Improvement in the turnover rate of the stratum corneum in false aged model rats by the administration of geniposidic acid in Eucommia ulmoides OLIVER leaf

We earlier reported that collagen synthesis in false aged model rats was st imulated by the administration of a methanol extract from the leaves of Euc ommia ulmoides OLIVER. When the methanol extract was fractionated to n-hexa ne, ethyl acetate, acetone and methanol fractions by silica gel chromatogra phy, we discovered that geniposidic acid and aucubin, contained in the acet one fraction, were the active ingredients. In the current study, we set out to examine if active compounds found in the Eucommia ulmoides OLIVER leaf (EUOL) improved the low turnover rate in the stratum corneum of false aged model rats. The turnover rate in the stratum corneum in rats was measured a s 50% dansyl chloride clearance day. In the first experiment, administratio n of a 2.4% water soluble methanol extract (WSME) of EUOL, along with an 11 % protein diet, led to a 20% higher turnover rate in the stratum corneum (p <0.05, Mann-Whitney) than the control value. The WSME mainly contained irid oid mono-glycosides such as geniposidic acid. In the second experiment trea tment with geniposidic acid similarly caused a higher turnover rate in the stratum corneum, increasing turnover by 23% (p<0.05, Mann-Whitney) compared to the control value. In this paper we reveal that the WSME contains compo unds effective against aging, and one of them is geniposidic acid.