In vitro assessment of the phytochemical composition and antimicrobial activity of Punica granatum peel extract against oral pathogens

Background: This study aimed to assess the bioactive potential of peel extract from Punica granatum L. as a therapeutic agent against oral infections in response to the global problem of antimicrobial resistance and the increasing desire for natural, affordable alternatives to antibiotics. Methods: In eastern Algeria, peels were collected, dried, and then cold macerated with 80% methanol. The extract was evaluated in vitro against nine microbial strains (two bacterial and seven fungal) isolated from oral infections using agar diffusion and broth microdilution tests. Phytochemical studies were used to quantify total phenolics, flavonoids, tannins, and antioxidant activity (DPPH test). Results: The extract demonstrated significant antibacterial action, particularly against Streptococcus spp., Serratia odorifera, and Candida albicans, with inhibition zones ranging from 8 to 38.6 mm. MIC and MBC/MFC values (MBC/MIC < 2) indicated strong bactericidal and fungicidal potential. Phytochemical screening identified intermediate flavonoids (55.05 mg QE/g), high polyphenolics (193.79 mg GAE/g), and tannins (11.80 mg TAE/g). An antioxidant study showed a significant scavenging ability with an IC₅₀ = 40.93 μg/mL. Conclusions: The use of Punica granatum L. peel as a possible, eco-friendly antibacterial agent is supported by these findings. Its potential use in oral health is especially significant given the rise in antibiotic resistance and the need for readily accessible, plant-based treatment alternatives.