Hemidesmus indicus, an age-old plant: Study of its in vitro antioxidant and free radical scavenging potentials

In recent times, there is a lot of interest in 'phytonutrients' from plants, especially those used in traditional medicinal systems. The aim of the present study was to evaluate the in vitro antioxidant activities of Hemidesmus indicus root extract. A 70% methanolic extract of Hemidesmus indicus root was used in the in vitro study of total antioxidant activity and scavenging of radicals like hydroxyl, superoxide, nitric oxide, peroxynitrite, hydrogen peroxide, singlet oxygen & hypochlorous acid, and for iron chelating capacity, reducing power, lipid peroxidation inhibition and phenolic & flavonoid contents. Total antioxidant activity in terms of trolox equivalent antioxidant capacity (TEAC) was 0.67 ± 0.01. The IC₅₀ values for scavenging of free radicals were 257.78 ± 7.22 μg/ ml, 58.4 ± 3.93 μg/ml and 90.82 ± 4.75 μg/ml for hydroxyl, superoxide and nitric oxide, respectively, and those for the singlet oxygen, hypochlorous acid scavenging and lipid peroxidation inhibition activities were 421.47 ± 54.81 μg/ml, 276.45 ± 6.49 μg/ml and 25.93 ± 1.27 μg/ml, respectively. IC₅₀ value for the iron chelating property was found to be 655.48 ± 10.9 μg/ml. The reducing power increased with increasing amounts of extract. The plant extract (100 mg) yielded 55.7 ± 0.001 mg/ml gallic acid-equivalent phenolic content and 174.6 ± 0.007 mg/ml quercetin-equivalent flavonoid content. The present study provides evidence that a 70% methanol extract of Hemidesmus indicus root is a potential source of natural antioxidants.