Anatoliosides: Five Novel Acyclic Monoterpene Glylcosides from Viburnum orientale

Five new acyclic monoterpene glycosides 1 – 5 were isolated from the leaves of Viburnum orientale (Caprifoliaceae). Anatolioside ( 1 ) is a monoterpene diglycoside and its structure was elucidated as linalo-6-yl 2′-O-(α-L -rhamnopyranosyl)β-D -glucopyranoside (arbitrary numbering of linalool moiety). Compounds 2 – 5 are all derivatives of 1 , containing additional monoterpene and sugar units, connected by ester and glycoside bonds. Their structures were established as linalo-6-yl O-[(2E,6R)-6-hydroxy-2, 6-dimethylocta-2,7-dienoyl]-(1? → 4″)-O-α-L -rhamnopyranosyl-(1″? → 2″″)-β-D -glucopyranoside ( = anatolioside A; 2 ), linalo-6-yl O-β-D -glucopyranosyl-(1? → 6?)-O-[(2E,6R)-6-hydroxy-2,6-dimethylocta-2,7-dienoyl]-(1? → 4″)-O-α-L -rhamnopyranosyl-(1″ → 2′)–β-D -glucopyranoside ( = anatolioside B; 3 ), linalo-6-yl O-β-D ribo-hexopyranos-3-ulosyl-(1′? → 6?)-O-[(2E,6R)-6-hydroxy-2,6-dimethylocta-2,7-dienoyl]-(1? → 4″)-O-α-L -rhamnopyranosyl-(1″ → 2′)-β-D -glucopyranoside ( = anatolioside C; 4 ) and linalo-6-yl O-[(2E, 6R)-6-hydroxy-2,6-dimethylocta-2,7-dienoyl]-(1″? → 2″″)-O-β-D -glucopyranosly-(1″″ → 6?)-O-[(2E,6R)-6-hydroxy-2,6-dimethylocta-2,7-dienoyl]-(1? → 4″)-O-α-L -rhamnopyranosyl(1″ → 2′)-β-D -glucopyranoside ( = anatolioside D ; 5 ). The structure determinations were based on spectroscopic and chemical methods (acid and alkaline hydrolysis, acetylation and methylation).     

Two new quercetin glycoside derivatives from the fruits of Gardenia jasminoides var. radicans

Two new quercetin glycoside derivatives named quercetin-3-O-[2-O-trans-caffeoyl-α-l-rhamnopyranosyl-(1 → 6)-β-d-glucopyranoside] (1) and quercetin-3-O-[2-O-trans-caffeoyl-β-l-rhamnopyranosyl-(1 → 6)-β-d-glucopyranoside] (2) along with three known flavonoids, 5-hydroxy-6,7,3′,4′,5′-pentamethoxyflavone (3), 5,7-dihydroxy-8-methoxyflavone (4) and kaempferol 3-O-β-d-glucopyranoside (5), were isolated from the fruits of Gardenia jasminoides var. radicans. The structures of the new compounds were determined by means of extensive spectroscopic analysis (1D, 2D NMR and HR-ESI-MS), glycoside hydrolysis and sugar HPLC analysis after derivatisation. This is the first report on the isolation of a pair of compounds with α or β-l-rhamnopyranosyl configuration from plant and the first detail assignment of their NMR data.     

Three new acyltyramines from Anisodus luridus Link et Otto (Solanaceae)

Three new acyltyramines, N-[2-(4-hydroxyphenyl)ethyl]hentriacontanamide (1), N-[2-(4-hydroxyphenyl)ethyl]nonacosanamide (2) and N-[2-(4-hydroxyphenyl)ethyl]heneicosanamide (3) have been isolated from n-hexane extract of leaves of Anisodus luridus (Solanaceae). Successive extraction of defatted leaves of A. luridus with methanol afforded a residue on removal of solvent under reduced pressure. Residue was partitioned by means of chloroform and n-butanol. Chromatographic resolution of n-BuOH extract afforded six known compounds, apigenin (4), luteolin (5), quercetin (6), quercetin 3-O-α-l-rhamnoside (7), kaempferol 3-O-α-rhamnoside (8) and quercetin 3-O-α-l-rhamnopyranosyl-(1→6)-β-d-glucopyranoside (9). The structures of the isolated compounds were assigned with the help of spectroscopic techniques. This is the first report of isolation of these compounds from this plant.     

