Pomegranate Peels: A Promising Source of Biologically Active Compounds with Potential Application in Cosmetic Products

As a rich source of biologically active compounds, pomegranate peel is a valuable by-product with applications in the food, pharmaceutical and cosmetic sectors. The present study aimed to investigate the phytochemical composition, antioxidant and antimicrobial activity, photoprotective activity and application in a cosmetic emulsion of extracts obtained from pomegranate peel by different solvents. The analysis of phenolic compounds was determined by high-performance liquid chromatography (HPLC); the total phenolic content (TPC) and the total flavonoid content (TFC) were evaluated using standard spectrophotometric methods; the antioxidant activity was assessed by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging, ferric-reducing antioxidant power (FRAP) and 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays; antimicrobial screening was performed against twenty test microorganisms; the ultraviolet (UV) protection effect of extracts and cosmetic emulsion was assessed spectrophotometrically in the wavelength range of 290–320 nm. HPLC analysis revealed fourteen phenolic compounds, including four phenolic acids (ellagic, gallic, p-coumaric, and ferulic), two tannins (pedunculagin and punicalagin), six flavonoids (myricetin, hesperidin, quercetin, luteolin, kaempferol, and apigenin), and two quercetin glycosides (rutin and hyperoside). The four pomegranate peel extracts demonstrated high TPC, TFC and antioxidant potential (DMSO > 70% ethanolic > methanolic > aqueous), and significant antimicrobial activity. The four extracts showed a remarkable UV protection effect. When applied in a cosmetic emulsion, the ethanolic extract showed sun protection factor (SPF) values from 13.59 (0.5 mg/g) to 50.65 (5 mg/g). Based on the results obtained, we can conclude that pomegranate peel is a promising source of bioactive compounds, which can be successfully utilized by integration into various pharmaceutical and value-added skin health products.