What is Isoescin IB?
Feb 13，2020
Escin (aescin) is a mixture of triterpene saponins and constitutes the major active ingredient in horse chestnut (Aesculus hippocastanum) seed extracts. Escin exhibits remarkable anti-inflammatory, anti-edematous and vasoprotective properties in a dose-dependent manner which are quite evident at 10-6–10-7 M. Escin has been traditionally used to treat conditions such as chronic venous insufficiency, hemorrhoids, inflammation and cerebral ischemic damage.
The saponins found in escin exist in two forms, β-escin and α-escin, which can be distinguished by melting point, hemolytic index, specific rotation and solubility in water. β-Escin (mainly consisting of escin Ia and escin Ib) is the major active ingredient in horse chestnut seeds extracts. As the minor component of escin, α-escin (mainly consisting of isoescin Ia and isoescin Ib) exhibits lower bioactivity.
Similar to isoescin Ia is the isomer of escin Ia, Isoescin Ib is an isomer of escin Ib. Both of them were found to be isomerizable in vitro. Escin Ib and isoescin Ib exhibits stronger pharmacological activity than escin Ia and isoescin Ia. As the result, pharmacokinetics study of them would be helpful for improving the practice of escin application.
For the purpose to develop individual isomers of escin as pure drugs, detailed pharmacokinetic studies are required to support drug development. Studies on drug exposure and pharmacogenomic response have also been done at molecular level in humans, in which gene variation at SNP level may become relevant target for drug therapy. The Cmax, AUC and F values of isoescin Ib following a dose of isoescin Ib were higher than the corresponding values of escin Ib following a dose of escin Ib using both administration routes. The t1/2 and MRT values of escin Ib and isoescin Ib following the IV administration of sodium escinate were higher than the corresponding values following the IV administration of single isomers. The bidirectional interconversion of isomers was observed, and the conversion of escin Ib to isoescin Ib was found to be much faster in the forward direction compared to the reverse direction.
References
[1]. Cheng D, et al. The relationship between structurally different pyrrolizidine alkaloids and western flower thrips resistance in F (2) hybrids of Jacobaea vulgaris and Jacobaea aquatica. J Chem Ecol. 2011 Oct;37(10):1071-80
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