Background and Aim: Red ginger (RG) has reportedly been used in folk medicine for the management and prevention of hypertension. One of the hypertension study models in experimental animals is the unilateral ureteral obstruction (UUO). This study aimed at evaluating the effect of RG-extract (RGE) nanoemulsion on UUO-induced hypertension and angiotensin-converting enzyme (ACE) production in rats.

Materials and Methods: RG was extracted using ethanol, combined with virgin coconut oil, polysorbate 80, and polyethylene glycol 400 to form the oil phase. The particle sizes of RGE nanoemulsions were analyzed using a particle size analyzer. The UUO method was used to induce chronic kidney disease in rats (504 mg/200 g and 360 mg/200 g b/w per oral for 7 days). The systolic and diastolic blood pressure was determined non-invasively in conscious state by tail plethysmography using an automated blood pressure monitor. ACE in serum was measured using enzyme-linked immunosorbent assay.

Results: The RGE nanoemulsions exhibited a particle size of 32.8 nm and a polydispersity index (PI) of 0.268, indicating a homogenous nanoemulsion. UUO rats treated with RGE nanoemulsion (360 mg/200 g b/w) experienced a significant decrease in both their systolic blood pressure (p<0.05) from 142±1 mmHg to 107±6 mmHg and their diastolic blood pressure from 106±1 mmHg to 84±4 mmHg. Furthermore, treatment with RGE resulted in a 10.80% decrease in the level of ACE.

Conclusion: The size and the PI of the RGE used in this study suggest a stable and effective distribution of the particle size in the emulsions. RGE nanoemulsions at the dose of 360 mg/200 g bw can be used as potential ACE inhibitors because they were found to decrease the blood pressure of hypertensive UUO rats.

Keywords: angiotensin-converting enzyme, blood pressure, nanoemulsion, red ginger, unilateral ureteral obstruction.