon skeleton characteristic of their group. So, [[galantamine]] and homoaporphines do not contain [[isoquinoline]] fragment, but are, in general, attributed to isoquinoline alkaloids.<ref>[[#Hesse|Hesse]], pp. 44, 53</ref>
 
Main classes of monomeric alkaloids are listed in the table below:
<!--the table is translated from the ru.wiki article. Please fix translation glitches -->
{| Class = "wikitable"
|-
! Class
!Major groups
!Main synthesis steps
!Examples
|-
| colspan="4"  style="text-align:center; background:# DADADA;"|''Alkaloids with nitrogen heterocycles (true alkaloids)''
|-
| [[Pyrrolidine]] derivatives<ref name="ref34">[[#Plemenkov|Plemenkov]], p. 224</ref>
[[File:Pyrrolidine structure.svg|50px|center]]
|
| [[Ornithine]] or [[arginine]] → [[putrescine]] → N-methylputrescine → N-methyl-Δ<sup>1</sup>-pyrroline <ref name="ref35">[[#Aniszewski|Aniszewski]], p. 75</ref>
| [[Cuscohygrine]], [[hygrine]], hygroline, stachydrine<ref name="ref34" /><ref>[[#Orekhov|Orekhov]], p. 33</ref>
|-
| Rowspan = "2"|[[Tropane]] derivatives<ref name="ref38">[http://www.xumuk.ru/encyklopedia/2/4609.html Chemical Encyclopedia: Tropan alkaloids]. xumuk.ru</ref>
[[File:Tropane numbered.svg|100px|center]]
| Atropine group<br /><small>Substitution in positions 3, 6 or 7 </small>
| Rowspan = "2"|[[Ornithine]] or [[arginine]] → [[putrescine]] → N-methylputrescine → N-methyl-Δ<sup>1</sup>-pyrroline <ref name = "ref35 "/>
| [[Atropine]], [[scopolamine]], [[hyoscyamine]]<ref name="ref34" /><ref name="ref38" /><ref>[[#Hesse|Hesse]], p. 34</ref>
|-
| Cocaine group<br /> <small>Substitution in positions 2 and 3 </small>
| [[Cocaine]], [[ecgonine]] <ref name="ref38" /><ref>[[#Aniszewski|Aniszewski]], p. 27</ref>
|-
| Rowspan = "4"|[[Pyrrolizidine]] derivatives<ref name="ref45">[http://www.xumuk.ru/encyklopedia/2/3370.html Chemical Encyclopedia: Pyrrolizidine alkaloids]. xumuk.ru</ref>
[[File:Pyrrolizidine.svg|80px|center]]
| Non-esters
| Rowspan = "3"|In plants: [[ornithine]] or [[arginine]] → [[putrescine]] → [[homospermidine]] → [[retronecine]] <ref name="ref35" />
| [[Retronecine]], heliotridine, laburnine <ref name="ref45" /><ref>[[#Plemenkov|Plemenkov]], p. 229</ref>
|-
| Complex [[esters]] of monocarboxylic acids
| Indicine, lindelophin, sarracine <ref name="ref45" />
|-
| Macrocyclic diesters
| [[Platyphylline]], trichodesmine<ref name="ref45" />
|-
| 1-aminopyrrolizidines ([[Loline alkaloids|lolines]])
| In [[Neotyphodium|fungi]]: [[Proline|<small>L</small>-proline]] + [[homoserine|<small>L</small>-homoserine]] → ''N''-(3-amino-3-carboxypropyl)proline → norloline<ref name="Blankenship">{{cite journal|author=Blankenship JD, Houseknecht JB, Pal S, Bush LP, Grossman RB, Schardl CL|year= 2005|title=Biosynthetic precursors of fungal pyrrolizidines, the loline alkaloids|journal=Chembiochem|volume=6|pages=1016–1022|pmid=15861432|doi=10.1002/cbic.200400327|issue=6}}</ref><ref name="Faulkner et al. 2006">{{cite journal|author=Faulkner JR, Hussaini SR, Blankenship JD, Pal S, Branan BM, Grossman RB, Schardl CL|year= 2006|title=On the sequence of bond formation in loline alkaloid biosynthesis|journal=Chembiochem|volume=7|pages=1078–1088|pmid=16755627|doi=10.1002/cbic.200600066|issue=7}}</ref>
|Loline, ''N''-formylloline, ''N''-acetylloline<ref name="Schardl et al. 2007">{{cite journal|author=Schardl CL, Grossman RB, Nagabhyru P, Faulkner JR, Mallik UP|year=2007|title=Loline alkaloids: currencies of mutualism|journal = [[Phytochemistry (journal)|Phytochemistry]]|volume=68|pages=980–996|doi=10.1016/j.phytochem.2007.01.010|pmid=17346759|issue=7}}</ref>
|-
| Rowspan = "2"|[[Piperidine]] derivatives<ref>[[#Plemenkov|Plemenkov]], p. 225</ref>
[[File:Piperidin.svg|50px|center]]
|
| [[Lysine]] → [[cadaverine]] → Δ<sup>1</sup>-piperideine <ref>[[#Aniszewski|Aniszewski]], p. 95</ref>
| [[Sedamine]], lobeline, anaferine, [[piperine]] <ref name="ref24" /><ref>[[#Orekhov|Orekhov]], p. 80</ref>
|-
|
| [[Caprylic acid|Octanoic acid]] → coniceine → [[coniine]] <ref name="ref25" />
| [[Coniine]], coniceine <ref name="ref25" />
|-
| Rowspan = "5"|[[Quinolizidine]] derivatives<ref name="ref57">[http://www.xumuk.ru/encyklopedia/2/5011.html Chemical Encyclopedia: Quinolizidine alkaloids]. xumuk.ru</ref><ref>[[#Saxton|Saxton]], Vol. 1, p. 93</ref>
[[File:Quinolizidine.svg|80px|center]]
| [[Lupinine]] group
| Rowspan = "5"|[[Lysine]] → [[cadaverine]] → Δ<sup>1</sup>-piperideine <ref>[[#Aniszewski|Aniszewski]], p. 98</ref>
| [[Lupinine]], nupharidin <ref name="ref57" />
|-
| [[Cytisine]] group
| [[Cytisine]] <ref name="ref57" />
|-
| [[Sparteine]] group
| [[Sparteine]], [[lupanine]], [[anahygrine]]<ref name="ref57" />
|-
| [[Matrine]] group
| Matrine, oxymatrine, allomatridine<ref name="ref57" /><ref>[[#Saxton|Saxton]], Vol. 1, p. 91</ref><ref>{{cite journal|author = Joseph P. Michael|title = Indolizidine and quinolizidine alkaloids|doi = 10.1039/b208137g|journal=Nat. Prod. Rep|year = 2002|volume = 19|pages = 458–475}}</ref>
|-
| [[Ormosanine]] group
| Ormosanine, piptantine<ref name="ref57" /><ref>[[#Saxton|Saxton]], Vol. 1, p. 92</ref>
|-
| [[Indolizidine]] derivatives<ref>[[#Dewick|Dewick]], p. 310</ref>
[[File:Indolizidine.svg|80px|center]]
|
| [[Lysine]] → δ-semialdehyde of [[alpha-Aminoadipic acid|α-aminoadipic acid]] → [[pipecolic acid]] → 1 indolizidinone <ref>[[#Aniszewski|Aniszewski]], p. 96</ref>
| [[Swainsonine]], [[castanospermine]] <ref>[[#Aniszewski|Aniszewski]], p. 97</ref>
