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

Abstract

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 m2 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).

Conflict of interest statement

Ethics approval and consent to participate

Study protocol and consent was approved by the University of São Paulo School of Medicine Hospital das Clínicas Ethics Committee. Study participants provided written informed consent to participate.

Consent for publication

Not applicable.

Competing interests

The authors declare that they have no competing interests.

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Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Figures

Fig. 1

Consolidated Standards of Reporting Trials diagram showing the recruitment and follow-up of patients

Fig. 2

Changes in proteinuria (mg/day) during follow up. Values presented as mean and 95% CI for each time point according to the mixed-effect linear regression model. *P = 0.023 vs. placebo; †P = 0.006 vs. placebo; ‡P = 0.004 vs. placebo

Fig. 3

Changes in estimated glomerular filtration rate (eGFR, ml/min per 1.73 m2) during follow up. Values presented as mean and 95% CI for each time point. *P = 0.40 vs. placebo

Fig. 4

Changes in urinary monocyte chemoattractant protein-1 (MCP-1, pg/mg urinary creatinine) during follow up. Values presented as mean and 95% CI for each time point. *P = 0.038 vs. placebo

Fig. 5

Urinary albumin-to-creatinine ratio (UACR) in the subgroups of patients with type 2 diabetes, at baseline and 12 months (12 m). Propolis (n = 6) and Placebo (n = 5). Values presented as mean and 95% CI

Fig. 6

Changes in systolic and diastolic blood pressure, in mmHg. Values presented as mean and 95% CI for each time point. *P = 0.93 vs. placebo; #P = 0.089 vs. placebo