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Objective: Crude extracts were prepared from aerial parts of Euphorbia hirta Linn. in four solvents i.e. water, acetone, ethanol and petroleum ether. Extracts were investigated for their phytochemical, antibacterial and antioxidant properties.

Methods: Plant extracts were prepared by using Soxhlet apparatus. Antibacterial potential was assessed by disc diffusion method against six bacterial strains viz. Klebsiella pneumoniae (MTCC NO 109), Staphylococcus aureus (MTCC NO 96), Pseudomonas aeruginosa (MTCC NO 2453), Mycobacterium smegmatis (MTCC NO 992), Bacillus subtilis (MTCC NO 2057) and Chromobacterium violaceum (MTCC NO 2656). Minimum inhibitory concentration was determined by microbroth dilution method, only to those bacterial strains which showed a significant zone of inhibition by disc diffusion method. The extracts were also examined for the presence of various phytoconstituents, total phenolic and flavonoid content using standard methods. Free radical scavenging activity was assessed by DPPH method.

Results: The plant extracts showed a wide spectrum of inhibition against the test pathogens thus justifying the use of plant in traditional medicine. Acetone, aqueous and ethanol extracts exhibited stronger antibacterial activity as compared to the petroleum ether extract. The maximum activity recorded was 17.6±0.57 mm with 200 mg/ml concentration of ethanol extract against Klebsiella pneumoniae. Petroleum ether extract was found to be least effective as it showed zone of inhibition only against Chromobacterium violaceum. Aqueous extract of the plant showed highest antioxidant activity and minimum IC50 value (105.39 µg/ml) followed by acetone (371.0 µg/ml), ethanol (504.92 µg/ml) and petroleum ether (645.12 µg/ml) extracts. Aqueous extract showed highest TPC value (8.2 mgGAE/g), followed by acetone (6.4 mgGAE/g) and ethanol (5.84 mgGAE/g). Similarly, highest TFC value (4.6 mgQE/g) was also observed against aqueous extract, followed by acetone (2.05 mgQE/g) and ethanol extract (1.82 mgQE/g). Petroleum ether extract exhibited minimum TFC value i.e. 0.79 mgQE/g.

Conclusions: The present in vitro study revealed that E. hirta is a rich source of bioactive compounds with significant antibacterial and antioxidant activity. However, further investigation with ethno-pharmacological approach is needed for better understanding of its utility in health care.