|-
| Rowspan = "4"|[[Pyridine]] derivatives<ref name="ref72">[[#Plemenkov|Plemenkov]], p. 227</ref><ref name="ref73">[http://www.xumuk.ru/encyklopedia/2/3336.html Chemical Encyclopedia: pyridine alkaloids]. xumuk.ru</ref>
[[File:Pyridine.svg|50px|center]]
| Simple derivatives of pyridine
| Rowspan = "3"|[[Nicotinic acid]] → dihydronicotinic acid → 1,2-dihydropyridine <ref name="ref74">[[#Aniszewski|Aniszewski]], p. 107</ref>
| [[Trigonelline]], ricinine, [[arecoline]] <ref name="ref72" /><ref name="ref76">[[#Aniszewski|Aniszewski]], p. 85</ref>
|-
| Polycyclic noncondensing pyridine derivatives
| [[Nicotine]], [[nornicotine]], [[anabasine]], anatabine <ref name="ref72" /><ref name="ref76" />
|-
| Polycyclic condensed pyridine derivatives
| [[Actinidine]], gentianine, pediculinine <ref>[[#Plemenkov|Plemenkov]], p. 228</ref>
|-
| [[Sesquiterpene]] pyridine derivatives
| [[Nicotinic acid]], [[isoleucine]] <ref name="Aniszewski 110"/>
| Evonine, hippocrateine, triptonine <ref name="ref73" /><ref name="ref74" />
|-
| Rowspan = "26"|[[Isoquinoline]] derivatives and related alkaloids <ref name="Hesse 36">[[#Hesse|Hesse]], p. 36</ref>
[[File:Isoquinoline numbered.svg|90px|center]]
| Simple derivatives of isoquinoline <ref name="XimE: izoxinolin">[http://www.xumuk.ru/encyklopedia/1642.html Chemical Encyclopedia: isoquinoline alkaloids]. xumuk.ru</ref>
| Rowspan = "26"|[[Tyrosine]] or [[phenylalanine]] → [[dopamine]] or [[tyramine]] (for alkaloids Amarillis) <ref>[[#Aniszewski|Aniszewski]], pp. 77–78</ref><ref name="Begley">[[#Begley|Begley]], Alkaloid Biosynthesis</ref>
| Salsoline, lophocerine <ref name="Hesse 36"/><ref name="XimE: izoxinolin"/>
|-
| Derivatives of 1- and 3-isoquinolines <ref name="Saxton 122">[[#Saxton|Saxton]], Vol. 3, p. 122</ref>
| N-methylcoridaldine, noroxyhydrastinine <ref name="Saxton 122"/>
|-
| Derivatives of 1- and 4-phenyltetrahydroisoquinolines <ref name="XimE: izoxinolin"/>
| Cryptostilin <ref name="XimE: izoxinolin"/><ref name="Hesse 54">[[#Hesse|Hesse]], p. 54</ref>
|-
| Derivatives of 5-naftil-isoquinoline <ref name="ref83">[[#Hesse|Hesse]], p. 37</ref>
| Ancistrocladine <ref name="ref83" />
|-
| Derivatives of 1- and 2-benzyl-izoquinolines <ref>[[#Hesse|Hesse]], p. 38</ref>
| [[Papaverine]], [[laudanosine]], sendaverine
|-
| [[Cularine]] group<ref name="ref86">[[#Hesse|Hesse]], p. 46</ref>
| Cularine, yagonine <ref name="ref86" />
|-
| [[Pavine (molecule)|Pavine]]s and isopavines <ref name="ref88">[[#Hesse|Hesse]], p. 50</ref>
| Argemonine, [[amurensine]] <ref name="ref88" />
|-
| Benzopyrrocolines <ref name="ref90">{{cite journal|author = Kenneth W. Bentley|title = β-Phenylethylamines and the isoquinoline alkaloids|doi = 10.1039/NP9971400387|journal=Nat. Prod. Rep|year = 1997|volume = 14|pages = 387–411|pmid = 9281839|issue = 4|url=http://chemistry.mdma.ch/hiveboard/rhodium/pdf/archive/merbst/phenethylamines%20and%20isoquinolines%202001.pdf}}</ref>
| Cryptaustoline <ref name="XimE: izoxinolin"/>
|-
| Protoberberines <ref name="XimE: izoxinolin"/>
| [[Berberine]], [[canadine]], ophiocarpine, mecambridine, corydaline <ref name="ref91">[[#Hesse|Hesse]], p. 47</ref>
|-
| Phthalidisoquinolines <ref name="XimE: izoxinolin"/>
| [[Hydrastine]], [[narcotine]] (Noscapine) <ref>[[#Hesse|Hesse]], p. 39</ref>
|-
| Spirobenzylisoquinolines <ref name="XimE: izoxinolin"/>
| Fumaricine <ref name="ref88" />
|-
| [[Psychotria ipecacuanha|Ipecacuanha]] alkaloids<ref name="ref94">[[#Hesse|Hesse]], p. 41</ref>
| Emetine, protoemetine, ipecoside <ref name="ref94" />
|-
| Benzophenanthridines <ref name="XimE: izoxinolin"/>
| Sanguinarine, oxynitidine, corynoloxine <ref name="ref96">[[#Hesse|Hesse]], p. 49</ref>
|-
| [[Aporphine]]s <ref name="XimE: izoxinolin"/>
| [[Glaucine]], coridine, liriodenine <ref>[[#Hesse|Hesse]], p. 44</ref>
|-
| Proaporphines <ref name="XimE: izoxinolin"/>
| Pronuciferine, glaziovine <ref name="XimE: izoxinolin"/><ref name="ref90" />
|-
| Homoaporphines <ref name="ref99">[[#Saxton|Saxton]], Vol. 3, p. 164</ref>
| Kreysiginine, multifloramine <ref name="ref99" />
|-
| Homoproaporphines <ref name="ref99" />
| Bulbocodine <ref name="ref86" />
|-
| [[Morphine]]s<ref name="ref103">[[#Hesse|Hesse]], p. 51</ref>
| [[Morphine]], [[codeine]], [[thebaine]], [[sinomenine]] <ref name="ref104">[[#Plemenkov|Plemenkov]], p. 236</ref>
|-
| Homomorphines <ref>[[#Saxton|Saxton]], Vol. 3, p. 163</ref>
| Kreysiginine, androcymbine <ref name="ref103" />
|-
| Tropoloisoquinolines <ref name="XimE: izoxinolin"/>
| Imerubrine <ref name="XimE: izoxinolin"/>
|-
| Azofluoranthenes <ref name="XimE: izoxinolin"/>
| Rufescine, imeluteine <ref>[[#Saxton|Saxton]], Vol. 3, p. 168</ref>
|-
| [[Amaryllis]] alkaloids<ref>[[#Hesse|Hesse]], p. 52</ref>
| [[Lycorine]], ambelline, tazettine, [[galantamine]], montanine <ref>[[#Hesse|Hesse]], p. 53</ref>
|-
| [[Erythrina]] alkaloids<ref name="Hesse 54"/>
| Erysodine, erythroidine <ref name="Hesse 54"/>
|-
| [[Phenanthrene]] derivatives <ref name="XimE: izoxinolin"/>
| Atherosperminine <ref name="XimE: izoxinolin"/><ref name="ref91" />
|-
| [[Protopin]]s <ref name="XimE: izoxinolin"/>
| Protopine, oxomuramine, corycavidine <ref name="ref96" />
|-
| Aristolactam <ref name="XimE: izoxinolin"/>
| Doriflavin <ref name="XimE: izoxinolin"/>
|-
| [[Oxazole]] derivatives<ref name="Plemenkov 241">[[#Plemenkov|Plemenkov]], p. 241</ref>
[[File:Oxazole structure.svg|80px|center]]
