Some epoxylignans from the Vietnamese propolis of stingless Bee Trigona minor and their bioactivities

Abstract

AbstractTwo new epoxylignans, trigonan A (1) and trigonan B (2), were isolated from EtOAc extract of Vietnamese stingless bee propolis Trigona minor (Meliponini, Apidae), together with 15 known compounds. Their chemical structures were determined by extensive NMR and MS spectroscopic analysis. All compounds were tested for DPPH free radical scavenging activity; as a result, methoxylariciresinol (14) showed the best significant DPPH inhibitory activity with IC50 value of 3.0 μM, and had stronger activity than that of a positive control, trolox (IC50, 8.2 μM). In the α‐glucosidase inhibitory activity, syringaresinol (10) displayed the best activity with IC50 value of 17.8 μM, and its activity was more than a positive control, acarbose (IC50, 185.2 μM). For the cytotoxic activity against the HeLa cell line, de‐4'‐O‐methyleudesmin (7) exhibited the most cytotoxicity with IC50 value of 46.3 μM and was quite weaker than that of a positive control, paclitaxel (IC50, 0.0014 μM).