Phytochemical profiles and cellular antioxidant activity of Malus doumeri (bois) chevalier on 2,2′-azobis (2-amidinopropane) dihydrochloride (ABAP)-induced oxidative stress

The phenolic contents, antioxidant, and antiproliferative activities of Malus doumeri were evaluated. Heyuanxiaoguo variety contained higher level of total phenolics (101.9 mg GAE/g fruit, DW), whereas Xinyishanzha variety exhibited the highest total flavonoids (85.35 mg CE/g fruit, DW), and highest cellular antioxidant and antiproliferative activities. Higher ORAC and PSC values were found in Limushan variety. Chlorogenic acid, phloretin-2′-xyloglucoside and ursolic acid were the predominant phenolics in M. doumeri, their contents were highest in Limushan (1850 mg/100g fruit, DW), Xinyishanzha (2212 mg/100g fruit, DW), and Heyuanxiaoguo variety (506.3 mg/100g fruit, DW), respectively. Among the 14 compounds identified, chlorogenic acid and phloretin glycosides accounted for 55.95% of the extracellular antioxidant capacity, while quercetin, luteolin, ursolic acid, and chlorogenic acid contributed significantly to the intracellular antioxidant activity. Furthermore, the intracellular antioxidant property of the Xinyishanzha extracts was related to the protection of endogenous antioxidant enzymes activities and inhibition of reactive oxygen species production.