|
| [[Tyrosine]] → [[tyramine]] <ref>[[#Brossi|Brossi]], Vol. 35, p. 261</ref>
| Annuloline, halfordinol, texaline, texamine<ref>[[#Brossi|Brossi]], Vol. 35, pp. 260–263</ref>
|-
| [[Isoxazole]] derivatives
[[Image:isoxazole structure.png|80px|center]]
|
|[[Ibotenic acid]] → [[Muscimol]]
|Ibotenic acid, Muscimol
|-
| [[Thiazole]] derivatives<ref name="ref114">[[#Plemenkov|Plemenkov]], p. 242</ref>
[[File:Thiazole structure.svg|80px|center]]
|
| [[1-Deoxy-D-xylulose 5-phosphate]] (DOXP), [[tyrosine]], [[cysteine]] <ref>[[#Begley|Begley]], Cofactor Biosynthesis</ref>
| Nostocyclamide, thiostreptone <ref name="ref114" /><ref>{{cite journal|author = John R. Lewis|title = Amaryllidaceae, muscarine, imidazole, oxazole, thiazole and peptide alkaloids, and other miscellaneous alkaloids|journal = Nat. Prod. Rep|year = 2000|volume = 17|pages = 57–84|pmid = 10714899|issue = 1|doi = 10.1039/a809403i}}</ref>
|-
| Rowspan = "3"|[[Quinazoline]] derivatives<ref>[http://www.xumuk.ru/encyklopedia/2/5003.html Chemical Encyclopedia: Quinazoline alkaloids]. xumuk.ru</ref>
[[File:Quinazoline numbered.svg|90px|center]]
| 3,4-Dihydro-4-quinazolone derivatives
| Rowspan = "3"|[[Anthranilic acid]] or [[phenylalanine]] or [[ornithine]] <ref>[[#Aniszewski|Aniszewski]], p. 106</ref>
| [[Febrifugine]]<ref name="ref120">[[#Aniszewski|Aniszewski]], p. 105</ref>
|-
| 1,4-Dihydro-4-quinazolone derivatives
| Glycorine, arborine, glycosminine<ref name="ref120" />
|-
| Pyrrolidine and piperidine quinazoline derivatives
| [[Vazicine]] (peganine) <ref name="Plemenkov 241"/>
|-
| [[Acridine]] derivatives<ref name="Plemenkov 241"/>
[[File:Acridine.svg|100px|center]]
|
| [[Anthranilic acid]] <ref>{{cite journal|author = Richard B. Herbert|title = The biosynthesis of plant alkaloids and nitrogenous microbial metabolites|journal=Nat. Prod. Rep|year = 1999|volume = 16|pages = 199–208|doi = 10.1039/a705734b|last2 = Herbert|first2 = Richard B.|last3 = Herbert|first3 = Richard B.}}</ref>
| Rutacridone, [[acronicine]]<ref>[[#Plemenkov|Plemenkov]], pp. 231, 246</ref><ref>[[#Hesse|Hesse]], p. 58</ref>
|-
| Rowspan = "4"|[[Quinoline]] derivatives<ref>[[#Plemenkov|Plemenkov]], p. 231</ref><ref name="ref126">[http://www.xumuk.ru/encyklopedia/2/5014.html Chemical Encyclopedia: Quinoline alkaloids]. xumuk.ru</ref>
[[File:Quinoline numbered.svg|90px|center]]
| Simple derivatives of quinoline derivatives of 2 – [[quinolones]] and 4-quinolone
| Rowspan = "3"|[[Anthranilic acid]] → 3-carboxyquinoline <ref name="ref127">[[#Aniszewski|Aniszewski]], p. 114</ref>
| Cusparine, [[echinopsine]], evocarpine<ref name="ref126" /><ref>[[#Orekhov|Orekhov]], p. 205</ref><ref>[[#Hesse|Hesse]], p. 55</ref>
|-
| Tricyclic terpenoids
| Flindersine<ref name="ref126" /><ref name="ref131">[[#Plemenkov|Plemenkov]], p. 232</ref>
|-
| Furanoquinoline derivatives
| [[Dictamnine]], fagarine, skimmianine<ref name="ref126" /><ref>[[#Orekhov|Orekhov]], p. 212</ref><ref>[[#Aniszewski|Aniszewski]], p. 118</ref>
|-
| [[Quinine]]s
| [[Tryptophan]] → [[tryptamine]] → [[strictosidine]] (with [[secologanin]]) → korinanteal → [[cinhoninon]] <ref name="Begley"/><ref name = " ref127 "/>
| [[Quinine]], [[quinidine]], [[cinchonine]], cinhonidine <ref name="ref131" />
|-
| Rowspan = "10"|[[Indole]] derivatives<ref name="ref104" />
[[File:Indole numbered.svg|100px|center]]
{{See also|indole alkaloids}}
| colspan="3" style="text-align:center;"|''Non-isoprene indole alkaloids''
|-
| Simple indole derivatives <ref name="ref140">[[#Aniszewski|Aniszewski]], p. 112</ref>
| Rowspan = "3"|[[Tryptophan]] → [[tryptamine]] or 5-hydroxitriptofan <ref name="ref141">[[#Aniszewski|Aniszewski]], p. 113</ref>
| [[Serotonin]], [[psilocybin]], [[dimethyltryptamine]] (DMT), [[bufotenin]] <ref>[[#Hesse|Hesse]], p. 15</ref><ref>[[#Saxton|Saxton]], Vol. 1, p. 467</ref>
|-
| Simple derivatives of [[beta-carboline|β-carboline]] <ref>[[#Dewick|Dewick]], pp. 349–350</ref>
| Harman, [[harmine]], [[harmaline]], eleagnine <ref name="ref140" />
|-
| Pyrroloindole alkaloids <ref name="ref152">[[#Aniszewski|Aniszewski]], p. 119</ref>
| [[Physostigmine]] (eserine), etheramine, physovenine, eptastigmine<ref name="ref152" />
|-
| colspan="3" style="text-align:center;"|''Semiterpenoid indole alkaloids''
|-
| [[Ergoline|Ergot alkaloids]]<ref name="ref104" />
| [[Tryptophan]] → chanoclavine → agroclavine → elimoclavine → [[paspalic acid]] → [[lysergic acid]] <ref name="ref152" />
| [[Ergotamine]], ergobasine, ergosine<ref>[[#Hesse|Hesse]], p. 29</ref>
|-
| colspan="3" style="text-align:center;"|''Monoterpenoid indole alkaloids''
|-
| ''Corynanthe'' type alkaloids<ref name="ref141" />
| Rowspan = "3"|[[Tryptophan]] → [[tryptamine]] → [[strictosidine]] (with [[secologanin]]) <ref name="ref141" />
| Ajmalicine, sarpagine, vobasine, [[ajmaline]], [[yohimbine]], [[reserpine]], [[mitragynine]],<ref>[[#Hesse|Hesse]], pp. 23–26</ref><ref>[[#Saxton|Saxton]], Vol. 1, p. 169</ref> group [[strychnine]] and ([[Strychnine]] [[brucine]], aquamicine, [[vomicine]] <ref>[[#Saxton|Saxton]], Vol. 5, p. 210</ref>)
|-
| [[Iboga]]-type alkaloids<ref name="ref141" />
| [[Ibogamine]], [[ibogaine]], [[voacangine]]<ref name="ref141" />
|-
| [[Aspidosperma]]-type alkaloids<ref name="ref141" />
| [[Vincamine]], [[vinca alkaloids]], vincotine, aspidospermine<ref>[[#Hesse|Hesse]], pp. 17–18</ref><ref>[[#Dewick|Dewick]], p. 357</ref>
|-
| [[Imidazole]] derivatives<ref name="Plemenkov 241"/>
