This study investigated appropriate means to determine the total phenolic content and antioxidant activity of the leaves of Siparuna guianensis. Evaluation by thin layer chromatography (TLC) revealed phenolic compounds in all extracts. The results were confirmed by high-performance liquid chromatography (HPLC), with the identification and quantification of catechin, epigallocatechin gallate and rutin. The methanolic extract had the highest content of phenolic compounds, total tannins and condensed tannins (221.16 ± 3.39 mg GAE/g, 183.72 ± 1.85 mg GAE/g and 135.92 ± 1.00 μg/mL CE/g, respectively) and the strongest radical scavenging activity (IC50 = 37.54 ± 0.41 and 73.13 ± 2.09 μg/mL for DPPH and ABTS, respectively). The ethanolic and hydroethanolic extracts had the highest flavonoid (111.28 ± 4.59 and 103.27 ± 3.00 mg RE/g, respectively) and flavonol content (99.73 ± 0.64 and 77.31 ± 0.33 mg RE/g, respectively). In the correlation analysis, it was verified that tannins are the main phenolic compounds and antioxidants of S. guianensis leaves, and their flavonoid content consists mainly of flavonols. The data obtained establish S. guianensis as a new alternative source of antioxidant compounds, implying its potential application as a food preservative or in the production of nutraceutical and pharmacological products.
Key words: Flavonoid, polyphenol, condensed tannins, flavonol, plant extract, free radical scavenging
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