Method for preparing olive leaf extract

Abstract

The invention discloses a method for preparing olive leaf extract, belonging to the technical field of plant effective ingredient extraction and separation. The method for extracting and separating oleuropein from olive leaves in the invention has the following steps: extracting the olive leaves by polar solvent, precipitating by flocculant to obtain centrifugal solution and precipitate, extracting the centrifugal solution, further separating by preparative high performance liquid chromatography (HPLC) for acetic ether extractive phase, performing on-line detection by a differential refraction detector, objectively collecting oleuropein product segments, performing reduced pressure concentration on preparation liquid, and carrying out vacuum drying or spray drying to obtain the olive leaf extract in which the oleuropein content is larger than 90%. The invention has the advantages of simple procedures, realization of high purity oleuropein preparation, large preparation amount, high yield and good product quality and is suitable for industrialized production; and the prepared extract has no residual of harmful substances.

Description

Technical field [0001] The invention relates to a method for preparing an olive leaf extract, in particular to a method for preparing an olive leaf extract with an oleuropein content greater than 90%, and belongs to the technical field of extraction and separation of plant active ingredients. Background technique [0002] Olive (Olea europare Linn) belongs to the oleaceae family (oleaceae), the English name is olive, also known as foreign olive, olean fruit, and Alebe. It is a world-famous evergreen woody oil with the characteristics of "high yield, high quality and high efficiency" There are as many as 500 varieties of olive cultivars, and about 140 species are widely planted. Olives have vigorous growth ability, drought-tolerant and light-loving. They are mainly distributed in the European Mediterranean countries and the California area of ​​the United States. They were introduced to my country in a small amount in the 1950s and are widely planted in Fujian, Guangdong and Guang...

AI Technical Summary

Problems solved by technology

Oleuropein is easy to oxidize, sensitive to temperature and light, highly hygroscopic, and not easy to crystallize, so high-purity oleuropein is not easy to prepare, especially the preparation of oleuropein with high yield and suitable for production is very difficult. Disaster

The more cumbersome the processing process, the higher the purity of oleuropein but the lower the yield, which also increases the cost and is not suitable for large-scale production

Chinese patent 200410023233 discloses a method for extracting olive leaf extract, which uses water rinsing, chlorine dioxide disinfection, alcohol extraction, concentration and drying, and the active ingredients of the prepared extract are less than 35%, not only does not have a clear active ingredient, but also The content is low, and its medicinal use is limited

Chinese patent 200710118209.8 discloses a preparation method of olive leaf extract, which is purified by membrane separation technology after alcohol extraction, and the content of oleuropein reaches more than 40%, but its cost is high and it is not suitable for large-scale production

Chinese patent 200710107642.1 discloses a production process of olive leaf extract. The olive leaf is dried at low temperature and protected from light with ethanol or methanol by reflux, impregnation, percolation, ultrasonic extraction, vacuum drying, membrane separation and ion exchange separation and purification to obtain olive bitter glycosides, total phenols and flavonoids, but the obtained oleuropein content is only 2-6%, and the ion exchange raw materials have not been replaced, and the residues of the extracts are unknown

Wang Chengzhang et al. reported a method for the extraction, separation and structural identification of oleuropein in the olive leaves of the introduced species (Forest Products Chemistry and Industry, June 2009), using 60% ethanol to extract, then petroleum ether, ethyl acetate extraction , and then separated by silica gel column chromatography, and finally 95% of oleuropein monomer was obtained by HPLC semi-preparative chromatography. The goal is to obtain oleuropein monomer, without considering the yield and cost and the residue of harmful substances, the process is cumbersome

Direct extraction after alcohol extraction requires a lot of work, low extraction efficiency, difficult filtration of the concentrated solution, high cost of silica gel column chromatography, and the use of chloroform methanol system. Chloroform is very toxic and cannot be decomposed in the human body. Accumulative toxicity residues, the scope of application of the product is greatly limited, the preparative liquid chromatography it adopts is analytical HPLC chromatography, and mg-level products can be obtained, which is suitable for research but not suitable for production. Oleuropein monomer has been prepared, but the process is cumbersome and costly, the product yield is low, and the utilization value of the process is greatly limited

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