Evaluation of the antioxidant and antibacterial activity of the flower extract of Hibiscus sabdariffa and Hibiscus rosa-sinensis

Abstract

Introduction: Hibiscus rosa-sinensis belongs to the family Malvaceae, is used in folk medicine to relieve menstrual cramps, to assist in childbirth, to alleviate headache, fever, inflammation, respiratory problems, skin infections, digestive disorders among others. Hibiscus sabdariffa also belongs to the family Malvaceae, in folk medicine is used as diuretic, gastrointestinal treatment, liver infections, fever and hypertension. Objective: To evaluate the antioxidant capacity by the free radical reduction method DPPH, Minimum Inhibitory Concentration (MIC) and Minimum Bacterial Concentration (MBC). Methodology: For the evaluation of the antioxidant capacity, the free radical sequestration method DPPH (2,2 Diphenyl-1-picrylhydrazyl) was used in a spectrophotometer. For analysis of the antimicrobial activity, four Bacteria of the American Culture Collection, Escherichia coli, Staphylococcus aureus, Listeria monocytogenes and Streptococcus agalactiae were used. Results: H. rosa-sinensis presented an EC 50 = 10.33 μg / mL, while H. sabdariffa had EC50 = 20.38 μg / mL. In the study of the antibacterial activity, the H. sabdariffa species presented CBM of 1000 μg / mL against L. monocytogenes and higher than 2000 μg / mL against the other species of evaluated bacteria, while the H. rosa-sinensis species had CBM higher than 2000 μg / mL for all species evaluated. Conclusion: The methanolic extract of H. sabdariffa and H. rosa-sinensis presented the ability to sequester free radicals, being higher in some concentrations to the BHT standard. In addition, the evaluated species present a potential antibacterial action especially against L. monocytogenes.