Antimicrobial Potentials of Dolichos Lablab Linn (Hyacinth Bean)

Dolichos lablab Linn is used as a traditional medicine against different ailments. To elucidate its antimicrobial activity, the plant underwent phytochemical screening, which indicated that the leaf and pod extracts contain triterpenes, alkaloids, flavonoids, sterols, tannins, and glycosides, which provide a broad antimicrobial spectrum against different microorganisms. Plant extracts were analyzed to test the antibacterial activities against gram-negative (Escherichia coli) and gram-positive (Staphylococcus aureus) bacteria. Minimum Inhibitory Concentrations (MIC) were measured. Dolichos lablab Linn leaf and pod extracts showed the same inhibition zone (10.00 mm) against Escherichia coli and Staphylococcus aureus. The leaf and pod extracts exhibited complete inhibitory activity at 25% concentrations as compared to the effects of Amikacin for Escherichia coli and partial and complete inhibitory activities of the leaf and pod extracts, respectively, for Staphylococcus aureus as compared to Oxacillin. The inhibitor activity of Dolichos lablab Linn is found to be positive, indicating that Dolichos lablab Linn leaf and pod extracts partially inhibited Aspergillus niger. The ethanolic extracts of the leaf and pods showed minimal activity against Aspergillus niger. Dolichos lablab Linn may not possess antifungal activities against Candida albicans since it did not produce inhibition zones. The leaf and pod extracts had MIC (Minimum Inhibitory Concentration) values (.39 mg/ml) from Escherichia coli and (1.56 mg/ml) for Staphylococcus aureus. Findings showed that the ethanolic extract of the leaf and pod exerted a greater antibacterial effect on Escherichia coli than Staphylococcus aureus. Low MIC indicates that an excellent candidate for antimicrobial agents against Escherichia coli and Staphylococcus aureus.

Keywords: antimicrobial activity, bioassay, inhibitory activity, minimum inhibitory concentration, phytochemical