Antibacterial activity of secondary metabolites from the roots of Solanum dasyphyllum: A combined in vitro and in silico study

Solanum dasyphyllum is widely utilized for folk medicine in Ethiopia. The chromatographic separation of root extract of S. dasyphyllum led to the isolation of six compounds: tremulacin (1), scopoletin (2), stigmasterol (3), β-sitosterol (4), palmitic acid (5) and 2,3-dihydroxypropyl-9Z,12Z-octadecadienoate (6). The structures of the compounds were determined using NMR (1D and 2D), MS and comparison with literature data. The extract and isolated compounds were in vitro assayed against six bacterial strains and displaying activity against the tested strains. The extract exhibited stronger activity against E. coli, K. pneumoniae, and P. aeruginosa, with MIC values of 0.195±0.0, 0.391±0.0, and 0.195±0.0 mg/mL, respectively. The isolated compounds also showed good antibacterial activity with the highest activity was recorded for compound 2, with MIC values of 0.313±0.0 mg/mL against K. pneumoniae, while for the ciprofloxacin is 0.195±0.0 mg/mL against the same strain. In silico molecular docking analyses were performed for compounds 1, 2 and 3 against E. coli DNA gyrase B, P. aeruginosa LasR protein, and K. pneumoniae using AutoDock Vina and showed better binding activity. The in vitro antibacterial results and in silico analysis of the compounds revealed the potential of these compounds to be lead compound for antibacterial drug discovery. KEY WORDS: Solanum dasyphyllum, Chromatographic separation, Antibacterial activity, Molecular docking Bull. Chem. Soc. Ethiop. 2024, 38(6), 1843-1860. DOI: https://dx.doi.org/10.4314/bcse.v38i6.26