[[File:Imidazole structure.svg|50px|center]]
|
| Directly from [[histidine]]<ref name="Aniszewski 104">[[#Aniszewski|Aniszewski]], p. 104</ref>
| [[Histamine]], pilocarpine, pilosine, stevensine<ref name="Plemenkov 241"/><ref name="Aniszewski 104"/>
|-
| [[Purine]] derivatives<ref>[[#Hesse|Hesse]], p. 72</ref>
[[File:Purin2.svg|90px|center]]
|
| [[Xanthosine]] (formed in purine biosynthesis) → 7 methylxantosine → 7-methyl [[xanthine]] → [[theobromine]] → [[caffeine]] <ref name="Begley"/>
| [[Caffeine]], [[theobromine]], [[theophylline]], [[saxitoxin]] <ref>[[#Hesse|Hesse]], p. 73</ref><ref>[[#Dewick|Dewick]], p. 396</ref>
|-
| colspan="4"  style="text-align:center; background:# DADADA;"|''Alkaloids with nitrogen in the side chain (protoalkaloids)''
|-
| β-[[Phenylethylamine]] derivatives<ref name="ref90" />
[[File:Phenylethylamine numbered.svg|110px|center]]
|
| [[Tyrosine]] or [[phenylalanine]] → [[dioxyphenilalanine]] → [[dopamine]] → [[adrenaline]] and [[mescaline]] [[tyrosine]] → [[tyramine]] phenylalanine → 1-phenylpropane-1,2-dione → [[cathinone]] → [[ephedrine]] and [[pseudoephedrine]] <ref name="Aniszewski 110"/><ref name="ref31" /><ref>[http://www.plantcyc.org:1555/PLANT/NEW-IMAGE?type=NIL&object=PWY-5883 PlantCyc Pathway: ephedrine biosynthesis]{{dead link|date=March 2013}}</ref>
| [[Tyramine]], [[ephedrine]], [[pseudoephedrine]], [[mescaline]], [[cathinone]], [[catecholamines]] ([[adrenaline]], [[noradrenaline]], [[dopamine]])<ref name="Aniszewski 110"/><ref>[[#Hesse|Hesse]], p. 76</ref>
|-
| [[Colchicine]] alkaloids <ref name="ref179">[http://www.xumuk.ru/encyklopedia/2069.html Chemical Encyclopedia: colchicine alkaloids]. xumuk.ru</ref>
[[File:Colchicine.svg|120px|center]]
|
| [[Tyrosine]] or [[phenylalanine]] → [[dopamine]] → [[autumnaline]] → [[colchicine]] <ref>[[#Aniszewski|Aniszewski]], p. 77</ref>
| [[Colchicine]], colchamine<ref name="ref179" />
|-
| [[Muscarine]] <ref name="ref182">[[#Hesse|Hesse]], p. 81</ref>
[[File:Muscarine.svg|100px|center]]
|
| [[Glutamic acid]] → 3-ketoglutamic acid → muscarine (with [[pyruvic acid]])<ref>[[#Brossi|Brossi]], Vol. 23, p. 376</ref>
| [[Muscarine]], allomuscarine, epimuscarine, epiallomuscarine<ref name="ref182" />
|-
| Benzylamine<ref name="ref185">[[#Hesse|Hesse]], p. 77</ref>
[[File:Benzylamine.svg|90px|center]]
|
| [[Phenylalanine]] with [[valine]], [[leucine]] or [[isoleucine]]<ref>[[#Brossi|Brossi]], Vol. 23, p. 268</ref>
| [[Capsaicin]], [[dihydrocapsaicin]], nordihydrocapsaicin <ref name="ref185" /><ref>[[#Brossi|Brossi]], Vol. 23, p. 231</ref>
|-
| colspan="4"  style="text-align:center; background:# DADADA;"|''Polyamines alkaloids''
|-
| [[Putrescine]] derivatives<ref name="ref189">[[#Hesse|Hesse]], p. 82</ref>
[[File:Putrescine.svg|90px|center]]
|
| Rowspan = "3"|[[ornithine]] → [[putrescine]] → [[spermidine]] → [[spermine]]<ref>[http://www.chem.qmul.ac.uk/iubmb/enzyme/reaction/misc/spermine.html Spermine Biosynthesis]</ref>
| Paucine <ref name="ref189" />
|-
| [[Spermidine]] derivatives<ref name="ref189" />
[[File:Spermidine.svg|110px|center]]
|
| Lunarine, codonocarpine<ref name="ref189" />
|-
| [[Spermine]] derivatives<ref name="ref189" />
[[File:Spermine.svg|130px|center]]
|
| Verbascenine, aphelandrine <ref name="ref189" />
|-
| colspan="4"  style="text-align:center; background:# DADADA;"|''Peptide (cyclopeptide) alkaloids''
|-
| Rowspan = "2"|Peptide alkaloids with a 13-membered cycle <ref name="ref27" /><ref name="ref196">[[#Plemenkov|Plemenkov]], p. 243</ref>
| Nummularine C type
| Rowspan = "8"|From different amino acids <ref name="ref27" />
| Nummularine C, Nummularine S <ref name="ref27" />
|-
| [[Ziziphine]] type
| Ziziphine A, sativanine H <ref name="ref27" />
|-
| Rowspan = "5"|Peptide alkaloids with a 14-membered cycle <ref name="ref27" /><ref name="ref196" />
| Frangulanine type
| Frangulanine, scutianine J <ref name="ref196" />
|-
| Scutianine A type
| Scutianine A <ref name="ref27" />
|-
| Integerrine type
| Integerrine, discarine D <ref name="ref196" />
|-
| Amphibine F type
| Amphibine F, spinanine A <ref name="ref27" />
|-
| Amfibine B type
| Amphibine B, lotusine C <ref name="ref27" />
|-
| Peptide alkaloids with a 15-membered cycle <ref name="ref196" />
| Mucronine A type
| Mucronine A <ref name="ref23" /><ref name="ref196" />
|-
| colspan="4"  style="text-align:center; background:# DADADA;"|''Pseudoalkaloids ([[terpenes]] and [[steroids]])''
|-
| Diterpenes <ref name="ref23" />
[[File:Isoprene.svg|80px|center]]
| Lycoctonine type
| [[Mevalonic acid]] → [[izopentenilpyrophosfate]] → [[geranyl pyrophosphate]] <ref>[http://www.xumuk.ru/encyklopedia/2/4392.html Chemical Encyclopedia: Terpenes]. xumuk.ru</ref><ref>[[#Begley|Begley]], Natural Products: An Overview</ref>
| [[Aconitine]], [[delphinine]] <ref name="ref23" /><ref>{{cite journal|author = Atta-ur-Rahman and M. Iqbal Choudhary|title = Diterpenoid and steroidal alkaloids|url = http://www.rsc.org/publishing/journals/NP/article.asp?doi=NP9971400191|journal=Nat. Prod. Rep|year = 1997|volume = 14|pages = 191–203|pmid = 9149410|issue = 2|doi = 10.1039/np9971400191}}</ref>
|-
| [[Steroids]]<ref>[[#Hesse|Hesse]], p. 88</ref>
[[File:Cyclopentenophenanthrene.svg|100px|center]]
|
| [[Cholesterol]], [[arginine]]<ref>[[#Dewick|Dewick]], p. 388</ref>
| Solasodine, [[solanidine]], veralkamine, [[batrachotoxin]]<ref>[[#Plemenkov|Plemenkov]], p. 247</ref>
|}
 
