Antiplasmodial prenylated flavanonols from Tephrosia subtriflora

The CH₂Cl₂/MeOH (1:1) extract of the aerial parts of Tephrosia subtriflora afforded a new flavanonol, named subtriflavanonol (1), along with the known flavanone spinoflavanone B, and the known flavanonols MS-II (2) and mundulinol. The structures were elucidated by the use of NMR spectroscopy and mass spectrometry. The absolute configuration of the flavanonols was determined based on quantum chemical ECD calculations. In the antiplasmodial assay, compound 2 showed the highest activity against chloroquine-sensitive Plasmodium falciparum reference clones (D6 and 3D7), artemisinin-sensitive isolate (F32-TEM) as well as field isolate (KSM 009) with IC₅₀ values 1.4–4.6 μM without significant cytotoxicity against Vero and HEp2 cell lines (IC₅₀ > 100 μM). The new compound (1) showed weak antiplasmodial activity, IC₅₀ 12.5–24.2 μM, but also showed selective anticancer activity against HEp2 cell line (CC₅₀ 16.9 μM).     

Three Prenylated Isoflavones from Erythrina variegate

Two new prenylated isoflavones (erythrivarones A and B) were isolated from the stem bark of Erythrina variegata Linn, together with the known compound alpinumisoflavone (1). The structures of erythrivarones A and B were characterized as dihydroalpinumisoflavone (2) and 4′-hydroxy-[6″,6″-dimethyldihydropyrano(2″,3″:5,6)]-[6?,6?-dimethyldihydropyrano(2?,3?:7,8)]isoflavone (3), respectively, by means of spectroscopic analysis.     

Saikachinoside A, a novel 3-prenylated isoguanine glucoside from seeds of Gleditsia japonica

A new isoguanine glucoside designated saikachinoside A has been isolated from the seeds of Gleditsia japonica. The structure was determined as 7-β-d-glucopyranosyl-3-[(Z)-4-hydroxy-3-methyl-2-butenyl]isoguanine by interpretation of the spectroscopic data and was confirmed by X-ray crystallographic analysis. Saikachinoside A accelerated acetylcholinesterase activity.     

Unequivocal assignments of flavonoids from Tephrosia sp. (Fabaceae)

¹H and ¹³C NMR chemical shifts of praecansone B, pongaflavone and dehydrorotenone isolated from Tephrosia egregia Sandw and obovatin from T. toxicaria Pers. were unambiguously assigned by 1D and 2D NMR experiments including ¹H, ¹H COSY, gHMQC and gHMBC, allowing the correction of literature assignments.Copyright © 2009 John Wiley & Sons, Ltd.     

Highly glycosylated flavonoids from the pods of Bobgunnia madagascariensis

Methanolic extracts of the pods of Bobgunnia madagascariensis (Leguminosae) yielded four pentaglycosylated flavonoids, including the 3-O-α-l-rhamnopyranosyl(1→3)-α-l-rhamnopyranosyl(1→2)[α-l-rhamnopyranosyl(1→6)]-β-d-glucopyranoside-7-O-α-l-rhamnopyranosides of 3,5,7-trihydroxy-2-(4-hydroxyphenyl)-4H-benzopyran-4-one (kaempferol) and 3,5,7-trihydroxy-2-(3,4-dihydroxyphenyl)-4H-benzopyran-4-one (quercetin), which were characterized by a novel O-linked branched tetrasaccharide. Spectroscopic and chemical methods were used to determine the structures of the latter, which co-occurred with the corresponding β-d-galactopyranosyl isomers, and two saponins. Conformational isomerism of quercetin 3-O-α-l-rhamnopyranosyl(1→3)-α-l-rhamnopyranosyl(1→2)[α-l-rhamnopyranosyl(1→6)]-β-d-glucopyranoside-7-O-α-l-rhamnopyranoside was detected in solution by NMR, a phenomenon previously associated only with C-glycosylflavonoids.     

Synthesis of amino-silane modified magnetic silica adsorbents and application for adsorption of flavonoids from <Emphasis Type="Italic">Glycyrrhiza uralensis</Emphasis> Fisch

Magnetic separation technology was applied in the separation of flavonoids from the licorice root in this work. Licorice flavonoids (LF) displayed a remarkable array of biological and pharmacological activities. The magnetic adsorbents with functional —NH₂ groups were synthesized by immobilization of amino-silane on the surface of the magnetic silica supports, which were prepared by co-precipitation method. The adsorption and desorption characteristics of the magnetic adsorbents for the separation of LF have been evaluated. The purity of an enriched extract with this method was 16.7% while the crude extract only had about 6.8% purity. Therefore, it can be concluded that these kinds of magnetic adsorbents have selectivity to the flavonoids to some extent. The affinity selectivity of the adsorbents is based on the formation of hydrogen bonding between the —NH₂ on the magnetic adsorbents and —OH, —CO on the flavonoids. Supported by the National High Technology Research and Development Program of China (Grant No. 2002AA302211) and the National Science Fund for Creative Research Groups of China (Grant No. 20221603)     

