Phytochemical investigation through cytotoxicity bioassay-guided isolation of Geniotrigona thoracica propolis led to the identification of five cycloartane-type triterpenes, including mangiferonic acid 1, ambonic acid 2, mangiferolic acid 3, ambolic acid 4 and cycloartenol 5. Their structures were established based on detailed spectroscopic analysis and comparison with literature data. Compounds 1-5 were isolated for the first time in this species. From cytotoxicity MTT assay, compound 3 inhibited the growth of breast (MCF-7) and hepatocellular carcinoma (HepG2) cancer cell lines with IC50 of 5.08 and 4.82 µg/mL, respectively. Cytotoxicity of compounds 1-5 were reported for the first time against HepG2 cancer cell lines. Compounds 1-4 were suggested to serve as main and/or analytical markers for G. thoracica propolis based on HPLC analysis. To our knowledge, this is the first report on the isolation of bioactive constituents and identification of chemical markers for G. thoracica propolis.
Propolis is a sticky substance produced by stingless bees for construction and defence of their hive. It has notable anti-inflammatory, antioxidant, antibacterial, antifungal, anti-hyperglycemic, and wound healing effects. The present review summarised and examined the phytochemical properties, mode of action and current research prospects of Malaysian propolis. A database search using Google Scholar, Web of Science and ScienceDirect generated 780 references; 30 relevant articles were included in the present review, of which 23 were in vitro studies and 7 were in vivo or animal studies. Propolis demonstrated antioxidant, antibacterial, antifungal, anti-inflammatory and anti-hyperglycemic properties, indicating potential as a wound healing agent. Despite favourable findings, due to the scarcity of studies in the literature, more in-depth research and clinical validation on the synergistic effects, efficacy and optimum dosage of propolis are needed.