European Journal of Nutrition

, Volume 45, Issue 1, pp 7–18

Stability and biotransformation of various dietary anthocyanins in vitro

  • J. Fleschhut
  • F. Kratzer
  • G. Rechkemmer
  • S. E. Kulling
ORIGINAL CONTRIBUTION

DOI: 10.1007/s00394-005-0557-8

Cite this article as:
Fleschhut, J., Kratzer, F., Rechkemmer, G. et al. Eur J Nutr (2006) 45: 7. doi:10.1007/s00394-005-0557-8

Summary

Background

Anthocyanins, which are found in high concentrations in fruit and vegetable, may play a beneficial role in retarding or reversing the course of chronic degenerative diseases. However, little is known about the biotransformation and the metabolism of anthocyanins so far.

Aim of the study

The aim of the study was to investigate possible transformation pathways of anthocyanins by human faecal microflora and by rat liver microsomes as a source of cytochrome P450 enzymes as well as of glucuronyltransferases.

Methods

Pure anthocyanins, an aqueous extract of red radish as well as the assumed degradation products were incubated with human faecal suspension. The incubation mixtures were purified by solid–phase extraction and analysed by HPLC/DAD/MS and GC/MS. Quantification was done by the external standard method. Furthermore the biotransformation of anthocyanins by incubation with rat liver microsomes in the presence of the cofactor NADPH (as a model for the phase I oxidation) and in the presence of activated glucuronic acid (as a model for the phase II glucuronidation) was investigated.

Results

Glycosylated and acylated anthocyanins were rapidly degraded by the intestinal microflora after anaerobic incubation with a human faecal suspension. The major stable products of anthocyanin degradation are the corresponding phenolic acids derived from the B–ring of the anthocyanin skeleton. Anthocyanins were not metabolised by cytochrome P450 enzymes, neither hydroxylated nor demethylated. However they were glucuronidated by rat liver microsomes to several products.

Conclusions

The gut microflora seem to play an important role in the biotransformation of anthocyanins. A rapid degradation could be one major reason for the poor bioavailability of anthocyanins in pharmacokinetic studies described so far in the literature. The formation of phenolic acids as the major stable degradation products gives an important hint to the fate of anthocyanins in vivo.

Key words

anthocyanins biotransformation human gut microflora degradation stability phenolic acids 

Abbreviations

aA1

Pelargonidin–3–sophorosid–5–glucoside acylated with ferulic

aA2

Pelargonidin–3–sophorosid–5–glucoside acylated with ferulic and malonic acid

API–ES

atmospheric pressure ionisation

Cy

cyanidin

Cy3glu

cyanidin–3–glucoside

DAD

diode array detection

DP

degradation product

DP2

Pg–glu/soph

DP3

Pg–soph

Dp

delphinidin

ESI

electrospray ionisation

HFM

human faecal microflora

HPLC

high performance liquid chromatography

MS

mass spectrometry

Mv3 glu

malvidin–3–glucoside

Mv

malvidin

Pn3 glu

peonidin–3–glucoside

Pg

pelargonidin

Pg–glu/soph

pelargonidin–3–sophorosid–5–glucoside

Pn

peonidin

Pt

petunidin

UDPGA

uridindiphosphate glucuronic acid

Copyright information

© Steinkopff-Verlag 2005

Authors and Affiliations

  • J. Fleschhut
    • 1
  • F. Kratzer
    • 1
  • G. Rechkemmer
    • 2
  • S. E. Kulling
    • 3
  1. 1.Institute for Nutritional PhysiologyFederal Research Centre for Nutrition and FoodKarlsruheGermany
  2. 2.Dept. of Food and NutritionTechnical University of MunichMunichGermany
  3. 3.Dept. of Food ChemistryInstitute of Nutritional Science, University of PotsdamPotsdam–Rehbrücke (Nuthethal)Germany

Personalised recommendations