ost of the flavonoids in foods exist as O-glycosidic form. However, C-glycosylated flavonoids, sepcially flavones, are widespread in a variety of plants. in most cases, flavone O-glycosides are hydrolyzed by enzymes or degraded by gut bacteria to their aglycones in the intestine, reduced and conjugated to form their O-glucuronides and O-sulfates in the liver. However, flavone C-glycosides exhibited different metabolism behaviours compared with flavone O-glycosides. Flavone C-monoglucosides such as orientin, vitexin, homoorientin, and isovitexin were poorly absorbed in the gastrointestinal tract of rats and consequently, they reached the colon. In colon, flavone C-monoglucosides were deglycosylated  and degraded to the smaller metabolites, for instance phloroglucinol, hydrocaffeic acid, and phloretic acid by human intestinal bacteria, which result very few metabolites found in urine and blood. Flavone C-multiglycosides are absorbed unchanged, not degraded in the intestine and hardly changed in the liver, then it returned to the gut by enterohepatic recirculation.

It's highly unlikely that intact glycosides would get absorbed in the GIT. The weak glycosidic bond is an easy target for microorganisms in the GIT. I have worked extensively on Bacopa monnieri absorption, but have never found an intact glycoside circulating in the blood of study animals. 

flavonoids may partial hydrolysis, and may affect by microflora

flavonoids  (as antioxidants) are secondary metabolities , my flora use it as a nutrient or as a life component

flavonoids configuration may change by enzymatic reaction in vivo

ost of the flavonoids in foods exist as O-glycosidic form. However, C-glycosylated flavonoids, sepcially flavones, are widespread in a variety of plants. in most cases, flavone O-glycosides are hydrolyzed by enzymes or degraded by gut bacteria to their aglycones in the intestine, reduced and conjugated to form their O-glucuronides and O-sulfates in the liver. However, flavone C-glycosides exhibited different metabolism behaviours compared with flavone O-glycosides. Flavone C-monoglucosides such as orientin, vitexin, homoorientin, and isovitexin were poorly absorbed in the gastrointestinal tract of rats and consequently, they reached the colon. In colon, flavone C-monoglucosides were deglycosylated  and degraded to the smaller metabolites, for instance phloroglucinol, hydrocaffeic acid, and phloretic acid by human intestinal bacteria, which result very few metabolites found in urine and blood. Flavone C-multiglycosides are absorbed unchanged, not degraded in the intestine and hardly changed in the liver, then it returned to the gut by enterohepatic recirculation.

I agree with jamwal suggestion.

I fully endorse Jianbo Xiao opinion .

Quercetin-glucosides are not present in plasma after consumption of either quercetin-3-glucoside or quercetin-4′-glucoside because they are converted to quercetin glucuronides, and these are major metabolites of these glucosides.

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The presence of glucosides of anthocyanidins have been reported in human plasma (see below).

"In human plasma, 30 min after ingestion of cyanidin-3-glucoside (Cy-g) and cyanidin-3,5-diglucoside (Cy-dg), Cy-g and traces of Cy-dg were detected. Cyanidin as aglycone of Cy-g and Cy-dg were not found in these plasma samples, neither were conjugated and methylated anthocyanins. The results indicated that anthocyanins are incorporated keeping structurally intact glycoside forms, from the digestive tract into the blood circulation system in mammals." 

http://www.ncbi.nlm.nih.gov/pubmed/10552420

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"Phenolic acid metabolites were found in the blood stream in much higher concentrations than their parent compounds. These metabolites could be responsible for the health benefits associated with anthocyanins. Some anthocyanins can reach the large intestine in significant amounts and undergo decomposition catalyzed by microbiota." 

http://www.tandfonline.com/doi/full/10.3109/03602532.2014.978080

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Absorption and excretion of conjugated flavonols, including quercetin-4′-O-β-glucoside and isorhamnetin-4′-O-β-glucoside by human volunteers after the consumption of onions.

http://www.tandfonline.com/doi/abs/10.1080/10715769800300291

"Isorhamnetin-4′-O-β-glucoside and quercetin-4′-O-β-glucoside accumulated in plasma with maximum levels, defined as proportion of intake, of 10.7 ± 2.6% and 0.13 ± 0.03% respectively. The time of the quercetin-4′-glucoside peak plasma concentration was 1.3 ± 0.2 h after the ingestion of onions while a value of 1.8 ± 0.7 h was obtained for isorhamnetin-4′-glucoside. Excretion in urine, as a proportion of intake, was 17.4 ± 8.3% for isorhamnetin-4′-O-β-glucoside and 0.2±0.1% for quercetin-4′-O-β-glucoside."