Antioxidant properties of some plants with potential for use in cosmetics

Cosmetics refer to the general category of products and applications used in skin, body, and hair care. Today, the cosmetics industry has achieved a significant market share, and interest in plant-based resources has increased. Plant extracts enrich cosmetic formulations with their natural components, providing skincare and beauty benefits. In recent years, research on plants as natural sources of antioxidants has intensified. Antioxidants neutralize free radicals, thereby preventing oxidative stress and cellular damage. In this study, the antioxidant activities of Citrullus lanatus (watermelon seed) and Quercus infectoria (oak gall) extracts were evaluated. The study assessed total flavonoid content, DPPH radical scavenging activity, reducing power, metal chelating activity, and phenolic compound analysis using the LC-MS/MS method. According to the findings, oak gall extracts had significantly higher concentrations of flavonoid components compared to watermelon seed extracts. It was demonstrated that oak gall had a notably high capacity for neutralizing DPPH radicals. Although watermelon seed exhibited considerable antioxidant activity, oak gall was found to have a stronger effect overall. Additionally, watermelon seed showed higher metal chelating activity than oak gall. However, regarding reducing power, the oak gall Soxhlet extract exhibited the highest capacity, while watermelon seed measured at lower levels. LC-MS/MS analysis revealed the presence of phenolic compounds such as gallic acid, tannic acid, ellagic acid, and quinic acid in oak gall extracts. In watermelon seed extracts, flavonoid compounds such as luteolin and apigenin were identified. These results demonstrate the strong antioxidant potentials of watermelon seed and oak gall extracts based on their phenolic and flavonoid compound contents.