Acetylated allose-containing flavonoid glucosides from Stachys anisochila

In continuation of our chemosystematic study of Stachys (Labiatae) we have isolated the previously reported isoscutellarein 7-O-[6″'-O-acetyl-β-D-allopyranosyl-(1 → 2)-β-D-glucopyranoside] (1) and 3′-hydroxy-4′-O-methylisoscutellarein 7-O-[6″'-O-acetyl-β-D-allopyranosyl-(1 → 2)-β-D-glucopyranoside] (4) and four new allose-containing flavonoid glycosides from S. anisochila. The new glycosides are hypolaetin 7-O-[6″'-O-acetyl-β-D-allopyranosyl-(1 → 2)-β-D-glucopyranside] (6) as well as the three corresponding diacetyl analogues of 1, 4 and 6, isoscutellarein 7-O-[6″'-O-acetyl-β-D-allopyranosyl-(1 → 2)-6″-O-acetyl-β-D-glucopyranoside], 3′-hydroxy-4′-O-methylisoscutellarein 7-O-[6″'-O-acetyl-β-D-allopyranosyl-(1 → 2)-6″-O-acetyl-β-D-glucopyranoside] and hypolaetin 7-O-[6″'-O-acetyl-β-D-allopyranosyl-(1 → 2)-6″-O-acetyl-β-D-glucopyranoside]. Extensive two-dimensional NMR studies (proton-carbon correlations, COSY experiments) allowed assignment of all ¹H NMR sugar signals and a correction of the ¹³C NMR signal assignments for C-2 and C-3 of the allose.     

Flavonoid glycosides from needles of Pinus massoniana

Seven flavonoids have been isolated from Pinus massoniana needles and identified as taxifolin and its 3′-O-β-D-glucopyranoside, (+)-catechin, naringenin-7-O-β-D-glucopyranoside and three new flavonoid glycosides, 6-C-methylaromadendrin 7-O-β-D-glucopyranoside, taxifolin 3′-O-β-D-(6″-O-phenylacetyl)-glucopyranoside and eriodictyol 3′-O-β-D-glucopyranoside.     

Die flavonolglykoside von Equisetum telmateja

Nine kaempferol glycosides, including the hitherto unkown 3-β-d-(6-O-acetylglucoside)-7-β-d-glucoside and 3-β-d-(6-O-acetylglucoside)-7-α-l-rhamnoside, have been isolated from Equisetum telmateja of European origin.     

Three flavonoid glycosides containing acetylated allose from stachys recta

By means of ¹³C and ¹H NMR spectroscopy three flavone glycosides, obtained from Stachys recta, were identified as 7-O-(2″-O-6″′-O-acetyl-β-D-allopyranosyl-β-D-glucopyranosides) of 4′-O-methylisoscutellarein, isoscutellarein and 3′-hydroxy-4′-O-methylisoscutellarein. The latter two compounds are isolated for the first time. Only mannose and glucose have been reported previously as sugar components of flavonoids of the genus Stachys.     

Two new guaiane sesquiterpenes from Datura metel L. with anti-inflammatory activity

Chemical investigation of an acidic methanol extract of the whole plants of Datura metel resulted in the isolation of two new guainane sesquiterpenes, 1β,5α,7β-guaiane-4β,10α,11-triol (1) and 1α,5α,7α-11-guaiene-2α,3β,4α,10α,13-pentaol (2), along with eight known compounds: pterodontriol B (3), disciferitriol (4), scopolamine (5), kaempferol 3-O-β-d-glucosyl(1 → 2)-β-d-galactoside 7-O-β-d-glucoside (6), kaempferol 3-O-β-glucopyranosyl(1 → 2)-β-glucopyranoside-7-O-α-rhamnopyranoside (7), pinoresinol 4′′-O-β-d-glucopyranoside (8), (7R,8S,7′S,8′R)-4,9,4′,7′-tetrahydroxy-3,3′-dimethoxy-7,9′-epoxy-lignan-4-O-β-d-glucopyranoside (9), and (7S,8R,7′S,8′S)-4,9,4′,7′-tetrahydroxy-3,3′-dimethoxy-7,9′-epoxylignan-4-O-β-d-glucopyranoside (10). Their structures were elucidated by extensive spectroscopic methods, including 1D and 2D NMR and MS spectra. Compounds 2-4 and 6-10 were shown to have modest anti-inflammatory effects through inhibition of NO production in LPS-stimulated BV cells.     

New water soluble flavone and xanthone glycosides from Hypericum canariense L.

