| In this paper, the effects of different processing methods on the contents of main chemical constituents and antioxidation of Eucommia Ulmoides Oliv leaves were studied. The optimum conditions extracting antioxidants from E. ulmoides leaves by supersonic wave were determined. As well as the contents of main chemical constituents in E. ulmoides leaves and E. ulmoides cortex from different models in different seasons were studied in order to provide scientific basis for the further processing of E. ulmoides. The results were as follows:1. After harvest, fresh leaves of E. ulmoides were prepared by five pretreatment methods: drying in the shade (the control group), heated in microwave oven, steam treatment, heated in oven, baking treatment. Evaluation of antioxidant activity of E. ulmoides leaves extracts by DPPH·assay. The results were as follows: the content of totle flavones was highly positive correlated with the DPPH radical scavenging activity and the coefficients was 0.9474; in addition, a moderate correlation was found between the contents of total phenolic compounds with the correlation coefficient of 0.6094. Various processing methods had different effects on the contents of totle flavones and total phenolic in the E. ulmoides leaves. Compared the maximum of each processing method with the control group, the content of totle flavones had the varying degree increase, the content of total phenolic and DPPH radical scavenging activity were increased compared to the control group besides baking treatment. Compared different processing methods separately, the best trestment conditions for microwave was high fire 2.5min to 5min, steam treatment was 3min or 20min, heated in oven for 30min at 120℃, baking treatment for 3min, 4min or 5min at 130℃. Considering the four kinds of treatment, microwave treatment heating quickly and evenly, the operation simple and easy to control, and it was found to be the best one for its maintenance of green color and the antioxidants in the E. ulmoides leaves.2. The main factors influenced the extract rate of eucommiol were anaysized. As for DPPH? scavenging rate and the extraction rate of extractum index, the main factors influenced the extract rate of antioxidant actives from the E. ulmoides leaves were anaysized. The best extract conditions were: ethanol concentration 60%, solid to liquid ratio 1:15, temperature 60℃and extracting time 30min.3. The contents of chlorogenic acid, eucommoil and geniposide in E. ulmoides leaves and Eucommia cortex from different models in different seasons analyzed. The results showed as followed: The accumulation dynamic principle of chlorogenic acid in E. ulmoides leaves beween the tree models were the same. From April to June the content of chlorogenic acid was increased with the growth of leaves, maximum value appeared in June, the content of chlorogenic acid in leaf modle leaves was 2.77%, the content of chlorogenic acid in tree modle leaves was 2.12%. From July to October the content decreased gradually, and increased slowly in November. The content of chlorogenic acid in leaf modle cortex reached its first maximum in August, and then reached its second maximum in October, which was the highest of the whole year. The content of chlorogenic acid in tree modle cortex reached its first maximum in June, which was the highest of the whole year. The other two peak values were in August and October, and two minimum values appeared in July and September. Considering to different models and different parts, the content of chlorogenic acid in leaves was 10 times as more as in cortex of two models.The accumulation dynamic principle of eucommoil in E. ulmoides leaves beween the tree models were the same. From May to September the content of eucommoi increased gradually, the peak value appeared in September, then decreased until leaves fell in November, and the content of eucommoi in the two modles about the same. The accumulation dynamic principle of eucommoil in E. ulmoides cortex beween the tree models were the same. The content of eucommoi appeared two peak values in the whole growing season, the first peak appeared in May which is the vigorous growing stage of trees. The second peak was in August which is the second growth peak of trees with more secondary metabolites, then declined rapidly. Considering to different models and different parts, the content of eucommoil in leaves was 5 times as more as in cortex of two models.The accumulation dynamic principle of geniposide in E. ulmoides leaves beween the tree models were slightly different. The content of geniposide in leaf modle leaves showed its maximum values in July, and the peak value in tree modle leaves appeared in June, then decreased. The accumulation dynamic principle of geniposide in E. ulmoides cortex beween the tree models were different. The content of geniposide in leaf modle cortex increased month by month, until November reached the peak value. The content of geniposide in tree modle cortex increade from May to June, followed by a downward trend and minimum in August, and increased gradually then, the peak value appeared in November, and it was about 6 times in E. ulmoides leaves in the same period. |
