ALKALOIDS FROM MELODINUS-HEMSLEYANUS

Twenty alkaloids were isolated from the aerial parts of Melodinus hems leyanus Diels. Fifteen of them were known, viz., tabersonine, 11-metho xytabersonine, 11-hydroxytabersonine, 11,19R-dihydroxytabersonine, 11- hydroxy-14,15-alpha-epoxytabersonine, scandine, 10-hydroxyscandine, me loscine, meloscandonine, venalstonine, venalstonidine, vindolinine, pi cralinal, picrinine and akuammidine. The other five alkaloids were new . Their structures were established as 11-hydroxyvincadifformine, 14,1 5-epoxyscandine, 19-epimeloscandonine, 16beta-hydroxy-19R-vindolinine and 16beta-hydroxy-19S-vindolinine by means of spectroscopic and chemi cal methods. A pharmacological test revealed that 11-hydroxyvincadiffo rmine has significant antifertility activity.