RESUMEN
Background: Proteinuria is a significant clinical manifestation that causes edema in several diseases, including Nephrotic Syndrome (NS). Untreated proteinuria is strongly linked to the progression of kidney failure. One of the adjuvant therapies could be used to reduce proteinuria such as Angiotensin Receptor Blocker (ARB) including Losartan®. Gambier is a traditional medicinal plant widely known for its antioxidant effects. Catechin, a compound contained in Gambier Extract (GE), has been used to reduce microalbuminuria in diabetics. However, its application in NS has not been widely studied. Objective: This study compared the effects of GE and ARB in reducing proteinuria and increasing antioxidant activity levels, as well as reported histopathological findings in the nephrotic Wistar rat model. Methods: An experimental design study with a control group and a posttest was conducted. The experimental animals were divided into four groups: the control group (K1), the group with puromycin aminonucleoside (PAN) injection (K2), the group with PAN injection + GE (K3), and the group with PAN injection + Losartan® (K4). The standard GE used was Sarie Uncariae® by Toyo Brothers, PT while the ARB (Losartan®) was obtained from Novell, PT. Protein urine, the activity level of total superoxide dismutase (T-SOD), and malondialdehyde (MDA) were assessed using the colorimetric method. Renal histopathology was assessed based on Rollerman's criteria. Results: Gambier extract significantly reduced proteinuria, as depicted by a decrease in protein/volume urine (p = 0.009), increased antioxidant activity, as illustrated by an elevation in T-SOD activity levels (p = 0.007), and tended to decrease MDA levels compared to Losartan®. Based on histopathological findings, GE tended to reduce the percentage of kidney damage in rats induced by puromycin. Conclusion: Gambier extract has been shown a higher antioxidant effect by increasing T-SOD activity levels, reducing proteinuria and also exhibiting a tendency to diminish kidney damage.