Polymorphism for Novel Tetraglycosylated Flavonols in an Eco-model Crucifer, Barbarea vulgaris

• Published in: Journal of agricultural and food chemistry Vol. 59; no. 13; pp. 6947 - 6956
• Main Authors: Dalby-Brown, Lea, Olsen, Carl Erik, Nielsen, Jens Kvist, Agerbirk, Niels
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 13-07-2011
• Subjects: Animals; Barbarea - chemistry; Barbarea - genetics; Bioactive Constituents; Biological and medical sciences; Chromatography, High Pressure Liquid; Flavonoids - analysis; Flavonoids - chemistry; Flavonoids - genetics; Food industries; Fundamental and applied biological sciences. Psychology; Glycosylation; Insecta; Plant Leaves - chemistry; Polymorphism, Genetic; Seasons; Solid Phase Extraction; NMR; α-l-rhamnosidase; β-d-glucosidase; glycosylation; structural elucidation; polymorphism; flavonoid; quantitative analysis; Enzyme; β-D-glucosidase; Glycosylation; α-L-rhamnosidase; Flavonoid; Glycosylases; Polyphenol; β-Glucosidase; Glycosidases; Hydrolases; Models; Quantitative analysis; Polymorphism
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf200412c

Nineteen apparent flavonoids were determined by HPLC-DAD in foliage of a chemotype (G-type) of Barbarea vulgaris, and four were isolated. Two were novel tetraglycosylated flavonols with identical glycosylation patterns, kaempferol 3-O-(2,6-di-O-β-d-glucopyranosyl)-β-d-glucopyranoside-7-O-α-l-rhamnopyranoside (1) and quercetin 3-O-(2,6-di-O-β-d-glucopyranosyl)-β-d-glucopyranoside-7-O-α-l-rhamnopyranoside (2). The identification of d/l configuration was tentatively based on susceptibility to α-l-rhamnosidase and β-d-glucosidases. A characteristic feature of 1 and 2 was appreciable water solubility, an expected consequence of the extensive glycosylation. A less complex pair of flavonols comprised 3-O-β-d-glucopyranoside-7-O-α-l-rhamnopyranosides of kaempferol and quercetin. Two natural chemotypes of B. vulgaris differed in levels of 1 and 2, with the P-type deficient in 1 and 2 and the insect-resistant G-type rich in 1 (ca. 3–4 μmol/g dry wt) and with moderate levels of 2 (ca. 0.3–0.8 μmol/g dry wt). However, there was only modest seasonal variation in flavonols 1 and 2, in contrast to a strong seasonal variation in insect resistance.