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

Abstract

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.

Graphical abstract