We have reported that collagen synthesis was stimulated by the administration of a hot water extract from the leaves of Eucommia ulmoides OLIVER, Eucommiaceae (Du-Zhong leaves) in false aged model rats. In this paper, we set out to examine the compounds in Du-Zhong leaves that stimulated collagen synthesis in false aged model rats. In experiment 1, a methanol extract of Du-Zhong leaves also stimulated collagen synthesis in aged model rats. An acetone fraction was derived from the methanol extract by silica gel chromatography in experiment 2. The acetone fraction mainly contained iridoides mono-glycosides such as geniposidic acid and aucubin. The administration of geniposidic acid or aucubin stimulated collagen synthesis in aged model rats in experiments 3 and 4 (significance (p<0.05)). The reported pharmacological effects of Du-Zhong leaves, including healing organs and strengthening bone and muscle, are closely related to collagen metabolism. It appears that geniposidic acid and aucubin are the actual compounds in Du-Zhong which caused the effect in our experiments.

No abstract

No abstract

No abstract

The muscle of eels fed tochu (Eucommia ulmoides Oliver) leaf powder was 1.8 times harder than the control. The component analysis showed no difference in moisture, lipid, or protein content between the muscles of the control and the tochu-fed eels. Not only the extracted neutral fat but also the compound fat of the raw muscles of the tochu-fed eel and the control had the same TLC patterns and fatty acid composition by gas chromatographic analysis. There was a great difference between the tochu-fed eel and the control concerning the amount of muscle protein stroma fraction which mainly consisted of collagen. The microscopic observation showed that the perimysium and endmysium which were the main components of the stroma fraction of the muscle of the tochu-fed eel were firm and thick compared to those of the control. These findings suggested that the intake of tochu leaf powder hardened the muscle.