Hydroxybenzoic acid glycosides

Flaveria haumanii, Cotinus coggygria, Coreopsis spp. and pre Columbian Andean textiles Okanine, luteolin, butein (as aglycones, glycosides or as methyl ethers), quercetin, isorhamnetin (as sulfate esters), sulfuretin, fisetin, hydroxybenzoic acids HCI/Me0H/H20, HCOOH/MeOH A H20 B ACN C H20 with HCOOH 254, 350 nm/ESI (+) Column C4 7... 

The glycosidic alkaloid grandifoline (amorphous) from this plant was shown to have structure 139 in which R is a 2-0- -D-gluoopyrano-syl-L-arabinose residue. Acid methanalysis yielded laburnine and the disaccharide as well as the chroman derivatives of the presumed intermediate methyl ester of 3,5-diisopentenyl-4-hydroxybenzoic acid 162). 

The more complex groups of phenols found in combination with carbohydrates in plants are summarized in formulas (1) to (13). In addition, there are also simple mono-, di-, and tri-hydric phenols existing as glycosides some of these phenols possess additional functional groups, such as methoxyl, primary hydroxyl, and aldehyde groups. Hydroxybenzoic acids and some of their aliphatic esters, and hydroxycinnamic acids, are found as glycosides, and the acids themselves may also be esterified with mono- or oligo-saccharides. 

Gentisic acid glycosides act as leaf movement factors in Mimosa species (E 2.2). Gallic acid is an inhibitor of flowering in Kalanchoe blossfeldiana (E 2.2). Benzoic acid, p-hydroxybenzoic acid as well as protocatechuic acid methyl and ethyl esters are secreted from the pygidial glands of water beetles as antiseptics and feeding deterrents (E 5.1). 

The simple phenol hydroquinone (see above) is derived from hydroxybenzoic acid. Upon glucosylation, arbutin, a simple phenol glycoside, is formed. 

Malt and hop contain various hydroxybenzoic acids, which are retained at least partially up to the final beer (Fig. 75.4). Total hydroxybenzoic acids - mainly p-hydroxybenzoic, vanillic, and gallic acids - usually reach a few ppms in beer. They have also been fotmd as glycosides or other bound forms [8, 11-14, 70-74]. 

Hydroxybenzoic and vanillic acids are also present in numerous fruits and vegetables [1], and the native forms are frequently simple combinations with glucose (Table 1). Other derivatives have been detected in certain fruits [1,2] the methyl ester of />-hydroxybenzoic acid in passion fruit, 3,4-dihydrox-ybenzoic aldehyde in banana, a phenylpropene benzoic acid derivative in fruits of Jamaican Piper species, and benzoyl esters and other derivatives in the fruits of Aniba riparia. Different new glycosides of HBA showing radical-scavenging activity [e.g., a new guaiacylglycerol-vanillic acid ether (Fig. 1)] have been identified in the fruits of Boreava orientalis [20]. 

The amine 26 has been proposed as a putative intermediate in the biosynthesis of 3-amino-5-hydroxybenzoic acid and the m-CyN unit in the ansamycin antibiotics, and it has been prepared from the methyl ester-methyl glycoside of 3-deoxy-D-araWn<3-heptulosonic acid by a double inversion at C-4.31... 

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