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 electrophilic nature. Recent studies have shown gastro-protection to mediate through a reaction between the electrophilic compounds and sulfhydryl groups of the mucosa. Hence it was found worthwhile to evaluate the interaction between the
oxidant and
antioxidant functions in the structure of the same compound. The effects of
ninhydrin pretreatment on gastric mucosal
injuries caused by 80%
ethanol, 25% NaCl and 0.2M NaOH were investigated in rats. The gastric tissue in
ethanol-treated rats was analyzed for different histopathological lesions. In addition, the effects on
ethanol-induced changes in the gastric levels of
proteins,
nucleic acids, non-
protein sulfhydryl (NP-SH) and
malondialdehyde (MDA) were also evaluated.
Ninhydrin, as such, failed to induce any significant changes in normal gastric mucosa, while its pretreatment at oral doses of 5, 10 and 20 mg/kg was found to provide a dose-dependent protection against the
ulcers induced by
ethanol, NaOH and NaCl. The results of histopathological evaluation revealed a protective effect of
ninhydrin on congestion,
hemorrhage,
edema, erosions and
necrosis caused by
ethanol. Furthermore, the pretreatment afforded a dose-dependent inhibition of the
ethanol-induced depletion of
proteins,
nucleic acids, NP-SH and increase of MDA in the gastric tissue. The results obtained clearly demonstrate the anti-ulcerogenic 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 injury. Further studies are warranted to investigate the toxicity and detailed mechanism of action of this potent compound before any clinical trials, especially at the effective lower doses.