Studies On Resource Chemistry Investigation, Extraction And Separation Technology Of Corosolic Acid In Loquat Leaves

Loquat [Eriobotrya japonica (Thunb.) Lindl.] leaf is a traditional Chinese herbal resource. Triterpene acids are broad bioactive substances in loquat leaves. The research on corosolic acid called "plant-insulin" has been becaming a hot issue because of its pharmacological function on curing typeâ…¡diabetes, anti-obesity and anti-hypertension in recent years. We collected the Loquat leaves, established the quality and quantitative analytic methods of corosolic acid and applied technique of solvent extraction, decoloring and column chromatogram. Finnally we investigated resource chemistry of corosolic acid in loquat leaves and developed the best extract technique of corosolic acid from loquat leaves, separated and purified the different products of corosolic acid. The results of the studies were as follow:1 Constituted the TLC qualitive and RP-HPLC quantitative analysis of crosolic acid. According to the different ratio of CHCl₃ to CH₃OH of devolopment solvents filtration system of TLC quality analysis, finded the volume ratio of development solvents in TLC was 96:4-95:5 and the compounds were visualized by spraying 10% sulphunic acid-ethanol liquid. Adjusted mobile phase, the RP-HPLC quantitative analysis was acetonitrile:water liquid(the volume ratio) was 88:12, fixedness grades solution, detection wavelength was 210nm, flow rate was 0.8mL/min, the columniation temperature was 35℃, retaining time about 9.424min.2 Systemicly discovered on the distribution of corosolic acid content in loquat leaves. Based the Loquat leaves investigations of different parts, different tender degree, different varieties in Putian Fujian, different pluck periods, storage time, different preparations Loquat leaves on materials, we investigated the distribution of corosolic acid content in loquat leaves through RP-HPLC quantitative analysis. The distribution of the corosolic acid content was leaves>flesh>flower>stem>root in the loquat plant. Defoliation was the highest one in different tender leaves and "Zaobell 6th" specie was the upmost in the investigated loquat leaves of Putian-Fujian varieties. Chongqing-Bei's loquat leaves was the highest one in our investigated loquat leaves in seven different provinces. April was the best time of the higest corosolic acid content in our investigated different pluck periods and the content of corosolic acid loquat leaves increased with storage days in one year in Liuyang-Hunan. As well as removed villus of the corosolic acid content from loquat leaves was higher than unremoved villus.3 Optimized extract technique of loquat leaves. Regarded the loquat leaves from Putian of Fujian province as raw materials, we carried through the single factor and orthogonal experiments. Through the adoption of RP-HPLC quantitative analysis, fixed Solvent extract optimize processing was 95% ethanol liquid, for two hours, at 70℃and the stock ratio 1:20 (g/mL) of the raw material and solvent, at twice, 4.74% corosolic acid content of extract was obtained. Ultrasonic extract optimized processing was 95% ethanol liquor, for 20 mins, at 40℃and the stock ratio 1:20 (g/mL) of the raw material and solvent, 4.81% corosolic acid content of extract was obtained.4 Obtained products with different content of corosolic acid from ethanol loquat leaves extracts. Corosolic acid products from loquat leaves was obtained through the technique of water-washing, active carbon and sherwood oil decoloring, macroporous resin and silica gel chromatogram. Corosolic acid contents of products reached to 26.30%, 47.86%, and 82.52% respectively.These results will be provided science foundational for all-around, systemic and reasonable exploitation and utilization of loquat leaves, so it has significance application value.