Bioassay-guided isolation of cycloartane-type triterpenes, their cytotoxic properties and identification of potential chemical markers from Geniotrigona thoracica propolis

Abstract

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.

Graphical Abstract

Keywords:

• Stingless bee propolis
• cycloartane
• cytotoxicity
• chemical marker
• bioassay-guided isolation

Acknowledgements

The authors would like to thank Desy Fitrya Syamsumir, Siti Aishah Radzi and Nurul Najihah Ahmad Tanazi from Institute of Climate Adaptation and Marine Biotechnology, Universiti Malaysia Terengganu for the NMR support and assistance. The authors thank Noor Aida Nawawi and Faris Hamzah from Centralised Lab Management Centre, Universiti Sultan Zainal Abidin for the HPLC technical support.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The work is supported by the grant from Universiti Sultan Zainal Abidin (UniSZA) under Dana Penyelidikan Universiti 2.0 (UniSZA/2021/DPU2.0/02-R0329).