THE ISOLATION AND IDENTIFICATION OF PAF INHIBITORS FROM PIPER WALLICHII (MIQ.) HAND-MAZZ AND P. HANCEI MAXIM.

Platelet activating factor (PAF) is a highly potent endogenous phospholipid mediator, involved in various inflammatory and cardiovascular disorders. As part of a research program dealing with PAF inhibitors isolated from Piper plant species,we have isolated kadsurenone(Ⅰ),denudatin B( Ⅱ ), and N-isobut yl-deca-trans- 2-trans-4 -dienamide( Ⅲ ) from Piped wallichii (Miq.) Hand-Mazz. and P. hancei Maxim. In a continuing search for potential PAF inhibitor from plants, using PAF induced platelet aggregation as a guide, a new neolignan named hancinone D (Ⅳ) was isolated from P. hancei maxim. By X-ray analysis it was identified as a racemate.The X-ray analysis led to a revision of the previously made structure assignment of hancinone C. Another new neolignan named wallichinine (Ⅴ), which was identified as an analogue of(Ⅳ), along with the known compounds hancinone C (Ⅵ), galgravin(Ⅶ), di hydropi perlonguminine(Ⅷ )and crotepoxide (IX) were isolated from P.wallichii (Miq.) Hand-Mazz.The structure determination was based upon spectroscopic analysis. All of the compounds were for the first time obtained from both plants.In the test of platelet aggregation caused by PAF, Ⅰ ,Ⅱ, Ⅴ,Ⅵ, Ⅶ showed inhibitory activity, whereas Ⅲ, Ⅳ, Ⅶ, Ⅸ showed no activity.