Antiproliferative properties of honey types from the Western Balkans

Abstract

Honey is a natural sweetener used not only for food, but also for therapeutic purposes. It contains carbohydrates, primarily glucose and fructose (85–95%) but also contains about 200 substances present in small amounts (minerals, proteins, enzymes, amino acids, organic acids, vitamins, polyphenols and others). The type of honey is characterized by the type of pollen, insect secretions, as well as climatic conditions and soil composition. The health benefits of honey results from its antioxidant nature, antimicrobial and antiproliferative activity. Several studies demonstrate the anticancer activity of honey, namely honey shows a chemopreventive effect against various cancer cell lines and tissues in in vitro and in vivo studies. This activity can be explained by different mechanisms including cell cycle arrest, induction of apoptosis, modulation of oxidative stress and immuno-modulation. Therefore, honey can be applied in alternative medical treatment of human tumors. With the aim to assess the antiproliferative properties of different types of honey characteristic for The Western Balkans, nineteen samples (acacia, linden, heather, sunflower, phacelia, basil, anise, sage, chestnut, hawthorn, buckwheat, lavender and meadow) were collected from different locations in the mentioned region and examined. The quality of honey samples was also tested to ensure that they meet the requirements defined by the national and international legislation. All tested honey samples were in accordance with the regulations of national and EU regulations. The antiproliferative activity of honey samples was evaluated using human tumor cell lines HeLa (cervcal carcinoma), MCF7 (breast epithelial adenocarcinoma), HT-29 (colon adenocarcinoma) and MRC-5 (normal fetal lung fibroblasts). The most active samples were linden honey sample from Fruška gora (IC50MCF7 = 7.46 ± 1.18 mg/mL and IC50HeLa = 12.4 ± 2.00 mg/mL) and meadow sample 2 (IC50 MCF7 = 12.0 ± 0.57 mg/mL, IC50 HeLa = 16.9 ± 1.54 mg/mL and IC50 HT-29 = 23.7 ± 1.33 mg/mL) towards breast (MCF7), cervix (HeLa), and colon (HT-29) cancer cells. The most active samples, linden and meadow 2 also affected the growth of MRC-5 cells derived from healthy lung tissue with IC50MRC-5 = 9.93 ± 0.68 mg/mL and IC50MRC−5 = 12.9 ± 0.34 mg/mL, respectively. Colon carcinoma cell line HT-29 was the least sensitive to the evaluated samples. Standard (glucose) had lower and uniform cell growth effect with IC50 values ranging from 33–40 mg/mL towards all evaluated cell lines, indicating that active components in samples other than sugars contributed to cell growth activity. These compounds are probably polyphenols. Polyphenolic profile investigation will be needed to correlate antiproliferative activities and polyphenol contents for evidences of the mechanisms of their action.