Total Phenolic Content, Flavonoid Content and Antioxidant Potential of Wild Vegetables from Western Nepal

Eight selected wild vegetables from Nepal (<i>Alternanthera sessilis</i>, <i>Basella alba</i>, <i>Cassia tora</i>, <i>Digera muricata</i>, <i>Ipomoea aquatica</i>, <i>Leucas cephalotes</i>, <i>Portulaca oleracea</i> and <i>Solanum nigrum</i>) were investigated for their antioxidative potential using 2,2-dyphenyl-1-picrylhydrazyl (DPPH) scavenging, hydrogen peroxide (H₂O₂), ferric reducing antioxidant power (FRAP), and ferric thiocyanate (FTC) methods. Among the selected plant extracts <i>C. tora</i> displayed the highest DPPH radical scavenging activity with an IC₅₀ value 9.898 μg/mL, whereas <i>A. sessilis</i> had the maximum H₂O₂ scavenging activity with an IC₅₀ value 16.25 μg/mL-very close to that of ascorbic acid (16.26 μg/mL). <i>C. tora</i> showed the highest absorbance in the FRAP assay and the lowest lipid peroxidation in the FTC assay. A methanol extract of <i>A. sessilis</i> resulted in the greatest phenolic content (292.65 ± 0.42 mg gallic acid equivalent (GAE)/g) measured by the Folin-Ciocalteu reagent method, while the smallest content was recorded for <i>B. alba</i> (72.66 ± 0.46 GAE/g). The greatest flavonoid content was observed with extracts of <i>P. oleracea</i> (39.38 ± 0.57 mg quercetin equivalents (QE)/g) as measured by an aluminium chloride colorimetric method, while the least was recorded for <i>I. aquatica</i> (6.61 ± 0.42 QE/g). There was a strong correlation between antioxidant activity with total phenolic (DPPH, R² = 0.75; H₂O₂, R² = 0.71) and total flavonoid content (DPPH, R² = 0.84; H₂O₂, R² = 0.66). This study demonstrates that these wild edible leafy plants could be a potential source of natural antioxidants.