Flavans from the leaf of Ilex centrochinensis

Phytochemical investigation of the leaf of Ilex centrochinensis led to the isolation and characterization of four flavans, one flavanone (5), and one flavone (6), including a new compound whose structure was elucidated as (2S)-5,3′,4′-trihydroxy-7-methoxyflavan (1) and a new natural product whose structure was elucidated as (2S)-5-hydroxy-7,3′,4′-trimethoxyflavan (4) on the basis of spectroscopic methods especially 1D and 2D NMR, CD, and mass spectral analyses. Compounds 1 and 4 exhibited weak cytotoxic activity against Huh7 cell line and no cytotoxic activity against Caco-2 cell line.     

Cytotoxic C-Methylated Chalcones from Syzygium samarangense.

Abstract

The flavonoids 2′-hydroxy-4′,6′-dimethoxy-3′-methylchalcone (1), 2′,4′-dihydroxy-6′-methoxy-3′,5′-dimethylchalcone (2), 2′,4′-dihydroxy-6′-methoxy-3′-methylchalcone (3), 2′,4′-dihydroxy-6′-methoxy-3′-methyldihydrochalcone (4) and 2′,4′-dihydroxy-6′-methoxy-3′,5′-dimethyldihydrochalcone (5), isolated from Syzygium samarangense. (Blume) Merr. & L.M. Perry (Myrtaceae), were subjected to cytotoxicity testing using the dimethylthiazoldiphenyl tetrazolium (MTT) assay. The cell lines used were the Chinese hamster ovarian (CHO-AA8) and the human mammary adenocarcinoma, (MCF-7 and SKBR-3). Among the test compounds, 2 exhibited significant differential cytotoxicity against the MCF-7 cell line with an IC₅₀ of 0.0015 ± 0.0001 nM. It was also cytotoxic against the SKBR-3 cell line with an IC₅₀ of 0.0128 ± 0.0006 nM. Doxorubicin, the positive control, had an IC₅₀ of 2.60 ± 0.28 × 10^?4 nM against the MCF-7 cell line and an IC₅₀ of 2.76 ± 0.52 × 10^?5 nM against the SKBR-3 cell line. When tested in a mechanism-based yeast bioassay for detecting DNA-damaging agents using genetically engineered Saccharomyces cerevisiae. RS322Y (RAD52) mutant strain and (LF15/11) (RAD+) wild-type strain, 2 showed significant selective cytotoxicity against the RAD52 yeast mutant strain. It had an IC₁₂ of 0.1482 nM, as compared with the positive control, streptonigrin, which had an IC₁₂ of 0.0134 nM. Hence, 2 is a cytotoxic natural product with potential anticancer application.     

New flavonoids and other constituents from Lespedeza cuneata

Two new flavonoids, 6,8,3′,4′-tetrahydroxy-2′-methoxy-7-methylisoflavanone (1) and 6,8,3′,4′-tetrahydroxy-2′-methoxy-6′-(1,1-dimethylallyl)-isoflavone (2), were isolated from the 95% ethanolic extract of the dried roots of Lespedeza cuneata together with betulinic acid (3), β-sitosterol (4), hexacosanoic acid 2,3-dihydroxy-propyl ester (5), which were isolated from this plant for the first time. Their structures were elucidated by spectral analysis.     

A new para-quinone-type flavan from the leaves of Ilex centrochinensis and its anti-inflammatory activities

A new para-quinone-type flavan, (2S)-7-methoxy-3′,4′-dihydroxy-5,8-quinoflavan (1), together with three known compounds, were isolated from the leaves of Ilex centrochinensis. Their structures were elucidated by detailed spectroscopic analyses for new structure and in comparison with published data for known compounds. Moreover, the new compound was evaluated its cytotoxic and anti-inflammatory activities in vitro on LPS induced RAW 264.7 cells and the results showed that 1 has promising anti-inflammatory activities.     

Two new 5,8-quinoflavans from the leaf of Ilex centrochinensis

Two new 5,8-quinoflavans were isolated from the leaf of Ilex centrochinensis, and their structures were elucidated as (2R)-7,3′,4′-trimethoxy-5,8-quinoflavan and (2S)-7-methoxy-4′-hydroxy-5,8-quinoflavan on the basis of spectroscopic methods, especially 1D and 2D NMR, CD, and mass spectral analyses. Both of them exhibited weak cytotoxic activity against HuH7 cell lines and no cytotoxic activity against CaCO-2 cell lines.     

