Evaluation of Antibacterial Properties, Acute Toxicity and Immuno-stimulatory Potential of <i>Scoparia dulcis</i>

Abstract

Traditional herbal medicines still remain the basic health care means for a large majority of rural and urban dwellers in Nigeria. Scoparia dulcis is a medicinal plant widely used for the traditional remedy of upper respiratory tract infections including pneumonia. Methanolic extract of the plant was assessed for antibacterial activity against Haemophilus influenzae and Klebsiella pneumonia by agar-cup diffusion method. The extract was active against both pathogens with zones of inhibition measuring 23.0 and 20.5 mm for H. influenzae and K. pneumonia respectively. The minimum inhibitory concentration of the extract against the test organisms were 6.25 and 12.5 mg/ml respectively. The minimum bactericidal concentration was 25 mg/ml for both organisms. The extract was found to be non toxic with LD50 of 3807(mg//kg body weight). The plant extract also showed a good immunostimulatory activity with a significant increase (p<0.05) in white blood cell proliferation when administered into mice at doses of 100 and 1000mg/ml. The result of this investigation supports the popular use of this plant for the traditional remedy of pneumonia possibly caused by these test organisms and as blood tonic.

Key words: Scoparia dulcis, Methanolic extract, antibacterial activity, immune-stimulatory