A pilot study on the immunomodulatory effect of bulgarian propolis

Abstract

Propolis is a product from the honey bee A. mellifera with various pharmacological properties. Its immunomodulatory activity is in the focus of the current research. Peripheral blood mononuclear cells (PBMC) from heparinized venous blood of healthy donors (n=6) were cultured for 24 h in the presence of propolis from the Eastern Rodopi Mountain (ethanol extractions with concentration 0, 01; 1; 2,5; 5 and 10 mg/L) or CAPE in concentration 2, 4, 8 and 16 mg/L. PBMC cultured in serum free RPMI only were used as controls. The percentage of T helper/inducer (CD4+CD3+), T cytotoxic (CD8+CD3+), B (CD19+CD3-) and NK (CD56+CD16+CD3-) lymphocyte subsets, as well as the proportion of apoptotic (Annexin V+) cells within each subset were determined before and after the cultivation by flow cytometry (FACS Calibur, BD). The percentage of CD19+ cells decreased in high concentrations of both of substances, but in low concentrations they had a protective effect on the proliferation and B cell activity. Low dozes had no effect on the percentage of CD4+ and CD8+ T cells. The high concentrations of propolis (10 mg/L) and CAPE (16 mg/L) induced apoptosis in a large portion of all of cells types. All concentrations tested had no negative effect on the proliferation and vitality of NK cells. Our results evidence that high propolis concentrations are toxic for human PBMC, but low concentrations modulate cellular immunity‥. © 2010 Taylor and Francis Group, LLC.