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 kaa and stevia), 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 mu mol 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.

Automated summary

This study analyzed the polyphenol content and antioxidant activity of eight selected leaves used in traditional medicine in the Northeast region of Brazil. The results showed high levels of phenolics and flavonoids in the extracts, along with strong antioxidant activity. Various organic acids and important compounds such as quinic acid and citric acid were identified.