In vitro metabolism of anthocyanins by human gut microflora

Anna-Marja Aura (Corresponding Author), Pilar Martin-Lopez, Karen Anne O'Leary, Gary Williamson, Kirsi-Marja Oksman-Caldentey, Kaisa Poutanen, Celestino Saltos-Buelga

Research output: Contribution to journalArticleScientificpeer-review

267 Citations (Scopus)

Abstract

Background Only a small part of the dietary anthocyanins are absorbed. Thus large amounts of the ingested compounds are likely to enter the colon. In vitro and in vivo studies have shown that colonic bacteria transform various flavonoids to smaller phenolic acids. However, there is very little information on bacterial transformations of anthocyanins. Aim of the study was to explore if anthocyanin glycosides were deglycosylated,whether the resulting aglycones were degraded further to smaller phenolic compounds by colonic bacteria, and to characterise metabolites. Methods Isolated cyanidin–3–glucoside and –rutinoside were fermented in vitro using human faecal microbiota as an inoculum. Metabolites were analysed and characterised by HPLC–DAS and LC–MS. They were identified by comparing their characteristics with those of available standards, and semi–quantified using the amount of substrate analysed from samples at initial timepoint. Results Cyanidin–3–glucoside and cyanidin aglycone could be identified as intermediary metabolites of cyanidin–3–rutinoside. At early timepoints (before 2 h), the formation of protocatechuic acid as a major metabolite for both cyanidin glycosides and detection of lower molecular weight metabolites show that anthocyanins were converted by gut microflora. Furthermore, reconjugation of the aglycone with other groups, non–typical for dietary anthocyanins, was evident at the later (after 2h) timepoints. Conclusion Bacterial metabolism of anthocyanins involves the cleavage of glycosidic linkages and breakdown of the anthocyanidin heterocycle.
Original languageEnglish
Pages (from-to)133 - 142
JournalEuropean Journal of Nutrition
Volume44
Issue number3
DOIs
Publication statusPublished - 2005
MoE publication typeA1 Journal article-refereed

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Anthocyanins
Glycosides
Bacterial Transformation
Bacteria
Microbiota
Gastrointestinal Microbiome
In Vitro Techniques
Flavonoids
Colon
Molecular Weight

Keywords

  • anthocyanins
  • deglycosylation
  • alpha,L-rhamnosidase
  • beta,D-glycosidase
  • bacterial metabolism
  • heterocycle breakdown

Cite this

Aura, Anna-Marja ; Martin-Lopez, Pilar ; O'Leary, Karen Anne ; Williamson, Gary ; Oksman-Caldentey, Kirsi-Marja ; Poutanen, Kaisa ; Saltos-Buelga, Celestino. / In vitro metabolism of anthocyanins by human gut microflora. In: European Journal of Nutrition. 2005 ; Vol. 44, No. 3. pp. 133 - 142.
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title = "In vitro metabolism of anthocyanins by human gut microflora",
abstract = "Background Only a small part of the dietary anthocyanins are absorbed. Thus large amounts of the ingested compounds are likely to enter the colon. In vitro and in vivo studies have shown that colonic bacteria transform various flavonoids to smaller phenolic acids. However, there is very little information on bacterial transformations of anthocyanins. Aim of the study was to explore if anthocyanin glycosides were deglycosylated,whether the resulting aglycones were degraded further to smaller phenolic compounds by colonic bacteria, and to characterise metabolites. Methods Isolated cyanidin–3–glucoside and –rutinoside were fermented in vitro using human faecal microbiota as an inoculum. Metabolites were analysed and characterised by HPLC–DAS and LC–MS. They were identified by comparing their characteristics with those of available standards, and semi–quantified using the amount of substrate analysed from samples at initial timepoint. Results Cyanidin–3–glucoside and cyanidin aglycone could be identified as intermediary metabolites of cyanidin–3–rutinoside. At early timepoints (before 2 h), the formation of protocatechuic acid as a major metabolite for both cyanidin glycosides and detection of lower molecular weight metabolites show that anthocyanins were converted by gut microflora. Furthermore, reconjugation of the aglycone with other groups, non–typical for dietary anthocyanins, was evident at the later (after 2h) timepoints. Conclusion Bacterial metabolism of anthocyanins involves the cleavage of glycosidic linkages and breakdown of the anthocyanidin heterocycle.",
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In vitro metabolism of anthocyanins by human gut microflora. / Aura, Anna-Marja (Corresponding Author); Martin-Lopez, Pilar; O'Leary, Karen Anne; Williamson, Gary; Oksman-Caldentey, Kirsi-Marja; Poutanen, Kaisa; Saltos-Buelga, Celestino.

