In vitro evaluation of antioxidant activity in fruit and cladode extracts of Opuntia ficus-indica (L.) Mill.

Reactive oxygen species (ROS) are implicated in various degenerative diseases and the search for potent natural antioxidants remains a major focus of current research. The present study evaluates the in vitro antioxidant potential of Opuntia ficus-indica (L.) Mill. fruit and cladode extracts prepared using methanol, ethyl acetate and n-butanol. The antioxidant activity was assessed using four complementary assays- 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, reducing power, nitric oxide (NO) radical inhibition and hydrogen peroxide (H₂O₂) scavenging with gallic acid and ascorbic acid as standards. The methanolic extract of O. ficus-indica fruit exhibited the highest DPPH radical scavenging activity (70.69 ± 1.93 %) with an IC₅₀ value of 13.72 µg mL-1, which was comparable to that of gallic acid (IC₅₀ = 9.39 µg mL-1). In reducing power assays, the methanol extract showed the strongest Fe3+-reducing ability, indicating the presence of potent electron-donating antioxidants. Methanol extracts also demonstrated superior NO (IC₅₀ = 68.44 µg mL-1) and H₂O₂ (IC₅₀ = 62.94 µg mL-1) scavenging capacities compared to other solvent fractions. These findings suggest that O. ficus-indica is a promising source of natural antioxidants and represents a potential natural source of antioxidant compounds, which warrants further investigation.