DPPH Free-radical Scavenging and Cytotoxic Activities of Leeamacrophylla

Abstract

                        Structural damage inflicted to a wide variety of bioorganic compounds (DNA, protein, carbohydrates, and lipid) may occur as a consequence of oxidative damage which is naturally attributed to our daily lifestyle. A number of mechanisms are exploited to neutralize the reactive oxygen species. Medicinal plant can play a pivotal role of detoxifying the generated ROS. Leeamacrophylla (Leeaceae), a wild medicinal plant, has been taken into consideration of having antioxidant and cytotoxic properties. In this study, in vitro DPPH free radical scavenging activity, total phenolic content and total flavonoid content of methanol extract from the leaves of L. macrophylla were determined with using UV spectrophotometric method. Antioxidant activity of the crude extract was expressed as percentage of DPPH free radical inhibition and IC₅₀ value (μg/ml). The IC₅₀ value of L. macrophylla was found to be 152.40μg/ml. Compared to standard ascorbic acid (4.36 μg/ml), L. macrophylla leaf extract has moderate antioxidant property. The total phenolic content was 65.75 mg/g of dry weight of extract, expressed as gallic acid equivalents. The total flavonoid concentration was 59.8 mg/g, expressed as quercetin equivalents. In the brine shrimp lethality test, LC₅₀value of crude methanolic extract obtained from the best-fit line slope was 3.06μg/ml which was significant comparing with control (vincristine sulphate). Above results suggested that the L. macrophylla can be regarded as a promising candidate for natural plant sources of antioxidants with high value.