Bioactive steroids against ovarian cancer cell line isolated from Malaysian green propolis

Propolis has shown evidence of its effectiveness in various biological studies such as anticancer, antioxidant, anti-inflammatory, antibiotic and antifungal agents [1].

In this study, we apply metabolomics tools utilising nuclear magnetic resonance (NMR) and liquid chromatography-high resolution mass spectrometry (LC-HRMS) data as a promising approach in targeting the isolation of the bioactive metabolites. The green propolis sample was collected from Malaysia (B-B Town Sdn. Bhd. Malacca, Malaysia) which was colonized by Trigona sp. bees. The bees tend to visit different kind of the host plants, one is Tectona grandis, which is natively found in Southeast Asia including Thailand, Vietnam and later was introduced in Malaysia.

The propolis sample (800 mg) was subjected to extraction using 1:1 water to methanol ratio, followed by using acetone and methanol to obtain the crude extract. All extracts were screened for anticancer activity against the ovarian cancer cell line (A2780). The obtained HRLCMS data was processed with MZmine 2.10 and dereplicated with in-house Excel macro coupled to the Dictionary of Natural Products 2016 (DNP). A supervised multivariate analysis was done by orthogonal partial least squares discriminant analysis (OPLS-DA) in SIMCA-P 14.0 to predict and pinpoint the plausible bioactive components.

Based on the mass spectral data, there were three bioactive compounds that were successfully isolated from the predicted bioactive metabolites. All compounds were steroid and triterpenoid derivatives, which were confirmed with 1D and 2D NMR experiments.

[1] Watanabe M. A. E, Amarante, M. K, Conti B. J, Sforcin J. M. Journal of Pharmacy and Pharmacology; 2011: 63, 1378 – 1386