Anti-inflammatory, analgesic activity, acute toxicity and hypericins content of Iranian hypericum perforatum

ABSTRACT

Hypericum perforatum is a medicinal plant which has been known in traditional medicine as anti-inflammatory and healing agent. This study was done to determine the effect of anti inflammatory, analgesic activity and acute toxicity of this plant. In this experimental study the plant extracted by soxhlet with methanol. The anti-inflammatory and analgesic effects of extract were studied using carrageenan induced rat paw edema, formalin, hot plate and writhing tests. Motor coordination was assessed using Rotarod test and acute toxicity [LD[50]] was determined using probit method. ANOVA followed by Student-Newman-Keuls test were used to determine significant differences between groups and p<0.05 was considered significant. Similar activity against carrageenan-induced rat paw edema was observed with hypericum perforation extract [100 and 150 mg/kg] and indomethacin [4 mg/kg]. In the formalin test, the extract [25-250 mg/kg, i.p.] caused graded inhibition of both phases of formalin-induced pain [p<0,001]. In the hot plate test, the i.p. administration of the extract at the doses of 25- 250 mg/kg significantly raised the pain threshold at an observation time of 30 min in comparison with the control group [p<0.001]. In the writhing test, the extract at doses of 25 mg/kg [p<0.05], 50, 75, 100 and 150mg/kg [p<0.001] produced a significant decrease in the number of writhing in comparison with the control group. The extract, at antinociceptive doses, did not affect motor coordination of animals when assessed in the rotarod model. The 72 hr acute LD[50] value of this extract after i.p. administration in mice was 1111.47 mg/kg. The total content of hypericins was determined 0.101 +/- 0.003 in this plant. Based on these results, hypericum perforatum can be introduced as an anti-analgesic and anti-inflammatory plant