Acylphloroglucinol and xanthones from Hypericum ellipticum

An acylphloroglucinol, elliptophenone A, and two xanthones, elliptoxanthone A and elliptoxanthone B, were isolated from the aerial portions of Hypericum ellipticum together with three known xanthones, 1,3,7-trihydroxy-8-(3-methyl-2-butenyl)-9H-xanthen-9-one, 1,6-dihydroxy-4-methoxy-9H-xanthen-9-one, and 1,4,5-trihydroxy-9H-xanthen-9-one. Their structures were determined by spectroscopic analyses. The acylphloroglucinol and xanthones were evaluated for cytotoxicity using three human colon cancer cell lines cell lines (HT-29, HCT-116 and Caco-2) and a normal human colon cell line (CCD-18Co).     

Xanthones from Hypericum chinense

Six xanthones, 1,3,7-trihydroxy-2-(2-hydroxy-3-methyl-3-butenyl)-xanthone (1), 1,7-dihydroxy-2,3-[2'-(1-hydroxy-1-methylethyl)-dihydrofurano]-xanthone (2), 1,3,7-trihydroxy-5-methoxyxanthone (3), 1,7-dihydroxy-5,6-dimethoxyxanthone (4), 4,5-dihydroxy-2,3-dimethoxyxanthone (5), 1,3-dihydroxy-2,4-dimethoxyxanthone (6) and 21 known xanthones were isolated from the leaves and stems of Hypericum chinense. Their structures were established based on spectroscopic studies.     

Sulfonated xanthones from Hypericum sampsonii

Xanthones, 1,3-dihydroxy-5-methoxyxanthone-4-sulfonate and 1,3-dihydroxy-5-O-beta-D-glycopyranosylxanthone-4-sulfonate, together with nine known compounds were obtained from H. sampsonii. This is the first report of sulfonated xanthonoids. Furthermore, compounds 1 and 2 exhibited significant cytotoxicity against the P388 cancer cell line.     

Anti-staphylococcal acylphloroglucinols from Hypericum beanii

As part of an ongoing project to investigate the anti-staphylococcal properties of the Hypericum genus, an acylphloroglucinol, 1,5-dihydroxy-2-(2'-methylpropionyl)-3-methoxy-6-methylbenzene (1), was isolated from the dichloromethane extract of the aerial parts of H. beanii (Guttiferae), together with a minor related acylphloroglucinol 1,5-dihydroxy-2-(2'-methylbutanoyl)-3-methoxy-6-methylbenzene (2) as a mixture in a 5:2 ratio. The known compounds 1,7-dihydroxyxanthone (3), stigmasterol, catechin and shikimic acid were also isolated from this plant. The structures of the compounds were characterized by extensive 1- and 2D NMR spectroscopy and mass spectrometry. The minimum inhibitory concentration (MIC) values the acylphloroglucinol mixture and (3) against a panel of multidrug-resistant strains of Staphylococcus aureus ranged from 16-32 microg/ml to 128-256 microg/ml, respectively.     

Phytochemical analysis and genetic characterization of six Hypericum species from Serbia

The secondary metabolite contents and genetic profiles of six Hypericum species (H. barbatum Jacq., H. hirsutum L., H. linarioides Bosse, H. maculatum Crantz, H. rumeliacum Boiss. and H. tetrapterum Fries), collected from different locations in Serbia, have been analyzed. Methanol extracts of the aerial parts of the plants were obtained by accelerated solvent extraction (ASE) at 40 degrees C and 100 bar, and analyzed for five pharmacologically important standard constituents (hyperoside, quercitrin, pseudohypericin, hyperforin and hypericin) by LC-MS/MS. The highest content of hypericin and pseudohypericin was observed in the H. barbatum extract, while the highest content of hyperforin and quercitrin was found in the H. tetrapterum extract and the highest content of hyperoside in the H. maculatum extract. A literature survey shows that the above six Hypericum species, with the exception of H. maculatum, have not been previously genetically profiled. In order to correlate the chemical constituents of the species under investigation with their genetic factors, genetic profiling of these species was undertaken using the random amplification of polymorphic DNA (RAPD) and single sequence repeat (SSR) profiles of the above selected plants. Among the 52 random primers used for the initial screening, only 10 yielded polymorphic RAPD profiles. A total of 111 polymorphic markers were generated using these primers. The SSR analysis shows that 8 out of the 10 primers used were polymorphic. The correlation among the species under investigation using the two genetic markers was performed using Jaccuard's coefficients of similarity and a high correlation (r=0.99) was obtained. The main conclusion from the above data is that there exists a stronger correlation for secondary metabolite contents with RAPD data than with SSR data among the six Hypericum species from Serbia.     

