Long-term use of NaNO2 in food preservatives causes a variety of health problems, particularly
for kidney function. Natural antioxidants that can reduce the effects of free radicals are required
to prevent these effects. The sweet flag plant is a medicinal plant with high antioxidant potential.
This study aims to determine the effect of sweet flag rhizome extract (SFRE) on the
morphology and histology of the kidneys of white rats induced by NaNO2. This study used 25
rats with 5 groups. Negative control was given CMC0,5% for 40 days, positive control was given
NaNO2. dose of 50 mg/kgBW on days 1-30 and CMC0.5% on days 16-40, treatment groups 1,
2 and 3 were given NaNO2 Dosage of 50 mg/kgBW on days 1-15, on days 16-30 was given
NaNO2 Dosage of 50 mg/kg BW+SFRE, on days 31-40 only given SFRE in graded doses
(T1=250,T2=500, and T3=750 mg/kgBW). The results obtained include SFRE has no effect on
kidney morphology. However, SFRE affects the diameter of the distal and proximal tubules
with both tubules getting P value=0.000. SFRE had an effect on the score of histological
damage with Pvalue=0.017. The safe and optimal dose of SFRE to improve renal histology is a
dose of 250 mg/kg BW