Blood pressure lowering and antidyslipidemic and nitric oxide modulatory effects of methanol extract of Struchium sparganophora leaves on dexamethasone-salt model of hypertension in rats

Background: The use of glucocorticoids causes elevation of blood pressure in man and experimental rats. We evaluated the antihypertensive potential of methanol extract of Struchium sparganophora leaves (SPA) on dexamethasone-salt induced hypertension in Rattus novergicus.

Methods: Rats were assigned randomly to 6 groups (n=4/group). Group A represented control, while blood pressure (BP) elevation (BP ≥ 140/90) was induced in groups B to F via single subcutaneous administration of dexamethasone at a dose of 2 mg/kg with 4 % NaCl substituted as drinking water for five days. Group B-F were treated twice daily for 10 days as follows: B; untreated, C; nifedipine 3 mg/kg, D; nifedipine 3 mg/kg + SPA 300 mg/kg, E; SPA 300 mg/kg and F; SPA 600 mg/kg. BP readings, and Plasma biochemical assays were done using established protocols.

Results: SPA at 300 and 600 mg/kg markedly decrease BP (P<0.05) which was increased by dexamethasone-salt in rats. Rats treated with SPA markedly showed increased serum HDL-cholesterol with decreased triglyceride concentration when compared to rats administered dexamethasone-salt only (P<0.05). SPA increases nitric oxide concentration (NO) in a dose-dependent manner in dexamethasone-salt hypertensive rats (P<0.05).

Conclusion: This study revealed that SPA might lower blood pressure by increasing NO concentration, and balancing lipid homeostasis in the dexamethasone-salt hypertensive rats.