Anti tubercular activity of Stereospermum colais (Bignoniaceae) leaf extracts

Abstract

Stereospermum colais (Buch. - Ham. ex Dillw.) Mabberley (Bignoniaceae) is a woody shrub aboriginal to Asian country where the plant parts are used in traditional human medication. It is traditionally named as Patala (Sanskrit) in India. The aim of the present study was to determine the antituberculosis activity of the ethanol and chloroform extracts of the leaves of S. colais. The preliminary phytochemical study has revealed that the ethanolic extract contains carbohydrates, proteins, amino acids, saponins, iridoid, flavonoids and the chloroform extract contains carbohydrates, steroids, cardiac and iridoid glycosides. The ethanol and chloroform extracts of the leaves of Stereospermum colais were evaluated for anti tubercular activity by Radiometric Respiratory Technique using the BACTEC method. Drug susceptibility testing was performed on Middle brook 7H12 medium. Two fold serial dilution were followed at the concentrations of 20mg/ml, 10mg/ml and 5mg/ml. The standard drug Rifampicin and Isoniazid were used for susceptibility testing of Mycobacterium tuberculosis. The Growth Index (GI) was noted for susceptible to Mycobacterium tuberculosis to a maximum of 11-15 days. ∆GI value for ethanol extract at 20mg/ml was -15. This shows that the ethanol extract has bacteriostatic action against Mycobacterium tuberculosis. Further study can be extrapolated to identify and isolate the compound responsible for the bacteriostatic activity.