Estudo in vitro do perfil de segurança de arbutina e formononetina presentes em Cyrtopodium glutiniferum Raddi e seu desempenho como protetores a danos químicos ao DNA

Abstract

Natural products of plants is the term that designates bioactive compounds, which are produced as a result of vegetal organisms facing biotic and abiotic stressors. They are of great interest to the pharmaceutical industry, and are object of popular empirical knowledge on healing plants with benefits to health. In the orchids family (Orchidaceae), the genus Cyrtopodium sp. is popularly kwown for its therapeutical properties. Recently, the crude aqueous extract of the species Cyrtopodium glutiniferum Raddi was assessed, presenting antiproliferative, antioxidant, and anti-inflammatory effects. However, there are no studies on its main phenolic components regarding their effects on health, the substances dihydroformononetin and arbutin. The present study aims to assess the safety and effectiveness of two bioactive compounds most abundantly found in the crude aqueous extract of Cyrtopodium glutiniferum Raddi (CYRTO), and their possible role as effectors of the therapeutic activity described of the orchid. To accomplish it, in vitro assays of prokaryotic and eukaryotic models were conducted: mutagenicity of formononetin (FMN) and arbutin (ARB) provoked to bacterial strains TA97, TA98, TA100, TA1535 and TA102 was assessed through Salmonella/microsome assay, in the absence and presence of exogenous metabolization; the possible antimutagenic potential of FMN and ARB was investigated in the strains TA98, TA100 and TA1535. In the eukaryotic models, the effect of exposure to FMN, ARB and CYRTO in hepatic lineages (HepG2 and F C3H) was assessed through in vitro cell viability assay, analyzed by the conversion of tetrazolium soluble salt (WST). Results indicate that there was no mutagenic damage to the DNA of Salmonella Typhimurium strains induced by FMN or ARB, whereas FMN exhibited cytotoxicity to TA97 and TA100 (starting at 0.1 µM/plate to TA97 and 1.0 µM/plate on TA100) cells after exogenous metabolization, and mutagenicity to TA1535 (10 µM/plate) in the same condition. Both FMN and ARB presented antimutagenic effect on a bacterial model, and therefore were capable of protecting the DNA structure against oxidative and alkylating chemical damages. In the eukaryotic cell cultures, FMN induced cytotoxicity to HepG2 and F C3H at 1000 µM/well, whereas ARB and CYRTO did not cause reduction in viability of the these hepatic cells. This study shows evidence that FMN and ARB are promising to the field of therapies of mutation-related diseases, since they demonstrated to be useful to the combat of chemical lesions on the DNA, acting as antioxidants and activating the DNA repair machinery. Besides a propitious panel of safety (barring FMN, in high concentrations and after biotransformation), FMN and ARB showed to be related to the plant’s known therapeutic activity, which validates traditional medicinal knowledge on its use and reinforces the need of scientifically investigate it