Phenolic constituents from Grevillea robusta

Seven phenolic compounds were isolated from a MeOH extract of the leaves of Grevillea robusta. Their structures were determined by various spectral methods including 2D NMR spectroscopy.     

Phenolic constituents from Drypetes armoracia

The methanol extract of the dried stem bark of Drypetes armoracia Pax & Hoffm. afforded two compounds named drypearmoracein A, (E)-4,5,6,7-tetrahydroxy-2-benzylhept-2-enoic acid and drypearmoracein B, 2,3-dihydroxy-9,10-tetrahydroanthra-1,4-quinone along with five known compounds: friedelan-3 beta-ol, friedelin, friedelane-3,7-dione, drypemolundein B and beta-stigmasterol. Their structures were established on the basis of spectroscopic analysis and chemical evidence.     

Phenolic constituents of Iris milesii rhizomes

Analysis of a methanol extract of the rhizomes of Iris milesii resulted in the isolation of a new isoflavone, 5,6,7,4′-tetrahydroxy-8-methoxyisoflavone along with prunetin, sakuranetin, 2:6-dimethoxy-1,4-benzoquinone, tectorigenin, irigenin,4-β(D-glucosyloxy)-ferulic acid methyl ester, quercetin-3-methyl ether, tectoridin, iridin and iristectorin B.     

Phenolic constituents of tomato fruit cuticles

Chalconaringenin, naringenin, naringenin-7-glucoside, and m- and p-coumaric acids have been identified in the fruit cuticles of three tomato cultivars. The phenolic content of the cuticles increased substantially during fruit development, those from immature green and mature ripe fruits of cv Ailsa Craig yielding respectively 2.8 and 61 μg/cm² (representing 1.4 and 6% of the total membrane wt). Coumaric acids, present only in the ‘cutin-bound’ phenolics, increased from 2 to 24 μg/cm² during fruit development. Flavonoids, synthesized mainly during the climacteric, occurred free in the epicuticular (0.3–7.2 μg/cm²) and cuticular (0.7–5.7 μg/cm²) phenolics but the major part of this class of constituents in ripe fruit cuticles was also ‘bound’ to the cutin matrix (30–43 μg/cm²). The composition of the flavonoid fraction was controlled by the spectral quality of incident radiation, red light favouring the formation of chalconaringenin.     

Phenolic constituents of Gnaphalium uliginosum L.

The herb Gnaphalium uliginosum L. is an annual plant widely used in Russian and Bulgarian phytotherapy in the treatment of hypertension, thrombophlebitis, phlebothrombosis and ulcers. Decoction and infusion of G. uliginosum are known to possess anti-inflammatory, astringent, and antiseptic properties. Oil extracts are used in the treatment of laryngitis, upper respiratory catarrh and tonsillitis. However, there is still lack of information about the active compounds.Ten phenolic compounds have been identified from the aerial parts of G. uliginosum including seven flavonoid glucosides and three phenylpropanoids. Their chemical structures were elucidated on the basis of 1D and 2D NMR and HRESIMS. Among the identified compounds the first full assignments of the ¹H and ¹³C NMR spectra of, 5,7,4′-trihydroxy-6,3′-dimethoxyflavone-7-O-β-d-(6″-O-caffeoyl)-glucopyranoside are firstly reported in this paper.     

Phenolic constituents of Semecarpus anacardium

GLC-MS analysis of methylated bhilawanol from S. anacardium nuts and its oxidation product, the methyl ester of an aromatic carboxylic acid, conclusively proved that it contains more than seven closely related compounds. Two of them are major components which were isolated and shown to be 1-pentadec-Δ^5′-enyl-2,3-dimethoxybenzene (I) and 1-pent biflavanoids A, B and C have been also isolated from defatted nuts of S. anacardium. The first of these has been characterized as its methyl ethers. A₁ and A₂, for which biflavanone structures (VI) and (VII) are suggested on the basis of chemical and spectral evidence. The biflavanones B and C have been also characterized as their methyl ethers. Suggested structures are O-methyl derivatives of a IB-3′, IIA-8-binaringenin (XIV) for the former and IB-3′, IIA-8-biliquiritigenin (XV) for the latter.     

