In Vitro Inhibitory Effect and Molecular Interaction Studies of the Bioactive Compounds In Ethanolic Extracts of Garlic, Turmeric, and Cinnamon on Ampicillin-Resistant Staphylococcus Aureus and Escherichia Coli

Abstract

Antimicrobial resistance occurs when microbes stop responding to antibiotics used to treat their infections. This study investigated the inhibitory effect of ethanolic extracts of garlic, cinnamon, turmeric and the combination of each plant extract with ampicillin to help overcome antimicrobial resistance. It also conducted molecular docking analysis of the bioactive compounds in garlic, cinnamon and turmeric to help in drug design to curb antimicrobial resistance. The inhibitory effect was carried out using the agar disc diffusion method whilst Gold software and BIOVIA Discovery Studio was used for the molecular docking studies. The Staphylococcus aureus was sensitive to the turmeric extracts, a combination of turmeric and ampicillin but moderately sensitive to the ampicillin. The molecular docking studies of curcumin, bisdemethoxycurcumin, demethoxycurcumin, tetrahydrocurcumin, zingiberene, curcumenol, and curcumol with Sortase A protein predicted the binding efficiency which are evidenced by a fitness score of 65.72%, 63.46%, 62.37%, 61.80%, 49.19%, 41.26%, and 37.47% respectively. The Escherichia coli was moderately sensitive to the cinnamon extract and ampicillin but sensitive to the combination of the cinnamon extract and ampicillin, the garlic extract, and a combination of the garlic and ampicillin. Molecular docking studies of eugenol, cinnamyl acetate, linalool, beta-caryophyllene, and cinnamaldehyde with beta-lactamase predicted the binding efficiency which are evidenced by a fitness score of 40.64%, 39.62%, 38.03%, 36.86%, and 35.25% respectively. Thus, the various extract were good inhibitors of the bacteria and molecular docking studies predicted the binding mode and binding efficiency of the ligands.