Characterization of Heterotrigona itama Propolis Extracts: Phytochemicals and Thermal Insights

This study was aimed to characterize the phytochemical composition and bioactive compounds in the Heterotrigona itama crude propolis extract (F1) and its alkaline hydrolyzed counterpart (F2). Ethanolic extraction yielded 10.06% w/w crude propolis extract, and the subsequent alkaline hydrolysis produced 3.27% w/w propolis extract. Analytical results showed TPC decreased from 1.21 ± 0.09 mg GAE/g (F1) to 0.83 ± 0.17 mg GAE/g (F2), while TFC declined from 14.79 ± 0.08 mg QE/g to 11.88 ± 0.10 mg QE/g, likely due to phenolic bond cleavage during hydrolysis. Compositional and structural analyses were performed using advanced analytical techniques such as scanning electron microscopy-energy dispersive x-ray spectroscopy (SEM-EDX), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), and differential scanning calorimetry (DSC). SEM-EDX revealed carbon (60.12%-62.35% w/w) and oxygen (28.74%-30.18% w/w) as major elements, with minor sodium and potassium. ATR-FTIR and GC-MS analyses identified bioactive compounds, including phenolics, terpenoids, steroids, and fatty acid esters which likely contributed to the antioxidant, anti-inflammatory, and antimicrobial properties. DSC thermogram showed a broad endothermic transition for F1, but sharper peaks for F2, indicating altered thermal stability after hydrolysis. The results highlighted the potential of H. itama propolis extracts those rich in bioactive compounds for the development of value-added products.