title: Structural Aspects of Antioxidant and Genotoxic Activities of Two Flavonoids Obtained from Ethanolic Extract of Combretum leprosum.
abstract: Combretum leprosum Mart., a member of the Combretaceae family, is a traditionally used Brazilian medicinal plant, although no evidence in the literature substantiates its antioxidant action and the safety of its use. We evaluated the antioxidant properties of the ethanolic extract (EE) from flowers of C. leprosum and its isolated products 5,3'-dihydroxy-3,7,4'-trimethoxyflavone (FCL2) and 5,3',4'-trihydroxy-3,7-dimethoxyflavone (FCL5) in Saccharomyces cerevisiae strains proficient and deficient in antioxidant defenses. Their mutagenic activity was also assayed in S. cerevisiae, whereas cytotoxic and genotoxic properties were evaluated by MTT and Comet Assays, respectively, in V79 cells. We show that the EE, FCL2, and FCL5 have a significant protective effect against H2O2. FCL2 showed a better antioxidant action, which can be related to the activation of the 3'-OH in the presence of a methoxyl group at 4' position in the B-ring of the molecule, while flavonoids did not induce mutagenesis in yeast, and the EE was mutagenic at high concentrations. The toxicity of these compounds in V79 cells increases from FCL2 = FCL5 < EE; although not cytotoxic, FCL5 induced an increase in DNA damage. The antioxidant effect, along with the lower toxicity and the absence of genotoxicity, suggests that FCL2 could be suitable for pharmacological use.
authors.affiliation: Department of Basic Health Sciences, Laboratory of Genetic Toxicology, Federal University of Health Sciences of Porto Alegre (UFCSPA), Rua Sarmento Leite 245, 90150-170 Porto Alegre, RS, Brazil; National Institute for Translational Research on Health and Environment in the Amazon Region, CNPq/INCT/INPeTAm, Rio de Janeiro, RJ, Brazil.
authors.forename: Cassiana Macagnan
authors.initials: CM
authors.lastname: Viau
authors.affiliation: Department of Pharmacosciences, Laboratory of Genetic Toxicology, UFCSPA, Rua Sarmento Leite 245, 90150-170 Porto Alegre, RS, Brazil.
authors.forename: Dinara Jaqueline
authors.initials: DJ
authors.lastname: Moura
authors.affiliation: Department of Basic Health Sciences, Laboratory of Genetic Toxicology, Federal University of Health Sciences of Porto Alegre (UFCSPA), Rua Sarmento Leite 245, 90150-170 Porto Alegre, RS, Brazil.
authors.forename: Pricila
authors.initials: P
authors.lastname: Pflüger
authors.affiliation: Núcleo de Ciência e Tecnologia, Universidade Federal de Rondônia, Avenida Presidente Dutra, Até 2965, lado Ímpar, Centro, 76801059 Porto Velho, RO, Brazil.
authors.forename: Valdir Alves
authors.initials: VA
authors.lastname: Facundo
authors.affiliation: Department of Basic Health Sciences, Laboratory of Genetic Toxicology, Federal University of Health Sciences of Porto Alegre (UFCSPA), Rua Sarmento Leite 245, 90150-170 Porto Alegre, RS, Brazil; National Institute for Translational Research on Health and Environment in the Amazon Region, CNPq/INCT/INPeTAm, Rio de Janeiro, RJ, Brazil.
authors.forename: Jenifer
authors.identifier: 0000-0002-5372-2934
authors.initials: J
authors.lastname: Saffi