High-performance liquid chromatography analysis of phenolic acid, flavonoid, and phenol contents in various natural Yemeni honeys using multi-walled carbon nanotubes as a solid-phase extraction adsorbent.

A simple method has been described for simultaneous determination of phenolic acid, flavonoid, and other phenol contents in various natural honey samples collected from various regions of Yemen. Multi-walled carbon nanotubes were used as a solid-phase adsorbent for extraction of the polyphenols from honey samples. The total contents of phenolic acids, flavonoids, and phenolic components of the 12 different samples were found in the range of 363-2658, 261-1646, and 224-1355 μg/100 g of honey samples, respectively. The major phenolic acid, flavonoid, and phenolic compound in these samples were found to be 4-hydroxybenzoic acid (1410 μg/100 g), chrysin (850 μg/100 g), and cinnamic acid (1336 μg/100 g), respectively. A total of 25 compounds (10 phenolic acids, 9 flavonoids, and 6 phenols) were analyzed, and a total of 24 were detected, while only 23 compounds were determined quantitatively in the honey samples. The developed method showed potential usefulness for the analysis of honey and was used for the determination of polyphenols in honey extracts.