ChEBI: Serpentine is an indole alkaloid that is 18-oxayohimban dehydrogenated at positions 3, 4, 5, 6, 16 and 17 and substituted by a methyl group at the 19alpha position and by a methoxycarbonyl group at position 16. It is an indole alkaloid, a member of quinolizines, a carboxylic ester, an iminium betaine and a zwitterion. It is a conjugate base of a serpentine(1+). It derives from a hydride of a 18-oxayohimban.