Flavonoids from Portuguese heather honey

Zusammenfassung

Die Flavonoide aus portugiesischem Heidehonig wurden mit der HPLC in reversed-phase-Technik analysiert. Die Fraktionen wurden durch Adsorptionsund Gelchromatographie gereinigt, ihre Gesamtausbeute betrug 60 bis 500 μg/100 g Honig. Als Hauptkomponenten wurden Pinocembrin und Pinobanksin (Flavanone) sowie Chrysin und Galangin (Flavone) identifiziert. Alle Proben erhielten ein ähnliches Muster aus mindestens 22 Flavonoiden. Charakteristisch waren Myricitin sowie dessen 3- und 3'-Methylether sowie Tricetin. Derartige Verbindungen wurden bisher in keinem anderen Honig gefunden und eignen sich möglicherweise als Herkunftsnachweis für Heidehonig.

Abstract

The flavonoids present in twenty samples of Portuguese heather honey were analysed by reversed-phase HPLC. The flavonoid fraction was purified by a combination of chromatography on Amberlite XAD-2 and Sephadex LH-20 columns. The total amount of flavonoids ranged between 60 and 500 μg/100g honey, values which are much smaller than those previously found for Spanish rosemary honey samples (500-2000 μg/100 g honey). The main flavonoids present in Portuguese heather honey were the flavanones pinocembrin and pinobanksin and the flavones chrysin and galangin. These analyses showed that all the samples contained a similar flavonoid pattern composed of at least 22 compounds. The most characteristic substances were myricetin, myricetin 3-methyl ether, myricetin 3'-methyl ether and tricetin. These four flavonoids have in common the structural feature of having a trioxygenated ring B (3',4',5'-trioxygenation), this being an attribute not found in the flavonoids detected in any other honey sample of different plant origin analysed so far, suggesting that these substances could probably be used as markers for the botanical origin of heather honey.