Inhibitors of cyclic AMP phosphodiesterase in Picrasma quassioides Bennet, and inhibitory activities of related .BETA.-carboline alkaloids.

Abstract

CAMP phosphodiesterase inhibitors present in P. quassioides Benn. [a medicinal plant] were identified as 1-methoxycarbonyl-.beta.-carboline, 4,5-dimethoxycanthin-6-one and 5-hydroxy-4-methoxycanthin-6-one. The structure-inhibitory activity relationships were studied in 31 derivatives of .beta.-carboline, 2 dimeric derivatives of .beta.-carboline and 12 derivatives of canthin-6-one. .beta.-Carboline derivatives with a methoxycarbonyl group and canthin-6-one derivatives with a methoxyl group generally had a strong inhibitory effect on cAMP phosphodiesterase.