Portulaca oleracea seeds extract does not prevent dexamethasone-induced hypertension in rats

Introduction: Portulaca oleracea is used as a nutritional and medicinal plant. The aim of this study was to assess the effect of hydroalcoholic extract of P. oleracea seeds in dexamethasone -induced hypertension in rats. Methods: For induction of hypertension, dexamethasone (30 μg/kg/d, subcutaneously) was administered for 14 days. Animals received P. oleracea extract as a pretreatment at various doses of 100, 200 and 400 mg/kg/d orally from 4 days before dexamethasone administration and during the test period. Systolic blood pressure (SBP) and heart rate were measured using tail-cuff method. The weight of thymus gland was estimated as a marker of glucocorticoid activity. Results: Dexamethasone injection significantly increased SBP (P < 0.001) while decreased the body and thymus weights (P < 0.05 and P < 0.001, respectively). Oral administration of P. oleracea could not prevent rising in SBP and decreasing in thymus weight. It also increased heart rate in hypertensive rats at the dose of 400 mg/kg/d (P < 0.05). Conclusion: The results of this study revealed that hydroalcoholic extract of P. oleracea seeds aggregates hypertension in dexamethasone-induced hypertensive rats. Hence, it should be used with caution in hypertensive patients receiving glucocorticoids.