Investigação http://publicacoes.unifran.br ISSN 2177-4080 (on-line) ARTIGO ORIGINAL Investigação. 2013;13:11-14 Recebido em: 1/10/11 | Revisado em: 11/8/12 | Aceito em: 18/10/12 | Disponível online em: 30/7/13 ■ ■ Evaluation of the antioxidant activity of some Brazilian medicinal plant extracts Avaliação da atividade antioxidante de extratos de algumas plantas medicinais brasileiras Antônio Eduardo Miller Crotti 1* , Gabriela de Paula Aguiar 1 , Daniela de Paula Aguiar 1 , André LuisLembi Mantovani 1 , Larissa Costa Keles 1 , Moara Helena Garcia Martins 1 , Ana Laura Marques Barcelos 1 , Fernanda Ribeiro Guerra 1 , Herbert Júnior Dias 1 , Milton Groppo, 2 Wilson Roberto Cunha 1 , Rodrigo Cassio Sola Vene- ziani 1 1 Universidade de Franca, Franca, São Paulo, Brasil; 2 Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil *AUTOR CORRESPONDENTE Endereço: Av. Dr. Armando Salles de Oliveira, 201 – Parque Universitário, CEP 14404-600, Franca, SP, Brasil. Fone/Fax: (16) 3711-8871. E-mail: millercrotti@unifran.br We used the DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) radical photometric assay to assess the antioxidant activity of forty- -two extracts obtained from eleven Brazilian medicinal plants. The methanol extracts of the flowers of Bidenssulphurea (91.7%) and Coreopsis lanceolata (86.5%) and of the leaves of Syzygiumaromaticum (90.8%), Artemisia absinthum (88.1%), and Bidenssulphurea (87.1%) displayed the highest antioxidant activity, attributed to their phenolic compounds content, especially flavonoids Keywords: Bidenssulphurea, Coreopsis lanceolata, DPPH. RESUMO A atividade antioxidante de quarenta e dois extratos obtidos de onze plantas medicinais brasileiras foi avaliada pelo método do DPPH (hidrato de 2,2-difenil-1-picril-hidrazila). Os extratos metanólicosdas flores de Bidenssulphurea (91,7%) e de Coreopsislanceolata (86,5%) e das folhas de Syzygiumaromaticum (90,8%), Artemisiaabsinthum (88,1%) e Bidenssulphurea (87,1%) foram os que apre- sentaram atividade antioxidante mais promissora. Esta atividade foi associada à presença de compostos fenólicos, principalmente flavonoides. Palavras-chave: Bidenssulphurea, Coreopsislanceolata, DPPH. ABSTRACT Introduction Molecular oxygen is essential to human life: it allows for respi- ration and production of adenosine triphosphate. However, in the form of reactive oxygen species (ROS), oxygen can be dan- gerous (1). Oxidative stress, an imbalance between the rate of oxidizing agents production and degradation, accounts for ROS generation in living organisms (2). In humans, excess ROS attack lipids, proteins, and DNA, leading to various diseases (3) such as Parkinson’s disease, atherosclerosis, complications of Diabetes mellitus, and other aging-related conditions (2). To prevent food deterioration, the food industry employs synthe- tic antioxidants such as BHA (butylatedhydroxyanisole), BHT (butylatedhydroxytoluene), and TBHQ ( tert -butylhydroquinone), which act by inhibiting lipid degradation. Governmental laws restrict the use of these substances, because they are poten- tially carcinogenic. Natural antioxidants may be used at higher concentrations without the concerns associated with synthetic equivalents, so they have received great attention in recent de- cades (3). Tocopherol, carotenoids, catechins, and polyphenols, which are found in fruits and vegetables, are well-known natural antioxidants (1).