Antibacterial activities and phytochemical analysis of Cassia fistula (Linn.) leaf

Cassia fistula Linn. which belongs to family Leguminosae is a medium-sized tree and its different parts are used in ayurvedic medicine as well as home remedies for common ailments. Sequential extraction was carried out using solvents viz. petroleum ether, chloroform, ethanol, methanol and water from leaf of the plant were investigated for preliminary phytochemical and antibacterial property. Results of the study showed that all the extracts had good inhibitory activity against Gram-positive test organism. Although all five extracts showed promising antibacterial activity against test bacterial species, yet maximum activity was observed in ethanol extract. The minimum inhibitory concentration ranged in between 94 to 1 500 μg/ml. Evaluation of phytochemicals such as alkaloids, flavonoids, carbohydrates, glycosides, protein and amino acids, saponins, and triterpenoids revealed the presence of most of constituents in polar extracts (ethanol, methanol, and aqueous) compared with nonpolar extracts (petroleum ether and chloroform). Furthermore, the ethanol extract was subjected to TLC bioautography and time-kill study against Staphylococcus epidermidis. All the findings exhibit that the leaf extracts have broad-spectrum activity and suggest its possible use in treatment of infectious diseases.