Antioxidant properties of medicinal mushrooms
Introduction There are many metabolic processes in humans that can produce oxygen-centered free radicals and other reactive oxygen species (ROS) as byproducts. Oxidative damage caused by free radicals may be related to aging and diseases such as atherosclerosis, cancer, cerebral ischemia and rheumatoid arthritis. Humans and other organisms possess antioxidant defense and repair systems that have evolved to protect them against oxidative damage, including the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (Gpx), as well as the biological antioxidants reduced glutathione (GSH), vitamin C and vitamin E. However, these systems are insufficient to totally prevent the accumulation of oxidative damage over time. Dietary supplementation of antioxidants could conceivably protect the human body from the negative effects of free radicals and ROS effects and slow the progress of many chronic diseases. Commonly used antioxidants are butylated hydroxyanisole (BHA), butylated hydroxyltoluene (BHT), propyl gallate and tert-butylhydroquinone. However, BHA and BHT are suspected to contribute to liver damage (Thompson and Moldéus, 1988) and carcinogenesis (Saito et al., 2003). Consequently, natural sources of potential antioxidative properties are being investigated. Chemical assays for antioxidant activity DPPH· assay DPPH· (2,2-diphenyl-2-picrylhydrazyl) is a stable free radical that changes colour (from deep violet to light yellow) when reduced by a hydrogen-donating antioxidant compound. The color change may be quantified as a decrease in absorption at 515 nm, which can be measured with a spectrophotometer. The greater the antioxidant activity of the extract, the more rapidly the absorbance decreases. The DPPH· assay is commonly used to measure the antioxidant activity of specific compounds or extracts across a short time scale. The following mushrooms with antioxidant properties have been described on this website:References Thompson D, Moldéus P.
Cytotoxicity of butylated hydroxyanisole and butylated hydroxytoluene in isolated rat hepatocytes.
Biochem Pharmacol. 1988 37(11):2201-7.
Pubmed Saito M, Sakagami H, Fujisawa S.
Cytotoxicity and apoptosis induction by butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT).
Anticancer Res. 2003 23(6C):4693-701.
Pubmed
