Author(s):

Gouollaly Tsiba, Timoléon Andzi-Barhé, Hubert Makomo, Blondy Mboungou, Sarrha Boumba, Marie Claire Makambila and Pascal Robin Ongoka

Abstract: The fight against these radicals, calls for the use of polyphenolic compounds whose content often remains reserved for plants. This is the purpose of this present work, which proposes to measure the contents in polyphenols and evaluate radical scavenging capacities of the extract and the fractions obtnained after the separation on a polyamide column of Eugenia uniflora. For that purpose, we noted that the chromatographic profiles on TLC, remain dominated by fluorescence compounds (Orangy yellow, lemon green and blue) materializing the presence of polyphenols (flavonoids and phenols acids) in the leaves. The quantitative analysis of flavonoidic compounds of the hydro-ethanolic extract and the four fractions vary between 11.3 and 29.8 mgECa/gMs. The hydro-ethanolic extract and the fraction F1 have the smallest total flavonoids content, respectively 11.3 and 15.6 mgECa/g MS while those of the fractions F2, F3 and F4 are the highest ones, respectively 27.6, 28.4 and 29.8 mgECa/gMs. The contents in total polyphenolic compounds are the highest compared with total flavonoidic compounds and show very high concentrations for the fractions F4 (259.1 mgEAG/gMs) followed by F3 (226.2 mgEAG/gMs) and F2 (202.4 mgEAG/gMS). The hydro-ethanolic extract and the fraction F1 have the lowest content. This large production of polyphénolic compounds is confirmed by the radical scavenging ability very pronounced observed on the DPPH radical for the fractions F2 (3.1 μg/mL), F3 (2.7 μg/mL) and F4 (2.7 μg/mL) comparable with that of quercetin (2,7 µg/ml) and the gallic acid (1.6 µg/ml) two reference compounds used in the present study. The results¶thtttt observed correlate positively with total phenol content, strongly plead in favour of the use of this extract and fraction as potential food additives in replacement of synthetic compounds.

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