Phenol content and scavenging activity on DPPH radicals in moringa leaves from Argentina

Moringa oleifera is well known for its beneficial properties with potential uses in medicine and human nutrition. In particular, the leaves contain abundant antioxidant and elevated scavenging activity on DPPH radicals as determined in previous works in our laboratory. At present, the natural product market is increasing and so is the request for the dry leaves. Moringa cultivation started a few years ago in several areas of Argentina. The objective of this work was to study how the genotype affected the antioxidant and total phenolic content as well as the antioxidant activity on 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH). In this study, we sampled leaves from plants cultivated in Buenos Aires province, an area that is considered a border zone for climatic reasons. Extraction of the antioxidants was made by methanol and determination of the phenolic compounds was performed through the Folin-Ciocalteau reagent expressed as tannic acid. Scavenging activity was expressed as a percentage of the control absorbance. The extract from leaves collected from plant 2, which was in active vegetative growth, resulted in a phenol content that was 1.6 times superior in respect to leaves collected from the other plants. Similar results were observed in scavenging activity where the extract from leaves taken from plant 2 were 1.8 times more active than leaves taken from the other plants. These results highlight the importance of considering the genotype performance of moringa trees to obtain seed production or leaves with nutraceutical properties.