Isolation, characterization, and docking studies of campesterol and β-sitosterol from Strychnos innocua (Delile) root bark
Ahmed Jibrin Uttu, M. S. Sallau, Hamisu Ibrahim, Ogunkemi Risikat Agbeke Iyun
Abstract
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. The chromatographic separation of S. innocua (root bark) ethyl acetate extract resulted in the isolation of campesterol (1) and β-sitosterol (2). 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 β-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. This study indicated that S. innocua root bark is rich in campesterol and β-sitosterol. In silico molecular docking demonstrated that the compounds interact well with the binding sites of S. aureus and P. aeruginosa.