展毛野牡丹酚类化学成分的研究

为了明确展毛野牡丹的化学成分,该研究采用Diaion HP20SS、MCI gel、Sephadex LH-20柱层析和反相高效液相色谱等方法,对展毛野牡丹根和茎的醇提物分别进行了分离纯化。结果表明:从展毛野牡丹中分离得到11个化合物,它们的结构经波谱数据分析和鉴定。它们分别是4-羟基-3-甲氧基苯酚1-O-β-D-(6’-O-没食子酰)-吡喃葡萄糖苷(1)、3,4-二羟基苯乙醇4-O-β-D-(6’-O-没食子酰基)-吡喃葡萄糖苷(2)、龙胆酸5-O-β-D-(6’-O-没食子酰基)-吡喃葡萄糖苷(3)、2,4,6-三甲氧基苯酚1-O-β-D-(6’-O-没食子酰)-吡喃葡萄糖苷(4)、甲基6-O-没食子酰基-β-D-吡喃葡萄糖苷(5)、乙基6-O-没食子酰基-β-D-吡喃葡萄糖苷(6)、6’-O-没食子酰基黑樱苷(7)、没食子酸甲酯(8)、没食子酸乙酯(9)、2,6-二甲氧基对苯二酚4-O-β-D-吡喃葡萄糖苷(10)、2-甲氧基对苯二酚4-O-β-D-吡喃葡萄糖苷(11)。所有化合物均为首次从展毛野牡丹中分离得到,化合物2-7、10和11为首次从该属植物中分离得到。     

Phenolic constituents of the cell walls of monocotyledons

Monocotyledons of 104 species in 52 families were divided into two groups depending on the UV fluorescence behaviour of their cell walls. The unlignified cell walls of the first group, fluoresced blue, which changed to green with increased intensity after treatment with NH₃ due to the presence of bound ferulic acid. The isolated cell walls of members of the first group were shown to contain bound ferulic, p-coumaric and diferulic acids. These acids were absent from cell walls of the second group. The first group contained families of the Commelinidae of Cronquist, the Palmae (part of the Arecidae), and the Philydraceae, Pontederiaceae, and Haemodoraceae (all part of Liliidae). The other families of the latter two subclasses and those of the Alismatidae belonged to the second group.     

Phenolic and terpenoid heartwood constituents of Libocedrus yateensis

The heartwood of Libocedrus yateensis has been found to contain cumic acid and several related hydroxyacids so far not reported from any conifer, a sesquiterpene (?)-cryptomerione and (E, E)-1,4-bis-(p-hydroxyphenyl)-buta-1,3-diene, both known from Taxodiaceae. Further constituents were ‘conioids’; hinokiresinol and a related ketone, probably dehydroagatharesinol, a lignan, ‘yatein’, and a novel diphenylbutane derivative, yateresinol. Structural relations between conioids, lignans and diphenylbutanes are discussed.     

Phenolic constituents of Convolvulus dorycnium L. flowers

The new phenolic metabolites 3-(2-butoxy-3-caffeoyl-1-hydroxycyclobutyl)-3-hydroxypropanoic acid, named as dorycnic acid (1), and 4-O-(4′-carboxymethyl-2′,4′,6′-trihydroxycyclohexyl)-vanillic acid (2), together with scopolin (3), kaempferol 3-rutinoside (4), scopoletin (5), and methyl caffeate (6) were isolated from the flowers of Convolvulus dorycnium L. Their structures were elucidated on the basis of spectroscopic evidence, and comparison with authentic samples. Compounds 1–6 were evaluated for their antioxidative activity in the 1,1-diphenyl-2-picrylhydrazyl assay, where the caffeic acid derivative 1 proved to possess the most potent scavenging activity, with an IC₅₀ value of 31.5 μM.     

Coelonin,A 9,10-dihydrophenanthrene from the orchids Coelogyne ochracea and Coelogyne elata

2,7-Dihydroxy-4-methoxy-9,10-dihydrophenanthrene was isolated and identified from the whole plant of Coelogyne ochracea and C. elata.     

Phenolic and other constituents of fresh water fern Salvinia molesta

Two glycosides, 6'-O-(3,4-dihydroxy benzoyl)-beta-D-glucopyranosyl ester (1), and 4-O-beta-d-glucopyranoside-3-hydroxy methyl benzoate (2), along with five known compounds methyl benzoate (3), hypogallic acid (4), caffeic acid (5), paeoniflorin (6) and pikuroside (7) were isolated for the first time from a fresh water fern Salvinia molesta D.S. Mitch. These compounds showed a potent antioxidant radical scavenging activity in a non-physiological assay. Their structures were determined by NMR spectroscopic and CID mass spectrometry techniques.     

