Study On Preparation Of Arbutin

Arbutin, named p-Hydroxyphenyl- β -D-glucopyranoside, firstly is found in the leaves of Arctostapylos Bearberry. Arbutin had been used in medicine because of its anti-inflammation and anti-bacterial actions. Since 1980s, researches suggested that arbutin could inhibit reversible the activity of tyrosinase as a competitive inhibitor. Tyrosinase is the key catalyst in accelerating the formation of melanin. So the arbutin had the effect of skin whitening. Because of inhibition of the formation of melanin, SHISEIDO Company first applied arbutin in cosmetics. Many domestic companies also added arbutin into whitening cosmetics. So the arbutin had the promising application with a great demand.The main contents of this paper were as follows:1) The thin layer chromatographic (TLC) methods to qualitatively analyze arbutin was developed. The optimal conditions of TLC were as follows: silica gel GF254 as stationary phase, ethyl actate-methanol-water(7-2-1, v/v/v) as mobile phase. The R_f value of Arbutin was 0.56. The R_f value of Hydroquinone was 0.67.2) A method of reverse phase high performance liquid chromatographic(HPLC) determination of Arbutin in cosmetics was developed. A effective pretreatment of extraction of arbutin from cream cosmetics was established including ultrasonic concussive extraction with chloroform-saturated sodium chloride(2:1,v/v). The optimal HPLC conditions were as follows: Apollo C₁₈ column (250mm × 4.6mm, 5 μ m) as stationary phase, methanol- phosphate buffers(pH6.0)- acetic acid(10:90:1,v/v/v) as the mobile phase,1ml/min of flow rate, UV detector(254nm). Under these conditions, a baseline separation of Arbutin was obtained, and the retention time of arbutin and hydroquinone are 5.2min and 7.9min, respectively. As for arbutin, the linear range is 0.01¹g/L, the calibration equation is A=175543X+1763.1,r²=0.9959, the limits of arbutin detection was 24ng; As for hydroquinone, the linear range is 0.01¹g/L, the calibration equation is A=16772X-3380.8, r²=0.9957, the limits of hydroquinone was 21ng.3) A synthesis method of Arbutin by phase-transfer catalytic reaction withNaHC03 as catalyst is developed. The key intermediate pentabutyryl Arbutin was synthesized with TBAB as phase-transfer catalytic agent instead of using expensive metal catalyst, which pollutes the environment seriously. The total yield obtained reaches 37.6%.4) The synthesized arbutin sample was indented by IR, 'H-NMR ,13C-NMR , ESI-MS. The main characteristic peaks in IR, [H-NMR ,13C-NMR , ESI-MS were assigned.5) The isolated strains from soil were screened to produce the glycosidase. In the mean while, the other glycosidase was also extracted from almond. The activity, thermo-stability and the stability of these enzymes in organic solvents were studied. It showed the glycosidase from almond be ability to synthesis of arbutin by reverse hydrolysis reaction6) The attempt to synthesize arbutin by reversed enzymatic hydrolysis. The glycosidase from almond and 90% tert-butyl alcohol solvent were used. The reaction conditions such as enzyme concentration, shaking speed, temperature, buffers were studied.