Lupanine-Biological Source It is obtained from the herb of Genista tinctoria L. (Fabaceae) (Dyer’s Broom)

B. Lupanine

Biological Source It is obtained from the herb of Genista tinctoria L. (Fabaceae) (Dyer’s Broom).

Chemical Structure

(7α, 7aα, 14α, 14aβ)-Dodecahydro-7, 14-methano-2H, 11H-dipyridiol [1, 2-a: 1’, 2’-e] diazocin-11-one; (C₁₅H₂₄N₂O].

Isolation The racemic and optical isomers of lupanine have been duly isolated from various species of Lupinus (Fabaceae/Leguminosae) as stated below:

(±)-Lupanine—from white lupins;

d-Lupanine—from blue lupins;

l-Lupanine—from the natural racemic form;

Characteristic Features The physical parameters of the above three forms of lupanine are given below:

dl-Lupanine: It is obtained as orthorhombic prisms obtained from acetone having mp 98-99°C; bp1.0 185-195°C; It is soluble in ethanol, ether, chloroform and water; and insoluble in petroleum ether.

d-Lupanine (Synonym: 2-Oxosparteine): It is obtained as syrup crystallizing difficultly in hygroscopic needles having mp 40-44°C; bp₃ 190-193°C; n_D²⁴ 1.5444; [α]_D²⁵  +84^o (C = 4.8 in ethanol). It is found to be freely soluble in water, ethanol, ether and chloroform.

l-Lupanine (Synonym: Hydrorhombinine): It is a viscous liquid having bp1.0 186-188°C; [α]_D - 61^o in acetone.

Identification Test Lupanine forms the corresponding lupanine hydrochloride dihydrate (C₁₅H₂₄N₂O.HCl.2H₂O) which is obtained as rhombic crystals from water having mp 127°C (dry).

---------------------------------------------

* Couch, J.F., J. Am. Chem. Soc., 56, 2434 (1934).
Source:Pharmacognosy And Pharmacobiotechnology By Ashutosh Kar