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A new phenanthrenoid dimer, junceffusin (1), has been isolated from the inflorescences of Juncus effusus var. decipiens, together with eight known compounds, effususin C (2), quercetin (3), nobiletin (4), luteolin (5), luteolin-5,3′-dimethyl ether (6), luteolin 7-glucoside (7), eriodictyol (8), and 5,7,2′,5′-tetrahydroxyflavone (9). The structure of the new compound 1 was determined using spectroscopic and MS analyses. Among the isolates, quercetin (3), luteolin (5), luteolin 7-glucoside (7), eriodictyol (8), and 5,7,2′,5′-tetrahydroxyflavone (9) showed potent inhibition, with IC50 values of 25.54 ± 2.24, 17.13 ± 1.36, 28.01 ± 2.88, 15.63 ± 1.15, and 27.44 ± 2.47 μM respectively, against lipopolysaccharide-induced nitric oxide generation. [ABSTRACT FROM AUTHOR]

A new naphthalene derivative, 7-acetyl-8-hydroxy-3-methoxy-6-methylnaphthalen-1-yl acetate (1), has been isolated from the stem of Rhamnus crenata, together with eight known compounds 2–9. The structure of new compound 1 was determined through spectroscopic and MS analyses. Among the isolates, emodin (3), physcion (4), quercetin 3-O-α-L-rhamnopyranoside (5), and quercetin 7-O-α-L-rhamnopyranoside (6) showed potent inhibition with IC50 values of 33.18 ± 2.73, 35.52 ± 3.27, 28.05 ± 1.85, and 26.41 ± 3.01 μM, respectively, against LPS-induced NO generation. In addition, compounds 3, 5, and 6 also showed potent DPPH radical scavenging activities with IC50 values of 95.47 ± 6.18, 68.27 ± 5.38, and 66.25 ± 4.20 μM, respectively. [ABSTRACT FROM AUTHOR]

Monosubstituted quercetin conjugates were synthesized via Mannich reactions from 1-aryl-(or H)-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinolines in 75–96% yields. Compounds with antihypoxic activity more effective than that of quercetin were found among them. [ABSTRACT FROM AUTHOR]

A study of phenolic compounds from four species of the genus Prunella (P. grandiflora, P. laciniata, P. vulgaris, and P. vulgaris subsp. asiatica) led to the isolation of 18 compounds, including the new flavonoid 1. UV and NMR spectroscopic and mass spectrometric data established that 1 was quercetin 3-O-(4′′-O-β-Dxylopyranosyl-6′′-O-α-L-rhamnopyranosyl)-β-D-glycopyranoside. [ABSTRACT FROM AUTHOR]

The chemical composition of two species in the family Boraginaceae, Nonea rossica Steven and Tournefortia sibirica L., in which alkaloids, hydroxycinnamates, and flavonoids, including two new acylglycosides 1 and 2 were observed, was studied. UV and NMR spectroscopy and mass spectrometry found that the new compounds were quercetin 3-O-(2′′-O-caffeoyl-6′′-O-acetyl)-β-D-glucopyranoside (noneaside, 1; from N. rossica) and kaempferol 3-O-(2′′-O-caffeoyl-6′′-O-acetyl)-β-D-glucopyranoside (tournefoside, 2; from T. sibirica). Both flavonoids possessed antiradical activity. [ABSTRACT FROM AUTHOR]

A new sesquiterpene glycoside, ceibanoside (1), was isolated from the leaves of Bombax ceiba, together with the previously-reported quercetin (2), kaempferol (3), naringenin (4), (+)-epicatechin (5), and procyanidin B2 (6). The structure of the new sesquiterpene glycoside was elucidated using chemical and physical evidence. Compound 2 showed antibacterial activity against Staphylococcus aureus, producing an inhibition zone with a diameter of 16.0 mm. [ABSTRACT FROM AUTHOR]

