The Antihypertensive Effect of Hydro-methanolic Extract of Tulbaghia acutiloba Harv. in L-NAME induced Hypertensive Rats

Abstract

Background

Traditional use of Tulbaghia acutiloba (TA) in South Africa includes treating various illnesses, such as infectious diseases and hypertension. However, the effect of this indigenous plant on renal and haematological parameters (as indicators of antihypertensive efficacy) has not been investigated yet.

Objective

This study aimed to evaluate the change of renal and haematological parameters after treatment with the hydro-methanolic extract of the leaf of Tulbaghia acutiloba Harv. in L-NAME- induced hypertensive rats.

Methods

Male albino Wistar rats received an oral dose of 50 mg·kg^-1 body weight (bw) of N_ω-Nitro-L-arginine methyl ester hydrochloride (L-NAME) daily for 5 weeks. Five groups (7 animals in each group) were identified to receive different treatments as concurrent daily doses of (40, 60 and 80 mg·kg^-1 bw), ramipril (10 mg·kg^-1 bw) (positive control) and water (hypertension model). Mean arterial blood pressure was measured weekly using the tail-cuff method. A 24-hour urine sample was collected for each rat weekly. On day 36, the rats were euthanized, and blood samples were collected for the determination of renal function and haematological analysis. Kidney mRNA gene expression was performed for NF-kB, Ho1 and eNos.

Results

The treatment of the hypertensive rats with TA resulted in a significant reduction in the mean arterial blood pressure, with a pronounced effect observed in the 80 mg·kg^-1 dose of TA compared to the positive control. The TA-treated group showed increased creatinine clearance (Ccr), urine volume and a reduction in serum creatinine, proteinuria and urine protein-creatinine ratio (UPr/UCr). TA treatment also decreased lipid peroxidation in renal tissues and erythrocytes while increasing SOD, CAT, GSH and NO levels. Moreover, red cell distribution width (RDW), white blood cells (WBC), neutrophil to lymphocyte ratio (NLR), lymphocyte to monocyte ratio (LMR), platelet and mean platelet volume (MPV) were significantly reduced in the TA and ramipril treated groups with the maximum effect occurring at the dose of 80 mg·kg^-1 of TA. No significant difference was observed in the haemoglobin levels in all experimental groups. TA administration resulted in a significant decrease in renal NF-kB gene expression while increasing Ho1 and eNos gene expression in renal tissues.

Conclusion

TA extract improved renal function and haematological profile (markers for the antihypertensive efficacy) in L-NAME-induced hypertensive rats.