Isolation Techniques for Flavonoids

TLC determination of flavonoids from different cultivars of Allium cepa and Allium ascalonicumThis study comprises the optimization and validation of a new TLC method for determination of flavonols in the bulbs of seven cultivars of onions and shallots. Separation was performed on RP-18 plates with the solvent mixture tetrahydrofuran/water/formic acid (40+60+6, V/V/V) as a mobile phase. The method was evaluated for precision, linearity, LOD, LOQ, accuracy and robustness. Chromatographic analysis of the extracts revealed the presence of three main flavonols, quercetin, quercetin-4'-O-glucoside and quercetin-3,4'-O-diglucoside in the majority of analyzed cultivars. The content of flavonols in the analyzed extracts of onion bulbs varied from 123 ('Exihibition') to 1079 mg kg -1 fresh mass (fm) ('Hybing') in edible parts, and from 1727 ('Hyline') to 28949 mg kg -1 fm ('Red Baron') in outer scales. The bulbs of two shallot cultivars contained 209 ('Ambition') and 523 mg kg -1 fm ('Matador') of flavonols in edible parts and 5426 and 8916 mg kg -1 fm in outer scales, respectively.

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“…It was obtained as a white, crystalline substance. Compound structure was confirmed by chromatographic and spectroscopic methods (13). …”

Section: Isolation and Identification Of Compoundmentioning

confidence: 96%

“…Quercetin-3,4'-diglucoside, kaempferol-3,4'-diglucoside and isorhamnetin-3,4'-diglucoside were isolated from the herb Echinocystis lobata and its structure elucidation was based on UV, 1 H NMR, 13 C NMR and MS data (12). The standards were dissolved in methanol (1 mg mL -1 ).…”

Section: Chemicalsmentioning

confidence: 99%

TLC determination of flavonoids from different cultivars of Allium cepa and Allium ascalonicum

et al. 2016

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“…3'-and 4'-hydroxyl groups. 14 The glycoside on hydrolysis with dilute HCl afforded an aglycone which exhibited a 18 nm hypsochromic shift in band I in the UV spectrum in presence of AlCl 3 /HCl with respect to AlCl 3 indicating an orthodihydroxyl system in either ring A or B. The presence of orthodihydroxylgroup in ring B was ruled out by another spectrum in NaOAc/H 3 BO 3 as stated above.…”

Section: Resultsmentioning

confidence: 89%

Three New Flavonoid Glycosides from the Fruits of Luffa echinata Roxb.- a Hepatoprotective Plant

Alam

Harrasi

Ahmed

et al. 2017

Dhaka Univ. J. Pharm. Sci

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Phytochemical investigation of bioactive polar extracts of Luffa echinata Roxb. fruits led to the isolation and characterization of three new flavone glycosides viz., 3,5,7,3′,4′-pentahydroxyflavone (2), and 5,7,8,4′-The structures of the newly isolated compounds were elucidated on the basis of spectral data and chemical evidences.The isolated compounds are found to be new analogs of tricetin, quercetin and isoscutellarin.

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“…Compound 1 afforded UV data, which suggested free hydroxyls at C-5, C-7, and C-4 [8][9][10]. The assignment of the 1 H and 13 C NMR data supported by NOESY and HMBC correlations confirmed the aglycone as isorhamnetin (3'-O-methylquercetin) substituted at C-3.…”

Section: Resultsmentioning

confidence: 99%

<b>Further flavonol glycosides of <i>Embelia schimperi</i> leaves</b>

Manguro

Ugi

Lemen

2004

Bull. Chem. Soc. Eth.

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ABSTRACT. Fractionation of the methanolic extract of Embelia schimperi leaves has led to the isolation of two novel flavonol glycosides. The compounds were characterized as isorhamnetin 3-O-rhamnoside. Also reported from the same extracts were known compounds quercetin, myricetin, quercetin 3-O-α-rhamnoside, quercetin 3-O-β-glucoside, quercetin 3-O-rutinoside, myricetin 3-O-β-xyloside, isorhamentin 3-O-β-glucoside and myricetin 3-O-β-glucoside. Their structural elucidation was accomplished using spectral measurements and chemical methods.

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Isolation Techniques for Flavonoids

Cited by 51 publications

References 162 publications

TLC determination of flavonoids from different cultivars of Allium cepa and Allium ascalonicum

TLC determination of flavonoids from different cultivars of Allium cepa and Allium ascalonicum

Three New Flavonoid Glycosides from the Fruits of Luffa echinata Roxb.- a Hepatoprotective Plant

<b>Further flavonol glycosides of <i>Embelia schimperi</i> leaves</b>

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