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), ß-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.

Isolation, characterization, and docking studies of campesterol and ß-sitosterol from Strychnos innocua (Delile) root bark.

Objectives: Phytosterols obtained from medicinal plants are well known for their anti-diabetic, anti-cardiovascular, anti-cancer, and anti-microbial properties. Strychnos innocua (a member of the Loganiaceae family) grows in several African nations and is frequently used for medicinal purposes. Methods: The chromatographic separation of S. innocua (root bark) ethyl acetate extract resulted in the isolation of campesterol (1) and ß-sitosterol (2). Results: The structures of 1 and 2 were confirmed by mass spectrometry, nuclear magnetic resonance (1D and 2D NMR), and literature data. This is a novel report of campesterol and ß-sitosterol from S. innocua. Docking studies revealed that the binding affinities of 1 with the binding sites of Staphylococcus aureus pyruvate carboxylase (PDB: 3HO8) and Pseudomonas aeruginosa virulence factor regulator (PDB: 2OZ6) were -7.8 and -7.9 kcal/mol, respectively. Furthermore, 2 had binding affinities of -7.6 and -7.7 kcal/mol with binding sites of S. aureus and P. aeruginosa, respectively, whereas ciprofloxacin (a standard drug) had binding affinities of -6.6 and -8.7 kcal/mol. Conclusion: This study indicated that S. innocua root bark is rich in campesterol and ß-sitosterol. In silico molecular docking demonstrated that the compounds interact well with the binding sites of S. aureus and P. aeruginosa.

Flavonoids with antimicrobial activity from the stem bark of Commiphora pedunculata (Kotschy & Peyr.) Engl.

The first reported investigation into the phytochemical constituents of Commiphora pedunculata led to the isolation of two flavonoids: kaempferol and dihydrokaempferol from the ethyl acetate-soluble fraction of the methanol extract of the stem bark of the plant. The structures of these compounds were characterised by comparing their spectral data including 1D and 2D NMR with those reported in the literature. The two compounds were active against 6 out of 10 tested microorganisms including two resistant strains [methiciline-resistant Staphylococcus aureus and vancomycin-resistant entrococci (VRE)], Candida albicans and Escherichia coli. The zones of inhibition ranged between 24 and 30 mm for both compounds against the microorganisms. The MIC value was as low as 6.25 µg/mL against VRE and Staphylococcus aureus. This is the first report of the isolation of these compounds from the plant.