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Title

CHARACTERIZATION OF WILD BLUEBERRY POLYPHENOLS BIOAVAILABILITY AND KINETIC PROFILE OVER 24-HOUR PERIOD IN HUMAN SUBJECTS

Creator

Zhong, Siqiong

Date

2016, 2016-12

Description

Diets abundant in phenolic compounds have been linked to decreased risk of cardiovascular disease, obesity and diabetes. Wild blueberries (WBB...
Show moreDiets abundant in phenolic compounds have been linked to decreased risk of cardiovascular disease, obesity and diabetes. Wild blueberries (WBB) are one of the richest sources of dietary phenolic compounds, particularly anthocyanin compounds. They also contain hydroxycinnamic acids, namely chlorogenic acids (CGA). Understanding their metabolic fate may provide insight to their health benefits and protection against chronic disease development. The purpose of this study was to (1) identify WBB anthocyanin and CGA metabolites in human plasma (2) assess bioavailability and biotransformation of WBB anthocyanin and CGA in human (3) measure the acute e↵ects of WBB consumption on glucose homeostasis and lipid metabolism. This was a pilot study with healthy male and female volunteers (n=12). Plasma samples were collected at baseline (t=0h), 0.25h, 0.5h, 1h, 2h, 4h, 6h, 8h, 10h and 24h after consuming a WBB drink (25 g freeze dried WBB powder) with a standard polyphenol free breakfast. The anthocyanins in the WBB drink and their metabolites in human plasma were identified using HPLC-ESI-Q-TOF and quantified by dynamic MRM transitions on HPLC-ESI-QQQ. A total of 30 anthocyanins were identified in the WBB drink. These included glycosides of cyanidin, delphinidin, malvidin, petunidin and peonidin, which were detected in positive mode. Glucose was the most abundant glycoside attachment followed by galactose, arabinose, acetylated glucose, acetylated galactose and xylose. CGAs were also found in the WBB drink in negative mode and confirmed with standards. All the anthocyanins in the WBB drink were found in plasma as well as 3-CGA. The bioavailability for delphinidin, cyandin, malvidin, peonidin, and petunidin were each less than 1% and total bioavailability of WBB anthocyanins was 1.09%. The bioavailability for 3-CGA was 0.22% after consuming 25g WBB powder. The Tmax (time of maximum concentration was achieved) of anthocyanins and 3-CGA was ⇠2h post ingestion. Tmax of phase II metabolites, including petunidin- glucuronide, peonidin-glucuronide, delphinidin-glucuronide and cyanidin-glucuronide was 8.8, 2.6, 6.3 and 7h, respectively. Phenolic acids metabolites, including vanillic acids, ferulic acids, 2,3-dihydroxybenzoic acid, phloroglucinaldehyde, syringic acid were also detected in human plasma during the 24 h period. These results suggest that anthocyanins and CGAs from a WBB drink can be partly absorbed in their intact form in humans and partly transformed to conjugated and degraded metabolites. The data also indicate that there are early phase and late phase appearing metabolites in the blood of humans, which could have important health promoting implications. Future studies will need to be conducted to determine how these pools of metabolites impact physiology and the most sensitive systems to their e↵ect. In the present study, no significant di↵erences on glucose homeostasis and lipid metabolism were apparent. This study provides a foundation for further understanding on health benefits of dietary anthocyanins and their metabolites.
M.S. in Food Safety and Technology, December 2016
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