Phenolic constituents from the wood of Morus australis with cytotoxic activity

A new methylated flavonol, 5,7,2',4'-tetrahydroxy-3-methoxyflavone (1), had been isolated from the methanol extract of the wood of Morus australis, along with nine known compounds, kuwanon C (2), morusin (3), morachalcone A (4), oxyresveratrol (5), 4'-(2-methyl-2-buten-4-yl)oxyresveratrol (6), moracins M (7) and C (8), alboctalol (9), and macrourin B (10). The structures of these compounds were determined based on spectral evidence, including UV, IR, NMR, and mass spectra. Cytotoxic properties of compounds 1-10 were evaluated against murine leukemia P-388 cells. The prenylated stilbene 6 and 2-arylbenzofuran 8, and morusin (3) were found to have strong cytotoxic effects with IC50 values of 6.9, 8.7, and 10.1 microM, respectively.     

Phenolic constituents from the core of kenaf (Hibiscus cannabinus)

Four lignans, boehmenan H [2-(4-hydroxy-3-methoxyphenyl)-5-[3-(4-hydroxy-3-methoxycinnamoyloxy)propyl]-3-hydroxymethyl-7-methoxybenzodihydrofuran], boehmenan K [2-(4-hydroxy-3-methoxyphenyl)-5-[3-(4-hydroxycinnamoyloxy)-1-propenyl]-3-(4-hydroxy-3-methoxycinnamoyloxymethyl)-7-methoxybenzodihydrofuran], threo-carolignan H [threo-1-(4-hydroxy-3-methoxyphenyl)-2-[4-[3-(4-hydroxy-3-methoxycinnamoyloxy)propyl]-2-methoxyphenoxy]-1,3-propanodiol], and threo-carolignan K [threo-1-(4-hydroxy-3-methoxyphenyl)-3-(4-hydroxy-3-methoxycinnamoyloxy)-2-[4-[3-(4-hydroxycinnamoyloxy)-1-propenyl]-2-methoxyphenoxy]-1-propanol] as well as several other lignans, aldehydes and a tyramine derivative were isolated from the acetone extract of core of kenaf (Hibiscus cannabinus). All the structures were established by spectroscopic methods. The hitherto unreported 13C NMR spectra of some compounds are also presented and discussed. 2D NMR techniques have allowed the revision of certain previously reported 13C NMR assignments of some scarce naturally occurring compounds.     

Phenolic constituents from the roots of Rosa laevigata (Rosaceae)

Chemical investigation of the root of Rosa laevigata led to the isolation of sixteen phenolic compounds, including seven flavonoids (1–7), five condensed tannins (8–12), two stilbenes (13 and 14) and two benzoic acid derivatives (15 and 16). Their structures were identified as (+)-catechin (1), (+)-gallocatechin (2), (2R, 3S, 4S)-cis- leucocyanidin (3), (2R, 3S, 4S)-cis-leucofisetinidin (4), (2S, 3R, 4R)-cis- leucofisetinidin (5), dehydrodicatechin A (6), phloridzin (7), procyanidin B3 (8), fisetinidol-(4α, 8)-catechin (9), guibourtinidol- (4α, 8)-catechin (10), ent- isetinidol -(4α, 6)-catechin (11), fisetinidol-(4β, 8)-catechin (12), (Z)-3-methoxy-5-hydroxy- stilbene (13), (Z)-piceid (14), gallic acid (15) and 4-hydroxybenzoic acid- 4-O-β-D-glucopyranoside (16). Among them, compounds 3–7, 9–14, and 16 were isolated from R. laevigata for the first time, and compounds 3–7, 9, 10, 12–14 and 16 were reported for the first time from the genus Rosa. The chemotaxonomic significance of these compounds was summarized.     

Phenolic constituents of Artemesia tridentata spp. Vaseyana

Ten coumarins and four flavonoids have been isolated from a single collection of Artemesia tridentata ssp. vaseyana (Rydb.) Beetle. The coumarins are 7-methylesculin, esculin, umbelliferone, skimmin, cichoriin, isoscopoletin, scopoletin, scoparon, esculetin and a new natural product, artelin (5,6,7,8-tetramethoxy coumarin). The flavonoids are luteolin, luteolin-7-glucoside, axillarin and eupafolin.