Isolation and identification of polyphenols from Marsilea quadrifolia with antioxidant properties in vitro and in vivo

Marsilea quadrifolia is an edible aquatic medicinal plant used as a traditional health food in Asia. Four new polyphenols including kaempferol 3-O-(2″-O-E-caffeoyl)-β-d-glucopyranoside (1), kaempferol 3-O-(3″-O-E-caffeoyl)-α-l-arabinopyranoside (3), 4-methy-3′-hydroxypsilotinin (4) and (±)-(E)-4b-methoxy-3b,5b-dihydroxyscirpusin A (18) together with 14 known ones (2, 5–17) were isolated from the ethanol extract of M. quadrifolia. Structures of the new compounds were elucidated by extensive spectroscopic analyses. In DPPH and oxygen radical absorbance capacity antioxidant assays, some compounds showed stronger antioxidant activities and quercetin (9) was the most potent antioxidant in both assays. In a restraint-induced oxidative stress model in mice, quercetin significantly attenuated the increase in plasma ALT and AST levels as well as liver MDA content of restrained mice. Liver SOD activity was also significantly increased by quercetin, indicating a significant in vivo antioxidant activity. As a rich source of polyphenols with strong antioxidant activities, M. quadrifolia may be developed to a product for relieving oxidative stress.     

Study on the phenolic constituents of the flowers and leaves of Trifolium repens L

The flowers and leaves of Trifolium repens L. (Fabaceae) were subjected to phytochemical investigation in order to identify their major chemical constituents and to evaluate in?vitro antioxidant activity of the isolated compounds against DPPH˙. A total of 12 flavonoids, pterocarpan and methyl caffeate were isolated, then characterised by UV, MS, NMR spectroscopy and identified as quercetin and kaempferol 3-O-(6″-α-rhamnopyranosyl-2″-β-xylopyranosyl)-β-galactopyranosides (1, 2), kaempferol 3-O-(2″,6″-α-dirhamnopyranosyl)-β-galactopyranoside, mauritianin (3), quercetin and kaempferol 3-O-(2″-β-xylopyranosyl)-β-galactopyranosides (4, 5), kaempferol and quercetin 3-O-β-(6″-O-acetyl)-galactopyranosides (6, 7), trifolin (8), hyperoside (9), myricetin 3-O-β-galactopyranoside (10), quercetin (11), ononin (12), medicarpin 3-O-β-glucopyranoside (13) and methyl caffeate (14). Mauritianin, ononin, pterocarpan and methyl caffeate have been reported in this plant for the first time. The compounds 4, 7, 9, 10, and 11 were tested for their antioxidant effect against DPPH˙. All studied compounds were found to have potent activity, but the most effective in the test were compounds 9, 10 and 11 (EC(50) values in the range 7.51-9.52?μM).     

27-Ald-triterpenoid saponins from Adina rubella

Four new triterpenoid saponins were isolated from the roots of Adina rubella Hance. They were characterized as adinaic acid 3β-O-[α-L-rhamnopyranosyl(l→2)-β-D-glucopyranosyl(l→2)-β-D-glucurono-pyranoside-6-O-methyl ester]-28-O-β-D)-glucopyranoside, adinaic acid 3β-O-[α-L-rham-nopyranosyl(l→2)-β-D-glucopyranosyl(l→2)-β-D-glucuronopyranoside-6-O-butyl ester]-28-O-β-D-glu-copyranoside, adinaic acid 3β-O-[β-D-glucopyranosyl(l→2)-β-D-glucopyranosyl]-(28→1)-β-D-gluco-pyranosyl(l→6)-β-D-glucopyranosyl ester, 27-hydroxyursolic acid 3β-O-[α-L-rhamnopyranosyl (l→2)-β-O-glucopyranosyl(l→2)-β-D)-glucuronopyranoside-6-O-methyl ester]-28-O-β-D)-glucopyranoside. Their structures were elucidated by spectral methods, especially with the aid of 2D NMR techniques. Their complete assignments of the 1H and 13C NMR signals were carried out.     