Two new flavonoids from the roots of Scutellaria baicalensis

One new flavone, 5,7-dihydroxy-8,2′,3′,6′-tetramethoxyflavone (1), and one new flavonol, 5,7,6′-trihydroxy-2′-methoxyflavonol (2), were isolated from the roots of Scutellaria baicalensis, and their structures were elucidated on the basis of extensive spectroscopic evidences, especially 1D and 2D NMR and HR-ESI-MS experiments. The structure features of these new compounds lie in the substitution at both C-2′ and C-6′ positions of B-ring by hydroxyl or methoxyl groups.     

Anti-inflammatory coumarins from Paramignya trimera

Context: Paramignya trimera (Oliv.) Burkill (Rutaceae) has been used to treat liver diseases and cancer. However, the anti-inflammatory effects of this medicinal plant and its components have not been elucidated.

Objective: This study investigated chemical constituents of the P. trimera stems and evaluated anti-inflammatory effects of isolated compounds.

Materials and methods: Cytotoxicity of isolated compounds (5–40?μM) toward BV2 cells was tested using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) for 24?h. Inhibitory effects of isolated compounds (5-40?μM) on nitrite and PGE₂ concentrations were determined using Griess reaction and PGE₂ ELISA kit, respectively (pretreated with the compounds for 3?h and then stimulated for 18?h with LPS). Inhibitory effects of compounds (5-40?μM) on iNOS and COX-2 protein expression were evaluated by Western blot analysis (pretreated with the compounds for 3?h and then stimulated for 24?h with LPS).

Results: Seven coumarins were isolated and identified as: ostruthin (1), ninhvanin (2), 8-geranyl-7-hydroxycoumarin (3), 6-(6′,7′-dihydroxy-3′,7′-dimethylocta-2′-enyl)-7-hydroxycoumarin (4), 6-(7-hydroperoxy-3,7-dimethylocta-2,5-dienyl)-7-hydroxycoumarin (5), 6-(2-hydroxyethyl)-2,2-dimethyl-2H-1-benzopyran (6), and luvangetin (7). Compounds 1–4 and 7 inhibited NO and PGE₂ production in LPS-stimulated BV2 cells, with IC₅₀ values ranging from 9.8 to 46.8 and from 9.4 to 52.8?μM, respectively. Ostruthin (1) and ninhvanin (2) were shown to suppress LPS-induced iNOS and COX-2 protein expression.

Discussion and conclusion: The present study provides a scientific rationale for the use of P. trimera in the prevention and treatment of neuroinflammatory diseases. Ostruthin and ninhvanin might have potential therapeutic effects and should be considered for further development as new anti-neuroinflammatory agents.     

Two new compounds from Trifolium resupinatum var. microcephalum

An investigation of CH₂Cl₂ and EtOH extracts of Trifolium resupinatum L. var. microcephalum Zoh. has led to the isolation of two new compounds characterized as 4,15-dimethyl-2-(1,2-dihydroxyethyl)-hexadecene (1) and 1-undecene-1-O-β-2′,3′,4′,6′-tetraacetyl glucopyranoside (2a). Their structures were established by 1D and 2D NMR techniques, and mass spectroscopy.     

Structural elucidation of a new flavone from Sarcopyramis nepalensis

A novel flavone, named 4′-methoxy-3′,5,7-trihydroxy-8-(1″-(3?,4?,5?-trihydroxyphenyl)ethyl)flavone (1), was isolated from Sarcopyramis nepalensis, along with two known compounds syringaresinol (2) and aralidioside (3). Their structures were established by the spectroscopic analysis, especially by 2D NMR. All of the three compounds were isolated from the plant for the first time.     

