In vivo antioxidative activity of a quantified Pueraria lobata root extract

Aim of the studyOxidative stress has been associated with many pathological disorders such as atherosclerosis, diabetes and cancer. Supplementation with exogenous antioxidants, including phenolic compounds from plant sources, may help to restore the pro-oxidative/antioxidative balance. To take into account effects of absorption, metabolisation, plasma protein binding, distribution, and elimination, antioxidative research should not be limited to in vitro assays but be extended to in vivo models.Materials and methodsIn the present work a quantified 50% EtOH root extract of Pueraria lobata (Willd.) Ohwi (Fabaceae) was selected to determine its in vivo antioxidative activity in a diabetic rat model, where diabetes and the accompanying oxidative stress were induced by intraperitoneal administration of streptozotocin. This root extract was found to contain 10.42 ± 0.15% puerarin as the main constituent and smaller amounts of the related isoflavonoids 3′-hydroxypuerarin, 3′-methoxypuerarin, 6″-xylosylpuerarin, daidzin, genistin, daidzein and genistein, as determined by a validated HPLC method. This extract was administered orally at a daily dose of 500 mg/kg root extract, corresponding to 50 mg/kg puerarin, during 3 weeks. In addition the effect on the plasma concentration of some fat-soluble antioxidants (co-enzyme Q9, α- and γ-tocopherol) was evaluated.Results and conclusionsThe level of malondialdehyde (MDA) in plasma, used as a marker of oxidative damage to lipids, was reduced to the same level as in healthy control animals, and as in the positive control group treated daily with 50 mg/kg α-tocopherol acetate. No obvious signs of toxicity were observed by administration of 10× the treatment dose.

In a diabetic rat model, where diabetes was induced by streptozotocin, oral administration of a quantified Pueraria lobata root extract at a daily dose of 500 mg/kg, corresponding to 50 mg/kg puerarin, during 3 weeks, resulted in a reduction of the level of malondialdehyde (MDA) in plasma, used as a marker of oxidative damage to lipids, to the same level as in healthy control animals, and to the same level as in the positive control group treated with 50 mg/kg α-tocopherol acetate.Figure optionsDownload as PowerPoint slide