Abstract (EN):
In this work the phenolic profile of Moringa oleifera leaves from trees located in Oued Souf and Tamanrasset, desert region south Algeria, was characterized by a real-time HPLC coupled to the DPPH assay, together with high resolution mass spectrometry (HPLC-DAD-ESI-MSn) studies. The contribution of single component to the overall radical scavenging capacity was evaluated for water, hydroalcoholic and hydroacetonic extracts of M. oleifera leaves. Hydroacetonic extracts (70% acetone) exhibit the highest amount of phenolic compounds (57 +/- 3 mg GAE/g), as well as the highest flavonoid content (9.12 +/- 0.01 mg QE/g). Twelve compounds, mainly phenolics, were identified by high-resolution orbitrapmass spectrometry. Among these, chlorogenic acids (3-caffeoylquinic acid and 4-caffeoylquinic acid) and quercetin glycosides (quercetin-3-O-glucoside, quercetin-3-O-galactoside and quercetin 3-O-(6 ''-malonyl) glucoside) are the most potent quenchers of DPPH radical both for hydroethanolic and hydroacetonic extracts. Aqueous extracts exhibit a quite different behaviour, with citric acid and quinic acid, arising from the oxidation of the chlorogenic acids, acting as the unique antioxidants.
Language:
English
Type (Professor's evaluation):
Scientific
No. of pages:
9