Antioxidant flavonol glycosides from Dorycnium hirsutum

Seven flavonol glycosides were isolated and identified from the aerial parts of Dorycnium hirsutum, together with catechin, D-pinitol, β-sitosterol, and stearic acid. The extracts and the isolated flavonol glycosides were evaluated for their antioxidant activity, using the DPPH test (radical scavenging) and the lipoxygenase assay (lipid peroxidation). Dedicated to the memory of Prof. I. Morelli. Published in Khimiya Prirodnykh Soedinenii, No. 3, pp. 233–235, May–June, 2006.     

Antioxidant galloylated flavonol glycosides from Calliandra haematocephala

Three new acylated quercetin rhamnosides have been isolated from the leaves and stem of Calliandra haematocephala Hassk. (Fabaceae) and their structures were established as quercitrin 2'-O-caffeate (1), quercitrin 3'-O-gallate (2) and quercitrin 2',3'-di-O-gallate (3). Also, 17 known compounds were identified as gallic acid (4), methyl gallate (5), caffeic acid (6), myricitrin (7), quercitrin (8), myricetin 3-O-beta-D-4C1-glucopyranoside (9), afzelin (10), isoquercitrin (11), myricetin 3-O-(6'-O-galloyl)-beta-D-glucopyranoside (12), myricitrin 2'-O-gallate (13), quercitrin 2'-O-gallate (14), afzelin 2'-O-gallate (15), myricitrin 3'-O-gallate (16), afzelin 3'-O-gallate (17), 1,2,3,4,6-penta-O-galloyl-beta-D-4C1-glucopyranose (18), myricitrin 2',3'-di-O-gallate (19), quercetin 3-O-methyl ether (20), for the first time from the genus Calliandra except for 6. Compounds 7, 8, 13, 14, 16 and 19 exhibited moderate to strong radical scavenging properties on lipid peroxidation, hydroxyl radical, superoxide anion generation and DPPH radical in comparison with that of quercetin as a positive control in vitro. Compounds 7 and 8 exhibited lethal effect towards brine shrimp Artemia salina.     

Antioxidant flavonol glycosides from Elaeocarpus serratus and Filicium decipiens

Chemical investigation of the leaves of Elaeocarpus serratus yielded myricitrin (1), mearnsetin 3-O-β-D-glucopyranoside (2), mearnsitrin (3), tamarixetin 3-O-α-L-rhamnopyranoside (4) and the fruits of Filicium decipiens yielded three flavonol glycosides, kaempferol 3-O-rutinoside (5), kaempferol 3-O-robinobioside (6) and trifolin (7). Compound 1 showed strong antioxidant activity against DPPH.     

Anti-inflammatory activity of a novel flavonol glycoside from the Bauhinia variegata Linn

Bauhinia variegata Linn. (Leguminosae) is commonly known as 'Kachnar' in Hindi. It is distributed almost throught India. Its powdered bark is traditionally used for tonic, astrain, ulcers. It is also useful in skin diseases. The roots are used as antidote to snake poison. The present article deals with the isolation and structural elucidation of a novel flavonol glycoside 5,7,3',4'-tetrahydroxy-3-methoxy-7-O-alpha-L-rhamnopyranosyl(1-->3)-O-beta-galactopyranoside (1) from the roots of Bauhinia Variegata and its structure was identified by spectral analysis and chemical degradations. The novel compound (1) showed anti-inflammatory activity.     

Acylated flavonol glycosides with anti-complement activity from Persicaria lapathifolia.

