ABSTRACT
The antistress effect of a seven-day treatment (100 and 200 mg / kg, p.o.) of the hydroalcoholic extract of Argyreia speciosa root (ASE) was evaluated by using the swimming endurance test, acetic acid–induced writhing test, pentylenetetrazoleinduced convulsion test, anoxic tolerance test, cold-restraint, stress-induced gastric ulcers, aspirin-induced ulcers, and biochemical, and histopathological changes in the cold-restraint stress test. The immunomodulatory activity was also evaluated for the same doses, and treatment of ASE was done using the hemagglutination test. Both the doses of ASE showed antistress activity in all the tested models. The ASE-treated animals showed a decrease in immobility time and an increase in anoxic tolerance time in swimming endurance and the anoxic tolerance tests, respectively. The effect of glacial acetic acid and pentylenetetrazole were also reduced by decreasing the number of writhing responses and increasing the onset of convulsions, respectively. In the cold restrained stress and aspirin-induced gastric ulcer models, ASE showed a significant reduction in the ulcer index. Pretreatment with ASE significantly ameliorated the cold stress-induced variations in biochemical levels such as increased plasma cholesterol, triglyceride, glucose, total protein, and cortisol. ASE was also effective in preventing the pathological changes in the adrenal gland, due to cold restrained stress, in rats. In mice immunized with sheep red blood cells, the treatment groups subjected to restraint stress prevented the humoral immune response to the antigen. The immunostimulating activity of the ASE was indicated by an increase in the antibody titer in mice pre-immunized with sheep red blood cells and subjected to restraint stress. The findings of the present investigations indicate that the ASE has significant antistress activity, which may be due to the immunostimulating property and increased resistance, nonspecifically, against all experimental stress conditions.