In: European Journal of Nutrition, Vol. 44, No. 3, 2005, p. 133 - 142.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - In vitro metabolism of anthocyanins by human gut microflora

AU - Aura, Anna-Marja

AU - Martin-Lopez, Pilar

AU - O'Leary, Karen Anne

AU - Williamson, Gary

AU - Oksman-Caldentey, Kirsi-Marja

AU - Poutanen, Kaisa

AU - Saltos-Buelga, Celestino

PY - 2005

Y1 - 2005

N2 - Background Only a small part of the dietary anthocyanins are absorbed. Thus large amounts of the ingested compounds are likely to enter the colon. In vitro and in vivo studies have shown that colonic bacteria transform various flavonoids to smaller phenolic acids. However, there is very little information on bacterial transformations of anthocyanins. Aim of the study was to explore if anthocyanin glycosides were deglycosylated,whether the resulting aglycones were degraded further to smaller phenolic compounds by colonic bacteria, and to characterise metabolites. Methods Isolated cyanidin–3–glucoside and –rutinoside were fermented in vitro using human faecal microbiota as an inoculum. Metabolites were analysed and characterised by HPLC–DAS and LC–MS. They were identified by comparing their characteristics with those of available standards, and semi–quantified using the amount of substrate analysed from samples at initial timepoint. Results Cyanidin–3–glucoside and cyanidin aglycone could be identified as intermediary metabolites of cyanidin–3–rutinoside. At early timepoints (before 2 h), the formation of protocatechuic acid as a major metabolite for both cyanidin glycosides and detection of lower molecular weight metabolites show that anthocyanins were converted by gut microflora. Furthermore, reconjugation of the aglycone with other groups, non–typical for dietary anthocyanins, was evident at the later (after 2h) timepoints. Conclusion Bacterial metabolism of anthocyanins involves the cleavage of glycosidic linkages and breakdown of the anthocyanidin heterocycle.

AB - Background Only a small part of the dietary anthocyanins are absorbed. Thus large amounts of the ingested compounds are likely to enter the colon. In vitro and in vivo studies have shown that colonic bacteria transform various flavonoids to smaller phenolic acids. However, there is very little information on bacterial transformations of anthocyanins. Aim of the study was to explore if anthocyanin glycosides were deglycosylated,whether the resulting aglycones were degraded further to smaller phenolic compounds by colonic bacteria, and to characterise metabolites. Methods Isolated cyanidin–3–glucoside and –rutinoside were fermented in vitro using human faecal microbiota as an inoculum. Metabolites were analysed and characterised by HPLC–DAS and LC–MS. They were identified by comparing their characteristics with those of available standards, and semi–quantified using the amount of substrate analysed from samples at initial timepoint. Results Cyanidin–3–glucoside and cyanidin aglycone could be identified as intermediary metabolites of cyanidin–3–rutinoside. At early timepoints (before 2 h), the formation of protocatechuic acid as a major metabolite for both cyanidin glycosides and detection of lower molecular weight metabolites show that anthocyanins were converted by gut microflora. Furthermore, reconjugation of the aglycone with other groups, non–typical for dietary anthocyanins, was evident at the later (after 2h) timepoints. Conclusion Bacterial metabolism of anthocyanins involves the cleavage of glycosidic linkages and breakdown of the anthocyanidin heterocycle.

KW - anthocyanins

KW - deglycosylation

KW - alpha,L-rhamnosidase

KW - beta,D-glycosidase

KW - bacterial metabolism

KW - heterocycle breakdown

U2 - 10.1007/s00394-004-0502-2

DO - 10.1007/s00394-004-0502-2

M3 - Article

VL - 44

SP - 133

EP - 142

JO - European Journal of Nutrition

JF - European Journal of Nutrition

SN - 1436-6207

IS - 3

ER -