Antioxidant and Antimutagenic Properties of Hibiscus Tiliaceus L. Methanolic Extract RENATO MOREIRA ROSA, † MARIA INE Ä S S. MELECCHI, ‡ RAFAEL DA COSTA HALMENSCHLAGER, † FERNANDA C. ABAD, ‡ CRISTINA ROSAT SIMONI, † ELINA B. CARAMA ˜ O, ‡ JOA ˜ O ANTONIO PE ˆ GAS HENRIQUES, †,§ JENIFER SAFFI,* ,†,§ AND ANA Lı ´GIA LIA DE PAULA RAMOS* ,† Departamento de Biofı ´sica and Instituto de Quı ´mica, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil, and Laborato ´rio de Gene ´tica Toxicolo ´gica, Universidade Luterana do Brasil, ULBRA, Canoas, RS, Brazil The genus Hibiscus thrives in a variety of climates and produces a diversity of natural compounds with bioactive properties. We have studied the chemical composition and the in vivo antioxidant properties of Hibiscus tiliaceus L. methanolic flower extract, as well as its mutagenic/antimutagenic effects. Vitamin E and some stigmasterol derivatives that might confer an antioxidant effect to the extract were present. Treatment with this extract protected several Saccharomyces cerevisiae strains defective in antioxidant defenses against H 2 O 2 and t-BOOH cytotoxicities, showing a clear antioxidant activity. The effect is the same for all strains used, independent of the antioxidant defense disrupted, suggesting that protection may be due to molecules that act as versatile and wide spectrum nonenzymatic antioxidants, such as vitamins or phytosterols. The extract was not mutagenic in either Salmonella typhimurium or S. cerevisiae and showed a significant antimutagenic action against oxidative mutagens in S. cerevisiae. KEYWORDS: Phytotherapics; antioxidant; Hibiscus tiliaceus L.; Saccharomyces cerevisiae; antimu- tagenesis; Ames INTRODUCTION In recent times, focus on plant research has increased all over the world and a large body of evidence has been collected to show the immense potential of medicinal plants used in traditional systems. Various medicinal plants have been studied using modern scientific approaches, and the results have revealed the potential of medicinal plants in the area of pharmacology (1). There is a considerable amount of epidemiological evidence revealing an association between diets rich in fruits and vegetables and a decreased risk of cardiovascular disease and certain forms of cancer (2-4). It is generally assumed that components of higher plants are active dietary constituents that contribute to these protective effects. For instance, R-tocopherol, -carotene, and polyphenolic compounds may act as antioxidants or in other ways protect against cancers and cardiovascular diseases (5). Species of the genus Hibiscus have been used in several applications, for example, as an antidote to poisoning with chemicals and venomous mushrooms in traditional medicine and as a source of fiber in the pulp and paper industries. Members of the genus Hibiscus thrive in a variety of climates and produce a diversity of natural compounds with bioactive properties, such as lignanamides, naphthalenes, polyphenol compounds, carotenoids, tochopherols, flavonoids, anthocyanins, phytosterols, and long-chain fatty esters (6). Hibiscus tiliaceus L. is a typical plant of tropical climates found in the regions of mangroves in significant quantities (7). It is also known as “Algodoeiro da Praia” (beach cotton) and occurs in mangroves in Santa Catarina state, in the south of Brazil. Their flowers are widely used in birth control in Asian and African countries (8-10). An infusion of the dried wood was used in folk medicine to expel the placenta and to combat postparturition disorders (11). An aqueous extract of wood and fresh flowers is registered for skin diseases (12-15). However, its chemical composition and biological and pharmacological effects are still poorly defined. The aim of the present work was to evaluate the antioxidant and antimutagenic properties of H. tiliaceus L. methanolic flower extracts (HME) in vivo and to correlate these properties with the chemical composition of the extract. For the investiga- * To whom correspondence should be addressed. (J.S.) Tel: +55 51 3477 4000 ext. 2774. Fax: +55 51 3477 9239. E-mail: jenifer.saffi@ ulbranet.com.br. (A.L.L.P.R.) Tel: +55 51 3316 7605. Fax: +55 51 3316 7003. E-mail: ana.ramos@ufrgs.br. † Departamento de Biofı ´sica, Universidade Federal do Rio Grande do Sul. ‡ Instituto de Quı ´mica, Universidade Federal do Rio Grande do Sul. § Laborato ´rio de Gene ´tica Toxicolo ´gica, Universidade Luterana do Brasil. 7324 J. Agric. Food Chem. 2006, 54, 7324-7330 10.1021/jf061407b CCC: $33.50 © 2006 American Chemical Society Published on Web 08/29/2006