During a search for biologically active compounds from traditional medicines, a crude extract of Persicaria lapathifolia was found to have anti-complement activity. Bioassay-guided chromatographic separation of the active constituents led to the isolation of a new acylated kaempferol glycoside (1) and three known acylated quercetin glycosides (2-4). The structures of compounds 1-4 were characterized as kaempferol 3-O-beta-D-(6"-p-hydroxybenzoyl)-galactopyranoside, quercetin 3-O-beta-D-(6"-feruloyl)-galactopyranoside, quercetin 3-O-beta-D-(2"-galloyl)-rhamnopyranoside and quercetin 3-O-beta-D-(2"-galloyl)-glucopyranoside, respectively. Compounds 1-4 showed strong anti-complement activity (IC50 values of 4.3, 9.7, 3.9 and 7.6 x 10(-5) M, respectively) on the classical pathway of the complement. On the other hand, six isolated flavonol glycosides (5-10) did not show any activity on this system.     

New flavonol glycosides from the leaves of Caragana brachyantha

Two new flavonol glycosides, brachysides C and D, together with three known flavonol glycosides, were isolated from the leaves of Caragana brachyantha. The structures of brachysides C and D were elucidated on the basis of detailed spectroscopic analysis as quercetin 5-O-[α-l-rhamnopyranosyl-(1 → 6)-β-d-glucopyranoside]-7-O-[α-l-rhamnopyranoside] and quercetin 5-O-[α-l-rhamnopyranosyl-(1 → 6)-β-d-glucopyranoside]-7-O-[α-l-rhamnopyranoside]-4′-O-[α-l-rhamnopyranoside], respectively. The presence of flavonol tetra- and triglycosides bearing a sugar moiety at position 5 was the first report from this genus Caragana.     

Two new flavonol glycosides from Dimocarpus longan leaves

From the extracts of Dimocarpus longan Lour leaves, 2 unusual flavonol glycosides, quercetin 3-O-(3″-O-2?-methyl-2?-hydroxylethyl)-β-d-xyloside (1) and quercetin 3-O-(3″-O-2?-methyl-2?-hydroxylethyl)-α-l-rhamnopyranoside (2), as well as 10 known compounds including 2 flavonol glycosides, afzelin (3) and kaempferol-3-O-α-l-rhamnopyranoside (4), 2 flavans, ( ? )-epicatechin (5) and proanthocyanidin A-2 (6), 3 triterpenoids, friedelin (7), epifriedelanol (8) and β-amyrin (9), a peptide, N-benzoylphenylalanyl-N-benzoylphenylalaninate (10), and 2 sterols, β-sitosterol (11) and daucosterol (12) were isolated and identified by using combination of mass spectrometry and various 1D and 2D NMR techniques. This is the first report of flavonoid glycosides possessing a 2-methyl-2-hydroxylethoxyl group in sugar moiety from D. longan.     

Acylated flavonol glycosides from Sedum aizoon

A new acylated flavonol glycoside (1) and a known compound (2) have been isolated from the whole plant of Sedum aizoon L. Their structures have been established as quercetin 3-O-[β-D-(2‴-O-(E)-feruloyl)-xylopyranosyl]-(1 → 6)-β-D-glucopyranoside (1) and rutin (2) by means of spectroscopic analysis and chemical methods.     

Structures of flavone and flavonol glycosides

Summary Literature information on the structures of O-glycosides of flavones and flavonols has been generalized. Using the methods of combinatorial mathematics, the possibility of a great diversity of the structure of the glycosides has been shown without taking into account their acylation, the dimensions of the oxide rings of the sugars, and the nature of the glycosidic bonds.Pyatigorsk Pharmaceutical Institute. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 413–425, July–August, 1972.     

Two new acylated flavonol glycosides from Vicia amurensis

Two new acylated flavonol glycosides, named amurenosides A and B, together with quercetin 3-(2,6-di-O-alpha-rhamnopyranosyl-beta-galactopyranoside), have been isolated from the whole plant of Vicia amurensis. Their structures were elucidated as quercetin 3-O-alpha-L-(3-feruloylrhamnopyranosyl)(1-->6)-[alpha-L-rhamnopyra nosyl(1-->2)]-beta-D-galactopyranoside and quercetin 3-O-alpha-L-(2-feruloylrhamnopyranosyl)(1-->6)-[alpha-L-rhamnopyra nosyl(1-->2)]-beta-D-galactopyranoside on the basis of various NMR techniques, FAB mass spectrometry and chemical reactions.     

