Fragmentation study and comprehensive profilling of Esscin, a mixture of triterpene saponins from Aesculus Hyppocastanum, by LC-MS/MS

摘要

Escin is a mixture of over 30 triterpene saponins. It is extracted from the seeds of Aesculus Hyppocastanum. Escin has phlebotonic and anti-inflamatory properties. It is administered orally in chronic venous insufficiency, and locally for reducing oedemas and haematomas. The general structural formula of Escin is shown in Fig. 1. The most abundant components are Escin Ia (R1 = GlurGluGlu, R2 = R3 = H, R4 = Ac, R5 = Tig) and Escin Ib (isomer of Escin Ia with R5 = Ang). A summary of the existing literature: (1) Structural elucidation of the major Escin components has been performed mainly by NMR after extraction and isolation of the pure compounds1,2. (2) An early LC-MS profile of Escin was performed in 1999 by Thermospray LC-MS3 (3) A MSn fragmentation study on Sodium-cationized Escin Ia and Ib has been reported4, obtaining information on the oligosaccharide chain. Some analytical aspects to consider: Extensive structural complexity: tens of components, including: (1) positional isomers (the beta- and iso- forms of each species) (2) diastereoisomers (tigloyl- and angeloyl-, glucosyl- and galactosyl- analogues) Standard substances unavailable for most components HPLC method (UV) available in Pharm. Eur.5, but: (1) No information of peak identities (2) Possibility of co-elution of some components / impurities, especially during stability studies (3) Interferences from excipients in the drug formulations