A new triterpenoid, methyl 2α-(4-hydroxybenzoyl)oxy-3β-hydroxy-urs-12-en-28-oate (1), has been isolated from the leaves of Eriobotrya deflexa f. deflexa, together with five known compounds, quercetin (2), kaempferol 3-O-β-glucoside (3), naringenin (4), ursolic acid (5), and euscaphic acid (6). The structure of new compound 1 was determined through spectroscopic and MS analyses. Among the isolates, quercetin (2), naringenin (4), and ursolic acid (5) showed potent inhibition with IC50 values of 31.74 ± 1.87, 24.25 ± 1.68, and 18.05 ± 1.02 μM, respectively, against LPS-induced NO generation. [ABSTRACT FROM AUTHOR]

A new stilbenoid, methyl 2,4-dihydroxy-6-(4-hydroxyphenethyl)-3-methylbenzoate (1), along with 11 known compounds, cirsimaritin (2), cirsiliol (3), quercetin (4), apigenin (5), acacetin (6), genkwanin (7), luteolin (8), caffeic acid (9), esculetin (10), alternariol (11), and alternariol-5-O-methyl ether (12), was isolated from the 70% EtOH extract of Caryopteris incana. The structures of these compounds were established via extensive spectroscopic techniques, including 1D, 2D NMR, and HR-ESI-MS. Compound 1 exhibited moderate cytotoxic activity against human HepG2 and SMMC-7721 hepatoma cell lines with IC50 values of 21.3 and 20.1 μM, respectively. [ABSTRACT FROM AUTHOR]

A new coumarin derivative, 7-O-methylparamicoumarin A (1), has been isolated from the roots of Chionanthus retusus, together with seven known compounds. The structure of new compound 1 was determined through spectroscopic and MS analyses. Among the isolates, luteolin (3), quercetin (4), and apigenin (5) exhibited cytotoxicities with IC50 values of 13.69 ± 1.10, 10.41 ± 0.79, and 12.25 ± 0.91 μM, respectively, against DLD-1 cell line. Luteolin (3), quercetin (4), and apigenin (5) also exhibited cytotoxicities with IC50 values of 15.35 ± 1.24, 13.52 ± 0.87, and 19.48 ± 1.26 μM, respectively, against CCRF-CEM cell line. In addition, kaempferol (2), apigenin (5), 3,3′,5,5′,7-pentahydroxyflavanone (6), and oleuropein (8) showed potent inhibition with IC50 values of 24.84 ± 1.95, 27.18 ± 1.82, 25.18 ± 2.07, and 28.14 ± 1.66 μM, respectively, against LPS-induced NO generation. [ABSTRACT FROM AUTHOR]

The composition of flavonoids from leaves of Allium microdictyon Prokh. (Amaryllidaceae) was studied for the first time and included 14 compounds including two new flavonol glycosides 1 and 2. UV, IR, and NMR spectroscopic and mass spectrometric data determined that 1 was quercetin-3-O-(2″ -O-α-Lrhamnopyranosyl)-β-D-glucopyranoside-7-O-β-D-glucuronopyranoside (quercetin-3-O-neohesperidoside-7-O-glucuronide). Compound 2 had the structure kaempferol-3-O-(2″-O-α-L-rhamnopyranosyl)-β-Dglucopyranoside-7-O-β-D-glucuronopyranoside (kaempferol-3-O-neohesperidoside-7-O-glucuronide). [ABSTRACT FROM AUTHOR]