A new acylated flavonoid tetraglycoside with anti-inflammatory activity from Tipuana tipu leaves

A new acylated kaempferol glycoside, kaempferol 3-O-α-l-rhamnopyranosyl-(1 → 6)-O-[β-d-glucopyranosyl-(1 → 2)-4-O-acetyl-α-l-rhamnopyranosyl-(1 → 2)]-β-d-galactopyranoside, has been isolated from the leaves of Tipuana tipu (Benth.) Lillo growing in Egypt, along with three known flavonol glycosides, kaempferol 3-O-rutinoside, quercetin 3-O-rutinoside (rutin) and kaempferol 3-O-[α-l-rhamnopyranosyl-(1 → 6)]-[α-l-rhamnopyranosyl-(1 → 2]-β-d-glucopyranoside. Structure elucidation was achieved through different spectroscopic methods. Structure relationship with anti-inflammatory activity using carrageenin-induced rat paw oedema model is discussed.     

Phenolic constituents of the aerial parts of Impatiens glandulifera Royle (Balsaminaceae) and their antioxidant activities

As a continuation of investigating Impatiens L. genus, eight flavonoids, eriodyctiol, eriodyctiol 7-O-β-?-glucoside, kaempferol 3-O-β-?-glucoside, kaempferol 3-O-β-?-galactoside, kaempferol 3-rhamnosyl-di-glucoside, kaempferol 3-O-β-?-rutinoside, quercetin 3-O-β-?-glucoside and quercetin 3-O-β-?-galactoside, two phenolic acids – p-hydroxybenzoic acid and protocatechuic acid, and 2-methoxynaphthalene-1,4-dione were isolated from the aerial parts of I. glandulifera collected in Poland. The structures of the compounds were established by analysis of their spectroscopic (¹H and ¹³C NMR) and spectrometric (MS) data, as well as by comparison of these with those reported in the literature. Quercetin 3-O-β-?-glucoside, kaempferol 3-O-β-?-galactoside and kaempferol 3-O-β-?-rutinoside were isolated for the first time from the investigated taxon. In addition, the antioxidant activities in different tests of all obtained compounds were evaluated. The results clearly showed that among analyzed constituents, quercetin 3-O-β-?-glucoside exhibited antioxidant activity comparable or better than ascorbic acid and Trolox which were used as a positive control.     

地奥心血康中的两个新甾体皂苷

通过正相和反相硅胶柱层析, 从地奥心血康药粉的正丁醇萃取物中分离纯化出2个微量的新甾体皂苷, 通过MS和NMR(包括HMQC, HMBC和NOESY)等波谱解析, 结合化学降解分析将其结构鉴定为3β,26-二醇-25(R)-Δ^5,20(22)-二烯-呋甾-26-O-β-D-吡喃葡萄糖苷(1)和26-O-β-D-吡喃葡萄糖基-3β,20α,26-三醇-25(R)-Δ^5,22-二烯-呋甾-3-O-α-L-吡喃鼠李糖基(1→2)-[α-L-吡喃鼠李糖基(1→4)]-β-D-吡喃葡萄糖苷(2).     

Polar Chemical Constituents from Phoebe formosana

A chemical investigation on the H₂O-soluble constituents from the leaf of Phoebe formosana. led to the characterization often compounds including two C-glycosylflavone — vitexin ( 1 ), isovitexin ( 2 ); six O-glycosylflavonol — quercetin 3-O-galactoside ( 3 ), quercetin 3-O-α-L-arabinopyranoside ( 4 ), kaempferol 3-O-α-L-arabinofuranoside ( 5 ), kaempferol 3-O-α-L-rhamnoside ( 6 ), kaempferol 3-O-β-D-xylopyranoside ( 7 ); one dihydroflavonol -(+)-dihydroquercetin ( 8 ) and two nucleosides -adenosine ( 9 ), and adenine ( 10 ). Their structures were determined on the basis of spectral analysis.     

Antioxidant secondary metabolites from Geranium lasiopus Boiss. & Heldr

Chromatographic studies on the EtOAc soluble portion of the MeOH extract of Geranium lasiopus led to the isolation of eight flavonoids (kaempferol (1), quercetin (2), quercetin 3-O-β-glucopyranoside (3), quercetin 3-O-β-galactopyranoside (4), kaempferol 3-O-α-rhamnopyranosyl-(1?→?6)-β-glucopyranoside (5), quercetin 3-O-α-rhamnopyranosyl-(1?→?6)-β-glucopyranoside (6), kaempferol 3-O-α-rhamnopyranosyl-(1?→?2)-β-glucopyranoside (7) and quercetin 3-O-α-rhamnopyranosyl-(1?→?2)-β-glucopyranoside (8)), two simple phenolic compounds (gallic acid (9) and its methyl ester (10)) and a hydrolysable tannin (pusilagin (11)). The structures of the compounds were elucidated by 1- and 2-dimensional NMR techniques ((1)H, (13)C, COSY, HMBC, HMQC) and ESI-TOF-MS spectrometry. Inhibitory effects on H(2)O(2)-induced lipid peroxidation in human red blood cells of the different extracts of G. lasiopus, as well as isolated compounds, were investigated. All tested compounds showed comparable or higher activity than that of ascorbic acid and trolox.     

