Abstract
Sensitive and precise analytical methods are needed for flavonols, a subclass of flavonoids that has strong antioxidant activity. We report an improved method for identifying the predominant flavonols, quercetin and kaempferol, by collisionally activated dissociation (CAD) and quantifying them by high-performance liquid chromatography electrospray ionization mass spectrometry (HPLC-ESI-MS) in the selected ion monitoring mode. Practical applications of the method were demonstrated using several kale and biological samples. Two commercial kale samples were found to have 77 or 244 ppm quercetin and 235 or 347 ppm kaempferol (ppm = microg of quercetin/g of kale or microg of kaempferol/g of kale by fresh weight, 5-15% relative standard deviation). Blanching was found to reduce the flavonols to approximately 60% of the levels found in the unblanched kale. Isotopically labeled kale (cultivar Vates) grown in a greenhouse under an atmosphere of (13)CO(2) was found to have much lower flavonol levels. UV-A and UV-B supplementation during kale growth in the greenhouse was found to enhance both quercetin and kaempferol levels in Vates kale. The UV-B-supplemented kale not only produced more flavonols but the quercetin-to-kaempferol ratio was also higher than the UV-A-supplemented or the nonsupplemented kale. Recovery of flavonols from kale was approximately 60% based on spike and recovery trials with rutin, a glycoside of quercetin. Recovery of flavonols from biological samples spiked with rutin ranged from 96% for urine to 70% for plasma. Compared to UV detection, ESI-MS in the deprotonation mode provided lower detection limits, and both higher sensitivity and selectivity, in addition to structural characterization of the kale flavonols by CAD.
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Claims 13
Claim · model-written summary
An improved method identifies and quantifies quercetin and kaempferol.
- Taxon
- Kale
Brassica oleracea var. viridist0 - Outcome
- identifying the predominant flavonols, quercetin and kaempferole0
Not reportedComparatorValue
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Kale”
e0“We report an improved method for identifying the predominant flavonols, quercetin and kaempferol, by collisionally activated dissociation (CAD) and quantifying them by high-performance liquid chromatography electrospray ionization mass spectrometry (HPLC-ESI-MS) in the selected ion monitoring mode”
Claim · model-written summary
Two commercial kale samples contained 77 or 244 ppm quercetin.
- Taxon
- kaleBrassica oleracea var. viridise0
- Outcome
- quercetine0
- Value
- 77 or 244 ppme0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Two commercial kale samples were found to have 77 or 244 ppm quercetin and 235 or 347 ppm kaempferol”
Claim · model-written summary
Two commercial kale samples contained 235 or 347 ppm kaempferol.
- Taxon
- kaleBrassica oleracea var. viridise0
- Outcome
- kaempferole0
- Value
- 235 or 347 ppme0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Two commercial kale samples were found to have 77 or 244 ppm quercetin and 235 or 347 ppm kaempferol”
Claim · model-written summary
Blanching reduced kale flavonols to about 60% of unblanched levels.
- Taxon
- kaleBrassica oleracea var. viridise0
- Treatment
- Blanchinge0
- Outcome
- flavonolse0
- Direction
- reducee0
- Value
- approximately 60%e0
- Comparator
- unblanched kalee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Blanching was found to reduce the flavonols to approximately 60% of the levels found in the unblanched kale”
Claim · model-written summary
Isotopically labeled Vates kale grown under (13)CO(2) had much lower flavonol levels.
- Taxon
- kaleBrassica oleracea var. viridise0
- Material
- Vatese0
- Treatment
- under an atmosphere of (13)CO(2)e0
- Outcome
- flavonol levelse0
- Direction
- much lowere0
- Setting
- greenhousee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Isotopically labeled kale (cultivar Vates) grown in a greenhouse under an atmosphere of (13)CO(2) was found to have much lower flavonol levels”
Claim · model-written summary
UV-A supplementation enhanced quercetin and kaempferol levels in Vates kale.
- Taxon
- kaleBrassica oleracea var. viridise0
- Material
- Vatese0
- Treatment
- UV-Ae0
- Outcome
- quercetin and kaempferol levelse0
- Direction
- enhancee0
- Setting
- greenhousee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“UV-A and UV-B supplementation during kale growth in the greenhouse was found to enhance both quercetin and kaempferol levels in Vates kale”
Claim · model-written summary
UV-B supplementation enhanced quercetin and kaempferol levels in Vates kale.
- Taxon
- kaleBrassica oleracea var. viridise0
- Material
- Vatese0
- Treatment
- UV-Be0
- Outcome
- quercetin and kaempferol levelse0
- Direction
- enhancee0
- Setting
- greenhousee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“UV-A and UV-B supplementation during kale growth in the greenhouse was found to enhance both quercetin and kaempferol levels in Vates kale”
Claim · model-written summary
UV-B-supplemented kale produced more flavonols.
- Taxon
- kaleBrassica oleracea var. viridise0
- Treatment
- UV-B-supplementede0
- Outcome
- flavonolse0
- Direction
- moree0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The UV-B-supplemented kale not only produced more flavonols but the quercetin-to-kaempferol ratio was also higher than the UV-A-supplemented or the nonsupplemented kale”
Claim · model-written summary
UV-B-supplemented kale had a higher quercetin-to-kaempferol ratio than UV-A-supplemented or nonsupplemented kale.
- Taxon
- kaleBrassica oleracea var. viridise0
- Treatment
- UV-B-supplementede0
- Outcome
- quercetin-to-kaempferol ratioe0
- Direction
- highere0
- Comparator
- UV-A-supplemented or the nonsupplemented kalee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The UV-B-supplemented kale not only produced more flavonols but the quercetin-to-kaempferol ratio was also higher than the UV-A-supplemented or the nonsupplemented kale”
Claim · model-written summary
Flavonol recovery from kale was approximately 60%.
- Taxon
- kaleBrassica oleracea var. viridise0
- Outcome
- Recovery of flavonols from kalee0
- Value
- approximately 60%e0
- Qualifier
- spike and recovery trials with rutine0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Recovery of flavonols from kale was approximately 60% based on spike and recovery trials with rutin”
Claim · model-written summary
Flavonol recovery from spiked biological samples ranged from 96% for urine to 70% for plasma.
Not reportedTaxon
Verbatim
e0“Recovery of flavonols from biological samples spiked with rutin ranged from 96% for urine to 70% for plasma”
Claim · model-written summary
ESI-MS provided lower detection limits and higher sensitivity and selectivity than UV detection.
- Taxon
- kaleBrassica oleracea var. viridise0
- Outcome
- detection limits, and both higher sensitivity and selectivitye0
- Direction
- lowere0
- Comparator
- UV detectione0
Not reportedValue
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Compared to UV detection, ESI-MS in the deprotonation mode provided lower detection limits, and both higher sensitivity and selectivity, in addition to structural characterization of the kale flavonols by CAD”
Claim · model-written summary
CAD provided structural characterization of kale flavonols.
- Taxon
- kaleBrassica oleracea var. viridise0
- Outcome
- structural characterization of the kale flavonols by CADe0
Not reportedComparatorValue
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Compared to UV detection, ESI-MS in the deprotonation mode provided lower detection limits, and both higher sensitivity and selectivity, in addition to structural characterization of the kale flavonols by CAD”
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See all 24 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.