A new norneolignan derivative, clitorternalactone (1), has been isolated from the stems of Clitoria ternatea, together with six known compounds, clitorienolactone A (2), myricetin 3-glucoside (3), quercetin 3-glucoside (4), kaempferol 3-glucoside (5), taraxerol (6), and taraxerone (7). The structure of the new compound 1 was determined through spectroscopic and MS analyses. Among the isolates, compound 1 exhibited cytotoxicities with IC50 values of 2.54 ± 0.23, 3.68 ± 0.17, and 4.05 ± 0.43 μM, respectively, against DLD-1, CCRF-CEM, and IMR-32 cell lines. In addition, clitorternalactone (1), clitorienolactone A (2), quercetin 3-glucoside (4), and kaempferol 3-glucoside (5) showed potent inhibition with IC50 values of 3.05 ± 0.12, 5.44 ± 0.46, 10.20 ± 0.69, and 13.57 ± 0.36 μM, respectively, against LPS-induced NO generation. [ABSTRACT FROM AUTHOR]

The tetra-O-methyl ether of quercetin (QU) 3 (54%), 3,7,4′-tri-O-methyl ether 4 (30%), and a previously unreported 3,7,3-tri-O-methyl ether of QU 5 (7%) were obtained via methylation of QU by an excess of diazomethane in dioxane. Their structures were established using 2D NMR (1H–1H COSY, 1H–1H NOESY, 1H–13C HSQC, 1H–13C HMBC). Tetra-O-methyl ether of QU 3 exhibited pronounced hypoglycemic activity, reduced alloxan-induced hyperglycemia in rats by 44.5% compared to a control, and was 2.7 times more active than QU. [ABSTRACT FROM AUTHOR]

In this study it was shown that the EtOAc fraction exhibited the strongest inhibitory activity, ranging from 92% to 87%, at a final concentration of 50% and 25% mg/mL, while the second stronger was the Et SB 2 sb O fraction with the inhibitory activity ranging from 78% to 70% in the same concentrations. Ellagic acid is known for its exceptionally high ALR2 inhibitory activity, and ellagic acid derivatives were identified in the Et SB 2 sb O fraction by means of LC-DAD-MS (ESI+) analysis. The LOX inhibitory activity was accounted only for the Et SB 2 sb O extract, which showed 19% of inhibition, while other extracts/fractions showed zero inhibition. Although tetragalloyl glucose, pentagalloyl glucose, and quercetin are proved to be strong LOX inhibitors [[21]], the unripe fruit extracts showed otherwise. [Extracted from the article]

The major components of the studied I Actinodaphne i essential oils were as follows: I A. lancifolia i (leaf oil): , -selinene (28.9%), caryophyllene (10.0%), and decanal (20.3%) [[15]]; I A. lancifolia i (mesocarps oil): decanal (15.3%); I A. lancifolia i (seeds oil): longifolin (64.9%), I A. lancifolia i (roots oil): sesquirosefuran (79.2%) [[16]]; I A. longifolia i (leaf oil): caryophyllene (8.3%) and -elemene (7.5%) [[15]]; I A. cupularis i (leaf oil): isocaryophyllene (8.3%) and germacrene B (7.1%) [[17]]; I A. macrophylla i (leaf oil): germacrene B (16.8%) and globulol (16.0%) [[18]]; and I A. pruinosa i (leaf oil): globulol (17.8%) and spathulenol (12.0%) [[18]]. The essential oil showed moderate activity with IC SB 50 sb value of 58.2 g/mL (quercetin IC SB 50 sb = 10.5 g/mL). Although many members of the family Lauraceae are renowned for their valuable essential oils, the genus I Actinodaphne i is still poorly explored as far as its essential oil composition is concerned. [Extracted from the article]

5,7,2′,3′,4′,5′-Hexahydroxyflavone 6-C-glucoside (1), 5-hydroxy-4′,7-dimethoxyflavone, luteolin-7,3′,4′-trimethyl ether, 5,3′-dihydroxy-7,4′-dimethoxyflavone, persicogenin, quercetin-3-O-rhamnoside, kaempferol-3-O-rhamnoside, isorhamnetin-3-O-rhamnoside, tamarixetin-3-O-rhamnoside, (+)-syringaresinol, (+)-diasyringaresinol, (+)-epi-syringaresinol, liriodendrin, methyl-β-D-xylopyranoside, methyl-β-Dglucopyranoside, and methyl-β-D-galactopyranoside were isolated from the seeds of Aquilaria agallocha (Thymelaeaceae). Among them, 1 is a new hexahydroxyflavone 6-C-glucoside. The structures of these compounds were characterized and identified by spectral analyses. [ABSTRACT FROM AUTHOR]

