Phenolic Content and Scavenging Activity in Moringa oleifera Lam. with Two Types of Leaf Color

Abstract

Background: Mostly, Moringa plants (Moringa oleifera Lam.) are commercially prop-agated by seeds; however, there are some plantations from stem cuttings. Thus, seedling popula-tions show a high morphological diversity level due to segregation. In particular, differences in leaf color can be commonly observed. This work aimed to characterize leaf color from different moringa plants and relate it to phenolic leaf content, including some flavonoids, and to the DPPH radical scavenging activity of leaf extracts. Methods: Three plants with red leaf petioles and three plants with green leaf petioles were ran-domly chosen among a plot of 50 potted 3-year-old, 2m-high seed plants grown in the city of Morón (Argentina) (34º 64’ 62.61'' SL; 58º 62' 09.69'' WL). Leaves were harvested from the basal, medial, and apical parts of the plant stem (3 leaves per section) in April, and subsequently, each leaf was also divided into basal, medial, and apical sections. Leaf color, total phenol content, indi-vidual phenol composition, and DDPH radical scavenging activity were determined. Results: Petiole and leaflet color were significantly different for a* and b* values. Consequently, ΔE* was-0.12 and 0.27 for red leaf plants, but it was higher (-3.09) for red and green leaves. In-terestingly, leaflets from the red leaf type had more green and yellow dyes than those of the green leaf type. Phenolic content and DPPH radical scavenging activity were significantly higher in red leaf plants (10.9 mg tannic acid and 45.6%, respectively) than in green plant leaves (9.1 mg tannic acid and 31.1%, respectively). The red leaf type had the smallest amounts of rutin and naringenin content, which were not present in the green leaf type. Nevertheless, the green leaf type showed more catechin hydrate content than the red leaf type. Conclusion: Phenolic content and antioxidant activity are modified with sampling and leaf color, so these factors must be considered as well as the selection of red leaf plants.