Polyphenolic diversity in different ethanolic extract of Malaysian Heterotrigona itama propolis: Correlation with antioxidant and cytotoxic properties

Propolis, a resinous substance produced by bees, is often regarded as a waste by-product in the beekeeping and honey production industry. However, its promising medicinal and therapeutic properties elevate it into a highly valued resource for numerous applications. Nevertheless, a key challenge lies in the varying phytochemical content, which may contribute to the inconsistency in its bioactivity and therapeutic effects. Therefore, this study aimed to produce a standardized propolis extract based on specific chemical markers and to evaluate its antioxidant and cytotoxic activities. Bioactive compounds from three different ethanolic extracts were analyzed using chromatographic and spectrophotometric techniques. Among these extracts, the 70 % ethanolic extract of propolis (EEP) showed the most abundant phytochemical profiles with benzenecarboxylic acid (benzoic acid) identified as the key compound. The 70 % EEP exhibited high total phenolic content (TPC) and total flavonoid content (TFC), which strongly correlated with its potent antioxidant activity and selective cytotoxicity. Moreover, this extract demonstrated considerable growth inhibitory effect with IC₅₀ value of 50.35 µg/mL, 55.47 µg/mL, 71.67 µg/mL against MCF-7, A549 and THP-1 macrophages, respectively. These findings highlight the importance of phenolic content in determining propolis bioactivity and support the development of standardized, bioactive natural products for therapeutic use.