HPLC Separation of O-Acylated Flavonoids and Biflavones from Some Species of Gymnospermae

Flavonoids present in the extracts from leaves of Pseudotsuga menziesii (Pinaceae), Ginkgo biloba (Ginkgoaceae) and Podocarpus dacrydioides (Podocarpaceae) were separated by use of the reversed phase HPLC method. The analysed compounds belong to different groups of flavonoids – biflavones (amentoflavone, bilobetin, 5–methoxybilobetin, podocarpusflavone A, sequoiaflavone, podocarpusflavone B, ginkgetin, isoginkgetin, sciadopitysin, kayaflavone, hinokiflavone, 2,3–dihydrosciadopitysin, 2,3–dihydroisoginkgetin), O–acylated flavonol glycosides (daglesiosides I, II, III, IV, trans–tiliroside, trans–ditiliroside), flavonol O–glycosides (astragalin, isoquercetin) and flavonol aglycones (kaempferol, quercetin, isorhamnetin). The conditions for flavonoid separation were optimized using various RP–18 columns. The chromatographic resolution was performed with isocratic or gradient elution – optimized by Drylab program or by traditional trial-and-error method, depending on the composition of flavonoid complex.     

Takaneones A-C, prenylated butylphloroglucinol derivatives from Hypericum sikokumontanum

Three new prenylated butylphloroglucinol derivatives, takaneones A-C (1-3), were isolated from the MeOH extracts of the aerial parts of Hypericum sikokumontanum together with two new prenylated phloroglucinol derivatives, takaneols A and B (4 and 5). The structures of the isolated compounds were elucidated by exhaustive spectroscopic analysis. The cytotoxicities of the isolated compounds against human cancer cell lines were evaluated. Compounds 2-4 showed cytotoxicities against K562/Adr multi-drug resistant (MDR) cancer cells with IC₅₀ values ranging from 4.7 to 10.0 μg/mL, which were slightly more potent than doxorubicin. Their potency of cytotoxicities against MDR cancer cell lines (KB-C2 and K562/Adr) were similar to those against sensitive cell lines (KB and K562).     

Antioxidant flavonoids from <Emphasis Type="Italic">Tamus communis</Emphasis> ssp. <Emphasis Type="Italic">cretica</Emphasis>

A new flavonoid, kaempferol-3,4′-di-O-α-L-rhamnopyranoside (1), and three known flavonoids (2–4) were isolated from the aerial parts of T. communis L. The structure of the new compound was elucidated on the basis of spectroscopic data. Compounds 1 and 2 showed significant antioxidant activity (IC₅₀ 187.151 ± 0.821 μM, and 92.079±0.513 μM, respectively), whereas compounds 3 and 4 showed moderate activity in DPPH free radical scavenging assays. Published in Khimiya Prirodnykh Soedinenii, No. 3, pp. 295–297, May–June, 2009.     

Penioxalamine A,a novel prenylated spiro-oxindole alkaloid from Penicillium oxalicum TW01-1

Penioxalamine A (1), a novel prenylated spiro-oxindole alkaloid having a unique seven-membered nitrogen heterocycle system, was isolated from the fungus Penicillium oxalicum TW01-1. The structure of 1 was elucidated on the basis of the spectral data, single-crystal X-ray diffraction, and CD analysis. Compound 1 showed moderate cytotoxicity against HL-60 cell line. The possible biosynthetic pathway of 1 was also proposed.     

Cytotoxic flavonoids from two Lonchocarpus species

A new isoflavone, 4′-prenyloxyvigvexin A (1) and a new pterocarpan, (6aR,11aR)-3,8-dimethoxybitucarpin B (2) were isolated from the leaves of Lonchocarpus bussei and the stem bark of Lonchocarpus eriocalyx, respectively. The extract of L. bussei also gave four known isoflavones, maximaisoflavone H, 7,2′-dimethoxy-3′,4′-methylenedioxyisoflavone, 6,7,3′-trimethoxy-4′,5′-methylenedioxyisoflavone, durmillone; a chalcone, 4-hydroxylonchocarpin; a geranylated phenylpropanol, colenemol; and two known pterocarpans, (6aR,11aR)-maackiain and (6aR,11aR)-edunol. (6aR,11aR)-Edunol was also isolated from the stem bark of L. eriocalyx. The structures of the isolated compounds were elucidated by spectroscopy. The cytotoxicity of the compounds was tested by resazurin assay using drug-sensitive and multidrug-resistant cancer cell lines. Significant antiproliferative effects with IC₅₀ values below 10 μM were observed for the isoflavones 6,7,3′-trimethoxy-4′,5′-methylenedioxyisoflavone and durmillone against leukemia CCRF-CEM cells; for the chalcone, 4-hydroxylonchocarpin and durmillone against its resistant counterpart CEM/ADR5000 cells; as well as for durmillone against the resistant breast adenocarcinoma MDA-MB231/BCRP cells and resistant gliobastoma U87MG.ΔEGFR cells.     

