Abstract
Various thiamine analogues with or without vitamin activity were tested to see whether vitamin activity is related to anti-inflammatory effect. The anti-inflammatory properties of thiamine, its related substances (biologically active, inactive, or antagonistic) and the modified radicals per se freed from the molecule of the active compounds were examined using (1) rat paw edema, (2) capillary permeability and (3) granuloma assay. These agents were compared with known anti-inflammatory drugs in the effect.
Thiamine (300 mg/kg, i.p.) showed no effect in rat paw edema induced with carrageenin and formaldehyde. Oxythiamine—a thiamine antagonist—and disulfide-typed thiamines, e.g. TDS (thiamine disulfide), TTFD (thiamine tetrahydrofurfuryl disulfide) and NTDS (O-nicotinyl thiamine disulfide) were all effective in anti-edema test. Furan-ring freed from TTFD molecule failed to show anti-edema effect, while nicotinic acid showed potent effect. However disulfide-typed thiamines exerted no suppressive effect on increased capillary permeability induced with histamine and bradykinin. TDS, oxythiamine and nicotinic acid inhibited the granuloma induced with filter-paper discs. However, this effect of oxythiamine seemed false, because the animals on it lost body weight. By any methods, no distinct antiinflammatory effects were shown with desthio-thiamine and thiaminic acid, which have no vitamin activity.
From these, it was clarified that anti-inflammatory effects of thiamine derivatives are related to either the vitamin activity or the chemical structure. But we found that antiinflammatory potency vary remarkably according to various experimental methods and various radicals bound to the thiamine disulfide structure.
