Study On The Inhibitory Effect Of Ectoine On Tyrosinase And Its Moisturizing Property

Objective:To study and analyze the inhibitory effect of Ectoine on tyrosinase,spectrophotometry and enzyme kinetics were used to illustrate its mechanism and type.In addition,a new type of moisturizing agent Ectoine is used as the raw material,and the emulsification system ratio and process are optimized through orthogonal design experiments to develop a new type of moisturizing emulsion and test its performance.Methods:The inhibition rate of tyrosinase was measured and analyzed by spectrophotometric method with different mass fractions of Ectoine and its combination with whitening agent,and the type of inhibition of tyrosinase by Ectoine was investigated by enzyme kinetic method.The moisture absorption rate and moisture retention rate of Ectoine were analyzed by comparing several humectants commonly used in the market of Ectoine through moisture absorption experiment and moisture retention experiment.And through orthogonal design experiments to optimize the ratio and process of emulsification system,add Ectoine as moisturizing raw material,develop a new type of moisturizing emulsion and test its performance.Results:（1）The inhibition rate of tyrosinase by Ectoine increased with the ascended of its concentration,and when the concentration was greater than 2.0%,rising trend of the inhibition rate leveled off,and its semi-inhibitory concentration(IC₅₀)was 4.58g/L.The inhibition effect of tyrosinase was significantly increased when Ectoine was combined with VC ethyl ether and nicotinamide,respectively,especially 2.5%Ectoine was the best,and the inhibition rate The inhibition type of Ectoine was non-competitive in the reversible inhibition,and the inhibition constant（K_m）was0.41 g/L.The inhibition effect of Ectoine was significantly improved when combined with VC ethyl ether and nicotinamide,especially 2.5%Ectoine,with the inhibition rate of 75.03%and 66.17%,respectively.（2）At relative humidity（RH）80%,the hygroscopic rate effect was hyaluronic acid（HA）>Ectoine>sodium pyroloalkanone carboxylate（PCA-Na）>betaine>alginate>D-panthenol>glycerol;at RH RH 44%,the hygroscopic rate effect was HA>Ectoine>betaine>alginate>D-panthenol>glycerol>PCA-Na.At RH 80%and RH 44%,the moisture absorption rate was 2%D-panthenol>2%Ectoine>10%PCA-Na>10%glycerol>2%betaine>2%alginate>0.1%HA.（3）When the ratio of compound emulsifier（cetearyl polyether-6 and cetearyl polyether-25）was 5%,octadecanol 2%,glycerol 4%,triisostearyl 3%and isohexadecane 1%,Ectoine was applied to prepare moisturizing emulsion,and the optimal emulsification system was glycerol 4%,octadecanol 2%,triisostearyl 3%,isohexadecane 2%and compound emulsifier(cetearyl polyether-6 and The optimal emulsification process was oil-hydrate phase method,stirring rate 7000 r/min,emulsification time 5 min and emulsification temperature 75°C.The results of in vitro and in vivo experiments showed that the optimal addition of Ectoine as a moisturizing ingredient was 1.5%.（4）The safety and irritation test results of the lotion showed that the lotion was mild and non-irritating,and the safety was reliable.The analysis results of the hygienic indexes of the emulsions were all lower than the national cosmetic regulations and testing limits.Conclusion:（1）Ectoine has a certain inhibitory effect on tyrosinase activity,and has a synergistic effect on the inhibition of tyrosinase in combination with VC ethyl ether and nicotinamide respectively,and its mechanism and type of action are non-competitive in reversible inhibition.（2）There is an excellent hygroscopic and moisturizing properties in Ectoine and is superior to glycerol,PCA-Na,alginose and betaine.（3）Ectoine was applied to prepare moisturizing emulsions with the optimal emulsification system of glycerol 4%,octadecanol 2%,triisostearyl alcohol 3%,isohexadecane 2%and compound emulsifier（cetearyl polyether-6 and cetearyl polyether-25）5%,and the optimal process for the emulsions was oil aqueous phase method,stirring rate 7000 r/min,emulsification time 5 min and emulsification temperature 75°C The best addition of Ectoine as a moisturizing ingredient was1.5%,and the Ectoine moisturizing emulsion prepared by this formula was evenly distributed and fine in texture.（4）The physicochemical properties and hygienic indexes of Ectoine moisturizing emulsion were in accordance with the Safety Technical Specification for Cosmetics（2015 version）,which is safe and reliable.