Antioxidant Properties of a Water-soluble Extract from Culture Medium of Ganoderma lucidum (Rei-shi) Mycelia and Antidiabetic Effects in Streptozotocin-treated Mice / 日本補完代替医療学会誌

ABSTRACT

<i>Objective</i> <i>Ganoderma lucidum</i> (Rei-shi) is widely used as an alternative medicine agent to promote health and longevity. The water-soluble extract from culture medium of <i>Ganoderma lucidum</i> mycelia (WER) is prepared from a solid medium composed of bagasse and rice bran overgrown for 3–4 months with <i>Ganoderma lucidum</i> mycelia.<br> <i>Design</i> In this study, we evaluate antioxidant activity of WER <i>in vitro</i>, and examined the effects of oral treatment of WER on oxidative stress in streptozotocin (STZ)-induced diabetic mice.<br> <i>Method</i> Male ICR mice were treated with STZ (150 mg/kg, i.p.) and were housed for a week for induction of experimental diabetic state. WER (1 g/kg daily) was orally administered for an additional 9 weeks, and the levels of blood glucose, oxidative stress in plasma, liver and kidney of the mice were assessed.<br> <i>Result</i> WER inhibited generation of superoxide anion and lipid peroxidation in concentration dependent manner<i> in vitro</i>. Oral administration of WER to diabetic mice significantly reduced the levels of blood glucose, hydroperoxides, triglyceride, ALT, and AST. Moreover, WER prevented the increase in lipid peroxide levels and the decrease in activity of antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase) in liver and kidney of diabetic mice. In addition, histochemical studies revealed that treatment of WER precluded the sinusoidal dilation in liver and expansion of mesangial matrix in kidney of diabetic mice. Normal mice treated with WER showed no change in any parameters studied.<br> <i>Conclusion</i> These data suggested that WER can act as an antioxidant <i>in vivo</i>, and show the antidiabetic effects by relieving diabetic hyperglycemia-induced oxidative stress.<br>