Evaluation of Antimicrobial Activity of Punica granatum Pericarp Extracts against Helicobacter pylori Resistant to Clarithromycin and Metronidazole

Helicobacter pylori (H. pylori) is the responsible bacteria for many gastric disorders such as gastritis, gastric ulcer, and gastric cancer. Half of the world's population is infected with H. pylori. The recent surge in multidrug resistant bacteria necessitate the need for additional preventative and therapeutic options to conventional drugs. Interestingly, the use of medicinal plants such as Punica granatum, commonly known as pomegranates, is being increasingly used throughout the world because of their efficacy and low toxicity.
The present study indicates the presence of various bioactive components in aqueous and ethanolic crude extracts such as alkaloids, flavonoids, glycosides, tannins, and saponins. Ethanolic extract contains all detected chemical compounds compared with aqueous extract, making the ethanolic extraction more potent than aqueous extraction. The aqueous and ethanolic extracts of P. granatum pericarp were tested for their antibacterial activity against ten identified clinical isolates of H. pylori (have resistance pattern to clarithromycin (25 µg) and metronidazole (5µg), or one of them) by disc diffusion technique. There is inverse relationship between the concentration of the aqueous or ethanolic extract of the pomegranate peel and the growth of bacteria, whereas, high concentration decrease growth of bacteria. Ethanolic extract significantly reduces the growth of H. pylori in a higher degree (with best MIC 2mg/ml), compared with aqueous extract (with best MIC 3mg/ml). In conclusion, present study showed that pomegranate peel extracts were capable to inhibit the growth of H. pylori in vitro, possibly via its high antioxidant activity that it contain.