Investigation of Standardized Ethanolic Extract of Ocimum sanctum Linn. (Holy Basil) Leaves for its in vitro Antioxidant Potential and Phenolic Composition

Abstract

Antioxidant activities of standardized ethanolic (90 %) extract of Ocimum sanctum (EEOS) leaves was studied for its free radical scavenging property on different in vitro models e.g., 1,1- diphenyl-2-picryl-hydrazyl radical (DPPH), superoxide anion radical, nitric oxide radical, hydroxyl radical scavenging and reducing power assays. The extract showed significant activities in all antioxidant assays and measurement of total phenolic compounds by Folin-Ciocalteu phenol reagent indicated that the extract (1 mg) contained 56.7 μg pyrocatechol equivalent of phenolics. Moreover, the reductive power of ethanolic extract of Ocimum sanctum and butylated hydroxy toluene found to be 1.155 and 0.771 at 500 μg/mL, respectively. The antioxidant activities of ethanolic extract of Ocimum sanctum increased in a concentration dependent manner. The IC₅₀ values were found to be 31.37, 31.83, 29.17 and 400.90 mg/mL, respectively, in DPPH radical scavenging, nitric oxide radicals generated from sodium nitroprusside, scavenging the superoxide generated by phenazine methosulphate (PMS)/nicotinamide adenine dinucleotide (NADH)-nitroblue tetrazolium (NBT) system and hydroxyl radical generated by Fenton's reaction. The results obtained in the present study indicate that the antioxidant property of ethanolic extract of Ocimum sanctum may be due to high content of phenolic compounds and justify the therapeutic applications of the plant in the indigenous system of medicine, augmenting its therapeutic value.