The water soluble portion of the aerial parts of Hypericum canariense L. yielded after acetylation the 5,7,3′4′-tetra- and 7,3′4′-triacetates of a new flavonoid 5,7,3′,4′-tetrahydroxy-3-O-β-d-(methyl 2,3,4-triacetoxypyranuronyl)-quercetin, the 3′-acetate of a new flavonoid 3′-hydroxy-5,7,4′-trimethoxy-3-O-β-d-(methyl 2,3,4-triacetoxypyranuronyl)-quercetin, the 3′-acetate and the 3′5′-diacetate of the new flavonoid 5,3′dihydroxy-7,4′-dimethoxy-3-β-d-(methyl 2,3,4-triacetoxypyranuronyl)-quercetin, the xanthone derivative mangiferin 2′,3′,4′,6′-tetraacetate and the latter's new 1,3,6,7′-tetramethoxy, 1,3,6-trimethoxy-4-acetoxy and 1,7-diacetoxy-3,6-dimethoxy analogs.     

7-O-methyl-(2R:3R)-dihydroquercetin 5-O-β-D-glucoside and other flavonoids from Podocarpus nivalis

In the course of a chemotaxonomic survey of New Zealand Podocarpus species, a number of new flavonoid glycosides have been isolated from P. nivalis. These are: luteolin 3′-O-β-D-xyloside, luteolin 7-O-β-D-glucoside-3′-O-β-D-xyloside, dihydroquercetin 7-O-β-D-glucoside, 7-O-methyl-(2R:3R)-dihydrokaempferol 5-O-β-D-glucopyranoside, 7-O-methyl-(2R:3R)-dihydroquercetin 5-O-β-D-glucopyranoside, 7-O-methylkaempferol 5-O-β-D-glucopyranoside and 7-O-methylquercetin 5-O-β-D-glucopyranoside. Diagnostically useful physical techniques for distinguishing substitution patterns in dihydroflavonols are discussed and summarized. Glucosylation of the 5-hydroxyl group in (+)-dihydroflavonols is shown to reverse the sign of rotation at 589 nm.     

Three new flavonoid glycosides from the aerial parts of Graptophyllum grandulosum Turril (Acanthaceae)

Grandulosides A-C, three new flavonoid glycosides, were isolated from the aerial parts of Graptophyllum grandulosum Turill and identified as chrysoeriol-7-O-β-d-apiofuranosyl-(1 → 2)-β-d-xylopyranoside (1), chrysoeriol-7-O-[4′′′-O-acetyl-β-d-apiofuranosyl-(1 → 2)]-β-d-xylopyranoside (2) and 7-O-α-l-rhamnopyranosyl-(1 → 6)-β-d-(4′′-Sodium hydrogeno sulfate) glucopyranoside (3). Four known compounds, chrysoeriol-7-O-β-d-xyloside (4), isorhamnetin-3-O-α-l-rhamnopyranosyl-(1 → 6)-β-d-glucopyranoside (5), luteolin-7-O-β-d-apiofuranosyl-(1 → 2)-β-d-xylopyranoside (6) and sucrose (7) were also obtained. The structures of these compounds were established by interpretation of their spectral data, mainly HR-TOFESIMS, 1D-NMR (¹H, ¹³C) and 2D-NMR (COSY, NOESY, HSQC and HMBC) and by comparison with the literature data.     

Unique flavonoid glycosides from the new zealand white pine, Dacrycarpus dacrydioides

A number of new flavonoid glycosides have been isolated from foliage of the New Zealand white pine, Dacrycarpus dacrydioides. These include tricetin 3′,5′-di-O-β-glucopyranoside; the 3′-O-β-xylopyranoside, 7-O-α-rhamnopyranoside and 7-O-α-rhamnopyranoside-3′-O-β-xylopyranoside of 3-O-methylmyricetin; the 3′-O-β-xylopyranoside, 7-O-α-rhamnopyranoside and 7-O-α-rhamnopyranoside-3′-O-β-xylopyranoside of 3-O-methyl-quercetin, and the 3′-O-β-xylopyranoside and 7-O-α-rhamnopyranoside-3′-O-β-xylopyranoside of 3,4′-di-O-methylmyricetin. The accumulation of 3-methoxyflavones and B-ring trioxygenated flavonoids appears to distinguish D. dacrydioides from all other New Zealand members of the classical genus Podocarpus. Support for De Laubenfels' proposed separation of Dacrycarpus from this genus is seen in the present work.     

