Antibacterial and antioxidant activities of Ri6 durian peel (Durio zibethinus L.) extracts

This study evaluates the antibacterial and antioxidant activities of Ri6 durian peel extracts. Peel samples collected from Dong Thap, Dak Lak, and Ben Tre were separated into thorny outer peel and inner spongy peel and extracted with 96% ethanol, 99% methanol, or 99% acetone. Total polyphenol and flavonoid contents, antioxidant activity, and antibacterial activity were determined using Folin - Ciocalteu, AlCl₃, DPPH, agar well diffusion, and MIC methods. Ethanol and methanol extracts recovered more bioactive compounds than acetone. The 96% ethanol extract of inner spongy peel showed the highest polyphenol and flavonoid contents and strongest antioxidant activity (IC₅₀ = 96.00 μg/mL). All extracts inhibited Staphylococcus aureus but showed no activity against Pseudomonas aeruginosa. Ri6 durian peel therefore represents a promising natural source of antioxidant and antibacterial compounds.