Phytochemical screening, antibacterial and free radical scavenging effects of Artemisia nilagirica, Mimosa pudica and Clerodendrum siphonanthus – An in–vitro study

Abstract

To evaluate methanolic extracts of leaves of Artemisia nilagirica, Mimosa pudica and Clerodendrum siphonanthus for phytochemical analysis, antibacterial activity and free radical scavenging activity. Antibacterial activity was performed by disc diffusion method against two gram positive and four gram negative strains. Free radical scavenging potential was evaluated using total antioxidant activity (thiocyanate method) and diphenyl-picryl-hydrazyl (DPPH) assay. Results of the present study showed that Clerodendrum siphonanthus exhibited significant antibacterial effect against Klebsiella pneumoniae (30 mm), Proteus mirabilis (16 mm), Salmonella typhi (16 mm), Staphylococcus aureus (12 mm), Escherichia coli (11.5 mm) and Bacillus subtilis (10 mm). Mimosa pudica and Artemisia nilagirica showed good antibacterial effects. Clerodendrum siphonanthus was found to be extremely effective in scavenging lipid peroxide (IC₅₀ 8 mg/mL) and DPPH radicals (IC₅₀ 7 mg/mL), whereas Artemisia nilagirica and Mimosa pudica showed moderate activity. Phytochemical analysis of these plants revealed presence of tannins, alkaloids, flavanoids, terpenoids and glycosides. This study showed that Artemisia nilagirica, Mimosa pudica and Clerodendrum siphonanthus may serve as a potential agent for new therapeutics.