Abstract: Objective: To optimize the extraction of flavonoids from durian seeds and to evaluate the antioxidant and anti-aging effects of the extract in Caenorhabditis elegans for the purpose of providing a theoretical basis for screening for bioactive substances with antioxidant and anti-aging properties. Methods: The optimization was performed by combined use of one-factor-a-time method and L9 (34) orthogonal array design. To evaluate the in vitro antioxidant capacity, the scavenging effects on 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl and superoxide anion radicals were determined by spectrophotometry, the phenanthroline-Fe2+ oxidation method and the pyrogallol autoxidation method, respectively. The effects of the flavonoid extract on the lifespan, mobility, reproductive capacity, paralysis relief and antioxidant enzymes activities of C. elegans as a model organism were determined. The results showed that the optimal extraction conditions were 40% ethanol concentration, 1:220 solid-to-solvent ratio, 400 W ultrasonic power, and 70 min ultrasonic duration. Experiments conducted under these conditions gave an average extraction rate of flavonoids of (9.25 ± 0.05)%. The flavonoid extract could scavenge DPPH (92.6%), hydroxyl (79.4%) and superoxide anion radicals (27.0%) effectively. It could prolong the lifespan of C. elegans, improve the mobility, significantly reduce the paralysis rate (P < 0.05), relieve amyloid β-protein (Aβ) toxicity on it, significantly increase the superoxide dismutase (SOD) activity (P < 0.05) and reduce the malondialdehyde (MDA) content (P < 0.01) without damaging the reproductive capacity. Conclusion: The flavonoid extract from durian seeds has antioxidant capacity in vivo and in vitro, and is able to alleviate oxidative stress and aging-induced diseases.

Key words: flavonoid extracted from durian seeds; extraction process; oxidative aging; Caenorhabditis elegans