Abstract: This study was aimed to investigate the changes in the total polyphenol and flavonoid contents and antioxidant activity of hawthorn during simulated gastrointestinal digestion. The effect of simulated gastrointestinal digestion on 5 main phenolic compounds was also determined using high performance liquid chromatography (HPLC). The results showed that hawthorn polyphenols were stable to gastric digestion; the contents of total polyphenols and flavonoids and antioxidant activity showed no significant changes during gastric digestion (P > 0.05). However, hawthorn polyphenols were easily degraded during intestinal digestion and the contents of total polyphenols and flavonoids and antioxidant activity decreased by 16.26%, 7.46% and 10.25% after 0.5 h, respectively. Furthermore, HPLC results indicated that 5 phenolic compounds revealed no remarkable changes during gastric digestion (P > 0.05), whereas the changes during intestinal digestion were not consistent. During intestinal digestion, hypericin and isoquercitrin did not change noticeably (P > 0.05), while epicatechin was completely degraded after 0.5 h. Moreover, the contents of chlorogenic acid and procyanidin B2 decreased by 40.78% and 28.99% after 0.5 h (P < 0.05).

Key words: hawthorn, simulated gastrointestinal digestion, polyphenols, antioxidant activity