Synthesis And Applied Research Of Natural Cosmetics Additives

In this thesis, the synthesis and optimization, performance identification,lightening and antioxidant activities of two natural antioxidants and cosmeticsadditives: daidzein(the main activity constituent of Soybean and Pueraria radix,etc.)and formononetin(the main activity constituent of Trifolium and Hedysarum,etc.)were primarily researched. Using deoxybenzoins route involving two steps to prepare daidzein andformononetin. 2,4,4'-trihydroxydeoxybenzoin and 2,4-dihydroxy-4'-methoxyldeoxybenzoin were the crucial intermediates in the synthesis of daidzein andformononetin ,respectively. They were prepared by Friedel-Crafts acylation ofresorcinol with p-hydroxyphenylacetic acid and p-methoxylphenylacetic acid in thepresence of lewis acid catalyst. After being recrystallizated and decolorized, theproducts were identified to be 2,4,4'-trihydroxydeoxybenzoin and 2,4-dihydroxy-4'-methoxyldeoxybenzoin by m.p., UV and IR. Their synthesis technologicalconditions of the two intermediates were optimized, the yield reached 85.83% and95.23%,respectively. Their purification conditions were also researched.Daidzein and formononetin were obtained by 2,4,4'-trihydroxydeoxybenzoin and2,4-dihydroxy-4'-methoxyldeoxybenzoin reaction with cyclization regents,respectively. Four cyclization methods were researched, and the better catalyst,twocyclization regents were found. After being purified, the products were identifiedto be daidzein and formononetin by m.p., UV, IR, 1H-NMR and MS. were achieved by singlefactor optimization experiments,and the purification conditions were also researched.Daidzein was prepared by DMF-POCl3 as cyclization regents, and the highest yieldrearched 89.15% by single factor optimization experiments. After being purified,thepurity reached 96.43% by HPLC. Formononetin was peepared by DMF-PCl5 as cyclizationregents, and the highest yield rearched 97.60% by single factor optimizationexperiments, which was better than 9O% reported. After being purified,the purity alsoreached 96.87% by HPLC.After being optimized, the deoxybenzoins route became a relatively mild easycontrol, simple manipulation and short reaction time route that could be applied tosynthesis of diadzein and formononetin on a large scale in industry,The test system of oil-soluble lighteners against tyrosinase was researched. Bydetermining the dissolution parameters of oil-soluble lightener isoliquiritigeninin organic solvents and water, and the inhibitory rates of these organic solventsagainst tyrosinase , a test system consisting a compound organic solvent( V(propanediol):V(ethyl acetate)=9:1) and water was found, which could be used todetermine inhibitory rates of oil-soluble or water-soluble lightenersagainst tyrosinase. This test system changed the restriction that the chemicalanalyticmethod on the basis of water could only be applied to water-soluble lighteners.That gave an easy method for development and evaluation of safe, good penetrationcapacity and more efficient oil-soluble lighteners. By this method, the inhibitoryrates of isoliquiritigenin,liquiritigenin,daidzein,formononetin and arbutinagainst tyrosinase were determined, the highest inhibitory rate rearched 97.5%,62.6% , 94.2% , 32.7% and 60.9%, respectively. It showed that daidzein andisoliquiritigenin were perfect oil-soluble lighteners.By critical Schaal oven method, the antioxidant activities of daidzein andformononetin on soybean salad oil were tested and compared with VE aceticester. Theresults showed that the antioxidant activity of daidzein was a little better thanformononetin, and their antioxidant activities were both better than VE aceticester.So daidzein and formononetin couled be used in cosmetics as natural safe antioxitantsto against skin aging.