Notoamide E: Biosynthetic incorporation into notoamides C and D in cultures of Aspergillus versicolor NRRL 35600

Notoamide E, a short-lived secondary metabolite, has been proposed as a biosynthetic intermediate to several advanced metabolites isolated from Aspergillus versicolor. In order to verify the role of this indole alkaloid along the biosynthetic pathway, synthetic doubly ¹³C-labeled notoamide E was fed to Aspergillus versicolor. Analysis of the metabolites showed significant incorporation of notoamide E into the natural products notoamides C and D.     

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).     

Two new diterpene and sesquiterpene from Pteris dispar

A new diterpene and a new sesquiterpene were isolated from Pteris dispar and identified on the basis of spectral data including 2D NMR.Compounds 1 and 2 showed potent cytotoxic activity against KB cell.     

Terpenes,Coumarins, and Flavones from <Emphasis Type="Italic">Acacia pennatula</Emphasis>

The chemical analysis of the acetone extract of the dried leaves from Acacia pennatula yielded triacontanol, β-sitosterol palmitate, β-sitosterol, squalene, nonaprenol, norphytane, lupenone, lupeol, daphnetin and catechin, while from the methanol extract were isolated catechin, epigallocatechin, eriodictyol, β-sitosteryl-β-D-glucopyranoside, and stigmasteryl-β-D-glucopyranoside. The structures of all these natural products were established based on their IR, ¹H, and ¹³C NMR and MS data.__________Published in Khimiya Prirodnykh Soedinenii, No. 3, pp. 240–241, May–June, 2005.     

Yojironins A−D, meroterpenoids and prenylated acylphloroglucinols from Hypericum yojiroanum

Two new meroterpenoids, yojironins A (1) and B (2), were isolated from the whole plants of Hypericum yojiroanum, together with two new prenylated acylphloroglucinols, yojironins C (3) and D (4). Their structures were elucidated by spectroscopic data. Yojironins A (1) and B (2) are biogenetically unique meroterpenoids, which seem to be composed of two acetate units with a 2-methylbutanoyl group and three isoprene units. Yojironin A (1) exhibited antimicrobial activity.     

Mildbraedin, a novel kaempferol tetraglycoside from the tropical forest legume Mildbraediodendron excelsum

Aqueous methanol extracts of the leaves of Mildbraediodendron excelsum yielded a novel flavonol glycoside characterized by an O-linked branched tetrasaccharide. The structure of the compound was determined by spectroscopic methods to be kaempferol 3-O-α-l-rhamnopyranosyl(1→3)-α-l-rhamnopyranosyl(1→2)[α-l-rhamnopyranosyl(1→6)]-β-d-galactopyranoside. This previously unrecorded natural product was the major phenolic component of leaf material obtained both from a living specimen of the plant and a historic collection made in the field in 1928.     

Rapid molecular typing of <Emphasis Type="Italic">Tuber melanosporum</Emphasis>, <Emphasis Type="Italic">T. brumale</Emphasis> and <Emphasis Type="Italic">T. indicum</Emphasis> from tree seedlings and canned truffles

We have developed new DNA extraction and purification procedures for investigation of mycorrhized seedlings and canned truffles. Use of these procedures on approximately 100 mg initial material enabled good sample representation. For mycorrhized seedlings, Taq polymerase inhibitors were discarded irrespective of tree species. In routine analysis we systematically used consensus primers ITS1/ITS4 to check the absence of Taq polymerase inhibitors and the presence of fungus DNA. Positive response with ITS validates other positive or negative PCR results. Absence of amplification with ITS prevents validation of other results. For canned truffles, DNA harvested from ascocarps sterilized for one and a half hours at 115°C was amplified with specific primers. We have developed consensus primers, named R12/F12, to check for the presence of amplifiable fungus DNA and the absence of Taq polymerase inhibitors. Here also, positive response with consensus R12/F12 validates other positive or negative PCR results. We have developed one primer pair specific for T. brumale and another specific for T. melanosporum. We can then characterize these two taxa, which enables the use of truffle or truffled French designations. We can also characterize T. indicum, the Asiatic black truffle that might fraudulently be sold as T. melanosporum and T. brumale. These three specific primer pairs were used independently of DNA extraction from tree seedlings or canned truffles. Our process is specific, sensitive, convenient, and quick.J.P. Douet and D. Mabru have contributed equally to this work     

A new sesquiterpene from the roots of Vladimiria souliei

A new sesquiterpene, named vladimenal (1), was isolated from the roots of Vladimiria souliei. The structure was elucidated on the basis of spectroscopic analysis.