ANTIMICROBIAL ACTIVITY AND PRELIMINARY PHYTOCHEMICAL SCREENING OF METHANOLIC LEAF EXTRACT OF SENNA TORA

Background: Senna tora is a medicinal plant traditionally used in several indigenous systems of medicine. The present study evaluated the preliminary phytochemical profile and in vitro antimicrobial activity of a leaf extract of Senna tora.

Methods: Leaves were collected from a local field in Gulbarga, Karnataka, authenticated, shade-dried, powdered and extracted by Soxhlet extraction using methanol. The concentrated extract was subjected to preliminary phytochemical screening. Antimicrobial activity was assessed by the agar well diffusion method against Escherichia coli, Staphylococcus aureus, Aspergillus niger and Aspergillus flavus at 25, 50, 75 and 100 µg/mL, with measurements performed in triplicate.

Results: The methanolic extract showed a yield of 1.44% w/w and was described as a semi-solid dark-green extract. Preliminary screening indicated the presence of carbohydrates, proteins, alkaloids, tannins, flavonoids and glycosides, while phenolic compounds and steroids were reported absent. For E. coli, mean inhibition zones for the methanolic extract increased from 3.8 mm at 25 µg/mL to 17.1 mm at 100 µg/mL; for S. aureus, from 3.7 mm to 16.9 mm. For A. niger, the corresponding values were 3.3–16.5 mm, and for A. flavus, 3.9–17.2 mm.

Conclusion: The findings reported in the source study indicate concentration-dependent antimicrobial activity of the methanolic leaf extract of Senna tora against the tested organisms. Further studies involving standardized susceptibility testing, MIC/MBC or MFC determination, isolation of active constituents, toxicity assessment and mechanistic evaluation are required before therapeutic conclusions can be drawn.

Keywords: Senna tora, Methanolic extract, Phytochemical screening, Antimicrobial activity and Agar well diffusion.