Heterocyclic phytometabolites formononetin and arbutin prevent in vitro oxidative and alkylation-induced mutagenicity

Abstract

Phenolic phytometabolites are promising bioactive compounds for management of genomic instability related diseases. Formononetin (FMN) and arbutin (ARB) are found in several plant sources. Our goal was to investigate the safety and efficacy of FMN and ARB using in vitro both standardized and alternative toxicogenetic methods. FMN and ARB were evaluated through the OECD’S guidelines No. 471 (Bacterial Reverse Mutation Test –Salmonella/microsome) and No. 487 (In vitro Mammalian Micronucleus Test – CBMN assay), accordingly to the mentioned recommendations. Also, antimutagenicity of FMN and ARB was assessed in S. Typhimurium strains TA98, TA100 and TA1535, following pre-, co- and post- treatment protocols. Liver human lineages HepG2 and F C3H were assayed for cytotoxicity after exposure to FMN and ARB (24, 48 and 72 h) using in vitro WST-1 test. ARB showed no mutagenicity in the Salmonella/microsome test under both metabolic conditions (in presence or absence of 4 % S9 mix), but FMN was cytotoxic to the TA97 and TA100 strains after metabolic activation. Under this same condition, FMN induced an increase in the mutagenic index of strain TA1535 at two of the highest tested concentrations. Even so, ARB and FMN exhibited protection against the induced alkylation of DNA in multiple action modes. In the antimutagenicity assay, FMN reached the maximum of 80 % of oxidative-provoked mutagenicity reduction in TA98 strain in co-treatment with known mutagen, besides 69 % of reduction in TA100 in the same exposure condition. ARB showed up to reduce induced mutagenicity in strains TA100 and TA1535, reaching percentages from 55 % to 100 % of antimutagenicity in all of the tested exposure models against alkylating agent. In the CBMN assay, no increase in micronuclei formation was observed. The results suggest that FMN and ARB prevent DNA from mutation using multi-targeted antimutagenic roles. Finally, our data suggests that FMN and ARB are not genotoxic and presented encouraging antimutagenicity action in vitro, being promising compounds for use in genomic instability-related diseases therapeutics.