A new compound, quercetin-8-(2″-pyrrolidinone-5″-yl)-3′-O-β-D-glucopyranoside, with 11 known flavonoids, was isolated from the traditional Chinese herb Abelmoschus manihot. The structure was elucidated by spectral analysis. [ABSTRACT FROM AUTHOR]

A new acylated quercetin glycoside and 36 known compounds were isolated from flowering runners of Spiraea salicifolia L. (Rosaceae). The structures of the new glycoside quercetin-3-O-[6″-(4‴-hydroxy-2‴-methylenebutyroyl)]-β-D-glucopyranoside (spireasalicin, 1) and the 36 known compounds were elucidated using UV, IR, and NMR spectroscopy and mass spectrometry. The biological screening of the isolated compounds showed that 1 inhibited α-glucosidase. The contents of several phenolic compounds in S. salicifolia organs were studied and found to be unevenly distributed in the separate plant parts. [ABSTRACT FROM AUTHOR]

A new flavonol glycoside, quercetin-3-O-(4″-galloyl)- α-L-rhamnopyranoside ( 1), along with two known ones, kaempferol-3-O- β-D-glucopyranoside ( 2) and quercetin-3-O-rutinoside ( 3), were isolated from the root barks of Sophora japonica. The chemical structures of the isolated compounds were elucidated by spectroscopic analysis, including extensive 1D and 2D NMR and MS techniques. [ABSTRACT FROM AUTHOR]

Quercetin (Q) methyl ethers were synthesized from CHI under various conditions. The principal products from the reactions of Q with alkylhalides (CHI, CHBr) in DMF were 3,7,4′-tri-O-alkyl ethers. The structures of the products were confirmed by PMR and C NMR spectra. The antioxidant activity of Q tetra- and tri-O-methyl ethers was demonstrated by chemiluminescence in model systems generating active oxygen species and promoting lipid peroxidation. [ABSTRACT FROM AUTHOR]

One new γ-butyrolactone derivative, acrocarpunilactone ( 1), was isolated and identified from the rice solidsubstrate fermentation culture of an actinomycete, Acrocarpospora punica, together with nine known compounds, hydroxychavicol acetate ( 2), 4-allylcatechol ( 3), trans-caffeic aldehyde ( 4), (-)-ent-4β-hydroxy-10α-methoxyaromadendrane ( 5), (6α,7α)-4β-hydroxy-10α-methoxyaromadendrane ( 6), futoamide ( 7), N-[8′-(4′-hydroxyphenylethyl)]-2-hydroxybenzoylamide ( 8), hemiariensin ( 9), and 3-ethyl-4-hydroxybenzoic acid ( 10). Furthermore, the inhibitory effects of some isolates (compounds 1- 6) on nitric oxide (NO) production in lipopolysaccharide (LPS)-activated macrophages were also evaluated. Compounds 1- 3 showed stronger inhibition on NO production than the positive control quercetin. [ABSTRACT FROM AUTHOR]

Four new flavonoids that were identified using chemical transformations and UV, MS, PMR, and C NMR spectroscopy were isolated from flower heads of Calendula officinalis (Asteraceae). The compounds were quercetin 3-O-(4″-α-L-rhamnopyranosyl)-β-D-glucopyranoside (calendoside I), quercetin 3-O-(3″-α-Lrhamnopyranosyl)-β-D-glucopyranoside (calendoside II), isorhamnetin 3-O-(4″-α-L-rhamnopyranosyl)-β-D-glucopyranoside (calendoside III), and isorhamnetin 3-O-(3″-α-L-rhamnopyranosyl)-β-D-glucopyranoside (calendoside IV). [ABSTRACT FROM AUTHOR]

