In vitro vasodilatory effect of aqueous leaf extract of Thymus serrulatus on thoracic aorta of Guinea pigs

Objective:To investigate the vasodilatory effecl of Thymus serrulatus(T.serrulatus) aqueous leaf extract on KCl(high K^+.80 mmol/L) induced precontracted isolated thoracic aorta rings on guinea pigs and the role of aorta endothelium on this action.Methods:Guinea pig thoracic aorta was removed and placed in an organ bath containing Krebs-Henseleit solution and aorta contractions were recorded isometrically.Results:The results revealed that T.serrulalus aqueous leaf extract(0.5-5 mg/mL)significantly(P<0.001) reduced KCl-induced contractions of guinea pig thoracic aorta in both intact(n=5) and denuded(n=5) endothelium in a concentration dependent manner,and the vasodilatory effect of the extract on intact endothelium was significantly(P<0.05) higher than that on denuded endothelium.Glibenclamide(10 μmol/L) significantly(P<0.001) increased the vasodilatory effect of extract in intact endothelium as compared to methylene blue(10μmol/L).atropine(10 μmol/L) and indomethacin(10 μmol/L).The effecl was more obvious on intact than that on denuded endothelium.Conclusions:The present findings demonstrate that T.serrulalus aqueous leaf extract has vasodilator)' activity which might result in antihypertensive effect and its vasodilatory effect is endothelium-dependent.This might support the traditional claim of the plant in hypertensive.

Antihyperglycemic and subchronic toxicity study of Moringa stenopetala leaves in mice

Objective:To evaluate the antihyperglycemic activity and subchronic toxicity of an extract ofMoringa stenopetala(M.stenopetala)leaves in mice.Methods:Antihyperglycemic activities of various solvent subfractions and chromatographic fractions were investigated in alloxan induced diabetic mice.All fractions were administered intragastrically using oral gavage at a dose of 500 mg/kg.For the subchronic toxicity investigation of the 70%ethanol extract of M.stenopetala leaves,a daily dose of 300 or 600 mg/kg body weight was administered to mice over 96 d.Some hematological and plasma biochemical parameters were measured as indices of organ specific toxicity.Preliminary phytochemical screening and antioxidant activity investigation was done using thin layer chromatography method.Results:Among the solvent subfractions of the 70%ethanol extract tested only butanol subfraction exhibited significant reduction of blood glucose level(P<0.05)at 2 h(53.44%)and 4.5 h(46.34%)in diabetic mice and it was further fractionated chromatographically.This resulted in isolation of three chromatographic fractions(fraction 1,2,and 3)which exhibited maximal blood glucose reduction(P<0.01)at 6 h(77.2%),at 4.5 h(69.1%)and at 4.5 h(71.96%)after administration.Furthermore,these fractions exhibited comparable antioxidant activity,and preliminary phytochemical screening indicated the presence of phenolic compounds which may be phenolic glycoside in all fractions.The subchronic toxicity study of the 70%ethanol extract of M.stenopetala leaves revealed that there were no significant differences in body weight,between controls and treated mice.Hematological analysis showed no differences in most parameters examined.Furthermore,it did not significantly affect plasma creatinine,urea,cholesterol,triglycerides and CA125 levels.It also did not significantly affect the plasma T3,T4 and THS level.It,however,caused a significant dose-dependent increases in aspartate aminotransferase and alkaline phosphatase.The plasma alanine aminotransferase increased in a dose dependent manner,though not significant.Conclusions:The present study revealed that the crude ethanol extract and solvent-solvent fractions as well as chromatographic fractions have antihyperglycemic effect.Furthermore,the crude ethanol extract have some effect on liver of the mice on subchronic administration.Therefore,further study should be done to identify the active principal compound responsible for antihyperglycemic effect and to rule out the safety in other animal model.