Reference

Effect of cucurbitacins on bilirubin-albumin binding in human plasma

All Rights Reserved. Effect of cucurbitacins on bilirubin-albumin binding in human plasma. Greige-Gerges, H.; Abou Khalil, R.In this study， 2222-07-3 and 635-65-4 are also used.; Chahine, R.; Haddad, C.; Harb, W.; Ouaini, N. (Faculty of Sciences and Computer Engineering, Holy Spirit University of Kaslik, Jounieh, Lebanon). Life Sciences, 80(6), 579-585 (English) 2007 Elsevier B.V. CODEN: LIFSAK. ISSN: 0024-3205. DOCUMENT TYPE: Journal CA Section: 1 (Pharmacology) Section cross-reference(s): 63 The aim of this study is to investigate the effect of three cucurbitacins (Cuc) E, D and I on the bilirubin-albumin binding, both in human serum albumin (HSA) and in plasma. Bilirubin-HSA soln. and plasma free of cucurbitacins were prepd. as well as others contg. serial concns. of cucurbitacins. The concn. of unbound bilirubin was detd. in bilirubin-HSA soln. and the direct and total bilirubin concns. were measured in plasma (with normal or elevated bilirubinemia) by Jendrassik and Grof method. In the conditions we adopted Cuc E and D (to a lesser extent), decreased the levels of unbound bilirubin in bilirubin-HSA soln. and decreased direct bilirubin concn. and total bilirubin concn. in plasma in a dose-dependent manner while Cuc I had no effect. The effect of Cuc is related to the presence of native HSA. Thus, when albumin was absent or has been denatured by heating or by urea, Cuc E did not modify bilirubin levels, suggesting that the native structure of albumin is essential for such activity. The interaction of HSA with Cuc E was investigated by fluorescence spectroscopy. Cuc E increased the intrinsic fluorescence of the protein and the magnitude of fluorescence intensity of bilirubin-albumin complex. We concluded that Cuc E and D produced a rearrangement in the structure of albumin, particularly in the domain-II, resulting in an increase in the binding of bilirubin to albumin regardless to whether it's conjugated to glucuronic acid or unconjugated. .