ANTIOXIDANT STUDY AND PHYTOCHEMICAL SCREENING OF ETHANOL LEAF EXTRACT OF CITRUS LEMON

Abstract Plants are important source of medicine and they play a key role in the provision of health to humans since ancient times. Herbal medicines proved to be the major remedy in traditional system of medicine. They have been used extensively in medical practices since ancient times. This prompts the development in the practices of medicinal plants. The reasons are because of their biomedical benefits as well as place in cultural beliefs in many parts of world in the development of potent therapeutic agents. Antioxidants significantly delay or prevent oxidation of oxidizable substrates when present at lower concentrations than the substrate. Antioxidants can be synthesized in vivo (e.g., reduced glutathione (GSH), superoxide dismutase (SOD), etc.) or taken as dietary antioxidants. Plants have long been a source of exogenous (i.e., dietary) antioxidants. It is believed that two-thirds of the world's plant species have medicinal importance, and almost all of these have excellent antioxidant potential. The interest in the exogenous plant antioxidants was first evoked by the discovery and subsequent isolation of ascorbic acid from plants Since then, the antioxidant potential of plants has received a great deal of attention because increased oxidative stress has been identified as a major causative factor in the development and progression of several life-threatening diseases, including neurodegenerative and cardiovascular disease. From the result obtained, the percentage yield of ethanol leaf extract of Citrus Lemon is 11% (55 g). The phytochemical screening revealed that the extract contains carbohydrates, saponins, tannins, flavonoid, cardiac glyloside, steroid and terpenoid while anthraquinone and alkaloid are absent. Quantitative Analysis of the Constituents of Ethanol Leaf Extract of Citrus Lemon extract shows that the extract contains 23 μg/g phenol, 8 μg/g flavanoids and 7 μg/g Saponins. Results of the invitro antioxidant assay of the Ethanol Leaf Extract of Citrus Lemon that the crude extracts possess potent invitro antioxidant DPPH scavenging activity at 1000, 500, 250, 125, 62.5, 31.25, and 15.625 µg/ml. The IC50 values revealed that the Ethanol Leaf Extract of Citrus Lemon has 99.16, 99.10, 98.80, 98.73, 95.09, 92.56 and 88.69 antioxidant potential value at 1000, 500, 250, 125, 62.5, 31.25, and 15.625 µg/ml respectively. The results showed that the extract radical scavenging activity is higher than ascorbic acid. This could be the reason why the extract is very effective in the treatment of cancer.