Chemical Composition of Volatile and Extractive Components of Canary (Tenerife) Propolis

Abstract

The vegetation of the Canary Islands is characterized by a large number of endemic species confined to different altitudinal levels. It can be assumed that these circumstances determine the characteristic features of the chemical composition of local beekeeping products, including propolis. We report, for the first time, the chemical composition of propolis from Tenerife (Canary Islands). The volatile emissions of three propolis samples collected from different apiaries are represented by 162 C1–C20 compounds, of which 144 were identified using the HS-SPME/GC-MS technique. The main group of volatiles, consisting of 72 compounds, is formed by terpenoids, which account for 42–68% of the total ion current (TIC) of the chromatograms. The next most numerous groups are formed by C6–C17 alkanes and alkenes (6–32% TIC) and aliphatic C3–C11 carbonyl compounds (7–20% TIC). The volatile emissions also contain C1–C6 aliphatic acids and C2–C8 alcohols, as well as their esters. Peaks of 138 organic C3–C34 compounds were recorded in the chromatograms of the ether extracts of the studied propolis. Terpene compounds form the most numerous group, but their number and content in different samples is within very wide limits (9–63% TIC), which is probably due to the origin of the samples from apiaries located at different altitudes. A peculiarity of the chemical composition of the extractive substances is the almost complete absence of phenylcarboxylic acids and flavonoids, characteristic of Apis mellifera propolis from different regions of Eurasia and North America. Aromatic compounds of propolis from Tenerife are represented by a group of nine isomeric furofuranoid lignans, as well as alkyl- and alkenyl-substituted derivatives of salicylic acid and resorcinol.