Mono-substituted spin-labeled compounds were synthesized from Mannich reactions of dihydroquercetin with 4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl, 3-amino-2,2,5,5-tetramethylpyrrolidine-1-oxyl, and 3-aminomethyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl. According to preliminary data, the compounds possessed antioxidant activity and selective cytotoxicity against various tumor cells and were promising for biomedical tests including magnetic resonance tomography. [ABSTRACT FROM AUTHOR]

Subfraction D2 was treated by silica gel CC (PE-acetone, 7:1) followed by Sephadex LH-20 column chromatography (CHCl SB 3 sb -MeOH, 1:1), then further purified by semipreparative HPLC (MeOH-H SB 2 sb O, 80:20) to yield compounds B 1-6 b . The inhibitory effects of compounds B 1 b , B 2 b , B 4 b , B 5 b , B 7 b , and B 9 b against -glucosidase were studied by the reported method [[14]] using quercetin as positive control. The PE part (70 g) was subjected to silica gel column chromatograph (PE-EtOAc, 1:0 to 0:1) to give eight fractions A-H. Fraction D (7.2 g) was decolored by MCI gel (CHP 20P) CC using a gradient system of CH SB 3 sb OH-H SB 2 sb O (95:5) and chromatographed by silica gel CC (PE-acetone, 10:1 to 5:1) to get three subfractions D1-D3. [Extracted from the article]

A total of 48 compounds and the new flavonoid glycoside ulmarioside, which was identified as quercetin-4′-O-α-rhamnopyranosyl-(1→6)-β-glucopyranoside (quercetin-4′-O-rutinoside), were isolated from Filipendula ulmaria (Rosaceae). Phenolic compounds from six species of Filipendula (F. camtschatica, F. denudata,F. palmata, F. stepposa, F. ulmaria, F. vulgaris) growing in Russia were compared. [ABSTRACT FROM AUTHOR]

A new flavonoid kaempferol-7,8-diglucoside was isolated for the first time along with two known flavonoid compounds, kaempferol and quercetin, from the methanol extract of Farsetia aegyptia Turra by chromatographic techniques. Two coumarin compounds were isolated and identified from the plant extract. The plant extract contains phenol, catechin, p-hydroxybenzoic acid, gallic acid, pyrogallic acid, p-coumaric acid, and coumarin compounds, which were identified by authentic samples using HPLC. The new compound and alcoholic extract of the plant were evaluated against some bacterial and fungal strains. They showed maximum inhibition against Klebsiella pneumonia. Moderate effects were observed to Aspergillus niger, while the extract did not show activity against Candida albicans. [ABSTRACT FROM AUTHOR]

New flavonoid oligosides were isolated from leaves and flowers of Astragalus falcatus Lam. It was found on the basis of chemical transformations, UV, IR, PMR, C NMR, HMBC, HSQC, 1D-TOCSY, and mass spectral properties that falcoside C had the structure quercetin 3-O-[ β-D-glucopyranosyl(1 → 3)- α-Lrhamnopyranosyl(1 → 6)]- β-D-galactopyranoside 7-O- β-D-glucopyranoside; falcoside D, isorhamnetin 3-O-[ β-D-xylopyranosyl(1 → 3)- α-L-rhamnopyranosyl(1 → 6)]- β-D-galactopyranoside 7-O- α-Lrhamnopyranoside. [ABSTRACT FROM AUTHOR]

The solubility and antioxidant activity of the bioflavonoid quercetin was increased from its mechanochemically prepared solid composites with metal carbonates and carbohydrate compounds. [ABSTRACT FROM AUTHOR]

The article reports on the modification of quercetin, the most well-known flavonoid and is widely distributed in the plant world, by pyrimidines. Quercetin and its derivatives are effective against several viruses because flavonoids inhibit key enzymatic systems. 870 compounds based on quercetin were synthesized since 1888.

