Anti-inflammatory and antitumour activity of various extracts and compounds from the fruits of Piper longum L.

Objectives: To explore effective extraction method and to find active constituents, we investigated the biological activity of three extracts and isolated active compounds from the fruits of Piper longum L.

Methods: Three extracts from the fruits were obtained by reflux, ultrasonic and supercritical fluid extraction, respectively. Active compounds were isolated by the bioassay-guided method. The anti-inflammatory activity, antiproliferation activity and cytotoxicity were evaluated. The apoptosis was detected by Hoechst 33258 staining assay. The relevant proteins were investigated by Western blot assay.

Key Findings: The anti-inflammatory activity and cytotoxicity of supercritical fluid extract (SE) were stronger than those of the other two extracts. Among all isolated compounds, the anti-inflammatory activity of eight compounds was stronger than that of indomethacin, and compounds 8, 9, 11, 14 and 15 were found to possess anti-inflammatory effect for the first time. Compounds 1, 2, 3 and 14 exhibited significant cytotoxicity against cancer cells. SE and piperine were found to reduce colony formation, inhibit cell migration and promote apoptosis through increasing cleaved PARP and the ratio of Bax/Bcl-2.

Conclusions: The anti-inflammatory and antitumour effects of SE were better than those of the other two extracts. The compounds responsible for the activity were elucidated. SE and piperine inhibit cell growth through apoptosis.