Background: Dinoxin B Withanolide was isolated from Datura inoxia and identified with its cytotoxic activity. But its antibacterial properties are not yet evaluated. We have previously reported the broad-spectrum antibacterial property of Dinoxin B Withanolide extracted from D.inoxia on standard strains. Objective: This research has focused to evaluate the efficacy of Dinoxin B Withanolide against infectious Staphylococcus aureus, including resistant strains. Methods: Electrospray Ionization-Mass Spectrometry is used to depict the presence of Dinoxin B withanolide from the chromatographic ethanolic leaf fraction. Antibacterial activity of different concentrations of Dinoxin B(12500-100000 μg/ml) was assessed using the agar diffusion, macro broth dilution, and time-kill assay methods. Docking studies and Drug likeness properties were analyzed. Result: Electrospray Ionization-Mass Spectrometry depicted the presence of Dinoxin B. All the isolates were susceptible to Dinoxin B within the range of 15±0.5mm to 24±0.5mm, and the bacteria were susceptible at a concentration rate of ≤12.5mg/ml. Time-kill assay showed that 25mg/ml of Dinoxin B displayed the highest inhibitory activity after four hours. The MBC values were compatible with the cidal concentration as seen in the time-kill study's growth curve. Computer-aided techniques resulted in a good Docking score towards Quorum-signaling Sar A protein (-7.82)and Penicillin Binding Protein(-6.9). Conclusion: Dinoxin B with its bactericidal properties and significant affinity towards Quorum-signaling Sar A protein and Penicillin Binding Protein can be considered as an effective bioactive compound against Methicillin Resistance Staphylococcus aureus.
Rapid Molecular Genotyping and Clonal Complex Assignment of Staphylococcus aureus Isolates by PCR Coupled to Electrospray Ionization-Mass Spectrometry
