Evaluation of bioactive compounds, phytochemicals profile and antioxidant potential of the aqueous and ethanolic extracts of some traditional fruit tree leaves used in Brazilian folk medicine.

The aim of this study was to analyze eight selected species of leaves, used in the traditional medicine of the Northeast region of Brazil obtained from several fruit trees (grageru, soursop, jambolanum, passion fruit, insulin, nogueira, pedra ume kaá and stévia), regarding their polyphenols contents and antioxidant activity. Condensed and hydrolysable tannins, phenolics and flavonoids contents were determined and the antioxidant activities measured by ABTS, FRAP and ORAC assays. Organic acids were analyzed by HPLC-DAD system. Phenolic compounds of aqueous and ethanolic extracts were determined by UHPLC-DAD-MS. The results revealed high contents of total phenolics (13.34 ± 0.19 - 127.65 ± 0.21 mg.g-1 of GAE:QE (2:1) of sample) and flavonoids (12.30 ± 0.42 - 71.79 ± 0.00 mg.g-1 QE of sample). The ABTS results exhibited extraordinary activity in the extracts (74.48 ± 6.23 - 1487.33 ± 2.67 µmol Trolox.g-1 of sample). Acids quinic, tartaric, citric, gallic, chlorogenic, p-coumaric, ferulic and vanillic along with naringenin, rutin, vanillin, catechin, epicatechin, kaempferol were the most important compounds. Thus, these leaves extracts may be considered as sources of phenolics compounds having a high potential as natural antioxidants. In addition, the polyphenols present in these leaves have many beneficial effects and can also be used in medicinal and nutraceuticals products with enhanced bioactivities.

Phytochemicals screening, antioxidant capacity and chemometric characterization of four edible flowers from Brazil.

Edible flowers are receiving renewed interest as potential sources of bioactive compounds. The present study aimed to investigate the presence of bioactive compounds and antioxidant activity of some exotic flowers present in Brazil such as Amaranthus hypochondriacus, Tropaeolum majus (red), Tropaeolum majus (orange) and Spilanthes oleracea L. The content of total phenolic compounds, flavonoids, condensed, hydrolysable tannins and antioxidante capacity were determined. The identification and quantification of the phenolic compounds was performed through the UHPLC-QDa-MS system. The compounds p-coumaric acid and ferulic acid were identified and quantified for the first time in all flowers. Tropaeolum majus (red) presented the hightest amounts of total phenolic compounds and hydrolysable tannins. Also, it presented the highest antioxidant capacity for ORAC and FRAP assays. Thus, this study showed the diversity and abudance of natural antioxidants present in edible flowers, which could be explored for application in functional foods and pharmaceuticals.