Fractionation of the EtOH extract of Justicia procumbens, guided by an
tiplatelet bioassay, led to the isolation of nine known arylnaphthalid
e lignans, neojusticin A (1), justicidin B (2), justicidin A (3), taiw
anin E methyl ether (4), neojusticin B (5), chinensinaphthol methyl et
her (6), taiwanin E (8), chinensinaphthol (9), and diphyllin (10), and
a new arylnaphthalide lignan that was characterized by spectral means
as 4'-demethylchinensinaphthol methyl ether (7). Compounds 1, 2, 4, a
nd 8 significantly inhibited platelet aggregation.