Aromatic acid derivatives from the lateral roots of Aconitum carmichaelii

Seven new aromatic acid derivatives (1–7), together with five known analogs, were isolated from the lateral roots of Aconitum carmichaelii. Structures of the new compounds were determined by spectroscopic and chemical methods as 4-methyl ( ? )-(R)-hydroxyeucomate (1), 4-butyl ( ? )-(R)-hydroxyeucomate (2), 4-butyl-1-methyl (+)-(R)-2-O-(4′-hydroxy-3′-methoxybenzoyl)malate (3), 1-butyl-4-methyl (+)-(R)-2-O-(4′-hydroxy-3′-methoxybenzoyl)malate (4), dimethyl (+)-(R)-2-O-(4′-hydroxy-3′-methoxybenzoyl)malate (5), dimethyl (+)-(R)-2-O-(4′-hydroxybenzoyl)malate (6), and methyl ( ± )-3-(4′-hydroxy-3′-methoxyphenyl)-3-sulfopropionate (7), respectively. Compounds 1 and 2 are 2-benzylmalates (eucomate derivatives), 3–6 belong to 2-O-benzoylmalates, and 7 is a rare phenylpropionate containing a sulfonic acid group. The absolute configurations of eucomate derivatives were confirmed by X-ray crystallographic analysis of 4-methyl eucomate (11).     

Ceramides and cerebrosides from the marine bryozoan Bugula neritina inhabiting South China Sea

From the marine bryozoan Bugula neritina inhabiting South China Sea, a new ceramide named (2S,3R,4E)-2-(14′-methyl-pentadecanoylamino)-4-octadecene-l,3-diol (1) and a new cerebroside named 1-O-(β-d-glucopyranosyl)-(2S,3R,4E)-2-(heptadecanoylamino)-4-octadecene-l,3-diol (6), together with one known ceramide (2) and three known cerebrosides (3, 4, and 5), were isolated. Their structures were deduced by extensive spectral analysis and chemical evidences. Compound 1 is branched with a methyl [–CH(CH₃)₂] in the fatty acid moiety, which is a rare structural feature among ceramides. Compound 6 is a new cerebroside with 17 carbons in the fatty acid moiety, while 5 is a new natural product which was isolated from a natural origin for the first time.     

A Novel 4′-O-Diglycoside of Decarboxyrosmarinic Acid from Blepharis ciliaris

Abstract

A novel natural phenolic 1 was isolated from the hydroalcoholic extract of the aerial parts of Blepharis ciliaris (L.) B.L. Burtt (Acanthaceae), in addition to apigenin 7-O-glucoside 2 and apigenin-7-O-(3″-acetyl-6″-E-p-coumaroyl glucoside) 3. The structure of 1 was established as 3′,4′-dihydroxy-β-phenyl ethyl caffeate-4′-β-O-D-galactopyranosyl-(1′″→4″)-α-O-L-rhamnopyranoside [= 9′-decarboxy rosmarinic acid-4′-O-(1→4)-galactosyl rhanmoside]. Structures were determined by conventional methods of analysis, as well as by different MS and NMR techniques.     

Two new compounds from the dry leaves of Pleioblastus amarus (Keng) keng f.

Two new compounds, xylitol 1-O-(6′-O-p-hydroxylbenzoyl)-glucopyranoside (1) and bambulignan B (2), together with three known ones gastrodin (3), glucovanillin (4), and rel-(7S,7′R,8R,8′S)-4,4′-dihydroxy-3,3′,5,5′-tetramethoxy-7,7′-epoxyligna-9,9′-diol-9(or)9′-O-β-glucopyranoside (5), were isolated from the 95% EtOH extract of the dry leaves of Pleioblastus amarus (Keng) keng f. Their structures were determined by UV, IR, HR-ESI-MS, CD, and 1D and 2D NMR data analyses as well as GC experiments.     

Two new bioactive prenylated dihydroflavanoids from the medicinal plant Dolichos tenuicaulis (Baker) Craib

Two new prenylated dihydroflavanoids have been isolated from the medicinal plant of Dolichos tenuicaulis (Baker) Craib. Their structures were elucidated as (2S)-5,2′,6′-trihydroxy-8-prenyl-6,7-(3-prenyl-2,2-dimethylpyrano)-3′,4′-(2,2-dimethyl-1-keone-cyclohexadiene)-flavanone (1) and (2S)-5,2′,6′-trihydroxy-8-prenyl-6,7-(3-prenyl-2,2-dimethyl-1-keone-cyclohexadiene)-flavanone (2) on the basis of spectroscopic analysis.     

A novel sulphur glycoside from the seeds of Descurainia sophia (L.)