A New (–)-5′,6-dimethoxyisolariciresinol-(3″,4″-dimethoxy)-3α-O-β-D-glucopyranoside from the bark of Aglaia eximia (Meliaceae)

New (–)-5′,6-dimethoxyisolariciresinol-(3″,4″-dimethoxy)-3α-O-β-d-glucopyranoside compound was isolated from the methanol extract of the bark of Aglaia eximia (Meliaceae). The chemical structure of the new compound were elucidated on the basis of spectroscopic data including, UV, IR, HR-ESI-TOFMS, 1D-NMR, 2D-NMR and comparison with those related compounds previously reported.     

A new anti-proliferative acylated flavonol glycoside from Fuzhuan brick-tea

Fuzhuan brick-tea (FBT) is unique for a fungal fermentation stage in its manufacture process and is classified in dark tea. A new acylated flavonol glycoside, kaempferol 3-O-[E-p-coumaroyl-(→2)][α-l-arabinopyranosyl-(1→3)][α-l-rhamnopyranosyl(1→6)]-β-d-glucopyranoside, which was trivially named as camellikaempferoside A (1), was isolated from FBT along with camelliquercetiside C (2). Their structures were unambiguously elucidated by combination of spectroscopic and chemical methods. Compound 1 showed anti-proliferative activity against MCF-7 and MDA–MB-231 cells with IC₅₀ values of 7.83 and 19.16 μM, respectively.     

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.     

NMR spectral analysis of flavonoids from <Emphasis Type="Italic">Chrysanthemum coronarium</Emphasis>

Naringenin 5-O-glucoside, apigenin 7-O-glucoside, luteolin 7-O-glucoside, kaempferol 3-O-glucoside, quercetin 3-O-glucoside, apigenin, luteolin, kaempferol, and quercetin, nine flavonoid derivatives, were isolated for the first time from the aqueous methanolic extract of the aerial parts of Chrysanthemum coronarium. Their structures were elucidated on the basis of chemical and spectroscopic (UV, ¹H, ¹³C NMR) analyses. 1-and 2-dimensional NMR spectroscopy of the rare naringenin 5-O-glucoside have been recorded and assigned for the first time. The flavonoid glucosides from Chrysanthemum coronarium showed week activity against Poliovirus I and Adenovirus type 7. Published in Khimiya Prirodnykh Soedinenii, No. 6, pp. 546–548, November–December, 2007.     

A new flavonol glycoside and other flavonoids from the aerial parts of Taverniera aegyptiaca

Isolation of flavonoids from the aerial parts of Taverniera aegyptiaca Bioss. (Fabaceae) led to identification of one new flavonol glycoside, isorhamnetin-3-O-α-l-rhamnopyranosyl-(1→2)-α-l-arabinopyranoside (1), along with eleven compounds, which previously have not been isolated from this plant quercetin-3-O-α-l-rhamnopyranosyl-(1→2)-[α-l-rhamnopyranosyl-(1→6)-β-d-galactopyranoside] (2), isorhamnetin-3-O-α-l-arabinopyranoside (3), quercetin-3-O-α-l-rhamnopyranosyl-(1→6)-β-d-glucopyranoside (4), isorhamnetin-3-O-α-l-rhamnopyranosyl-(1→6)-β-d-glucopyranoside (7), isorhamnetin 3-O-α-l-rhamnopyranosyl-(1→2)-[α-l-rhamnopyranosyl-(1→6)-β-d-galactopyranoside] (8), isorhamnetin 3-O-α-l-rhamnopyranosyl-(1→2)-[α-l-rhamnopyranosyl-(1→6)-β-d-glucopyranoside] (9), kaempferol 3-O-α-l-rhamnopyranosyl-(1→2)-[α-l-rhamnopyranosyl-(1→6)-β-d-galactopyranoside] (10), isorhamnetin (11), 4,4′-dihydroxy-2′-methoxychalcone (12), formononetin (13) and calycosin (15)] and some compounds already known from this plant [quercetin-3-O-robinobioside (5), isorhamnetin-3-O-robinobioside (6), afrormosin (14) and odoratin (16)].     

