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Structural characterization and detection of kale flavonoids by electrospray ionization mass spectrometry.
Anal Chem. 2003 Dec 01; 75(23):6401-7.AC

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.

Authors+Show Affiliations

Department of Chemistry and Biochemistry, University of Texas, Austin, Texas 78712, USA.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

14640707

Citation

Zhang, Junmei, et al. "Structural Characterization and Detection of Kale Flavonoids By Electrospray Ionization Mass Spectrometry." Analytical Chemistry, vol. 75, no. 23, 2003, pp. 6401-7.
Zhang J, Satterfield MB, Brodbelt JS, et al. Structural characterization and detection of kale flavonoids by electrospray ionization mass spectrometry. Anal Chem. 2003;75(23):6401-7.
Zhang, J., Satterfield, M. B., Brodbelt, J. S., Britz, S. J., Clevidence, B., & Novotny, J. A. (2003). Structural characterization and detection of kale flavonoids by electrospray ionization mass spectrometry. Analytical Chemistry, 75(23), 6401-7.
Zhang J, et al. Structural Characterization and Detection of Kale Flavonoids By Electrospray Ionization Mass Spectrometry. Anal Chem. 2003 Dec 1;75(23):6401-7. PubMed PMID: 14640707.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Structural characterization and detection of kale flavonoids by electrospray ionization mass spectrometry. AU - Zhang,Junmei, AU - Satterfield,Mary B, AU - Brodbelt,Jennifer S, AU - Britz,Steven J, AU - Clevidence,Beverly, AU - Novotny,Janet A, PY - 2003/12/3/pubmed PY - 2004/10/20/medline PY - 2003/12/3/entrez SP - 6401 EP - 7 JF - Analytical chemistry JO - Anal Chem VL - 75 IS - 23 N2 - 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. SN - 0003-2700 UR - https://www.unboundmedicine.com/medline/citation/14640707/Structural_characterization_and_detection_of_kale_flavonoids_by_electrospray_ionization_mass_spectrometry_ DB - PRIME DP - Unbound Medicine ER -