Amide and phenylpropanoid glycosides from the fruits of Piper longum L. and their anti-inflammatory activity.

Ten glycosidic compounds (1-10), including two novel amide glycosides and one new phenylpropanoid glycoside, were isolated from the fruits of Piper longum L. These novel compounds were identified as (E)-N-feruloylpiperidine 4'-O-β-d-glucopyranosyl-(1 → 4)-β-d-glucopyranoside (1), (E)-N-p-coumaroylpiperidine 4'-O-β-d-glucopyranosyl-(1 → 4)-β-d-glucopyranoside (2), and (E)-cinnamyl alcohol 9-O-β-d-glucopyranosyl-(1 → 4)-α-l-rhamnose-(1 → 6)-β-d-glucopyranoside (3) by detailed spectroscopic and spectrometric techniques. Acid hydrolysis was employed to determine the glycosidic linkages, facilitating the structural elucidation of these compounds. The anti-inflammatory activities of all isolated compounds were assessed, and the results demonstrated that compounds 8 and 9 exhibited moderate inhibitory effects on nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW264.7 cells.