Total phenolic contents, total flavonoid contents and antioxidant activities of endocarp and mesocarp of Malaysian local Durio Zibethinus (Musang King and Durian Kampung Peel)

This study aimed to determine and compare the total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activities of mesocarp and endocarp peel extract from two Malaysian local varieties of Durio Zibethinus, Durian Kampung (DK), and Musang King (MK). The extracts were analysed using Folin-Ciocalteu method for total phenolic content, aluminium chloride colorimetric method for total flavonoid content, as well as 2,2-diphenyl-1-picrylhydrazyl (DPPH), and ferric reducing antioxidant power (FRAP) assays for antioxidant activities. Findings showed Durian Kampung endocarp, and mesocarp peel extract had significantly higher total phenolic content (6.261 ± 0.442 mg GAE/g; 5.129 ± 0.162 mg GAE/g), total flavonoid content (32.30 ± 1.691 mg QE/g; 27.84 ± 0.701 mg QE/g), and DPPH radical scavenging activity IC₅₀ value (39.52 ± 1.400ug/mL; 46.62 ± 0.563 µg/mL) respectively compared to Musang King. Eventhough FRAP values of all the peel extracts showing no significant differences (p > 0.05), Durian Kampung endocarp consistently had the highest value of FRAP (1965.0 ± 174.6 µM TE/g), followed by its mesocarp (1923.2 ± 135.9 µM TE/g). The results showed Durian Kampung had better bioactivity than Musang King, and the endocarp peel had better bioactivity than the mesocarp peel. The total phenolic content, and total flavonoid content were strongly correlated with antioxidant DPPH IC₅₀ value (TPC; r = -0.964, TFC; r = -0.939), and moderately correlated with FRAP value (TPC; r = 0.658, TFC; r = 0.613), indicating that the antioxidant activities of durian peel extract are contributed by phenolic, and flavonoid. This finding can serve as baseline data for the antioxidant properties of Malaysian durian waste, and further studies are encouraged, as it is a potential nutraceutical source with good antioxidant qualities.