Extraction of flavonoids from durian (Durio zibethinus) fruit rinds and evaluation of their antioxidant, antidiabetic and anticancer properties

SummaryDurian (Durio zibethinus) fruit rinds are a promising source of bioactive phytochemicals, but they are currently wasted. This study optimised extraction conditions for flavonoids from durian fruit rinds and evaluated the biological activities of the flavonoid‐rich extracts. The highest flavonoid content of 82.17 mg QE g−1 extract was achieved when performing the extraction at 60 °C using 75% ethanol and maceration time of 24 h. The crude ethanolic extract was then fractionated using liquid–liquid extraction to obtain three fractions (CHF, EAF and AQF). Among them, CHF demonstrated the highest amount of flavonoids (271.11 mg QE g−1 extract) and quercetin (1006.19 μg g−1 extract). This fraction also exhibited the highest ferric reducing power (IC50 of 307.88 μg vitamin C g−1), DPPH radical scavenging activity (IC50 of 38.72 μg mL−1), α‐amylase and α‐glucosidase inhibitory activity (IC50 of 685.76 μg mL−1 and 441.10 μg mL−1, respectively) and cytotoxicity against HepG‐2 and MCF‐7 cells with IC50 values of 490.30 μg mL−1 and 343.38 μg mL−1 respectively. The current work suggested that durian fruit rinds are a potential source of flavonoids and the CHF could be further used for pharmaceutical applications.