PAF ANTAGONISTIC BENZOFURAN NEOLIGNANS FROM PIPER KADSURA

In a continuing search for PAF antagonists, five benzofuran neolignans have been isolated from the aerial part of Piper kadsura (Choisy) Ohwi, a Chinese traditional drug used for the treatment of inflammation and rheumatic conditions. The structure determination was based upon spec-troscopic analysis. Two of the neolignans were found to have new structures and were named as (—)-denudatin B(the enantiomer of denudatin B, Ⅱ) and kadsurenin M (78, 8S-3,4,3'-trimethoxy-7'-oxo-nor-8',9'-7. O. 4',8,5'-neolignan, V). The known compounds kadsurenone (Ⅰ), (—)-acuminatin(Ⅲ) and (+)-licarin A(Ⅳ) were also obtained from the same source. (—)-Denudatin B (Ⅱ) showed potent PAF antagonistic activity in ³H-PAF receptor binding assay.