Antioxidative and cytotoxic effects of prenylated stilbene derivative-rich Melinjo (Gnetum gnemon L.) fruit rind

The identification of fruit-bark of Melinjo was carried out using fractionation column chromatography resulted in 3 isolates A-C with presumption of containing five stilbene derivatives compounds (isorhapontigenin, resveratrol, gnetin D, gnetifolin K, gnetol) and one lignan compound ((+)-lirioresinol B) based on the results of the characterization of UV-Vis, FTIR, and LC-ESI-MS. Isolate C that containing gnetol and (+)-lirioresinol B was reacted through prenylation process with prenyl bromide as a source of prenyl group and K₂CO₃ as catalyst with reflux system at 60 °C for 24 h. Characterization using LC-ESI-MS showed that gnetol and (+)-lirioresinol B was successfully prenylated with one additional prenyl group. The prenylated stilbene showed comparable antioxidant effect and was slightly lower than the nature stilbene structure, as the impact of the attachment of prenyl moieties at their hydroxyl groups in stilbene, and showed moderate activity against P-388 murine leukemia b cells. The observed inhibition of the bioactivity test provides a reasonable mechanism for the potent cancer chemo preventive activity of prenylated stilbene compounds and may pose this compound as a valuable agent for the treatment of diseases.