Abstract

IN VITRO ANTIMICROBIAL ACTIVITY OF AQUEOUS AND METHANOLIC ROOT EXTRACT OF GLYCYRRHIZA GLABRA AGAINST PATHOGENIC MICROORGANISM ISOLATED FROM BOVINE MASTITIS

Rajni Prabha Mahto*, Reena Mukherjee, Suman Biswas,

ABSTRACT

The present study aimed to evaluate the antibacterial activity of aqueous and methanolic root extracts of Glycyrrhiza glabra against Staphylococcus aureus (S. aureus) and Streptococcus agalactiae (St. agalactiae) the major pathogens isolated from the cases of clinical and sub clinical bovine mastitis. Phytochemical screening of the herbal extract revealed the presence of alkaloids, glycosides, saponins, tannins, steroids and flavonoides. The antibacterial sensitivity test (ABST) of the aqueous extract and methanolic extract ranged between 10 mm to 22 mm against Staphylococcus aureus, Streptococcus agalactiae and E. coli at different concentrations. The methanolic extract was more effective than aqueous extract against Staphylococcus aureus (20 mm), Streptococcus agalactiae (22 mm) and E. coli (17 mm) at the concentration of 8 mg/disc. Minimum Inhibitory concentration (MIC) was determined by the tube dilution method. The MIC and MBC (Minimum bactericidal concentration) value of methanolic extract was 3.125 mg/ml for S. aureus, 1.56 mg/ml for St. agalactiae and 12.5 mg/ml. Whereas the aqueous extract having higher MIC and MBC values i.e. 6.25 mg/ml for S. aureus, 3.125 mg/ml for St. agalactiae and the result was negative for E. coli. The results of the present study showed that the methanolic root extract of G glabra at different concentrations depicted better antimicrobial activity compared to aqueous extract.

Keywords: Glycyrrhiza glabra, Bovine mastitis pathogens, Antimicrobial activity, MIC.