The promoting effect of eucommiol from Eucommiae cortex on collagen synthesis.

The effect of a methanol extract of Eucommiae Cortex on collagen synthesis was investigated in false aged model rats. Granuloma formation and collagen synthesis were significantly increased by the administration of the methanol extract of Eucommiae Cortex. The effective component of Eucommiae Cortex was then discussed by fractionating the methanol extract of Eucommiae Cortex. Eucommiol, a main component in the water fraction of the methanol extract, was found to be an effective compound. In our previous paper, we reported the promoting effect of Eucommia ulmoides OLIVER leaf on collagen synthesis, and found geniposidic acid and aucubin were the main effective compounds in the leaf. Based on our data in this paper, we clarified that the main effective components of the Eucommia ulmoides OLIVER leaf and Eucommiae Cortex were different. Geniposidic acid and aucubin were reported to be contained at a high concentration in the fresh cortex of Eucommia ulmoides OLIVER, but during the drying process and storage, most of them were destroyed by enzymes in the cortex and very little remained in the Eucommiae Cortex. Therefore, we investigated the effect of the methanol extract of fresh cortex of Eucommia ulmoides OLIVER. A stronger effect than Eucommiae cortex was shown, and geniposidic acid, aucubin and geniposide were concluded to be the main effective components. Although geniposide was found to be an effective compound, when the dose was higher than 50 mg/kg/d, toxicity was shown. The pharmaceutical effect of eucommiol was reported for the first time.