Flavonol Glycosides with α‐Glucosidase Inhibitory Activities and New Flavone C‐Diosides from the Leaves of Machilus konishii

Seventeen flavonoids, five of which are flavone C‐diosides, 1 – 5 , were isolated from the BuOH‐ and AcOEt‐soluble fractions of the leaf extract of Machilus konishii. Among 1 – 5 , apigenin 6‐C‐β‐D ‐xylopyranosyl‐2″‐O‐β‐D ‐glucopyranoside ( 2 ), apigenin 8‐C‐α‐L ‐arabinopyranosyl‐2″‐O‐β‐D ‐glucopyranoside ( 4 ), and apigenin 8‐C‐β‐D ‐xylopyranosyl‐2″‐O‐β‐D ‐glucopyranoside ( 5 ) are new. Both 4 and 5 are present as rotamer pairs. The structures of the new compounds were elucidated on the basis of NMR‐spectroscopic analyses and MS data. In addition, the ¹H‐ and ¹³C‐NMR data of apigenin 6‐C‐α‐L ‐arabinopyranosyl‐2″‐O‐β‐D ‐glucopyranoside ( 3 ) were assigned for the first time. The isolated compounds were assayed against α‐glucosidase (type IV from Bacillus stearothermophilus). Kaempferol 3‐O‐(2‐β‐D ‐apiofuranosyl)‐α‐L ‐rhamnopyranoside ( 12 ) was found to possess the best inhibitory activity with an IC₅₀ value of 29.3 μM .     

A novel acylated quercetin glycoside and compounds of inhibitory effects on α-glucosidase from Panax ginseng flower buds

Abstract

A novel acylated quercetin glycoside, floralpanasenoside A (1) and five known flavonoid glycosides, panasenoside (2), quercetin 3-O-(2''-β-D-glucopyranosyl)-β-D- galactopyranoside (3), trifolin (4) kaempferol 7-O-α-L-rhamnoside (5), and afzelin (6) were isolated from the flower buds of Panax ginseng. Their structures were established by spectroscopic data and comparison with the literature values. Four of the six isolated compounds including 1 (IC₅₀ = 62.4) exhibited α-glucosidase inhibitory activity with IC₅₀ values lower than acarbose (385.2?μM). The molecular docking study indicated that 1 bound to the active site of α-glucosidase with numerous hydrogen bond interactions.     

Structure elucidation and NMR assignment of two new eudesmane derivatives from Merremia yunnanensis

Two new eudesmane derivatives, 1α,6β,9β-trihydroxy-eudesm-3-ene-1-O-β-d -glucopyranoside ( 1 ) and 1α,6β,9β-trihydroxy-eudesm-3-ene-1-(6-cinnamoyl)-O-β-d -glucopyranoside ( 2 ) were discovered from Merremia yunnanensis. The structures were elucidated by analysis of their spectroscopic data including HR-ESI-MS, 1D, and 2D NMR. It should be noted that this is the first report about structure elucidation and NMR assignment of compounds from M. yunnanensis.     

Flavonoids of Alcea rosea L. and their immune stimulant,antioxidant and cytotoxic activities on hepatocellular carcinoma HepG-2 cell line

Alcea rosea L. is widely cultivated in gardens of Egypt as an ornamental plant and it has a great history of folkloric medicinal uses. In the present work, phytochemical investigation of the alcoholic extract of the flowers of A. rosea L. led to the isolation of six flavonoids (1–6). Dihydrokaempferol-4′-O-β-d-glucopyranoside (1), dihydrokaempferol (2), kaempferol-3-O-[6″-(E-coumaroyl)]-β-d-glucopyranoside (3), kaempferol-3-O-β-d-glucopyranoside (4), Apigenin (5) and kaempferol-3-O-α-l-rhamnopyranosyl-(1′″→6″)-β-d-glucopyranoside (6). Four of the isolated compounds were evaluated for their antioxidant, immunostimulant and cytotoxic activities against HepG-2 cell line. Compound (3) showed potent cytotoxic activity against HepG-2 cell line with high selectivity towards hepatocellular carcinoma in vitro (with IC₅₀ = 3.8 μg/mL). Compounds 1 and 2 exhibited significant antioxidant activity and compound 4 showed a significant immune stimulant activity. Compound 1 is isolated for the first time from genus Alcea and this is the first report for its biological investigation.