HPLC and in vitro evaluation of antioxidant properties of fruit from Malpighia glabra (Malpighiaceae) at different stages of maturation.

Malpighia glabra L. is indicated for the treatment of diseases due presenting several medicinal properties. The aim of the present study was quantify phenolic compounds and carotenoids, additionally, evaluate the antioxidant potential of different methanolic fractions (mature stage, intermediate stage and green maturity stage) of Malpighia glabra. Methanolic fractions of the three stages of maturation were characterized using HPLC-DAD. The antioxidant activity of fractions was evaluated using in vitro assay systems: iron-chelating activity (Fe2+), inhibition of the radical 1-1-diphenyl-2-picrylhydrazyl (DPPH) and inhibition of production of thiobarbituric acid reactive substances (TBARS). In quantifying compounds by HPLC-DAD showed that the compounds rutin and quercetin showed the highest peaks in the three samples tested. Regarding carotenoids, the ß-carotene stood in the analyze. The methanolic fraction of lyophilized pulp of green fruits showed better results for iron chelation and DPPH tests; TBARS by the methanolic fraction of the ripe fruits showed lower IC50 as the basal. When in the presence of iron as an inducer of peroxidation, the methanolic fraction of the pulp of green fruits showed the lowest IC50. Our research indicates that the o fruits of M. glabra good potential in scavenging free radicals and can be an important source of antioxidant phytochemical.

Chemical profile and antioxidant capacity verification of Psidium guajava (Myrtaceae) fruits at different stages of maturation.

Psidium guajava (Myrtaceae), a common plant in Cariri region, Ceara, Brazil, as well as in various parts of the world, contains high concentrations of bioactive compounds and in many communities its parts are used for therapeutic purposes. Studies describe antioxidant, antimicrobial and anti-diarrheal actions from extracts obtained from leaves, but information about the activities of the fruits and comparison of these at different maturity stages (immature, partially mature and mature) are scarce. This study aims to evaluate the antioxidant properties by quantifying the levels of phenolic and flavonoid compounds, carotenoids and vitamin C of P. guajava fruits at different stages of maturation. The content of phenolic compounds for the immature fruit, partially mature and mature were: 22.41; 34.61 and 32.92 mg of AG/g fraction. The flavonoid content for immature fruits, intermediate and mature were: 2.83; 5.10 and 5.65 mg RUT/g fraction, respectively. Following the same standards of maturation stages, the ascorbic acid content was determined with values of 0.48; 0.38 and 0.21 mg AA/g fraction, respectively. HPLC analysis identified and quantified the presence of gallic acid, catechin, chlorogenic acid, caffeic acid, epicatechin, rutin, quercitrin, isoquercitrin, quercetin, kaempferol, glycosylated campeferol, tocopherol, ß-carotene and lycopene. The antioxidant activity carried out by DPPH method showed the mature fruits bearing the best results, whereas chelation of Fe2+ ions showed higher percentage for the immature fruit. The results obtained by lipidic peroxidation were not satisfactory.