Chemical composition – biological activities of selected samples of propolis from South Greece

Abstract

Propolis (bee glue) is a well known natural product with healing properties. The chemical composition of propolis is highly variable and depends mainly on the local flora. Greece is characterized by high biodiversity flora, assuming different propolis composition. In the framework of our continuing work on propolis samples from Greece and all around the world, four propolis samples from Peloponnese and one from the island of Kos were analyzed by GC/MS after silylation. In these samples the diterpenes: totarol, totarolone, abietic acid, imbricataloic acid, isoagatholal, agathadiol, communic acid, junicedric acid, 13-epi-cupressic acid and isocupressic acid have been identified as major constituents while the characteristic propolis flavonoids were either in small amounts or even absent. These findings confirm the presence of conifer trees as propolis plant sources in Greek samples. Diterpenes have been previously found in propolis samples from North-West Greece [2], Crete and Italy (Sicily) [3] while propolis from the temperate zone having Populus spp. as plant sources [1] have large amounts of esters of phenolic acids and flavonoids. All the samples showed significant antibacterial activity against nine Gram-negative and -positive human pathogenic bacteria and three fungi, probably due to the large amounts of diterpenes, while the antioxidative activity of all samples has been assayed as well thorough Rancimat method.