Assessment of mineral substances level and antioxidant potential in leaves of three guava tree varieties

Abstract

Guava tree leaves are used empirically for the treatment and prevention of several pathologies, however, few studies report the chemical composition and the biological activity of the species. In this context, this study was conducted with the objective of evaluating the chemical composition and the antioxidant activity of the leaves of Paluma, Pedro Sato and Século XXI cultivars. The leaves were oven dried at 37°C, for five days. After drying they were ground in order to obtain the meal. The parameters analyzed were phenolic compounds, ascorbic acid, dietary fiber, minerals and antioxidant activity by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and beta-carotene/linoleic acid methods. The Século XXI cultivar presented the highest contents of phenolic compounds, dietary fiber and antioxidant activity by the DPPH method, as well as the contents of the minerals copper and manganese. The contents of ascorbic acid and iron were higher for Paluma and Século XXI cultivars. Cultivar Paluma presented the highest percentages of oxidation inhibition for linoleic acid and for the mineral magnesium. Cultivar Pedro Sato presented the highest iron content. Regarding zinc, there was no significant difference among the cultivars analyzed.