Antioxidant activities and antidiabetic potential of extract of fruits from the Myrtaceae family: inhibitory effects on α-amylase and α-glucosidase activities

There is a great diversity of plants which are grown in the Atlantic Forest region of Brazil that produce small, colorful, edible fruit that are used in empiric mode to treat several diseases, such as diabetes, as fruits are a rich source of dietary phenolic antioxidants. In this study, we investigated the inhibitory activity of methanolic fruit extracts from the Myrtaceae family - Psidium cattleianum (araçá), Syzygium cumini (jambolão), Campomanesia xanthocarpa (guabiroba), Eugenia uniflora (pitanga) and Eugenia pyriformis (uvaia) - against α-amylase and intestinal α-glucosidase (maltose and sucrose). The antioxidant activities were evaluated using two different in vitro assays: the 2,2’-azinobis(3-ethylbenzthiazoline-6-sulphonate) (ABTS) test and the 2,2’-diphenyl-1-picrylhydrazyl (DPPH) test. The extracts of P. cattleianum, S. cumini, E. pyriformis inhibited α-amylase activity between 13% and 60% (p<0.05). The extracts of P. cattleianum also inhibited α-glucosidase activity with either maltose or sucrose as substrate between 15% and 61% (p<0.05). Additionally, these fruits are rich in phenolic compounds with antioxidant activities.