PHARMACOGNOSTIC STANDARDIZATION AND PHYTOCHEMICAL CHARACTERIZATION OF PISTIA STRATIOTES WITH EMPHASIS ON ITS ANTIOXIDANT POTENTIAL

The present study evaluated the extractive values, phytochemical composition, quantitative constituents, and antioxidant activity of Pistia stratiotes leaf extracts using methanol and n-hexane as solvents. The extractive value results revealed that the methanolic extract exhibited a higher yield (17% w/w) compared to the n-hexane extract (9% w/w). This difference indicates that methanol, being a polar solvent, is more efficient in extracting a broader range of phytoconstituents from Pistia stratiotes leaves than the non-polar n-hexane. The higher yield also suggests the abundance of polar compounds in the plant material. Preliminary phytochemical screening confirmed the presence of several important bioactive compounds, including flavonoids, alkaloids, tannins, glycosides, phenols, and carbohydrates in both extracts. However, the methanolic extract showed comparatively better extraction of key phytochemicals such as saponins and glycosides, while n-hexane extract demonstrated stronger presence (+++) of flavonoids, tannins, and alkaloids. The absence of anthraquinones in both extracts indicates their negligible presence in the plant. Overall, the results suggest that solvent polarity plays a crucial role in determining the type and extent of phytochemical extraction. Quantitative analysis of the alcoholic (methanolic) leaf extract further supported the qualitative findings. Among the phytoconstituents, saponins were found in the highest concentration (2.42±0.56mg/ml), followed by phenols (1.44±0.055mg/ml). Alkaloids (0.058 ± 0.06 mg/ml) and flavonoids (0.046 ± 0.014 mg/ml) were present in relatively lower concentrations. The antioxidant activity assessed using the DPPH radical scavenging assay demonstrated that the extracts possess notable free radical scavenging ability. The methanolic extract showed considerable antioxidant activity, with percentage inhibition increasing in a concentration-dependent manner.