Unveiling the Antioxidant Potential of Underutilized Moringa oleifera Parts: A DPPH and CUPRAC-Based Study

Background and Objective: Moringa oleifera, a plant rich in flavonoids and phenolic compounds, is widely recognized for its antioxidant potential. This study aimed to evaluate the antioxidant activity of underutilized parts of M. oleifera (twigs and stems) compared to leaves (well-utilized part), expressed as ascorbic acid equivalents. Additionally, the relationships between total phenolic content (TPC), total flavonoid content (TFC) and antioxidant activity were investigated. Materials and Methods: TPC and TFC were determined using UV-Visible spectrophotometry. Antioxidant activity was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and Cupric Ion Reducing Antioxidant Capacity (CUPRAC) assays. Correlations among TPC, TFC and antioxidant activity were analyzed using Pearson's correlation, principal component analysis (PCA) and hierarchical cluster analysis (HCA). Flavonoid compounds were further characterized using TLC densitometry. Statistical significance among the data was analyzed using One-Way ANOVA in Minitab software at a significance level of p<0.05. Results: The ethanolic extract of M. oleifera leaves exhibited the highest antioxidant activity in both DPPH assays, while the ethyl acetate of M. oleifera twigs extract showed the highest activity using the CUPRAC assay. It is possible to develop twigs M. oleifera as a potential antioxidant agent resource. Conclusion: Among the tested plant parts, leaves demonstrated the highest antioxidant activity compared to twigs and stems. However, twigs also showed promising potential activity to be developed as source of antioxidant agent.