In vitro antibacterial activities of different solvent extracts of cajanus Cajan L. Seed coat and cotyledon

Abstract

Objectives: The present study was conducted to assess the antibacterial activity of seed coat and cotyledon of Cajanus cajan with various solvents such as petroleum ether, chloroform, ethanol, and aqueous. Methods: The crude extracts were obtained using Soxhlet successive extraction method. The antibacterial activity of seed coat and cotyledon extracts at different concentration (50 and 100 mg/mL) was evaluated against certain pathogenic Gram-positive bacteria of Bacillus subtilis, Staphylococcus aureus, and Streptococcus pneumoniae and Gram-negative bacteria of Salmonella typhi, Klebsiella pneumoniae, Escherichia coli, and Pseudomonas aeruginosa by agar well diffusion assay. Results: The results show that the ethanolic extract of seed coat had highest activity against B. subtilis (22.0±0.13 mm). Whereas, the aqueous extract of cotyledon had highest activity against S. aureus (20.0±0.02 mm) and S. typhi (20.0±0.04 mm) at 100 mg/mL. The S. pneumoniae and P. aeruginosa were completely resistant to all extracts of seed coat. Similarly, S. pneumoniae, K. pneumoniae, E. coli, and P. aeruginosa were totally resistant to all tested cotyledon extracts. The phytochemical results show the presence of alkaloids, steroids, phenols, flavonoids, tannins, lignins, glycosides, and absence of saponins in seed coat and cotyledon. Conclusion: This study shows that C. cajan seed coat and cotyledon had potential antibacterial activity against B. subtilis, S. aureus, and S. typhi. These extracts may be exploited for the development of antimicrobial and alternative remedies for infections and diseases caused by respective pathogens. © 2018 The Authors.