Analysis of Brazilian Plant Extracts as Potential Source of Antioxidant Natural Products Using Bench-Top Assays

Abstract

Introduction:The present work reported the antioxidant and chemical screening of Brazilian plant aqueous and organic extracts. Methods: An amount of 895 Brazilian Amazon aqueous and organic plant extracts were tested in thin layer chromatography plates (TLC) using 2, 2-diphenyl-1-picrylhydrazyl (DPPH), β-carotene, Dragendorff's reagent, Kedde's reagent, and KOH reagent so as to evaluate antioxidant activity and chemical profiles. Antioxidant and DPPH free radical scavenging activities results were submitted to chi-square analyses. Results: Only 8.60% of the extracts showed β-carotene/bleaching response, while 96.09% of the extracts responded as a radical scavenger, alkaloids occurred in 8.0% of the extracts whereas anthraquinones occurred in 0.89% of the extracts and cardenolides in 3.89% of the extracts. Conclusion: Present findings described that Amazon plant extracts have a huge potential to be a source of antioxidant compounds to be used in preventive medicine, as well as the chemical screening revealed that their plants can be strategically assessed as a source of alkaloids to be tested in further biological assays.

Evaluation of the Antioxidant Activity of Nine Plants Used Medicinally by the Ilkisonko Maasai Community of Kenya

“…Previous studies have shown the antioxidant activity to be higher in solvents with lower polarity as they dissolve higher molecular weight phenols giving the extract stronger antioxidant effects. 29 The observed negative correlation between the total phenolic/flavonoid content with the antioxidant IC 50 value is consistent with a research by Farasat et al 30 which shows that the higher the phenolic/flavonoid content, the lower the IC 50 value and hence the higher the antioxidant activity per gram of extract. Other studies have confirmed the direct relationship between phenolic content and antioxidant activity 28 and this lends credence that the observed antioxidant activity in the studied plants may be largely due to the phenolic content in the extracts.…”

“…28 It has been previously reported that the amount of phenolics may vary considerably in some plants due to geographical variations and environmental factors such as humidity and, temperature as well as leaf aging which invariably influence the antioxidant activity. 29 With a few exceptions, the phenolic content closely mirrored the antioxidant activity. Previous studies have shown the antioxidant activity to be higher in solvents with lower polarity as they dissolve higher molecular weight phenols giving the extract stronger antioxidant effects.…”