Biologically active compounds with antitumor activity in propolis extracts from different geographic regions

Abstract

Seven propolis samples (S1-S7) from different regions of Bulgaria and eight commercial products of propolis extracts (C8- C15) from various European countries were studied. Concentrations of five antitumor compounds: CAPE, quercetin, rutin, p-coumaric acid, and ferulic acid, were determined and a comparison between the propolis extracts from different regions was made. The results showed that among samples S1-S7, two were distinctive with their high concentrations of CAPE and quercetin: S1 (Asenovgrad region) - 9843.6 μg/mL and 2575.6 μg/mL, respectively, and S7 (Smolyan region) - 10270.2 μg/mL and 2575.6 μg/mL, respectively. Sample S4 (Plovdiv region) showed significant amounts of p-coumaric acid (1638.2 μg/mL) and ferulic acid (1186.5 μg/mL). Sample C11 from the commercial propolis extract products (Bulgaria) was distinctive with its high concentrations of CAPE (5802.3 μg/mL), p-coumaric acid (2955.2 μg/mL) and ferulic acid (1081.2 μg/mL). Samples C15 (Italy) and C8 (Austria) also contained significant amounts of CAPE, quercetin, p-coumaric acid, and ferulic acid. The overall results showed high content variability of the five biologically active substances analyzed. Nevertheless, each sample contained significant amounts of at least four of the biologically active compounds tested, which confirms that propolis remains a valuable source of antitumor compounds.