A model for the complete system of bioaccumulation, transport, and biotransformation of polyphenolic compounds (flavonols) that includes hemoglobin-containing red blood cells and serum albumin was proposed. The distribution of flavonols between the erythrocyte fraction and albumin was studied. Hemoglobin was shown to play a role in the biotransformation of flavonols. The formation of several intermediate and final products of pseudoperoxidase oxidation of flavonols catalyzed by methemoglobin was established by UV spectrophotometry and RP-HPLC. [ABSTRACT FROM AUTHOR]

The content of main flavonoids from Rhododendron adamsii R. leaves and stems was determined quantitatively using HPLC. It was found that myricetin and quercetin dominated the identified compounds (myricetin, quercetin, dihydroquercetin, rutin) in leaves; dihydroquercetin, in stems (1.1, 1.0, and 2.5 mass% of raw material, respectively). Dihydroquercetin and rutin were found for the first time in R. adamsii. [ABSTRACT FROM AUTHOR]

Some of the main oxidation products of quercetin were shown to be compounds formed by oligomerization of the starting flavonoid. Conditions for the preparative synthesis of these compounds were developed. Their structures were established using HPLC-MS and NMR methods. Quercetin oligomers in the natural sample, outer leaves of modified runners of Allium cepa L., were found using chromatographic procedures. The use of quercetin oligomers as indicators of its oxidation was proposed. [ABSTRACT FROM AUTHOR]

Luteolin, quercetin, cinaroside, quercimeritrin, and the new flavonol bioside gigantoside A were isolated from Cephalaria gigantea (Ledeb.) Bobr. (Dipsacaceae) flowers. Spectral properties and chemical transformations established that gigantoside A had the structure quercetin-7- O-[ α-L-arabinopyranosyl(1→6)]- β-D-glucopyranoside. [ABSTRACT FROM AUTHOR]

New flavonoid oligosides, the structures of which were established by chemical transformations and UV, IR, PMR, and 13C NMR spectra, were isolated from Astragalus galegiformis leaves. [ABSTRACT FROM AUTHOR]

A chromatographically inseparable crystalline mixture of the previously undescribed quercetin-4′- O-β-galactopyranoside and the known quercetin-3- O-β-glucopyranoside (isoquercitrin) in a 7:5 ratio was isolated from the extract of the aerial part of Filipendula ulmaria (L.) Maxim. [ABSTRACT FROM AUTHOR]

The reaction of dihydroquercetin, quercetin, and rutin with Cu(II) acetate in aqueous solution is studied. Quercetin and dihydroquercetin form complexes with Cu. The water-insoluble complexes are characterized as chelates of the 3,4-positions of the main γ-pyrone ring. Electronic spectroscopy showed the presence of stable polynuclear rutin complexes of composition rutin :Cu = 1:x, where x > 2. [ABSTRACT FROM AUTHOR]

A new natural compound, esculetin-5-O-β-D-glucopyranoside (1), along with two known flavonoids, quercetin (2) and kaempferol-3-β-D-glucopyranoside (3), was purified from the heartwood of Fraxinus velutina. Their chemical structures were elucidated by spectroscopic methods, including extensive 1D and 2D NMR, and MS techniques. [ABSTRACT FROM AUTHOR]

A new ent-kaurane diterpenoid glucoside, 7 α,14 β,15 α-trihydroxy-ent-kaur-16-ene-1 α-O- β-Dglucopyranoside ( 1), along with three known compounds, quercetin-3-O- β-D-glucoside ( 2), kaempferol-3- O- β-D-glucopyranoside ( 3), and kaempferol-3-O-rutinoside ( 4), was isolated from the roots of Rabdosia excisa. The structures were elucidated on the basis of spectral analysis. Compounds 3 and 4 were isolated from this plant for the first time. [ABSTRACT FROM AUTHOR]