Atividade antioxidante do óleo essencial das folhas e tubérculos da tiririca (Cyperus rotundus)

Abstract

The sedge (Cyperus rotundus) is a plant known worldwide as a weed for agriculture, but this plant has important applications in traditional medicine and also in cooking various Middle East countries, India, Japan and China. As public interest in the use of natural products is increasing significantly, essential oils with biological properties have been highlighted in research in order to use them in the food, cosmetic and pharmaceutical. In Brazil, the biological properties of sedge are still little studied, but the reports that this plant is used for medicinal and culinary purposes, this study aimed to analyze the presence of compounds with antioxidant potential in the essential oil of tubers (OET) and the essential oil from the leaves (OEF) of Cyperus rotundus, obtained by hydrodistillation. The content of phenolic compounds was determined using the Folin-Ciocalteau reagent and the results were expressed in equivalent of gallic acid (EAG). The antioxidant activity was determined by DPPH method, the result expressed in terms to the necessary concentration to inhibit 50% of DPPH radical and also qualified in termsof AAI (Antioxidant Activity Index). The OET showed 79.92 ± 1.40 μg EAG mg-1, while the OEF was 55.52 ± 1.49 μg EAG mg-1. For total antioxidant activity OET showed IC50 value (the concentration required to inhibit 50% of DPPH) of 75.6 mg mL-1 and AAI value of 5.13 x 10-4, as OEF for the IC50 was 126.39 mg mL-1 and AAI 3.07 x 10-4. The results show content of phenolic compounds and antioxidant activity higher for the essential oil obtained from tubers. Considering the AAI, concluded that both oils showed very weak antioxidant activity when compared to synthetic antioxidants, which have AAI grater than 2.0.