In vitro evaluation of antioxidant and antibacterial activities of crude and anthocyanin-rich fraction of Philippine rice wine (tapuy) lees

Abstract

This study investigated the antioxidant and antibacterial activities of Tapuy lees, a traditional rice wine fermentation by-product rich in anthocyanins. The crude methanolic and anthocyanin-rich fractions were evaluated for phytoconstituents and were subjected to antioxidant and antibacterial assays. Results showed various phytochemicals, including tannins, flavonoids, and anthocyanins. The methanolic extract exhibited substantial phenolic content. Meanwhile, the anthocyanin-rice aqueous fraction revealed the highest antioxidant activities against DPPH, superoxide, and hydroxyl radicals. Additionally, both extracts demonstrated antibacterial activity against Escherichia coli and Staphylococcus aureus, with the anthocyanin-rich fraction displaying superior efficacy. Specifically, the anthocyanin-rich fraction displayed larger zones of inhibition against both bacterial strains compared to the methanolic extract. These results suggest the potential of the anthocyanin-rich aqueous fraction of tapuy lees as a natural antibacterial agent, indicating its potential application in food and health industries. Further in vitro and in vivo studies are recommended to validate and complement these preliminary findings, paving the way for developing novel functional food products derived from waste.