Anti-Elastase and Anti-Tyrosinase Activities of Cistus salviifolius and Cistus laurifolius Leaf Extracts: Potential Natural Agents for Skin Regeneration and Depigmentation.

Background: Skin aging and pigmentation disorders are influenced by both intrinsic factors (genetics, metabolism, hormones) and extrinsic factors (ultraviolet radiation, pollution, chemicals). These factors contribute to progressive structural and functional alterations of the skin, clinically manifested as wrinkles, loss of elasticity, and hyperpigmentation. Among the key enzymes implicated in these processes are elastase and tyrosinase. In response to the growing demand for safer and more sustainable cosmetic ingredients, plant-derived extracts have attracted considerable interest as sources of natural anti-aging and depigmenting agents.

Methods: The present study investigated in vitro the inhibitory activities of hydroethanolic leaf extracts of Cistus salviifolius (CSLE) and Cistus laurifolius (CLLE) using spectrophotometric enzyme assays. Enzymatic inhibition was assessed using N-succinyl-Ala-Ala-Ala-p-nitroanilide as substrate for elastase and L-DOPA for tyrosinase, with elastatinal and kojic acid employed as reference inhibitors, respectively.

Results: CSLE exhibited notable anti-elastase activity with an IC₅₀ value of 43.0 µg/mL, significantly lower than that of CLLE (IC₅₀ =218.2 µg/mL), while the positive control elastatinal displayed an IC₅₀ of 0.5 µg/mL. Regarding tyrosinase inhibition, CSLE (IC₅₀ = 28.7 µg/mL) and CLLE (IC₅₀ = 30.2 µg/mL) demonstrated comparable activities, both slightly exceeding the efficacy of kojic acid (IC₅₀ = 31.1 µg/mL).

Conclusion: These findings highlight the potential of CSLE and CLLE extracts, particularly CSLE, as valuable natural sources of elastase and tyrosinase inhibitors, thereby supporting their prospective application in the formulation of cosmeceutical products.