The antimutagenic and antioxidant properties of Spirogyra neglecta (Hassall) Kützing

Spirogyra species is a freshwater filamentous green alga. Consumed as food in Northern Thailand, the algae have shown hypoglycemic ability in rats. The aims of this study were to investigate the chemical composition, antioxidant and antimutagenic activities in vitro of the aqueous extract of Spirogyra neglecta (Hassall) Kutzing. The antioxidant activity was evaluated by assessing the inhibition of 1,1diphenyl-2-picrylhydrazyl (DPPH) radicals. The IC 50 value of S. neglecta extract was 48.67±3.06 µg/ml in the DPPH scavenging assay. The mutagenicity and antimutagenicity were determined via the Ames test with and without metabolic activation. The extract did not enhance the numbers of revertant colonies of Salmonella typhimurium strains TA98 and TA100 in the absence and presence of metabolic activation; this indicates non-mutagenicity. The extract was strongly effective in reducing the mutagenicity induced by 2-aminoanthracene (2-AA), 2-aminofluorene (2-AF), aflatoxin B 1 (AFB 1) and 2-amino-3,4dimethylimidazo[4,5-f]quinoline (MeIQ) and weakly inhibited mutagenesis induced by 2-Amino-1-methyl6-phenylimidazo[4,5-b]pyridine (PhIP). The algae extract did not reduce the numbers of revertant colonies induced by a direct mutagen 2-(2-furyl)-3-(5-nitro-2-furyl)-acrylamide (AF-2) and NaN 3. The water extract of S. neglecta showed antioxidant activity and protection from indirect mutagens in S. typhimurium . The possible antimutagenic mechanism of S. neglecta aqueous extract might be due to the inhibition of some metabolizing enzymes of mutagen metabolism