== Properties ==
[[File:Cyclopelamb2.jpg|thumb|Head of a lamb born by a sheep that ate leaves of the [[Veratrum californicum|corn lily]] plant. The [[cyclopia]] in the calf is induced by the alkaloid [[cyclopamine]] present in the plant.]]
Most alkaloids contain oxygen in their molecular structure; those compounds are usually colorless crystals at ambient conditions. Oxygen-free alkaloids, such as [[nicotine]]<ref>[http://slovari.yandex.ru/dict/bse/article/00052/84600.htm Никотин]. [[Great Soviet Encyclopedia]] (1969–1978)</ref> or [[coniine]],<ref name="BSE: koniin"/> are typically volatile, colorless, oily liquids.<ref name="ref222">[[#Grinkevich|Grinkevich]], p. 131</ref> Some alkaloids are colored, like [[berberine]] (yellow) and [[sanguinarine]] (orange).<ref name="ref222" />
 
Most alkaloids are weak bases, but some, such as [[theobromine]] and [[theophylline]], are [[amphoteric]].<ref name="ref225">G. A. Spiller [http://books.google.com/books?id=Rgs_rVOceZwC&pg=PA140 ''Caffeine''], CRC Press, 1997 ISBN 0-8493-2647-8</ref> Many alkaloids dissolve poorly in water but readily dissolve in [[organic solvent]]s, such as [[diethyl ether]], [[chloroform]] or [[1,2-dichloroethane]]. [[Caffeine]],<ref>{{cite web|title=Caffeine|url=http://www.drugbank.ca/drugs/DB00201|work=DrugBank|accessdate=12 February 2013}}</ref> [[cocaine]],<ref>{{cite web|title=Cocaine|url=http://www.drugbank.ca/drugs/DB00907|work=DrugBank|accessdate=12 February 2013}}</ref> [[codeine]]<ref>{{cite web|title=Codeine|url=http://www.drugbank.ca/drugs/DB00318|work=DrugBank|accessdate=12 February 2013}}</ref> and [[nicotine]]<ref>{{cite web|title=Nicotine|url=http://www.drugbank.ca/drugs/DB00184|work=DrugBank|accessdate=12 February 2013}}</ref> are water soluble (with a solubility of ≥1g/L), whereas others, including [[morphine]]<ref>{{cite web|title=Morphine|url=http://www.drugbank.ca/drugs/DB00295|work=DrugBank|accessdate=12 February 2013}}</ref> and [[yohimbine]]<ref>{{cite web|title=Yohimbine|url=http://www.drugbank.ca/drugs/DB01392|work=DrugBank|accessdate=12 February 2013}}{{dead link|date=March 2013}}</ref> are highly water soluble (0.1–1 g/L). Alkaloids and acids form salts of various strengths. These salts are usually soluble in water and [[alcohol]] and poorly soluble in most organic solvents. Exceptions include [[scopolamine]] hydrobromide, which is soluble in organic solvents, and the water-soluble quinine sulfate.<ref name="ref222" />
 
