Antimicrobial potency of Punica granatum peel extract: Against multidrug resistant clinical isolates

Abstract

Normal human flora such as Staphylococcus aureus, Staphylococcus epidermidis, Cutibacterium acnes, Corynebacterium kroppenstedtii, and Escherichia coli could emerge as highly potent opportunistic skin and enteric pathogens. Due to their emerging resistance towards antibiotics, the scope of existing antibacterial therapy and treatment regime is very limited. In the present study, Punica granatum (P. granatum) peel extract is used as an antibacterial agent active against multidrug-resistant bacteria. Interaction with P. granatum peel extract showed strong antibacterial activity with minimum inhibitory concentration value and zone of inhibition ranging between 780 μg/ml to 6250 μg/ml and 20 ± 0.0 to 24.33 ± 2.082 mm respectively. These values evident a strong antibacterial efficacy against antibiotic-resistant Gram-positive (S. aureus, S. epidermidis, C. acnes, and C. kroppenstedtii clinical isolate NB-2) and Gram-negative (E. coli) bacteria. Interestingly, PGP extract also showed a concentration-dependent reduction of biofilm-embedded bacteria, observed 93.2 % ± 1.8 eradication at 25,000 μg/ml with respect to control, in S. epidermidis ATCC 35984 bacterium. PGP extract exhibited strong antioxidant activity and observed 94.7 ± 0.06 % scavenging activity at 1000 μg/ml PGP extract concentration as determined by the cell-free assay. Further, a promising synergistic effect of PGP extract with the commercial antimicrobials such as piroctolamine, zinc pyrithione, and tetracycline against multi-drug resistant, C. kroppenstedtii clinical isolate NB-2 is evaluated. Greater antibacterial potential of the synergistic effect of the peel's extract with the drugs has been observed when compared to the drug alone suggesting that the P. granatum could be the potent antimicrobial agent against antibiotic-resistant skin infection-causing bacteria.