Chromone acyl glucosides and an ayanin glucoside from Dasiphora parvifolia

Two new chromone acyl glucosides, 5-hydroxy-7-O-(6-O-p-cis-coumaroyl-β-D-glucopyranosyl)-chromone (1) and 5-hydroxy-7-O-(6-O-p-trans-coumaroyl-β-D-glucopyranosyl)-chromone (2), and a new flavonoid glucoside, ayanin 3′-O-β-D-glucopyranoside (3) were isolated from aerial parts of Dasiphora parvifolia, together with flavonoid glycosides (4–10), catechins (11, 12), and hydrolysable tannins (13, 14). The chemical structures of these compounds were elucidated on the basis of spectroscopic data. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and the hyaluronidase inhibitory activity of these compounds were evaluated.     

Cardiovascular protective flavonolignans and flavonoids from Calamus quiquesetinervius

Tricin-type flavonolignans, (2S)-dihydrotricin 4′-O-(erythro-β-guaiacylglyceryl) ether, (2S)-dihydrotricin 4′-O-(threo-β-guaiacylglyceryl) ether, (2S)-dihydrotricin 4′-O-(threo-β-4-hydroxyphenylglyceryl) ether, tricin 4′-O-(erythro-β-4-hydroxyphenylglyceryl) ether, tricin 4′-O-(threo-β-4-hydroxylphenylglyceryl) ether, and (2S)-dihydrotricin 4′-O-(β-6′′-methoxy-4′′-oxo-chroman-3′′-yloxy) ether namely calquiquelignan A–F, respectively, were isolated and characterized from the EtOAc extract of Calamus quiquesetinervius. Additionally, six known phenolic compounds, including dihydrotricin, tricin, salcolin A, p-hydroxybenzoic acid, (2S, 3S)-trans-dihydrokapempferol and (2S)-naringenin, were also obtained and identified from the extract. Structures of the flavonolignans were assigned based on spectroscopic analyses that included 1D and 2D NMR spectroscopic techniques, such as HMQC, HMBC, and NOESY. Bioassay results showed that calquiquelignan A, dihydrotricin and (2S)-naringenin exhibited significant vasodilatory potencies, as indicated by 60.3%, 80.3% and 60.9% relaxations, respectively, at 100 μM. Salcolin A showed potent platelet aggregation inhibition, compared with aspirin. Most of the tricin-type derivatives (calquiquelignan A–B, dihydrotricin and tricin) also exhibited more potent hydroxyl radical (OH) scavenging activity than trolox as characterized by the ultraweak chemiluminescence assay.     

Two new flavonoid glycosides from Iris tectorum

Phytochemical investigation of the ethanol extract of rhizomes of Iris tectorum resulted in the isolation and characterization of two new flavonoid glycosides, tectorigenin-7-O-β-d-fucopyranoside (1), 3,5,4′-trihydroxy-7,3′-dimethoxyflavanone-5-O-α-l-rhamnopyranoside (2), together with two known ones (3, 4). The rhamnose substituent at C-5 displayed uncommon connection in naturally occurring flavonoid glycosides. Their structures were elucidated on the basis of extensive spectroscopic analysis. All of the isolates were evaluated for their in vitro inhibitory activity against aldose reductase.     

Anti-inflammatory iridoid glycosides from fruits of Cornus officinalis

Three undescribed iridoid glycosides, cyc(7β-O-6′)-morroniside (1), 6′-methyl succinate-7β-O-methylmorroniside (2), and 7β-O-methyl phenyllactate morroniside (3) were isolated from 50% ethanol extract of Cornus officinalis fruits. The structures of the isolated compounds were determined by HRESIMS, ¹D NMR, ²D NMR, UV and IR spectroscopic methods. Compounds 1-3 exhibited moderate anti-inflammatory activities in vivo in a CuSO₄-induced zebrafish inflammation model (when evaluated at 50 μM).     

New spermidine alkaloids from Capparis spinosa roots

Three new spermidine alkaloids capparispine (1), capparispine 26-O-β-d-glucoside (2) and cadabicine 26-O-β-d-glucoside hydrochloride (3) were isolated from the roots of Capparis spinosa. Their structures were established on the basis of spectroscopic analysis, including 1D and 2D NMR experiments (¹H–¹H COSY, HSQC, HMBC).     