Most alkaloids have a bitter taste or are poisonous when ingested. Alkaloid production in plants appeared to have evolved in response to feeding by herbivorous animals; however, some animals have evolved the ability to detoxify alkaloids.<ref>[[#Fattorusso|Fattorusso]], p. 53</ref>  Some alkaloids can produce developmental defects in the offspring of animals that consume but cannot detoxify the alkaloids.  One example is the alkaloid [[cyclopamine]], produced in the leaves of [[Veratrum californicum|corn lily]]. During the 1950s, up to 25% of lambs born by sheep that had grazed on corn lily had serious facial deformations. These ranged from deformed jaws to [[cyclopia]] (see picture). After decades of research, in the 1980s, the compound responsible for these deformities was identified as the alkaloid 11-deoxyjervine, later renamed to cyclopamine.<ref>{{cite book|page=362|url=http://books.google.com/?id=nixyqfGIGHcC&pg=PA362|title=Poisonous plants and related toxins, Volume 2001|author=Thomas Acamovic, Colin S. Stewart, T. W. Pennycott|publisher=CABI|year= 2004|isbn=0-85199-614-0}}</ref>
 
==Distribution in nature==
[[File:Strychnos nux-vomica - Köhler–s Medizinal-Pflanzen-266.jpg|thumb|[[Strychnine tree]]. Its seeds are rich in [[strychnine]] and [[brucine]].]]
 
Alkaloids are [[anabolism|generated]] by various living organisms, especially by [[Vascular plant|higher plants]] – about 10 to 25% of those contain alkaloids.<ref>[[#Aniszewski|Aniszewski]], p. 13</ref><ref>[[#Orekhov|Orekhov]], p. 11</ref> Therefore, in the past the term "alkaloid" was associated with plants.<ref name="Hesse 4">[[#Hesse|Hesse]], p.4</ref>
 
The alkaloids content in plants is usually within a few percent and is inhomogeneous over the plant tissues. Depending on the type of plants, the maximum concentration is observed in the leaves ([[black henbane]]), [[fruit]]s or [[seed]]s ([[Strychnine tree]]), root ([[Rauwolfia serpentina]]) or bark ([[cinchona]]).<ref>[[#Grinkevich|Grinkevich]], pp. 122–123</ref> Furthermore, different tissues of the same plants may contain different alkaloids.<ref>[[#Orekhov|Orekhov]], p. 12</ref>
 
Beside plants, alkaloids are found in certain types of [[fungi]], such as [[psilocybin]] in the fungus of the genus [[Psilocybe]], and in animals, such as [[bufotenin]] in the skin of some toads.<ref name="Hesse 5" /> Many marine organisms also contain alkaloids.<ref>[[#Fattorusso|Fattorusso]], p. XVII</ref> Some [[amines]], such as [[adrenaline]] and [[serotonin]], which play an important role in higher animals, are similar to alkaloids in their structure and biosynthesis and are sometimes called alkaloids.<ref>[[#Aniszewski|Aniszewski]], pp. 110–111</ref>
 
==Extraction==
[[File:Piperine crystals.jpg|thumb|Crystals of [[piperine]] extracted from [[black pepper]].]]
 
Because of the structural diversity of alkaloids, there is no single method of their extraction from natural raw materials.<ref name="Hesse 116">[[#Hesse|Hesse]], p. 116</ref> Most methods exploit the property of most alkaloids to be soluble in organic solvents but not in water, and the opposite tendency of their salts.
 
Most plants contain several alkaloids. Their mixture is extracted first and then individual alkaloids are separated.<ref name="ref236">[[#Grinkevich|Grinkevich]], p. 132</ref> Plants are thoroughly ground before extraction.<ref name="Hesse 116"/><ref>[[#Grinkevich|Grinkevich]], p. 5</ref> Most alkaloids are present in the raw plants in the form of salts of organic acids.<ref name="Hesse 116"/> The extracted alkaloids may remain salts or change into bases.<ref name="ref236" /> Base extraction is achieved by processing the raw material with alkaline solutions and extracting the alkaloid bases with organic solvents, such as 1,2-dichloroethane, chloroform, diethyl ether or benzene. Then, the impurities are dissolved by weak acids; this converts alkaloid bases into salts that are washed away with water. If necessary, an aqueous solution of alkaloid salts is again made alkaline and treated with an organic solvent. The process is repeated until the desired purity is achieved.
 
In the acidic extraction, the raw plant material is processed by a weak acidic solution (e.g., [[acetic acid]] in water, ethanol, or methanol). A base is then added to convert alkaloids to basic forms that are extracted with organic solvent (if the extraction was performed with alcohol, it is removed first, and the remainder is dissolved in water). The solution is purified as described above.<ref name="Hesse 116"/><ref>[[#Grinkevich|Grinkevich]], pp. 132–134</ref>
 
Alkaloids are separated from their mixture using their different solubility in certain solvents and different reactivity with certain reagents or by [[distillation]].<ref>[[#Grinkevich|Grinkevich]], pp. 134–136</ref>
 
==Biosynthesis==
Biological precursors of most alkaloids are [[amino acid]]s, such as [[ornithine]], [[lysine]], [[phenylalanine]], [[tyrosine]], [[tryptophan]], [[histidine]], [[aspartic acid]], and [[anthranilic acid]].<ref name="Plemenkov 253">[[#Plemenkov|Plemenkov]], p. 253</ref> [[Nicotinic acid]] can be synthesized from tryptophan or aspartic acid. Ways of alkaloid biosynthesis are too numerous and cannot be easily classified.<ref name="Begley"/> However, there are a few typical reactions involved in the biosynthesis of various classes of alkaloids, including synthesis of [[Schiff bases]] and [[Mannich reaction]].<ref name="Plemenkov 253"/>
 
===Synthesis of Schiff bases===
{{Main|Schiff base}}
 
Schiff bases can be obtained by reacting amines with ketones or aldehydes.<ref>[[#Plemenkov|Plemenkov]], p. 254</ref> These reactions are a common method of producing C=N bonds.<ref name="Dewick 19">[[#Dewick|Dewick]], p. 19</ref>
 
[[File:Schiff base formation.svg|center]]
 
In the biosynthesis of alkaloids, such reactions may take place within a molecule,<ref name="Plemenkov 253"/> such as in the synthesis of piperidine:<ref name="ref19"/>
 
[[File:Schiff base formation intramolecular.svg|center]]
 
===Mannich reaction===
{{Main|Mannich reaction}}
 
An integral component of the Mannich reaction, in addition to an amine and a [[carbonyl]] compound, is a [[carbanion]], which plays the role of the nucleophile in the [[nucleophilic addition]] to the ion formed by the reaction of the amine and the carbonyl.<ref name = "Dewick 19" />
 
[[File:Mannich.png|center]]
 
The Mannich reaction can proceed both intermolecularly and intramolecularly:<ref>[[#Plemenkov|Plemenkov]], p. 255</ref><ref>[[#Dewick|Dewick]], p. 305</ref>
 
[[File:Mannich reaction intramolecular.svg|center]]
 
==Dimer alkaloids==
In addition to the described above monomeric alkaloids, there are also [[Dimer (chemistry)|dimer]]ic, and even [[trimer (chemistry)|trimer]]ic and [[tetramer]]ic alkaloids formed upon condensation of two, three, and four monomeric alkaloids. Dimeric alkaloids are usually formed from monomers of the same type through the following mechanisms:<ref>[[#Hesse|Hesse]], pp. 91–105</ref>
* [[Mannich reaction]], resulting in, e.g., voacamine
* [[Michael reaction]] (villalstonine)
* Condensation of aldehydes with amines (toxiferine)
* Oxidative addition of phenols (dauricine, tubocurarine)
* [[Lactone|Lactonization]] (carpaine).
 
