| The contents of chemical constituents in Eucommia ulmoides leaves in different seasons, cultivation directions, producing areas and processing methods were systematically studied, mainly primary metabolites (including total sugar, soluble sugar and polysaccharides, protein and fats), secondary metabolites (including chlorogenic acid, flavonoids, aucubin and geniposidic acid), and extracts (including aqueous and alcoholic extract) to provide scientific basis for the development and utilization of the leaves in the fields of medicine,food, feedstuff and industrial raw material. The results were as follows.1. Seasonal changes of the primary metabolites indicated that the content of total sugar showed its maximum values in June (32.21%) and September (35.02%), soluble sugar ranged from 19.19% to 23.77% in the whole growing season, and the poplysaccharides changed in the same pattern as total sugar (two peak values were in May and September); The content of protein showed its highest value in May (19.67%), then decreased gradually, minimum value appeared in October (12.33%), and increased slowly then; The content of fats in the whole growing season showed a arch-growth trend: lowest in May(4.14%), and increased gradually then, the peak value appeared in August (8.62%), then decreased gradually; The content of fiber was the highest in May (12.50%), and then decreased slowly; The content of ash in the whole growing season was a linear-growth trend, ranging from 6.51% in May to 16.75% in December. Considering secondary metabolites: The content of chlorogenic acid appeared the first peak value in June (3.57%), which was the highest in the whole growing season, followed by a downward trend, and minimum in August, and increased gradually then, a small peak value (2.68%) appeared in November, and dropped in December. The content of flavonoids in the whole growing season showed a " saddle-shaped curve " trend, the first peak value (2.46%) appeared in June, and the second one (2.63%) appeared in November. The content of aucubin increased rapidly from May (1.30%), and reached the highest peak value in June, declined rapidly then, and slowly afterwards. The content of geniposidic acid kept high levels in June and July (3.45% and 3.53% respectively), and then maintained downward linearly, stayed a steady state from October to December. The total content of secondary metabolites was the highest in June (10.79%), decreased then until October (5.79%), picked up in November (6.26%), lowest in December(4.83%). Considering extracts, amount of aqueous extract was the lowest (34.63%) in May, rose to 42.72% in June, declined to 41.43% in July, reached the highest (46.35%) in September. Seasonal changes of aqueous extract, total content of protein, soluble sugar and ash were positively correlated. The amount of alcoholic extract was also the lowest (32.84%) in May, highest (41.63%) in July, followed by a slow downward trend, and stayed in a steady state from September to December. Seasonal changes of alcohol extract, total content of secondary metabolites were also positively correlated. No correlation was found between primary metabolites and secondary metabolites.2. The contents of chemical constituents in the leaves of E. ulmoides cultivated in different directions (east, south, west and north slopes) were compared. The results showed that the contents of primary metabolites and secondary metabolites were the highest in those grown in the south slope, the total content of three major primary metabolites (total sugar, protein and fats) were 49.61%, the total content of four secondary metabolites (chlorogenic acid, flavonoids, aucubin and geniposidic acid) were 10.43%, followed by those in the east slope (46.52% and 9.85%) and north slope (45.53% and 9.19%), and west slope (43.35% and 8.61% for the total primary and secondary metabolites respectively).The amounts of extracts were also the highest in the south slope, 43.37% and 41.12% for the aqueous and alcoholic extract respectively, followed by the north slope (41.82% and 40.12% respectively) and the west slope (40.95% and 38.24%), and east slope (37.21% and 36.45%).Therefore, E. ulmoides leaves growed in the south slope of the mountain were in best quality.3.The contents of chemical constituents in the leaves of E. ulmoides in two traditional cultivation regions (Zunyi in Guizhou Province, Luoyang in Shaanxi Province) and an introduced region (Yangling in Shaanxi Province) were analyzed and compared. The results showed that the contents of chemical constituents were different in the three regions. Considering primary metabolites and extracts:Zunyi>Yangling>Luoyang.Considering secondary metabolites: Zunyi> Luoyang> Yangling. It indicated cultivation regions played an important role for the accumulation of chemical constituents.4.Effects of different processing methods on the contents of chemical constituents in the E. ulmoides leaves were investigated. The results showed that various processing methods had different effects on the contents of chemical constituents. The contents of aucubin and geniposidic acid increased, and the contents of chlorogenic acid and flavonoids decreased with small amplitude in those being treated by heating process. After the processed samples were stored for half a year, two iridoid compounds decreased dramatically in those treated by sunshine drying 74% decrease for aucubin and 59% for geniposidic acid, two phenols were not evidently decreased, chlorogenic acid and flavonoids decreased by 1.2% and 1.1% respectively. No significant decreases were found in those treated by different heating methods. And microwave treatment was found to be the best one for its maintenance of green color and acceptable flavor. No significant changes were found for the primary metabolites among those treated by different methods and stored samples.
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