Flavonoid Composition of Tunisian Honeys and Propolis

Abstract

Flavonoids and other phenolics of Tunisian honey samples and propolis were analyzed to find correlations between botanical and geographical origin and chemical composition. Flavonoid content of honey was very variable (20−2400 μg/100 g). The richest samples contained the characteristic propolis flavonoids, while those containing fewer flavonoids were devoid of these substances. This is a difference with honeys from temperate areas, in which the poplar-derived flavonoids are present in all honey samples. In Tunisian honeys, and propolis, a new flavonoid, myricetin 3,7,4',5'-tetramethyl ether, was detected. This is characteristic of Cistus spp. leaf exudates. Another minor compound was identified as quercetin 3,7,3'-trimethyl ether. They were present in high amounts in propolis but were only detected in small amounts in honey. These results show that in border areas, such as Tunisia, where poplars are not always available for propolis collection, other plant sources can be used and their constituents detected in honey. Keywords: Phenolics; honey; propolis; flavonoids; characterization; geographical origin; botanical origin