Polymorphism for novel tetraglycosylated flavonols in an eco-model crucifer, Barbarea vulgaris

TY - JOUR

T1 - Polymorphism for novel tetraglycosylated flavonols in an eco-model crucifer, Barbarea vulgaris

AU - Dalby-Brown, Lea

AU - Olsen, Carl Erik

AU - Nielsen, Jens Kvist

AU - Agerbirk, Niels

PY - 2011/7/13

Y1 - 2011/7/13

N2 - 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.

AB - 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.

U2 - 10.1021/jf200412c

DO - 10.1021/jf200412c

M3 - Journal article

C2 - 21615154

SN - 0021-8561

VL - 59

SP - 6947

EP - 6956

JO - Journal of Agricultural and Food Chemistry

JF - Journal of Agricultural and Food Chemistry

IS - 13

ER -