Anthocyanins and other flavonoids

Harborne, Jeffrey B.; Williams, Christine A.

doi:10.1039/a815631y

Cited by 128 publications

(97 citation statements)

References 231 publications

(118 reference statements)

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“…Moreover, a group of three compounds with very low intensities and similar migration time have been identified as three isoprenylated flavones with O-heterocyclic rings (closed furano and pyrano derivatives) very common in plant extracts. The introduction of these groups into the flavonoids converts them into more lipophilic substances [51]. It is also possible to find other compounds tentatively identified in Table 1.…”

Section: Characterization Of the Isolated Fractions By Ce-esi-tof-ms mentioning

confidence: 99%

A 2‐D‐HPLC‐CE platform coupled to ESI‐TOF‐MS to characterize the phenolic fraction in olive oil

et al. 2009

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A 2-D-HPLC/CE method was developed to separate and characterize more in depth the phenolic fraction of olive oil samples. The method involves the use of semi-preparative HPLC (C18 column 250x10 mm, 5 microm) as a first dimension of separation to isolate phenolic fractions from commercial extra-virgin olive oils and CE coupled to TOF-MS (CE-TOF-MS) as a second dimension, to analyze the composition of the isolated fractions. Using this method, a large number of compounds were tentatively identified, some of them by first time, based on the information concerning high mass accuracy and the isotopic pattern provided by TOF-MS analyzer together with the chemical knowledge and the behavior of the compounds in HPLC and CE. From these results it can be concluded that 2-D-HPLC-CE-MS provides enough resolving power to separate hundreds of compounds from highly complex samples, such as olive oil. Furthermore, in this paper, the isolated phenolic fractions have been used for two specific applications: quantification of some components of extra-virgin olive oil samples in terms of pure fractions, and in vitro studies of its anti-carcinogenic capacity.

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Section: Characterization Of the Isolated Fractions By Ce-esi-tof-ms mentioning

confidence: 99%

A 2‐D‐HPLC‐CE platform coupled to ESI‐TOF‐MS to characterize the phenolic fraction in olive oil

et al. 2009

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“…The flavonol myricetin is synthesized by a wide range of plant species and the B-ring monomethylated and dimethylated products, laricitrin and syringetin, respectively, are also naturally occurring flavonols (Harborne and Williams, 2001). Naturally occurring flavonols are generally glycosylated (Iwashina, 2000;Harborne and Williams, 2001). Van OMT-3 did have some activity against a glycosylated form of myricetin, myricitrin (myricetin-3-rhamnoside), but apparently the presence of the carbohydrate moiety was inhibitory to the methylation reaction.…”

Section: Expression Of Van Omt-2 and Van Omt-3 In E Colimentioning

confidence: 98%

“…Ethyl gallate and methyl gallate have been reported as secondary metabolites in some plants (Mendez and Mato, 1997;Abou-Zaid and Nozzolillo, 1999;Kandil et al, 1999;Cui et al, 2002;Riaz et al, 2004). The flavonol myricetin is synthesized by a wide range of plant species and the B-ring monomethylated and dimethylated products, laricitrin and syringetin, respectively, are also naturally occurring flavonols (Harborne and Williams, 2001). Naturally occurring flavonols are generally glycosylated (Iwashina, 2000;Harborne and Williams, 2001).…”

Section: Expression Of Van Omt-2 and Van Omt-3 In E Colimentioning

confidence: 99%

Evolution of Novel O-methyltransferases from the Vanilla planifolia Caffeic Acid O-methyltransferase

Rotter

Hartman

et al. 2006

Plant Mol Biol

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The biosynthesis of many plant secondary compounds involves the methylation of one or more hydroxyl groups, catalyzed by O-methyltransferases (OMTs). Here, we report the characterization of two OMTs, Van OMT-2 and Van OMT-3, from the orchid Vanilla planifolia Andrews. These enzymes catalyze the methylation of a single outer hydroxyl group in substrates possessing a 1,2,3-trihydroxybenzene moiety, such as methyl gallate and myricetin. This is a substrate requirement not previously reported for any OMTs. Based on sequence analysis these enzymes are most similar to caffeic acid O-methyltransferases (COMTs), but they have negligible activity with typical COMT substrates. Seven of 12 conserved substrate-binding residues in COMTs are altered in Van OMT-2 and Van OMT-3. Phylogenetic analysis of the sequences suggests that Van OMT-2 and Van OMT-3 evolved from the V. planifolia COMT. These V. planifolia OMTs are new instances of COMT-like enzymes with novel substrate preferences.

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“…The fraction C obtained from CHCl 3 -MeOH (9.5 : 0.5) was further subjected to medium pressure liquid chromatography over flash silica eluted with CHCl 3 -MeOH in increasing order of polarity. The fraction obtained from CHCl 3 -MeOH (9 : 1) was a mixture of two components which were subjected to preparative TLC (CHCl 3 Ϫ58.6°(cϭ0.14, MeOH).…”

Section: Methodsmentioning

confidence: 99%

“…The 1 H-and 13 C-NMR spectra of compound 1 exhibited signals characteristic of an aryl-tetralin type lignan-glycoside (Table 1). 8,9) The signals for the sugar moieties appeared at 3.72 (6H, s), and 3.36 (3H, s) and the downfield region of the spectrum showed two singlet at d 6.57 (1H, s, H-2) and 6.37 (2H, s, H-2Ј, 6Ј). The acid hydrolysis of 1 provided the glycone which could be separated and identified as D-glucose through its optical rotation sign and comparison of the retention time of its trimethylsilyl (TMS) ether with that of the standard in gas chromatography (GC).…”

mentioning

confidence: 99%