<center>
<gallery widths="220px" perrow="3">
File:Voacamine chemical structure.png|[[Voacamine]]
File:Villalstonine.svg|[[Villalstonine]]
File:Toxiferine I.png|[[Toxiferine]]
File:Dauricine.svg|[[Dauricine]]
File:Tubocurarine.svg|[[Tubocurarine]]
File:Carpaine.png|[[Carpaine]]
</gallery>
</center>
 
==The biological role==
The role of alkaloids for living organisms that produce them is still unclear.<ref>[[#Aniszewski|Aniszewski]], p. 142</ref> It was initially assumed that the alkaloids are the final products of [[nitrogen]] [[metabolism]] in plants, as [[urea]] in mammals. It was later shown that alkaloid concentrations varies over time, and this hypothesis was refuted.<ref name="Meyers"/>
 
Most of the known functions of alkaloids are related to protection. For example, [[aporphine]] alkaloid [[liriodenine]] produced by the [[Liriodendron tulipifera|tulip tree]] protects it from parasitic mushrooms. In addition, presence of alkaloids in the plant prevents insects and [[chordate]] animals from eating it. However, some animals adapted to alkaloids and even use them in their own metabolism.<ref>[[#Hesse|Hesse]], pp. 283–291</ref> Such alkaloid-related substances as [[serotonin]], [[dopamine]] and [[histamine]] are important [[neurotransmitter]]s in animals. Alkaloids are also known to regulate plant growth.<ref>[[#Aniszewski|Aniszewski]], pp. 142–143</ref> Another example of an organism that uses alkaloids for protection is the ''[[Utetheisa ornatrix]]'', more commonly known as the Ornate Moth. Pyrrolizidine alkaloids render these larvae and adult moths unpalatable to many of their natural enemies like coccinelid beetles, green lacewings, insectivorous hemiptera and insectivorous bats.<ref>W.E. Conner (2009). ''Tiger Moths and Woolly Bears—behaviour, ecology, and evolution of the Arctiidae''. New York: Oxford University Press. pp. 1–10. ISBN 0195327373.</ref>
 
== Applications ==
 
===In medicine===
Medical use of alkaloid-containing plants has a long history, and, thus, when the first alkaloids were isolated in the 19th century, they immediately found application in clinical practice.<ref>[[#Hesse|Hesse]], p. 303</ref> Many alkaloids are still used in medicine, usually in the form of salts, including the following:<ref name="Meyers"/><ref>[[#Hesse|Hesse]], pp. 303–309</ref>
 
{| Class = "wikitable"
|-
! Alkaloid
! Action
|-
| [[Ajmaline]]
| [[Antiarrhythmic agent|antiarrhythmic]]
|-
| [[Atropine]], [[scopolamine]], [[hyoscyamine]]
| [[anticholinergic]]
|-
| [[Caffeine]]
| [[Stimulant]], [[Adenosine receptor]] antagonist
|-
| [[Codeine]]
| [[cough medicine]], [[analgesic]]
|-
| [[Colchicine]]
| remedy for [[gout]]
|-
| [[Emetine]]
| [[antiprotozoal agent]]
|-
| [[Ergoline|Ergot alkaloids]]
| [[Sympathomimetics|sympathomimetic]], vasodilator, antihypertensive
|-
| [[Morphine]]
| [[analgesic]]
|-
| [[Nicotine]]
| [[Stimulant]], [[Nicotinic agonist|Nicotinic acetylcholine receptor agonist]]
|-
| [[Physostigmine]]
| inhibitor of [[acetylcholinesterase]]
|-
| [[Quinidine]]
| antiarrhythmic
|-
| [[Quinine]]
| antipyretics, antimalarial
|-
| [[Reserpine]]
| [[Antihypertensive drug|antihypertensive]]
|-
| [[Tubocurarine]]
| Muscle relaxant
|-
| [[Vinblastine]], [[vincristine]]
| [[Chemotherapy|antitumor]]
|-
| [[Vincamine]]
| [[Vasodilation|vasodilating]], [[Antihypertensive drug|antihypertensive]]
|-
| [[Yohimbine]]
| [[Stimulant]], [[Aphrodisiac]]
|}
 
Many synthetic and semisynthetic drugs are structural modifications of the alkaloids, which were designed to enhance or change the primary effect of the drug and reduce unwanted side-effects.<ref>[[#Hesse|Hesse]], p. 309</ref> For example, [[naloxone]], an [[opioid receptor]] [[receptor antagonist|antagonist]], is a derivative of [[thebaine]] that is present in [[opium]].<ref>[[#Dewick|Dewick]], p. 335</ref>
 
<center>
<gallery widths="200px" perrow="2">
File:Thebaine skeletal.svg|[[Thebaine]]
File:Naloxone.svg|[[Naloxone]]
</gallery>
</center>
 
=== In agriculture ===
Prior to the development of a wide range of relatively low-toxic synthetic [[pesticide]]s, some alkaloids, such as salts of nicotine and [[anabasine]], were used as [[insecticide]]s. Their use was limited by their high toxicity to humans.<ref>György Matolcsy, Miklós Nádasy, Viktor Andriska [http://books.google.com/books?id=fPiRSsUOpLEC&pg=PA21 ''Pesticide chemistry''], Elsevier, 2002, pp. 21–22 ISBN 0-444-98903-X</ref>
 
