Alstonia venenata R. Br.

Family:

Apocynaceae.

Habitat:

Peninsular India.

Folk:

Pazh-munipala (Tamil), Addasarpa (Kannada), Palamunpala (Malyalam).

Action:

Stembark and fruit—antiepileptic.

The plant is a rich source of indole alkaloids. Major alkaloids in the stembark are alstovenine, venenatine, 3-dehydroalstovenine, reserpine (0.003–0.3%), venoxidine and kopsinine.

Alstovenine, in lower doses, exhibits monoamine oxidase inhibitor activity; in higher doses, shows marked central stimulant effect (reversal of reserpine effects). Venenatine exhibits reserpine-like profile of activity (sedation, ptosis, reduction in motor activity).

The fruit contains vincadifformine type of alkaloids. Echitovenidine, the major alkaloid, shows monoamine oxidase-inhibitory activity both in vitro and in vivo.