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
This study investigated the mechanism underlying the inhibiting effect of (2R,3R)-2-(3',4'-dihydroxybenzyl)-3-(3'',4''-dimethoxybenzyl) butyrolactone (PP-6), a lignan from Piper philippinum, on superoxide anion production induced by the chemotactic peptide formyl-methionyl-leucyl-phenylalanine