Corynanthine

{{Short description|Chemical compound}}

{{Drugbox

| IUPAC_name = (16β,17α)-17-hydroxy-yohimban-16-carboxylic acid methyl ester

| image = File:Corynanthine.png

| width = 350px

| image2 = File:Corynanthine 3D.png

| width2 = 350px

| tradename =

| pregnancy_category =

| legal_status = Uncontrolled

| routes_of_administration = Oral

| bioavailability =

| metabolism =

| elimination_half-life =

| excretion =

| IUPHAR_ligand = 5345

| CAS_number = 483-10-3

| UNII_Ref = {{fdacite|correct|FDA}}

| UNII = F5Z7C9RK8U

| ATC_prefix = none

| ATC_suffix =

| PubChem = 92766

| ChemSpiderID = 83744

| synonyms = Rauhimbine

| C=21 | H=26 | N=2 | O=3

| SMILES = O=C(OC)[C@H]5[C@H]4C[C@H]3c2[nH]c1ccccc1c2CCN3C[C@@H]4CC[C@@H]5O

}}

Corynanthine, also known as rauhimbine, is an alkaloid found in the Rauvolfia and Corynanthe (including Pausinystalia) genera of plants.{{cite journal | vauthors = PHILLIPS DD, CHADHA MS | title = The alkaloids of Rauwolfia serpentina Benth | journal = Journal of the American Pharmaceutical Association | volume = 44 | issue = 9 | pages = 553–67 |date=September 1955 | pmid = 13251932 | doi = 10.1002/jps.3030440912}}{{cite journal | url = http://informahealthcare.com/doi/abs/10.1076/phbi.39.3.239.5923 | title = Alkaloids from Rauvolfia canescens; Pharmaceutical Biology - 39(3):Pages 239-240 - Informa Healthcare | journal = Pharmaceutical Biology | doi = 10.1076/phbi.39.3.239.5923 | s2cid = 85168336 | url-access = subscription }} It is one of the two diastereoisomers of yohimbine, the other being rauwolscine.{{cite journal | vauthors = Shepperson NB, Duval N, Massingham R, Langer SZ | title = Pre- and postsynaptic alpha adrenoceptor selectivity studies with yohimbine and its two diastereoisomers rauwolscine and corynanthine in the anesthetized dog | journal = The Journal of Pharmacology and Experimental Therapeutics | volume = 219 | issue = 2 | pages = 540–6 |date=November 1981 | pmid = 6270312 | url = http://jpet.aspetjournals.org/cgi/pmidlookup?view=long&pmid=6270312}}{{cite journal | vauthors = Doxey JC, Lane AC, Roach AG, Virdee NK | title = Comparison of the alpha-adrenoceptor antagonist profiles of idazoxan (RX 781094), yohimbine, rauwolscine and corynanthine | journal = Naunyn-Schmiedeberg's Archives of Pharmacology | volume = 325 | issue = 2 | pages = 136–44 |date=February 1984 | pmid = 6144048 | doi = 10.1007/bf00506193| s2cid = 24276613 }} It is also related to ajmalicine.

Corynanthine acts as an α₁-adrenergic and α₂-adrenergic receptor antagonist with approximately 10-fold selectivity for the former site over the latter.{{cite journal | vauthors = Shepperson NB, Duval N, Massingham R, Langer SZ | title = Pre- and postsynaptic alpha adrenoceptor selectivity studies with yohimbine and its two diastereoisomers rauwolscine and corynanthine in the anesthetized dog | journal = The Journal of Pharmacology and Experimental Therapeutics | volume = 219 | issue = 2 | pages = 540–6 |date=November 1981 | pmid = 6270312 | url = http://jpet.aspetjournals.org/cgi/pmidlookup?view=long&pmid=6270312}}{{cite journal | vauthors = Doxey JC, Lane AC, Roach AG, Virdee NK | title = Comparison of the alpha-adrenoceptor antagonist profiles of idazoxan (RX 781094), yohimbine, rauwolscine and corynanthine | journal = Naunyn-Schmiedeberg's Archives of Pharmacology | volume = 325 | issue = 2 | pages = 136–44 |date=February 1984 | pmid = 6144048 | doi = 10.1007/bf00506193| s2cid = 24276613 }} This is in contrast to yohimbine and rauwolscine which have around 30-fold higher affinity for the α₂-adrenergic receptor over the α₁-adrenergic receptor.{{cite journal | vauthors = Shepperson NB, Duval N, Massingham R, Langer SZ | title = Pre- and postsynaptic alpha adrenoceptor selectivity studies with yohimbine and its two diastereoisomers rauwolscine and corynanthine in the anesthetized dog | journal = The Journal of Pharmacology and Experimental Therapeutics | volume = 219 | issue = 2 | pages = 540–6 |date=November 1981 | pmid = 6270312 | url = http://jpet.aspetjournals.org/cgi/pmidlookup?view=long&pmid=6270312}}{{cite journal | vauthors = Doxey JC, Lane AC, Roach AG, Virdee NK | title = Comparison of the alpha-adrenoceptor antagonist profiles of idazoxan (RX 781094), yohimbine, rauwolscine and corynanthine | journal = Naunyn-Schmiedeberg's Archives of Pharmacology | volume = 325 | issue = 2 | pages = 136–44 |date=February 1984 | pmid = 6144048 | doi = 10.1007/bf00506193| s2cid = 24276613 }} As a result, corynanthine is not a stimulant (or an aphrodisiac for that matter), but a depressant, and likely plays a role in the antihypertensive properties of Rauvolfia extracts. Like yohimbine and rauwolscine, corynanthine has also been shown to possess some activity at serotonin receptors.{{cite journal | vauthors = Feuerstein TJ, Hertting G, Jackisch R | title = Endogenous noradrenaline as modulator of hippocampal serotonin (5-HT)-release. Dual effects of yohimbine, rauwolscine and corynanthine as alpha-adrenoceptor antagonists and 5-HT-receptor agonists | journal = Naunyn-Schmiedeberg's Archives of Pharmacology | volume = 329 | issue = 3 | pages = 216–21 |date=May 1985 | pmid = 2991775 | doi = 10.1007/bf00501871| s2cid = 19770424 }}