REACTION OF CYCLOHEXYLAMINE WITH HYPOCHLORITE AND ENHANCEMENT OF OXIDATION OF PLASMA SULFHYDRYL-GROUPS BY HYPOCHLORITE IN-VITRO

In this study we investigated the reaction of cyclamate and its major metabolite, cyclohexylamine (CyhNH(2)), with NaOCl. NaOCl at 100 mu M was allowed to react with various concentrations of cyclamate and CyhN H(2), and the reactivity was compared with those of reduced glutathion e (GSH) and ascorbic acid. The results showed that CyhNH(2) was less r eactive with NaOCl than GSH but was slightly more reactive than ascorb ic acid at concentrations below 50 mu M. CyhNH(2) at 75 and 100 mu Mdi d not further decrease NaOCl. Cyclamate was much less reactive than Cy hNH(2), with only 43% loss in NaOCl at 100 mu M cyclamate. When human blood plasma was incubated with 0.75 mu M NaOCl, inclusion of CyhNH(2) enhanced oxidation of sulfhydryl groups in a concentration-dependent manner, with complete oxidation of SH groups at 7.5 mM CyhNH(2). Cycla mate had no effect. This enhancement by CyhNH(2) suggests the formatio n of reactive products From the reaction of CyhNH(2) with NaOCl. Absor ption spectra demonstrated that reaction of CyhNH(2) with NaOCl at pH 7.4 produced N-mono-chloramine, as evidenced by the appearance of a ne w peak at 245 nm and by the disappearance of the 292-nm peak of NaOCl. Cyclamate, which contains a sulfamic acid instead of a primary amine, also reacted with NaOCl at pH 7.4, but the reaction was much less pro nounced and the product was probably not monochloramine since the peak was at 270 nm rather than at 245 nm. Because cyclamate is an importan t sweetener in many countries for people with diabetes mellitus, the p ossibility exists that CyhNH(2) may enhance oxidation of important pro teins by HOCl/OCl-. (C) 1998 Elsevier Science Ltd. All rights reserved .