Moon J.H., Nakata R., Oshima S., Inakuma T., Terao J. (2000) Accumulation of quercetin conjugates in blood plasma after the short-term ingestion of onion by women. Am J Physiol Regul Integr Comp Physiol 279:R461-7 PubMed (10938233)

Compound Mean content
Quercetin 3,4'-O-diglucoside 40.5 mg/100 g fresh weight
Quercetin 4'-O-glucoside 9.7 mg/100 g fresh weight
Quercetin 3-O-glucoside 0.3 mg/100 g fresh weight