Quadrigemine B, quadrigemine A, isopsychotridine C and psychotridine, isolated from PSYCHOTRIA FORSTERIANA, are potent inhibitors of the aggregation of washed human platelets induced by ADP, collagen or thrombin. The four compounds are active in the 1-10 microM range. The quadrigemine-type alkaloids
The chemical study of two Rubiaceae from New Caledonia, Psychotria lyciiflora and Psychotria oleoides, led to the isolation of several pyrrolidinoindoline alkaloids. Two dimers, the known meso-chimonanthine (9) and the new Nb-desmethyl-meso-chimonanthine (5), and a known trimer, hodgkinsine (1),