Lignans, an amide and anti-platelet activities from Piper philippinum.

Investigation of the stem extract of Piper philippinum led to isolation of eight compounds, piperphilippinins I-VI (1-6), philippinamide (7), and (+)-bornyl caffeate (8), together with 26 known compounds. Among the isolates, (-)-3',4'-O,O-demethylenehinokinin (10) and 3,4-methylenedioxycinnamaldehyde (23) showed anti-platelet activities in vitro.