Phytochemical Profiling in Different Solvent Systems and DPPH Radical Scavenging Activity of Cinchona pubescens Leaf Extract obtained from Ughelli, Delta State

Abstract

The present research investigated the phytochemical composition and antioxidant potential of Cinchona pubescens leaf extracts obtained using methanol and n-hexane as extraction solvents. Qualitative phytochemical screening revealed the presence of flavonoids, phenolics, alkaloids, terpenoids, tannins, and saponins—compounds widely recognized for their antioxidant and therapeutic properties. The differences observed between the two solvent extracts indicated that solvent polarity significantly influenced extraction efficiency and the diversity of bioactive constituents. Antioxidant activity was assessed using the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging assay, which demonstrated strong antioxidant capacity in both extracts in a concentration-dependent manner. The methanol extract showed slightly higher scavenging activity (88.2–93.2%) compared to the n-hexane extract (82.6–86.8%), while ascorbic acid, used as the standard antioxidant, exhibited the highest inhibition (90.8–96.7%). These results suggest that both polar and non-polar phytoconstituents, including terpenoids and fatty acid derivatives, contribute to the plant’s antioxidant activity. The findings validate the traditional medicinal use of Cinchona pubescens and highlight its significance as a potential natural source of antioxidant compounds. The coexistence of diverse metabolites in both polar and non-polar extracts underscores the plant’s biochemical richness and its promise as a precursor for developing natural antioxidant agents suitable for pharmaceutical and nutraceutical applications. Overall, the study provides scientific evidence supporting the therapeutic relevance of Cinchona pubescens and emphasizes its potential contribution to the formulation of health-promoting products derived from plant-based antioxidants.