In vitro antimicrobial studies of some major bioactive compounds isolated from Strychnos innocua (Delile) root bark

Plant based therapies are very essential in modern medicine, and have long been used to cure and prevent chronic diseases in many parts of the world. Medicinal herbs have been shown to have biological properties due to the presence of active compounds. Strychnos innocua, a medicinal plant from Loganiaceae, is commonly consumed for medicinal purposes in various African countries. The need to assess the usefulness of the plant's root bark in the treatment of disease spurred this study, which involved the isolation of six bioactive compounds and screening for antimicrobial properties against some pathogens using the agar well diffusion method. Chromatography separation led to first time isolation of Umbelliferone (1), Linalool (2), Nerolidol (3), Campesterol (4), β-sitosterol (5), and 2,13-Octadecadien-1-ol (6). GC-MS and NMR spectra, as well as comparisons with published data, were used to determine their structures. The compounds exhibited strong antimicrobial activity comparable to ciprofloxacin and fluconazole against MRSA, B. subtilis, S. pyogenes, S. aureus, K. pneumoniae, E. coli, P. aeruginosa, S. typhii, A. fumigatus, C. albicans, C. krusei, and A. nigre. The MIC as well as the MBC/MFC were determined. In conclusion, the compounds (1 - 6) isolated from S. innocua root bark have remarkable antibacterial action against pathogenic microbes.