Extraction Method And Composition Of Polyphenolic Compounds From Acacia Honey

Honey mostly consists of a high concentration of sugars and water, whereas amino acids, minerals, polyphenols are present in it with small amount. It was reported to have antioxidant, antibacterial, antiviral and immunoregulatory activities. These bioactivities are related to the presence of polyphenols.In order to choose the best solid sorbents for isolation and preconcentration of polyphenols of honey, six kinds of macroporous resins and eieht kinds of solid-phase extraction cartridges were tested in our study. The recoveries of caffeic acid and rutin were low in all macroporous resins. XAD-2 macroporous resin showed high caffeic acid and rutin adsorption rate. The highest caffeic acid recovery was only 11.79% via AB-8, the highest rutin recovery was 37.71% via HPD200。Basing on adsorption kinetics of different resins, all macroporous resins were slow adsorption type about caffeic acid, and the rapid adsorption type about rutin. On the other hand, SPE cartridges demonstrated higher polyphenolic recovery than that of all macroporous resins. The highest average content of caffeic acid recovery in reversed phase(RP) SPE cartridges and reversed phase-anion exchange(RP-AE) SPE cartridges were 88.36% and 92.86%. The rutin recoveries of all SPE cartridges were above 90%.Moreover, polyphenols illustrated significantly distinctions between RP SPE cartridges and RP-AE SPE cartridges. The average contents of phenolic and flavonoid of RP SPE cartridges were 326.17 μg/100 g and 289.60 μg/100g; and average contents of phenolic and flavonoid of RP-AE SPE cartridges were 375.15 μg/100 g and 318.49 μg/100 g. On the whole, the RP-AE SPE cartridges were better than RP SPE cartridges for the preconcentration of polyphenols from acacia honey. In addition, Strata-X-A cartridges showed the best extraction efficiency of polyphenols.20 phenolic compounds and abscisic in acacia honey were identified by HPLC-PDA. These compounds included 12 phenolic acids and phenolic acid esters, 8 flavonoids and absicisic. Chromatographic fingerprints of acacia honey samples were established. According to the chromatographic fingerprint, the characteristic compounds of acacia honey were indentified. And similarity between all acacia honey samples was more than 0.70, and the contents of characteristic compounds had some difference.Antioxidant activities and polyphenols in commercial acacia honeys were analysed. The results indicated that all samples had antioxidant activities. The quality of them was remarkably different. There were only four honey samples being good quality, two samples being poor quality because of much higher content of methyl syringate and lower content of polyphenols.