Development of a gel formulation with pomegranate peel extract (Punica granatum L.) for antimicrobial and wound healing action

Abstract

The aim of this study was to evaluate the feasibility of producing a gel from pomegranate peel extract for topical application, specifically for antimicrobial and wound healing purposes. Initially, the dry crude pomegranate peel extract (DCPPE) was analyzed for its phenolic profile using HPLC and by determining the total phenolic content (TPC), and total antioxidant activity (TAA). Carbomer-based gels were prepared and subjected to antimicrobial susceptibility tests to determine the optimal concentration of DCPPE (1.25 %, 2.5 %, and 3.75% w/w) in the formulations. Then, gel was produced in larger quantities and submitted to physicochemical and microbiological tests after being stored at room temperature or under refrigeration for 90 days. Gallic acid, ellagic acid, and punicalagin A and B were identified in DCPPE. The TPC was measured at 61.92 mg of gallic acid equivalent per gram (mg.GAE.g−1) and the TAA was 93.8 % (solution at 40 µL.mL−1), demonstrating superiority over butylhydroxytoluene (BHT) and gallic acid solutions at equivalent concentrations. Antimicrobial susceptibility tests indicated a significant difference (p < 0.05) for the 2.5% w/w DCPPE gel against Staphylococcus aureus and Candida albicans, which was the chosen concentration. Over a 30-day period under both storage conditions, there was no significant difference in pH values, and the reduction of TPC in the refrigerated formulation was <10 %, indicating good stability. Furthermore, the in vitro antimicrobial activity of the gel remained effective against all tested strains. These results suggest that the medicinal carbomer-based gel with DCPPE at 2.5% w/w has potential as a pharmaceutical form for antimicrobial and wound healing purposes. The utilization of DCPPE as a pharmaceutical bio-input for the gel is a sustainable approach to valorizing pomegranate peel biowaste.