Phenolic Glycosides with antiproteasomal activity from Centaurea urvillei DC. subsp. urvillei

A new flavanone glycoside, naringenin-7-O-β-d-glucuronopyranoside, and a new flavonol glycoside, 6-hydroxykaempferol-7-O-β-d-glucuronopyranoside were isolated together with 12 known compounds, 5 flavone glycoside; hispidulin-7-O-β-d-glucuronopyranoside, apigenin-7-O-β-d-methylglucuronopyranoside, hispidulin-7-O-β-d-methylglucuronopyranoside, hispidulin-7-O-β-d-glucopyranoside, apigenin-7-O-β-d-glucopyranoside, a flavonol; kaempferol, two flavone; apigenin, and luteolin, a flavanone glycoside; eriodictyol-7-O-β-d-glucuronopyranoside, and three phenol glycoside; arbutin, salidroside, and 3,5-dihydroxyphenethyl alcohol-3-O-β-d-glucopyranoside from Centaurea urvillei subsp. urvillei. The structure elucidation of the new compounds was achieved by a combination of one- (¹H and ¹³C) and two-dimensional NMR techniques (G-COSY, G-HMQC, and G-HMBC) and LC-ESI-MS. The isolated compounds were tested for their antiproteasomal activity. The results indicated that kaempferol, a well known and widely distributed flavonoid in the plant kingdom, was the most active antiproteasomal agent, followed by apigenin, eriodictyol-7-O-β-d-glucuronopyranoside, 3,5-dihydroxyphenethyl alcohol-3-O-β-d-glucopyranoside, and salidroside, respectively.     

Three flavone glycosides from citrus sudachi

Three flavone glycosides, sudachiins B, C and D, were isolated from the green peel of Citrus sudachi. On the basis of UV, ¹H NMR and ¹³C NMR spectral data sudachiins B and C were identified as sudachiin A 6″- (3-hydroxy-3-methyl)glutarateand 7-O-β-D-glucosyl sudachitin 6″-(3-hydroxy-3-methyl)glutarate, respectively. Sudachiin D was found to be a unique glycoside in which sudachiin A and 7-O-β-D-glucosylsudachitin were esterified at their 6″-positions with 3-hydroxy-3-methylglutaric acid.     

New glycosides from the leaves and rattan stems of Schisandra chinensis

Two new glycosides, vanillic acid 4-O-β-d-(6′-O-(Z)-2′'-methylbut-2′'-enoate)glucopyranoside (1), p-methoxycarvacrol-6-O-β-d-glucopyranoside (2), along with two known analogues (3-4), were isolated from the leaves and rattan stems of Schisandra chinensis. The structures of these isolates were determined by UV, HRESIMS, 1D and 2D NMR spectral analyses.     

Chalcone glycosides from aerial parts of Brassica rapa L. ‘hidabeni’, turnip

A phytochemical investigation of the aerial parts of Brassica rapa L. ‘hidabeni’, turnip resulted in the isolation of three new chalcone glycosides, 4′-O-β-d-glucopyranosyl-4-hydroxy-3′-methoxychalcone (1), 4′-O-β-d-glucopyranosyl-3′,4-dimethoxychalcone (2) and 4,4′-di-O-β-d-glucopyranosyl-3′-methoxychalcone (3) along with three known glycosides. The structures of the three newly isolated chalcone glycosides were elucidated on the basis of 1D and 2D NMR and mass spectroscopy.     

Canna indica flower: New source of anthocyanins

In this study the red flowers of Canna indica (Cannaceae) were extracted by using sonicator and isolation of anthocyanins have been carried out. Four anthocyanin pigments have been isolated apart from quercetin and lycopene. They are Cyanidin-3-O-(6′′-O-α-rhamnopyranosyl)-β-glucopyranoside (1), Cyanidin-3-O-(6′′-O-α-rhamnopyranosyl)-β-galactopyranoside (2), Cyanidin-3-O-β-glucopyranoside (3) and Cyanidin-O-β-galactopyranoside (4). These compounds were isolated by using HPLC and their structures were subsequently determined on the basis of spectroscopic analyses, i.e., ¹H NMR, ¹³C NMR, HMQC, HMBC, ESI-MS, FTIR, UV–Visible etc. The isolated compounds showed good antioxidant activity thus makes it suitable for use in food coloration and as a nutraceutical. Thus it is a promising pigment source for food applications.     

Flavonoid glycosides and triterpenoids from Atractylis flava

Two new flavonoid glycosides, together with twelve known compounds including seven flavonoids and five triterpenoids were isolated from the whole plant Atractylis flava Desf. The structures of new compounds have been elucidated as 6-hydroxykaempferol 6-methyl ether 7-O-β-glucopyranuronoside (1) and isorhamnetin 3-O-[(6″′-O-E-feruloyl)-β-d-glucopyranosyl-(1 → 2)]-β-d-galactopyranoside (2) named Atraflavoside A and B successively, on the basis of physical and spectroscopic analysis, including 1D and 2D NMR (¹H, ¹³C, COSY, TOCSY, HSQC, HMBC and NOESY) and mass spectrometry (HRESIMS) whereas those of the known compounds (3–14) were established by spectral comparison with those published in the literature.