Studies On Metabolism, Extraction Technology And Antioxidation Of Total Flavonoids In Chinese White Olive Leaves

Taking the leaves of Chinese white olive as material,the paper studied the methods of analyzing and determination of total flavonoids,the optimum extraction techniques of total flavonoids and the antioxidant activities of total flavonoids.PAL activity,C4H activity,4CL activity,the contents of flavonoids,anthocyanin and simple phenols in Tanxiang,Huiyuan and Changying were also determined during different stages,and the dynamic changes of those were analyzed.The results were as follows:1.The qualitative analysis of total flavonoids by color reaction showed that the extraction solution from Chinese white olive leaves contains flavones and flavonols. Spectrophotometry was applied to detect the content of total flavonoids in the experiment,the method presented good reproducibility and accuracy.2.The extraction process of the total fiavonoids from the leaves of Chinese white olive by single factor and orthogonaltest was studied.The optimum extraction condition was established as follows:solvent 60%(v/v)ethanol,extraction temperature(water bath)80℃,extraction time 1.5h,and ratio of liquid to material(mL /g)20:1.3.Taking the leaves of Tanxiang,Huiyuan and Changying as raw material,the experiment results showed that antioxidant might not be the main factor of influencing total flavonoids to synthesize.There was certain dependency relation between total flavonoids and simple phenols.There were synchronous trends of change among PAL activity,C4H activity and 4CL activity.The content of total flavonoids was correlated positively with PAL activity,C4H activity and 4CL activity. The correlation coefficient between flavonoids and PAL ranged from 0.9132 to 0.9389. The correlation coefficient between flavonoids and C4H ranged from 0.7518 to 0.788. The correlation coefficient between flavonoids and 4CL ranged from 0.801 to 0.806. PAL might play an important role in flavonoids synthesized.4.Compared with leaves of other plants,the content of total flavonoids in leaves of Chinese white olive was a little higher than middling which ranged from 3.09%to 5.63%The content of total flavonoids in Tanxiang was higher than Huiyuan and Changying,and leaves which had about five months of leaf age had the highest content of total flavonoids among three varieties.If we used the leaves of Chinese white olive as material to extract flavonoids,the best time for picking leaves were from December to January,and the best leaf age was between five months and nine months.5.The oxidationresistant experiments were studied by total flavonoids extracted from leaves of Chinese white olive,its ability of reducing power and scavenging.OH were stronger than that of V_C,but lower than that of BHT,its ability of scavenging O₂^-was stronger than that of BHT and V_C,its activity of scavenging DPPH was stronger than that of BHT,and when its concentration is lower,its activity of scavenging DPPH was lower than that of V_C,,however,when its concentration was higher,its activity of scavenging DPPH was stronger than that of V_C,.Base on the 50%effective dose of scavenging free radicals for total flavonoids,its scavenging effect on O₂^- was the strongest,the second on scavenging·OH,and the weakest on scavenging DPPH.The results showed total flavonoids of Chinese white olive leaves had well oxidationresistant ability.