Zones of Inhibition and Molecular Docking (In-silico Approach) of Piptadeniastrum africanum Extracts on Clinical and Multiple Antibiotic Resistant Isolates

The use of plants as medicines is an ancient practice common to especially Nigeria and Africa at large. The purpose of this research work is to evaluate the zones of inhibition, phytochemical screening and molecular docking (In-silico Approach) of Piptadeniastrum africanum against selected clinical and multiple antibiotic resistant isolates. Using agar well diffusion method, the antimicrobial activity of the stem bark and leaf extracts of Piptadeniastrum africanum was assayed against Escherichia coli , Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella typhi , Shigella sonnei , Proteus mirabilis , Bacillus substilis , Staphylococcus aureus , Aspergillus niger, and Candida albicans. The extract inhibits the growth of all the tests organisms at different concentrations, especially the Gram-negative bacteria and fungi Aspergillus niger which showed diameter zones of inhibition ranging from 21 mm to 10 mm at concentration of 100 mg/ml. The stem bark extracts also showed antimicrobial activity against multiple drug resistant (MDR) bacteria such as Proteus mirabilis, Enterobacter agglomerans, Salmonella subsp .3, Acinetobacter baumannii, Providencia stuarti with a zones of inhibition ranging between 11 mm and 19 mm at 100mg/ml. The leaf extract was less active against MDR bacteria while some showed little zone of inhibition. Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of the extracts ranges between 6.25 and 100 mg/ml. Qualitative and quantitative phytochemical screening reveals the presence of flavonoids, tannins, alkaloids, phenol, saponins, and cardial glycosides in the extracts at percentage range of 17.30% to 1.20%. Molecular docking of these phytochemicals using levofloxacin as template revealed the presence of compounds more effective in inhibiting DNA gyrase enzyme. Thus, the use of Piptadeniastrum. africanum as traditional medicine is justifiable and should be encouraged in the formulation and production of new antibiotic.