Effect of ninhydrin on the biochemical and histopathological changes induced by ethanol in gastric mucose of rats

Studies on the effect of ninhydrin in the normal gastric mucosa and against the ethanol induced gastric injury were undertaken in rats in view of the presence of a carbonyl function as well as hydroxyl groups in its chemical structure. In spite of its potentials to generate hydroxyl radicals, it is deemed to possess antioxidant property by virtue of its electrophillic natu re. Recent studies have shown gastroprotection to mediate through a reactio n between the electrophillic compounds and sulfhydryl groups of the mucosa. Hence it was found worthwhile to evaluate the interaction between the oxid ant and antioxidant functions in the structure of the same compound. The ef fects of ninhydrin pretreatment on gastric mucosal injuries caused by 80% e thanol, 25% NaCl and 0.2M NaOH were investigated in rats. The gastric tissu e in ethanol-treated rats was analyzed for different histopathological lesi ons. In addition, the effects on ethanol-induced changes in the gastric lev els of proteins, nucleic acids, non-protein sulfhydryl (NP-SH) and malondia ldehyde (MDA) were also evaluated. Ninhydrin, as such, failed to induce any significant changes in normal gastric mucosa, while its pretreatment at or al doses of 5, 10 and 20 mg/kg was found to provide a dose-dependent protec tion against the ulcers induced by ethanol, NaOH and NaCl. The results of h istopathological evaluation revealed a protective effect of ninhydrin on co ngestion, hemorrhage, edema, erosions and necrosis caused by ethanol. Furth ermore, the pretreatment afforded a dose-dependent inhibition of the ethano l-induced depletion of proteins, nucleic acids, NP-SH and increase of MDA i n the gastric tissue. The results obtained clearly demonstrate the anti-ulc erogenic activity of ninhydrin. The exact mechanism of action is not known. However, the carbonyl function in ninhydrin appears to achieve antioxidant balance and protect the gastric mucosa from the ethanol-induced gastric in jury. Further studies are warranted to investigate the toxicity and detaile d mechanism of action of this potent compound before any clinical trials, e specially at the effective lower doses. (C) 2000 Elsevier Science Inc. All rights reserved.