=== Use as psychoactive drugs ===
Preparations of plants containing alkaloids and their extracts, and later pure alkaloids, have long been used as [[Psychoactive drug|psychoactive substances]]. [[Cocaine]] and [[cathinone]] are [[stimulant]]s of the [[central nervous system]].<ref>[[#Veselovskaya|Veselovskaya]], p. 75</ref><ref>[[#Hesse|Hesse]], p. 79</ref> [[Mescaline]] and many of indole alkaloids (such as [[psilocybin]], [[dimethyltryptamine]] and [[ibogaine]]) have [[hallucinogen]]ic effect.<ref>[[#Veselovskaya|Veselovskaya]], p. 136</ref><ref>Geoffrey A. Cordell ''The Alkaloids: Chemistry and Biology''. [http://www.sciencedirect.com/science/bookseries/10994831/56 Vol. 56], Elsevier, 2001, p. 8, ISBN 978-0-12-469556-6.</ref> [[Morphine]] and [[codeine]] are strong narcotic pain killers.<ref>[[#Veselovskaya|Veselovskaya]], p. 6</ref>
 
There are alkaloids that do not have strong psychoactive effect themselves, but are [[precursor (chemistry)|precursor]]s for semi-synthetic psychoactive drugs. For example, [[ephedrine]] and [[pseudoephedrine]] are used to produce [[methcathinone]] and [[methamphetamine]].<ref>[[#Veselovskaya|Veselovskaya]], pp. 51–52</ref> [[Thebaine]] is used in the synthesis of many painkillers such as [[oxycodone]].
 
== See also ==
{{colbegin|3}}
* [[Amine]]
* [[Base (chemistry)]]
* [[Natural products]]
* [[Palau'amine]]
* [[Secondary metabolite]]
* [[Mayer's reagent]]
{{colend}}
 
== Notes ==
{{Reflist|group="nb"}}
 
== References ==
{{Reflist|25em}}
 
== Bibliography ==
{{Commons|Alkaloid}}
* {{cite book|ref=Aniszewski|author = Aniszewski, Tadeusz |title = Alkaloids – secrets of life|location = Amsterdam|publisher = [[Elsevier]]|year = 2007|isbn = 978-0-444-52736-3}}
* {{cite book|ref=Begley|author = Begley, Tadhg P. |title = Encyclopedia of Chemical Biology|year = 2009|publisher = Wiley|isbn = 978-0-471-75477-0|doi=10.1002/cbic.200900262}}
* {{cite book|ref=Brossi|author =Brossi, Arnold |title=The Alkaloids: Chemistry and Pharmacology|publisher= Academic Press|year= 1989}}
* {{cite book|ref=Dewick|author = Dewick, Paul M |title = Medicinal Natural Products. A Biosynthetic Approach. Second Edition|year = 2002|publisher = Wiley|isbn = 0-471-49640-5}}
* {{cite book|ref=Fattorusso|author = Fattorusso, E. and Taglialatela-Scafati, O. |title = Modern Alkaloids: Structure, Isolation, Synthesis and Biology|year = 2008|publisher = Wiley-VCH|isbn = 978-3-527-31521-5}}
* {{cite book|ref=Grinkevich|author = Grinkevich NI Safronich LN|title = The chemical analysis of medicinal plants: Proc. allowance for pharmaceutical universities|location = M|year = 1983}}
* {{cite book|ref=Hesse|author = Hesse, Manfred |title = Alkaloids: Nature's Curse or Blessing?|year = 2002|publisher = Wiley-VCH|isbn = 978-3-906390-24-6}}
* {{cite book|ref=Knunyants|author = Knunyants, IL|title = Chemical Encyclopedia|url = http://www.cnshb.ru/AKDiL/0048/base/RA/140004.shtm|publisher = Soviet Encyclopedia|year = 1988}}
* {{cite book|ref=Orekhov|author = Orekhov, AP|title = Chemistry alkaloids|edition = Acad. 2|location = M.|publisher = USSR|year = 1955}}
* {{cite book|ref=Plemenkov|author = Plemenkov, VV|title = Introduction to the Chemistry of Natural Compounds|location = Kazan|year = 2001}}
*{{cite book|ref=Saxton|author =Saxton, J. E. |title=The Alkaloids. A Specialist Periodical Report|place= London|publisher= The Chemical Society|year=1971}}
* {{cite book|ref=Veselovskaya|author =Veselovskaya, N. B., Kovalenko, A.E |title=Drugs|place=Moscow|publisher= Triada-X|year=2000}}
 
{{alkaloids}}
 
[[Category:Alkaloids|*]]
 
{{Link GA|ru}}

Revision as of 19:12, 19 August 2014

Template:No footnotes Template:Infobox Italian comune

Tower of St. Lorenzo Cathedral

Abano Terme (known as Abano Bagni until 1924) is a town and comune in the province of Padua, in the Veneto region, Italy, on the eastern slope of the Colli Euganei; it is 10 kilometers southwest by rail from Padua. Abano Terme's population is 19,062 (2001) (in 1901 it was only 4,556).

The town's hot springs and mud baths are the main economic resource. The waters have a temperature of some 80°C.

History

The baths were known to the Romans as Aponi fons or Aquae Patavinae. A description of them is given in a letter of Theodoric, the king of the Ostrogoths. Some remains of the ancient baths have been discovered (S. Mandruzzato, Trattato dei Bagni d'Abano, Padua, 1789). An oracle of Geryon lay near, and the so-called sortes Praenestinae (C.I.L. i., Berlin, 1863; 1438–1454), small bronze cylinders inscribed, and used as oracles, were perhaps found here in the 16th century.

The baths were destroyed by the Lombards in the 6th century, but they were rebuilt and enlarged when Abano became an autonomous comune in the 12th century and, again, in the late 14th century. The city was under the Republic of Venice from 1405 to 1797.

Main sights

  • Abano Cathedral, or the cathedral (duomo) of St. Lawrence. The current edifice was erected in 1780 over a pre-existing church which was allegedly destroyed by Cangrande della Scala. The bell tower has parts from the 9th/10th and 14th centuries.
  • The Montirone Gallery, housing works of Il Moretto, Palma the Younger, Guido Reni, Giandomenico Tiepolo and others.
  • The Sanctuary of the Madonna della Salute or of Monteortone (built from 1428). It lies on the site where the Madonna appeared to Pietro Falco, healing his wounds. The church is on the Latin cross plan, with a nave and two aisles with three apses decorated by a frieze. It has with a Baroque portal (1667), a noteworthy bell tower, presbytery frescoes portraying the Histories of St. Peter and Virgin by Jacopo da Montagnana (1495) and Palma the Younger's altarpiece depicting Christ Crucifixed Between St. Augustine and St. Jerome.

Just outside the city is San Daniele Abbey (11th century). 6 km from the city is also Praglia Abbey, founded in the 11th century by Benedictine monks and rebuilt in 1496–1550. The church of the Assumption, with a marble portal from 1548, has a Renaissance style interior. Noteworthy is the four cloister complex.

Notable people

References

  • L'Italia da scoprire, Giorgio Mondadori, 2006.

External links

Template:Province of Padua