Exploring the Potential of <i>Lemon</i> Peel Extracts in Cosmetics: Chemical Composition and Bioactive Properties

In this study, the potential of <i>lemon</i> peel extracts as cosmetic raw materials was explored, with focus on their composition, aroma, antimicrobial, and other bioactivities. Lemon peel essential oil (LPEO), extract (LPE) and absolute oil (LPAO) were prepared by hydrodistillation and organic solvent extraction, respectively. GC/MS analysis indicated that LPEO, LPE, and LPAO contained 22, 39, and 9 components, respectively, with terpenoids being the predominant component. LPE had the highest total flavonoid content and exceeded the total phenolic content. LPEO demonstrated the strongest aroma intensity and persistence, as measured by electronic nose. All three <i>lemon</i> peel extracts showed good antioxidant, anti-tyrosinase, and antimicrobial properties, while inhibition rates exceeded 90% in the experimental concentration range in a dose-dependent manner. Although the antioxidant and antibacterial effects of LPAO were stronger than those of LPEO, the latter had better anti-tyrosinase action. LPEO also demonstrated superior anti-inflammatory effects, with inhibitory rates of 87.79 ± 3.86% and 80.75 ± 2.33% on TNF-α and IL-6 at 1 × 10^-2 mg/ml. Moreover, LPEO promoted HaCaT cell migration better than LPE and LPAO, and the healing rate of scratched HaCaT cells treated with LPEO at 1 × 10^-2 mg/ml for 12 h was 95.29 ± 3.41%. In addition to its antioxidant and antibacterial properties, the overall performance of LPEO was superior by comparison with LPE and LPAO. In summary, the three extracts can be combined to expand their application as skincare and cosmetic additives with aroma-improving, antioxidant, whitening, antibacterial, anti-inflammatory, and wound-healing activities.