Scoulerine Explained

Scoulerine, also known as discretamine and aequaline, is a benzylisoquinoline alkaloid (BIA) that is derived directly from (S)-reticuline through the action of berberine bridge enzyme. It is a precursor of other BIAs, notably berberine, noscapine, (S)-tetrahydropalmatine, and (S)-stylopine, as well as the alkaloids protopine, and sanguinarine.^[1] It is found in many plants, including opium poppy,^[2] Croton flavens,^[3] and certain plants in the genus Erythrina.^[4]

Studies show that scoulerine is an antagonist in vitro at the α₂-adrenoceptor, α_1D-adrenoceptor and 5-HT receptor.^{[5] [6]} It has also been found to be a GABA_A receptor agonist in vitro.^{[3] [7]}

Notes and References

1. Hagel. Jillian M. Morris. Jeremy S. Lee. Eun-Jeong. Desgagne-Penx. Isabel. Bross. Crystal D. Chang. Limei. Chen. Xue. Farrow. Scott C. Zhang. Ye. 2015. Transcriptome analysis of 20 taxonomically related benzylisoquinoline alkaloid-producing plants. BMC Plant Biology. 15. 227. 10.1186/s12870-015-0596-0. 26384972. 4575454. free.
2. Frick S . Chitty JA . Kramell R . Schmidt J . Allen RS . Larkin PJ . Kutchan TM . Transformation of opium poppy (Papaver somniferum L.) with antisense berberine bridge enzyme gene (anti-bbe) via somatic embryogenesis results in an altered ratio of alkaloids in latex but not in roots . . 2004 . 607 - 613 . 13 . 6 . 15672841 . 10.1007/s11248-004-2892-6. 38780571 .
3. Eisenreich WJ . Hofner G . Bracher F . Alkaloids from Croton flavens L. and their affinities to GABA-receptors . . 2003 . 437 - 440 . 17 . 6 . 14577695 . 10.1080/1478641031000111516. 13192928 .
4. Ito K . Studies on the alkaloids of Erythrina plants . Yakugaku Zasshi . 1999 . 340 - 356 . 119 . 5 . 10.1248/yakushi1947.119.5_340 . 10375996. free .
5. Ko FN . Yu SM . Su MJ . Wu YC . Teng CM . Pharmacological activity of (−)-discretamine, a novel vascular α-adrenoceptor and 5-hydroxytryptamine receptor antagonist, isolated from Fissistigma glaucescens . . 1993 . 882 - 888 . 110 . 2 . 7902181 . 2175899 . 10.1111/j.1476-5381.1993.tb13895.x.
6. Ko FN . Guh JH . Yu SM . Hou YS . Wu YC . Teng CM . (−)-Discretamine, a selective α_1D-adrenoceptor antagonist, isolated from Fissistigma glaucescens . . 1994 . 1174 - 1180 . 112 . 4 . 7952879 . 1910235 . 10.1111/j.1476-5381.1994.tb13207.x.
7. Halbsguth C . Meissner O . Haberlein H . Positive cooperation of protoberberine type 2 alkaloids from Corydalis cava on the GABA(A) binding site . . 2003 . 305 - 309 . 69 . 4 . 12709895 . 10.1055/s-2003-38869. 260282359 .