Hawthorn Acid In Olive Pomace Extraction And Separation Of Structural Characterization

A systematic study of maslinic acid(MA) from Longnan introduced oil olive(Olea europaea L.) was carried out in this paper. Methods were established to extract, separate, purify and determine MA from olive pomace and leaves extracts, as well as the structural characterization of MA was identified by means of UV, IR,1H-NMR,13C-NMR and MS. Theoretical analysis and results showed as follows:1. Extraction of MA. The best solvent extraction process of MA from olive pomace and leaves was obtained by orthogonal design. And the optimal experimental conditions were:temperature 80℃; liquid feed ratio 20:1 of 90%(v/v) ethanol solution while extraction time 4h. The extraction amounts of MA from olive pomace and leaves were 4.78mg and 5.24mg respectively. Compared with solvent extraction, ultrasonic-assisted extraction need less time, but extraction amount was lower than that of solvent extraction; while soxhlet extraction has high extraction amount, but it's time-consuming and not conducive to enlarge the production in industry.2. Separation and purification of MA. The n-hexane was chosen to degrease the extraction of olive pomace, while leaf chlorophyll of olive leaves extraction was removed with petroleum ether. Then silica gel column chromatography was used for primary isolation of the extracts from olive pomace and leaves and crude maslinic acid and oleanolic acid(OA) were obtained. And then recrystallization was used for further purification.The content of MA was 54.2% in contrast to 17.65% without primary isolation with the yield 51.6%. Recrystallization was carried out for further purification and the content of MA was 86.98%, while high purity monomer of OA was obtained and its needle-like crystals appeared in ethanol solution. Preparative high pressure liquid chromatography (Pre-HPLC) was used for refining MA which was recrystallizated to get high purity monomer of MA(≧97%).3. Measurement and structural characterization of MA. The olive pomace and leaves extracts and the intermediate products of separation and purification were analyzed (qualitative and quantitative analysis) by RP-HPLC. And thin-layer chromatography(TLC) was also used for qualitative analysis in the process of silica gel column chromatography. The analysis conditions:Column, Kromasil C18 (250mm×4.6mm,5μm); Mobile phase, methanol-water-acetic acid=88:12:1(v/v); Flow rate, 1.0mL/min; Detection wavelength,λ= 215 nm; Column temperature, 25℃. The good linear relationship between peak area and concentration was obtained in the ranges of 3.15～36.0mg/mL for MA. The structure of MA isolated from olive pomace and leaves extracts was identified by means of UV, IR,1H-NMR,13C-NMR and MS.