Chemical composition and inhibitory activities on dipeptidyl peptidase IV and pancreatic lipase of two underutilized species from the Brazilian Savannah: Oxalis cordata A.St.-Hil. and Xylopia aromatica (Lam.) Mart

Brazil has the greatest vegetal biodiversity in the world, but products derived from native species are not optimally utilized. Oxalis cordata and Xylopia aromatica are two underutilized species whose leaves and fruits, respectively, have been used as food in the 19th century. In this study, we used chemical and in vitro assays to evaluate the potential of these species as functional foods. The inhibitory activity on pancreatic lipase and DPP-IV were evaluated using the crude extracts and fractions ethyl acetate, butanol and water of these two species. For polyphenols determination, samples were prepared with different solvents and these were analysed by chromatographic and spectroscopic methods. Finally, fatty acids profile was determinated by gas chromatography. The crude extract (IC₅₀ = 0.84 mg/ml), ethyl acetate extract (IC₅₀ = 0.88 mg/ml) an aqueous fraction (IC₅₀ = 0.63 mg/ml) of C. cordata were inhibitory on pancreatic lipase but inactive against dipeptidyl peptidase IV (DPP-IV). Extracts from X. aromatica were inactive against the lipase pancreatic enzyme, but a butanolic fraction inhibited DPP-IV (IC₅₀ = 0.71 ± 0.05 mg/ml). The phenolic acids orientin/isorientin, chlorogenic acid (0.32 g/100 g) and the flavonoid derivatives rutin (0.27 g/100 g), quercetin and luteolin were observed in all products. Additionally, fatty acid quantification showed that oleic (7.5 g/100 g) and linoleic acid (6.5 g/100 g) were predominant in X. aromatica fruit. This study confirms the potential for the use of both plants as functional foods due to their nutritional value, biological activity and important phytochemical content.