Antimicrobial Qualities of Senna Alata

Abstract

The antimicrobial activity of the root and leaf extracts of the Senna alata plant against some infectious bacteria (Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa etc) and fungi (spergillus flavus, Aspergillus niger, Candida albicans etc) as well as the physiochemical and microbiological quality of the plant was determined using the cup plate agar diffusion method. The freshly collected fresh mature leaves and roots were chopped into pieces and shade-dried at 32-35 0 C to constant weight for 5 days. 50g each of the plant parts was coarsely powdered using a mortar and pestle and finely powdered using an electric blender. Each of the powdered air-dried plant material was extracted with water, acetone and methanol. All the extracts demonstrated considerable activity against both Gram negative and Gram positive bacteria and some fungi with the organic extracts showing higher activity than the aqueous extracts. Stretococus pyogenes and S. aureus were the most susceptible to all the extracts followed by Salmonella typhi and Escherichia coli. The most susceptible fungi were Cryptococcus neoformans and Candida albicans while the least susceptible was Aspergillus flavus. The minimum inhibitory concentration and minimum bactericidal concentration of the methanol extracts ranged between 3-10 mg/ml and 25-50 mg/ml for bacteria and fungi respectively. Preliminary phytochemical analysis showed that the extracts contained tannins, saponins, glycosides, flavonoids and phenols. The results obtained show the basis for the local usage of S. alata Linn as an antimicrobial. Phytochemical result showed ethanol to be a better solvent for the extraction of the bioactive agents in Senna alata which include: glycosides, alkaloids, saponins, tannins, flavonoids and volatile oil. Despite the significant progress made in microbiology and the control of microorganisms, sporadic incidents of epidemics due to drug resistant microorganisms pose an enormous threat to public health. The use of medicinal plants for antimicrobial activities needs to be given more attention.