Effects of Anoectochilus roxburghii-Fagopyrum tataricum Mixed Extracts on Improving Oxidative Damage Induced by D-Galactose in Aging Mice

Objective: To study the synergistic antioxidant activity of Anoectochilus roxburghii-Fagopyrum tataricum Mixed Extracts (AFME) in vitro, and the effects of AFME on aging in mice exposed to D-galactose. Methods: The synergistic antioxidant activity of AFME in vitro was evaluated by isoradiation analysis, via determining the contents of total flavonoids and total polyphenols in AFME with different mass ratios of Anoectochilus roxburghii and Fagopyrum tataricum, and measuring the ability of which to scavenge DPPH and ABTS⁺ free radicals. Low, medium and high dosages of AFME (1:1) (700, 1400, 2800 mg/kg) (AFME-L group, AFME-M group, AFME-H group), and vitamine C (V_C) (100 mg/kg) (V_C group) were gavaged to the mice for 63 days, to evaluate the effects of AFME on aging in mice exposed to D-galactose, by measuring the body weight, organ index, liver tissue morphology, and oxidative damage in serum and liver. Results: AFME (1:1) showed the optimum synergistic antioxidant effects in vitro. Compared with the control group (C group), the body weight, brain index and thymus index of aging mice were decreased (P<0.05), and the liver index was increased (P<0.01). Also, a large number of pathological changes such as degeneration and necrosis of hepatocytes and dilatation were observed in liver tissue of aging mice. The activity of superoxide dismutase (SOD) was lowerd (P<0.05), and malondialdehyde (MDA) was up-regulated in serum (P<0.01) in mice treated with D-galactose. The activity of glutathione peroxide dismutase (GSH-Px) (P<0.01), and glutathione (GSH) (P<0.05) were down-regulated. MDA (P<0.01) and advanced glycation end products (AGEs) (P<0.05) were increased in liver of the aging mice. The abnormalities above in the aging mice were improved by different dosages of AFME (1:1). Especially, the higher body weight, the higher brain and thymus index (P<0.05), the lower liver index (P<0.01), and the improved pathological changes in the liver tissue were observed in AFME-H group. Additionally, the increased activity of SOD (P<0.01) and down-regulated MDA (P<0.01) in serum, as well as the increased activity of GSH-Px (P<0.01), the decreased AGEs (P<0.05), and up-regulated GSH (P<0.01) in liver were also observed in AFME-H group. Conclusion: AFME (1:1) showed the optimum synergistic antioxidant effects in vitro. The abnormalities of body weight, brain index, thymus index, liver index, degeneration and necrosis of hepatocytes, dilatation of hepatic sinuses, and also the oxidative stress in serum and liver in aging mice could be attenuated by treating with AFME (1:1) (2800 mg/kg, i.g., 63 d), in order to slow down the aging, through inhibition of oxidative stress.