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 novel flavanes from the leaves of Morus alba L.

Two new flavanes, (2R,4S)-2′,4′-dihydroxy-2H-furan-(3″,4″:8,7)-flavan-4-ol (1) and (2S)-2′,4′-dihydroxy-7-methoxyl-8-butyricflavane (2), together with four known flavonoids, were isolated from the leaves of Morus alba L. Their structures were determined on the basis of spectroscopic analysis.     

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.     

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.     

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 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.     

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).     

Two pairs of phenylpropanoid enantiomers from the leaves of Eucommia ulmoides

Abstract

Two pairs of phenylpropanoid enantiomers, (+)-(7S,8S)-alatusol D (1a), (?)-(7R,8R)-alatusol D (1b), (?)-(7S,8R)-alatusol D (2a) and (+)-(7R,8S)-alatusol D (2b) were isolated from the leaves of Eucommia ulmoides Oliver. Among them, 1a and 2b were firstly obtained by chiral enantiomeric resolution. Their structures were elucidated based on extensive spectroscopic analysis and the induced CD (ICD) spectrum caused by adding Mo₂(AcO)₄ in DMSO. All compounds were tested on Hep G2 tumor cell lines. However, none of the compounds showed potential cytotoxic activity against Hep G2 in vitro.     

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.     

One new ergostane-type steroid and three new phthalide derivatives from cultures of the basidiomycete Albatrellus confluens

One new ergostane-type steroid, (12β,15β,22R,23S,24S)-22,25-epoxy-12,15,23-trihydroxyergost-4,6,8(14)-trien-3-one (1), three new phthalide derivatives, 5-(2′,3′-epoxy-3′,3′-dimethylpropoxy)-7-methoxy-6-methylphthalide (2), (2′)-(Z)-5-(3′-hydroxymethyl-3′-methylallyloxy)-7-methoxy-6-methylphthalide (3), and 5-(3′,3′-dimethylallyloxy)-7-hydroxy-6-methylphthalide (4), along with one known phthalide derivative, 5-(3′,3′-dimethylallyloxy)-7-methoxy-6-methylphthalide (5), were isolated from cultures of the basidiomycete Albatrellus confluens. The structures of the new compounds were established on the basis of extensive spectroscopic data (IR, MS, 1D, and 2D NMR) analyses. All compounds were evaluated for their cytotoxic activities on five tumor cell lines.     

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.     

A new geranyl flavanone from Macaranga triloba

A new geranyl flavanone, 2′-hydroxy-macarangaflavnone A (1), and a known 4′,7-dihydroxy-8-methylflavan were isolated from the leaves of Macaranga triloba (Euphorbiceae). The structure of 1 was elucidated based on spectroscopic methods, including 1D and 2D NMR analysis.     

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.     

Two new neolignan glucosides from Arctii Fructus

Two new neolignan glucosides named (7S, 8R)-4,7,9,9′-tetrahydroxy-3,3′-dimethoxyl-7′-oxo-8-4′-oxyneolignan-4-O-β-d-glucopyranoside (1) and (7′S, 8′R, 8S)-4,4′,9′-trihydroxy-3,3′-dimethoxy-7′,9-epoxylignan-7-oxo-4-O-β-d-glucopyranosyl-4′-O-β-d-glucopyranoside (2), together with two small molecular peptides named 3-benzyl-6-(1-hydroxyethyl)-2,5-piperazinedione (3) and 3-benzyl-2,5-piperazinedione (4), were isolated from the extract of Arctii Fructus. Their structures and absolute configurations were elucidated by various spectroscopic methods (IR, HR-ESI-MS, 1D and 2D NMR, and CD).     

A new p-hydroxybenzoic acid derivative from an endophytic fungus Penicillium sp. of Nerium indicum

A new p-hydroxybenzoic acid derivative named 4-(2′R, 4′-dihydroxybutoxy) benzoic acid (1) was isolated from the fermentation of Penicillium sp. R22 in Nerium indicum. The structure was elucidated by means of spectroscopic (HR-ESI-MS, NMR, IR, UV) and X-ray crystallographic methods. The antibacterial and antifungal activity of compound 1 was tested, and the results showed that compound 1 revealed potent antifungal activity against Colletotrichum gloeosporioides, Alternaria alternata, and Alteranria brassicae with MIC value of 31.2 μg/ml.     

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.     

A new antibacterial compound from Luo Han Kuo fruit extract (Siraitia grosvenori)

Luo Han Kuo fruit (Siraitia grosvenori Swingle) has been used in China for centuries as a sweetening agent, and also used to treat sore throat and cough. In our recent study, a new bioactive compound, (2R,3S,4S)-2,3-trans-3,4-cis-5,3′-bimethoxy-7-(trans-2-propenal)-3,4-flavandiol (1), named siraitiflavandiol was obtained. The structure has been determined on the basis of spectroscopic studies including 1D and 2D NMR (¹H, ¹³C NMR, ¹H–¹H COSY, HSQC, HMBC, and NOESY), CD, EI-MS, and HR-EI-MS spectra. The new compound was evaluated in vitro for its inhibitory ability against the growth of oral bacterial species Streptococcus mutans, Porphyromonas gingivalis, and yeast Candida albicans. The minimum inhibitory concentrations were 6, 24, and 6 μg/ml, respectively.     

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.     

Indoloquinazoline alkaloids from Euodia rutaecarpa and their cytotoxic activities

Nine indoloquinazoline alkaloids (1–9) were isolated from the dried and nearly ripe fruits of Euodia rutaecarpa (Juss.) Benth. (Euodiae Fructus), along with limonin and β-sitosterol. Their structures were elucidated on the basis of their spectroscopic data. Among them, compounds 1 and 2 were new compounds and characterized as (7R,8S)-7-hydroxy-8-methoxy-rutaecarpine and (7R,8S)-7-hydroxy-8-ethoxy-rutaecarpine, respectively, and 1-hydroxy-rutaecarpine (3) and (7R,8S)-7,8-dihydroxy-rutaecarpine (4) were isolated from Euodiae Fructus for the first time. The nine indoloquinazoline alkaloids were evaluated for their cytotoxic activities against human promyelocytic leukemia HL-60 cells and human gastric carcinoma N-87 cells.     

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.