Evaluation of the Antioxidant Activity of Crude Whole Plant Methanolic Extract of Oxalis stricta Linn

Globally, it is well-known for some time now that the oxidation in vegetables and organisms is significant; it is responsible for cells’ existence. The side effects are free radicals, reactive oxygen species (ROS), and reactive nitrogen species. Every living organism has an antioxidant defense and maintenance system that enables it to handle the ROS produced. In a biological system or an organism, an imbalance of ROS and antioxidant capacity leads to a phenomenon called oxidative stress. Naturally, antioxidant defense and maintenance systems of most biological systems or organisms are unable to cater to the entire oxidative injury. Oxidative stress is known to result in chronic diseases, including autoimmune diseases, cancer, etc. Oxalis stricta Linn. is a valuable medicinal plant native to Florida and uses many diseases. This study was intended to assess antioxidant activity, evaluate the phenol contents, and screen for phytonutrients present in O. stricta Linn. The antioxidant activity was determined by 2, 2-Diphenyl-1-picrylhydranyl-hydrate (DPPH) assay and phosphomolybdate assay with ascorbic acid as reference antioxidant, while the phenol content was also determined using Folin-Ciocalteu assay. Phytochemical screening revealed that Oxalic acid, flavonoids, tannins, phenols, and glycosides were present. The total phenol content present in the crude methanolic extract was 25.26±1.02 mg gallic acid equivalent/g of dried extract. Antioxidant activity of extract by DPPH assay was expressed as IC50 values (μg/ml); the IC50 of the extract was 205.10 µg/ml and 85.04 µg/ml for ascorbic acid. The total antioxidant activity of the extract using phosphomolybdate assay was 24.73±1.14 mg ascorbic acid equivalent/g of dried extract. Therefore, the results suggest that the phenolic content of O. stricta Linn. provides substantial antioxidant activity. The authors recommend further investigations for the isolation and then the characterization of specific active components present in O. stricta Linn.