Biflavone, flavonol, and xanthone glycosides from Hypericum aucheri

Scientific Institute of Pharmacology and Pharmacy of the Medical Academy, Sofia. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 454–455, May–June, 1988.     

Three new flavonol glycosides from the aerial parts of Rodgersia podophylla

Three new flavonol glycosides were isolated together with five known flavonoids and six bergenin derivatives from the aerial parts of Rodgersia podophylla. The structures of these new compounds were elucidated by spectral methods as kaempferol-3-O-alpha-L-5'-acetyl-arabinofuranoside (1), kaempferol 3-O-alpha-L-3'-acetyl-arabinofuranoside (2), and quercetin-3-O-alpha-L-3',5'-diacetyl-arabinofuranoside (3).     

Two new flavonol glycosides from Sarcopyramis bodinieri var. delicate

Detailed chemical investigation of the herb Sarcopyramis bodinieri var. delicate resulted in the isolation of two new flavonol glycosides, namely, isorhamnetin-3-O-(6'-OE-feruloyl)-beta-D-glucopyranoside (1) and isorhamnetin-3-O-(6'-O-E-feruloyl)-beta-Dgalactopyranoside (2). In addition, four known compounds, quercetin-3-O-(6'-acetyl)-beta-Dglucopyranoside (3), isorhamnetin-3-O-(6'-acetyl)-beta-D-glucopyranoside (4), quercetin-3-O-(6'-O-E-p-coumaroyl)-beta-D-glucopyranoside (5), and isorhamnetin-3-O-(6'-O-E-pcoumaroyl)-beta-D-glucopyranoside (6) were obtained. The structures of the new isolates were determined by extensive spectroscopic analysis.     

Brauhenefloroside E and F; acylated flavonol glycosides from Stocksia brauhica Linn

Two new acylated flavonol glycosides, 3‐O‐{[2‐O‐β‐D ‐glucopyranosyl]‐3‐[O‐β‐D ‐glucopyranosyl]‐4‐[(6‐O‐p‐coumaroyl)‐O‐β‐D ‐glucopyranosyl]}‐α‐L ‐rhamnopyranosyl‐kaempferol 7‐O‐α‐L ‐rhamnopyranoside and 3‐O‐{2‐[(6‐O‐p‐coumaroyl)‐O‐β‐D ‐glucopyranosyl]‐3‐[O‐β‐D ‐glucopyranosyl]‐4‐[(6‐O‐p‐coumaroyl)‐O‐β‐D ‐glucopyranosyl]}‐α‐L ‐rhamnopyranosyl‐kaempferol 7‐O‐α‐L ‐rhamnopyranoside, trivially named as brauhenefloroside E (1) and F (2), respectively, were isolated from the fruits of Stocksia brauhica and their structures were elucidated using spectroscopic methods, including 2D NMR experiments. Copyright © 2010 John Wiley & Sons, Ltd.     

Cholestane glycosides from the bulbs of Galtonia candicans and their cytotoxicity

Further search for cytotoxic compounds contained in the bulbs of Galtonia candicans (Liliaceae) led to the isolation of four potent cytotoxic cholestane glycosides (1-4) based upon 3beta,16beta,17alpha-trihydroxycholest-5-en-22-one, three of which (2-4) have not been reported previously. A new cholestane bisdesmoside (5) and a new rearranged cholestane glycoside (6) were also isolated. The structural assignment of the new constituents was carried out by spectroscopic analysis and a few chemical transformations.     

Cypellogins A, B and C, acylated flavonol glycosides from Eucalyptus cypellocarpa

Three new acylated flavonol glycosides, cypellogins A (1), B (2) and C (3), along with eight known phenolic compounds, were isolated from the dried leaves of Eucalyptus cypellocarpa, and their structures were elucidated using spectroscopic methods, including 2D NMR experiments and chemical evidence.