Topic
Aglycone
About: Aglycone is a research topic. Over the lifetime, 2769 publications have been published within this topic receiving 57324 citations. The topic is also known as: aglycon & aglycones.
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TL;DR: It is concluded that humans absorb appreciable amounts of quercetin and that absorption is enhanced by conjugation with glucose.
934 citations
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TL;DR: Dietary quercetin is a promising agent for cancer prevention and further research is warranted, as it prevents chemically induced carcinogenesis and modulates several signal transduction pathways involving MEK/ERK and Nrf2/keap1.
621 citations
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TL;DR: The overall kinetic behaviour of quercetin differed remarkably after ingestion of quERCetin aglycone or rutin, and seemed to be associated with gender and use of oral contraceptives.
Abstract: Background: Quercetin is a flavonoid with a wide range of biological activities. It mainly occurs in plants as glycosides, such as rutin (quercetin rutinoside) in tea. Quercetin and rutin are used in many countries as vasoprotectants and are ingredients of numerous multivitamin preparations and herbal remedies. Objectives: The primary objective was to characterise and compare the absorption and the pharmacokinetics of quercetin from quercetin aglycone and rutin. A secondary objective was to investigate which forms of quercetin are present in plasma. Methods: In this double blind, diet-controlled, two-period cross-over study, 16 healthy volunteers received three different doses of quercetin and rutin orally. The doses corresponded to 8 mg, 20 mg and 50 mg quercetin aglycone. Blood samples were obtained between 0 h and 32 h post-dose. Results: The overall kinetic behaviour of quercetin differed remarkably after ingestion of quercetin aglycone or rutin. The mean area under the plasma concentration–time curve from 0 h to 32 h [AUC(0–32)] and maximum plasma concentration (Cmax) values of the two treatments were similar. However, time to reach Cmax (tmax) was significantly shorter after the quercetin aglycone treatment than after the rutin treatment (1.9, 2.7 and 4.8 versus 6.5, 7.4 and 7.5 h, for doses 1, 2 and 3, respectively). Also, the absorption of quercetin from quercetin aglycone was predictable and inter-individual variation was small. In contrast, after ingestion of rutin, inter-individual variations in AUC(0–32) and Cmax values were considerable and seemed to be associated with gender and use of oral contraceptives. Quercetin and rutin were found in plasma as glucuronides and/or sulfates of quercetin and as unconjugated quercetin aglycone, but no rutin was detected. Conclusions: In clinical trials, studying the effects of quercetin from rutin, bioavailability must be taken into consideration and plasma quercetin concentrations monitored. Whether our results apply to other glycosidic drugs as well, especially other rutosides, should be investigated.
470 citations
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TL;DR: 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.
Abstract: 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. 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. 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. 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. Bacterial metabolism of anthocyanins
involves the cleavage of
glycosidic linkages and breakdown
of the anthocyanidin heterocycle.
421 citations
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TL;DR: An array of glycoside compounds currently used in medicine but also with biological activity of some glycosidic metabolites of the known drugs are dealt with.
Abstract: Numbers of biologically active compounds are glycosides. Sometimes, the glycosidic residue is crucial for their activity, in other cases glycosylation only improves pharmacokinetic parameters. Recent developments in molecular glycobiology brought better understanding to the aglycone vs. glycoside activities, and made possible to develop new, more active or more effective glycodrugs based on these findings - very illustrative recent example is the story of vancomycin. This paper deals with an array of glycosidic compounds currently used in medicine but also with biological activity of some glycosidic metabolites of the known drugs. It involves glycosides of vitamins, polyphenolic glycosides (flavonoids), alkaloid glycosides, glycosides in the group of antibiotics, glycopeptides, cardiac glycosides, steroid and terpenoid glycosides etc. The physiological role of the glycosyl and structure-activity relations (SAR) in the glycosidic moiety (-ies) are discussed.
420 citations