Antimicrobial, Cytotoxic, and α -Glucosidase Inhibitory Activities of Ethanol Extract and Chemical Constituents Isolated from Homotrigona apicalis Propolis-In Vitro and Molecular Docking Studies.

The chemical investigation of propolis collected in Binh Dinh province, Vietnam, led to the isolation of nine compounds, including four sesquiterpenes: spathulenol (), 1H,5H-aromandendrane-4,10-diol (), 1,6-dihydroxy-4(15)-eudesmene (), and 1H,5H-aromandendrane-4,10-diol (); three triterpenes: acetyl oleanolic acid (), 3-hydroxytirucalla-8,24-dien-21-oic acid (), and ursolic acid (); and two xanthones: cochinchinone A () and -mangostin (). Sesquiterpens - and triterpene were isolated for the first time from stingless bee propolis. Plants in the and genus were suggested as resin sources of the propolis sample. In the antibacterial activity evaluation, the EtOH extract only showed moderate activity on , while the isolated compounds - showed good antibacterial activity, with IC values of 0.56 to 17.33 µg/mL. The EtOH extract displayed selective cytotoxicity against the A-549 cancer cell line, with IC values of 22.82 ± 0.86 µg/mL, and the xanthones and exhibited good activity against the KB, HepG-2, and A-549 cancer cell lines, with IC values ranging from 7.55 ± 0.25 µg/mL to 29.27 ± 2.07 µg/mL. The cytotoxic effects of xanthones and were determined by the inhibition of the EGFR and HER2 pathways using a molecular docking study. Compounds and displayed strong binding affinity with EFGR and HER2, with values of -9.3 to -9.9 kcal/mol. Compounds , and showed potential -glucosidase inhibitory activities, which were further confirmed by computational studies. The binding energies of compounds , and were lower than that of arcabose.