Abstract
This study investigates the influence of seasonal variation onthe phytochemicalcomposition and biological activities of Cistus creticus leaf extracts collected during spring, summer, autumn, and winter. Extracts are analyzed for phenolic and flavonoid contents and evaluated for antioxidant, enzyme inhibitory, anti-inflammatory, analgesic, antimicrobial, and photoprotective properties. Pronounced seasonal differences are observed. Spring and summer extracts, enriched in bioactive compounds, exhibit the strongest pharmacological potential, including notable antioxidant effects, potent enzyme inhibition, and high photoprotective capacity. The spring extract further demonstrates significant in vivo anti-inflammatory and analgesic effects, while the winter extract displays superior in vitro anti-inflammatory activity. These findings highlight the critical role of harvest season in modulating both phytochemical composition and bioefficacy. The superior performance of spring and summer extracts underscores the potential of C. creticus as a valuable natural source of antioxidants, enzyme inhibitors, and photoprotective agents. Overall, this work supports the strategic use of seasonal optimization to enhance the therapeutic and cosmeceutical applications of C. creticus.