Nitrous Acid and Diethyl Sulfate, as Chemical Mutagenic Agents, to Improve the Biomass, Metabolites, Enzyme Activity, and Antioxidant Activity of Wild Phellinus igniarius

Abstract

Various secondary metabolites with antioxidative effects have been reported to exist in Phellinus igniarius. However, the trace quantity of these metabolites in normal fermentation conditions deeply limits its medical values and potent clinical application. Some elicitors such as bioinducer and chemical inducer can improve the productivity of secondary metabolites which have certain biological activities in plants and fungus. In this study, nitrous acid (NA) and diethyl sulfate (DES), as potent killing and mutagenic chemical agents, to treat P. igniarius and enhance the metabolites contents. The variation of biomass, metabolite production, enzyme activity, and antioxidant efficacy of two mutant strains were investigated. The mutant strains exhibited better viability and produced more secondary metabolites. Altogether, these results indicate that chemical mutagenesis is an effective strategy to obtain high-activity mutant strains of P. igniarius with high yields of total flavonoids and total polysaccharides, the main constituents with antitumor and antioxidant activities.