Content Dynamic Changes Of Three Kinds Of Active Components And Isolation And Identification Of Oleuropein With The Analysis Of Antibacterial And Antioxidant Activities In Vitro From Olive Leaves

Olive (Olea europaea L.) is one of the important cash crops, and its fruit had important nutritional and medicinal value. This was due in large part to its high oil content, as well as to high monounsaturated fatty acids, polyphenols and tocopherols content. In addition, olive leaves also have extensive active polyphenols, and these material are similar to or even higher contents than olive fruit. Olive cultivation in China started late. The domestic studies are less for olive, and more research pay attention to the cultivation of olive or the yield of olive fruit and the quality of olive oil, however, ignore the use of their leaves. In the olive plantations, annual produce large amounts of foliage are discarded on pruning and fruit picking season, such as burning or animal feed and as a waste of resources. Therefore, In this paper, we studyed the contents of phenolic compounds, the change rules in a year and its biological activities from oilve leaves in Xichang. There have important guiding significance to the breeding of olive varieties and the production of olive. The main results are as follows:1. These contents of total polyphenol, flavonoids and oleuropein were used determination by these methods, including Folin-Ciocalteu method, subtraction method of UV-Vis spectroscopy and AICI3 method in a year with 29 varieties of olive leaves. The results showed that the contents of total polyphenol, flavonoids and oleuropein had large differences for different olive varieties and different months. Barnea had the highest average contents of oleuropein and total phenolic to 13.78% and 30.06%. Manzanillo had the highest oleuropein content to 19.57%, the minimum level was Manaki to 1.56%. The highest average content of flavonoids was Ottobratica to 0.82%, Chelmsford had the highest flavonoids content to 1.39%, the minimum level was Yuntai to 0.30%. The contents analysis for 29 olive varieties in a year showed that the highest content of total polyphenol was in January, the lowest levels in September; the highest content of oleuropein was in January, the lowest levels in July; the highest content of flavonoids was in April, the lowest levels in July. The winter and spring showed the higher levels, the lower levels showed in summer and autumn.2. The dry powder of olive leaves were extracted by ultrasonic assisted with five solvents to obtain different components, and analyzed main phenolics, antimicrobial and antioxidant activities of components. The results showed that the 80%methanol extract was the strongest on antibacterial and antioxidant activities. Antioxidant activities of the ethyl acetate extract was the weakest, antibacterial activities of the water extract was the weakest. LC-MS analysis showed that five solvent extracts had a total of nine main components, these components of water, methanol and ethanol extraction had more compounds. The water extract had unique two main components.3. Oleuropein was extracted from olive leaves by ultrasonic-assisted method and purified by silica gel column chromatography. The sample was identified as oleuropein by UV, IR, MS and NMR analysis with oleuropein standard as controls, and refer to previous reports.The results showed that the content of pure oleuropein was found to be 13.52% with a high purity to 96.54%, and the purification efficiency was 78.49%.4. Five methods were used to evaluate the antioxidant activities of oleuropein including DPPH, ABST, FRAP, total reducing power and nitrite scavenging ability, Vc always maintained the strongest antioxidant activities, oleuropein was a stronger antioxidant than BHT.5. Filter paper disc method was used to determine the antibacterial activities of oleuropein for Escherichia coli, Staphylococcus aureus and Bacillus subtilis. Dilution was used to analysis the effects of growth curve of oleuropein on three kinds of bacteria and obtained the minimum inhibitory concentrations (MIC). The results showed that oleuropein had inhibitory effect on three kinds of bacteria. Oleuropein had the strongest inhibitory effect on Escherichia coli, and MIC was 0.025 mg/mL. Followed was Staphylococcus aureus, MIC was 0.05 mg/mL. However, Bacillus subtilis showed moderately sensitive state, MIC was 0.4 mg/mL. The results showed that oleuropein had strong antioxidant and antibacterial activity.