Isolation, Characterization and In Silico Molecular Docking Studies of Two Terpenoids from Strychnos innocua (Delile) Root Bark for Antibacterial Properties

Terpenoids are definite secondary metabolites with active therapeutic components that contribute to plants’ medicinal potential. Strychnos innocua is a Loganiaceae family medicinal plant found in various African countries. This study reports the isolation, characterization, and molecular docking analyses of Linalool (1) and Nerolidol (2) from ethyl acetate root bark extract of S. innocua. Their structures were validated using mass spectrometry, nuclear magnetic resonance (1D and 2D NMR), and compared with literature data. This is a novel report of terpenoids isolated from S. innocua root bark. An in silico docking examination revealed the binding energies of Linalool with the binding sites of Staphylococcus aureus pyruvate carboxylase (PDB: 3HO8) and Pseudomonas aeruginosa virulence factor regulator (PDB: 2OZ6) were -4.7 and –5.6 kcal/mol, respectively. Furthermore, the binding energies of Nerolidol with the binding sites of S. aureus and P. aeruginosa were -5.8 and -6.9 kcal/mol, respectively. Compared to ciprofloxacin (standard drug), which showed binding energies of -6.6 and -8.7 kcal/mol, respectively. This study concluded that Linalool and Nerolidol are abundant in the root bark of S. innocua. At the same time, docking results revealed that the compounds had moderate interactions with S. aureus and P. aeruginosa, exhibiting antibacterial effects.