A new sulphur glycoside, named descurainoside (1), and the known compound sinapic acid (2) have been isolated from the seeds of Descurainia sophia (L.) Webb ex Prantl. The structure of 1 has been identified as (1R,6S,8R,9S,10S)-9,10-dihydroxy-4-[(4-hydroxy-3,5-dimethoxyphenyl)methylene]-8-(hydroxymethyl)-2,7-dioxa-5-thiabicyclo[4.4.0]decan-3-one by means of physico-chemical properties and spectroscopic methods (1D and 2D NMR, HRMS, ESI-MS).     

Flavonoids from silkworm droppings and their promotional activities on heme oxygenase-1

A new flavane glucoside, 7,2′-dihydroxy-8-hydroxyethyl-4′-methoxyflavane-2′-O-β-d-glucopyranoside (3), along with three known flavonoids, 7,2′-dihydroxy-8-prenyl-4′-methoxyflavane (1), euchrenone a₇ (2), and 7,2′-dihydroxy-8-prenyl-4′-methoxy-2′-O-β-d-glucopyranosylflavane (4), was isolated from silkworm droppings. The structures of the compounds were elucidated on the basis of 1D and 2D NMR spectroscopic analyses and optical rotational characteristics. The compounds isolated from silkworm droppings were evaluated for their effects on heme oxygenase-1 (HO-1) activity. Compounds 1 and 3 increased the expression of HO-1 in HepG2 cells. HO-1 is an antioxidant enzyme that catabolizes heme to carbon monoxide, free iron, and biliverdin, all of which are involved in the suppression of inflammatory mediators.     

Flavonoids from the leaves of Pleioblastus argenteastriatus

A new flavonoid, 5,7,3′-trihydroxy-6-C-β-d-digitoxopyranosyl-4′-O-β-d-glucopyranosyl flavonoside (1), along with four known flavonoids 5,7,4′-trihydroxy-3′,5′-dimethoxy flavone (2), 5,3′,4′-trihydroxy-7-O-β-d-glucopyranosyl flavonoside (3), 5,4′-dihydroxy-3′,5′-dimethoxy-7-O-β-d-glucopyranosyl flavonoside (4), 5,3′,4′-trihydroxy-6-C-[β-d-glucopyranosyl-(1 → 6)]-β-d-glucopyranosyl flavonoside (5) were isolated from 95% EtOH extract of the leaves of Pleioblastus argenteastriatus. Their structures were determined on the basis of spectroscopic techniques and chemical methods.     

Studies on the alkaloid constituents of Evodia rutaecarpa (Juss) Benth var. bodinaieri (Dode) Huang and their acute toxicity in mice

Six alkaloids (1–6) have been isolated from the fruits of Evodia rutaecarpa (Juss) Benth var. bodinaieri (Dode) Huang, two of which are new compounds, identified as 2-undecyl-4(1H)-quinolone (4) and 1-methyl-2-undecanone-10′-4(1H)-quinolone (5); the known compounds were identified as rutaecarpine (1), evodiamine (2), 1-methyl-2-undecyl-4(1H)-quinoline (3) and 2-undecanone-10′-4(1H)-quinolone (6). Compounds 1–5 were evaluated for their acute toxicity.     

Three new compounds from Arnebia euchroma

A new naphthoquinone dimer, arnebiabinone (1), a new phenolic compound, ethyl 9-(2′,5′-dihydroxyphenyl) nonanoate (2), and a new natural product, octyl ferulate (3), were isolated from the EtOH extract of dried roots of Arnebia euchroma (Royle) Johnst. Their structures were elucidated on the basis of chemical reaction and spectral analysis.     

Selaginellins I and J,two new alkynyl phenols,from Selaginella tamariscina (Beauv.) Spring

Selaginellins I (1) and J (2), two new compounds, were isolated from Selaginella tamariscina (Beauv.) Spring and were characterized as (R,S)-4-((2′,4′-dihydroxy-4-(hydroxymethyl)-3-((4-hydroxyphenyl)ethynyl)biphenyl-2-yl)(4-hydroxyphenyl)methylene)cyclohexa-2,5-dienone (1) and (R,S)-4-((3-((3,4-dihydroxyphenyl)ethynyl)-4′-hydroxy-4-(hydroxymethyl)biphenyl-2-yl)(4-hydroxyphenyl)methylene)cyclohexa-2,5-dienone (2) on the basis of UV, IR, 1D and 2D NMR, and HR-ESI-MS spectroscopic analysis.