In vitro antibacterial activity of Artemisia annua Linn. growing in India

The crude extracts obtained from the aerial parts of Artemisia annua Linn. (Asteraceae) were investigated for their antibacterial activity by using agar well diffusion assays against five Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis, Bacillus pumilus, Bacillus cereus, and Micrococcus luteus) and three Gram-negative bacteria (Escherichia coli, Salmonella typhi, and Pseudomonas aeruginosa). Of the various extracts, the methanol extract showed the strongest activity against most bacteria used in this study. The most sensitive organism to the extracts was M. luteus. The minimum inhibitory concentration (MIC) values were determined by the tube dilution method. The results showed that S. aureus required ~0.25 mg/mL of the methanol extract for inhibition. The HPTLC fingerprint of the methanol extract after derivatization with anisaldehyde sulphuric acid reagent showed a maximum number of separated components. TLC bioautography of the methanol extract showed that the area of inhibition around compounds differentiated at Rf = 0.32, Rf = 0.42, Rf = 0.46, Rf = 0.77, and Rf = 0.87 against S. aureus. This is the first report of the antibacterial activity of A. annua against food-borne bacteria. The results indicated that aerial parts of A. annua might be potential sources of new antibacterial agents. Key words: Antibacterial activity, Artemisia annua, MIC, TLC bioautography