Effects of Brazilian green propolis on proteinuria and renal function in patients with chronic kidney disease: a randomized, double-blind, placebo-controlled trial

BACKGROUND: Chronic kidney disease (CKD) is a public health problem worldwide, and proteinuria is a well-established marker of disease progression in CKD patients. Propolis, a natural resin produced by bees from plant materials, has anti-inflammatory, immunomodulatory, and anti-oxidant properties, as well as having been shown to have an antiproteinuric effect in experimental CKD. The aim of this study was to evaluate the impact of Brazilian green propolis extract on proteinuria reduction and the changes in the estimated glomerular filtration rate (eGFR). METHODS: This was a randomized, double-blind, placebo-controlled study including patients with CKD caused by diabetes or of another etiology, 18–90 years of age, with an eGFR of 25–70 ml/min per 1.73 m(2) and proteinuria (urinary protein excretion > 300 mg/day) or micro- or macro-albuminuria (urinary albumin-to-creatinine ratio > 30 mg/g or > 300 mg/g, respectively). We screened 148 patients and selected 32, randomly assigning them to receive 12 months of Brazilian green propolis extract at a dose of 500 mg/day (n = 18) or 12 months of a placebo (n = 14). RESULTS: At the end of treatment, proteinuria was significantly lower in the propolis group than in the placebo group—695 mg/24 h (95% CI, 483 to 999) vs. 1403 mg/24 h (95% CI, 1031 to 1909); P = 0.004—independent of variations in eGFR and blood pressure, which did not differ between the groups during follow-up. Urinary monocyte chemoattractant protein-1 was also significantly lower in the propolis group than in the placebo group—58 pg/mg creatinine (95% CI, 36 to 95) vs. 98 pg/mg creatinine (95% CI, 62 to 155); P = 0.038. CONCLUSIONS: Brazilian green propolis extract was found to be safe and well tolerated, as well as to reduce proteinuria significantly in patients with diabetic and non-diabetic CKD. Trial Registration. (ClinicalTrials.gov number NCT02766036. Registered: May 9, 2016). ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12882-019-1337-7) contains supplementary material, which is available to authorized users.