Yojironins E-I, prenylated acylphloroglucinols from Hypericum yojiroanum

Five new prenylated acylphloroglucinols, yojironins E-Ι (1-5), were isolated from the whole plants of Hypericum yojiroanum. Their structures were elucidated by spectroscopic data. Yojironin E (1) exhibited antimicrobial activity against Aspergillus niger, Candida albicans, Cryptococcus neoformans, and Trichophyton mentagrophytes.     

Pregnane, coumarin and lupane derivatives and cytotoxic constituents from Helicteres angustifolia

2alpha,7beta,20alpha-Trihydroxy-3beta,21-dimethoxy-5-pregnene (1), 6,7,9alpha-trihydroxy-3,8,11alpha-trimethylcyclohexo-[d,e]-coumarin (2), 3beta-hydroxy-27-benzoyloxylup-20(29)-en-28-oic acid (3), and 3beta-hydroxy-27-benzoyloxylup-20(29)-en-28-oic acid methyl ester (4), along with 24 known compounds were isolated and structurally characterized from roots and aerial parts of Helicteres angustifolia (Sterculiaceae). In a preliminary bioassay, the two cucurbitacin derivatives, cucurbitacin D and J exhibited significant inhibitory activities against the growth of both hepatocellular carcinoma BEL-7402 cells and malignant melanoma SK-MEL-28 cells in vitro.     

Phloroglucinol derivatives from Mallotus pallidus

From the leaves of Mallotus pallidus were isolated five phloroglucinol derivatives, namely pallidusol, dehydropallidusol, pallidol, mallopallidol and homomallopallidol. Their structures were determined by means of spectroscopic methods of analysis.     

Ellagic acid derivatives and cytotoxic cucurbitacins from Elaeocarpus mastersii

Bioassay-guided investigation of the bark of Elaeocarpus mastersii using KB (human oral epidermoid carcinoma) cells as a monitor led to the isolation of two cucurbitacins, cucurbitacin D and cucurbitacin F as cytotoxic principles, together with two ellagic acid derivatives, 4'-O-methylellagic acid 3-(2",3"-di-O-acetyl)-alpha-L-rhamnoside (1) and 4,4'-O-dimethylellagic acid 3-(2",3"-di-O-acetyl)-alpha-L-rhamnoside (2). These compounds were evaluated against a panel of human tumor cell lines.     

Antiprotozoal and cytotoxic naphthalene derivatives from Diospyros assimilis

Chemical investigation of the roots of Diospyros assimilis had led to the isolation and characterization of six naphthalene derivatives, two 2-naphthaldehyes, namely 4-hydroxy-3,5-dimethoxy-2-naphthaldehyde 1, 4-hydroxy-5-methoxy-2-naphthaldehye 2, its related isomer 5-hydroxy-4-methoxy-2-naphthaldehyde 3 and three commonly occurring naphthoquinones, diospyrin 4, 8'-hydroxyisodiospyrin 5 and the simple monomer, plumbagin 6. Their chemical structures were established by detailed NMR investigations including 1H and 13C NMR, HSQC, HMBC and NOESY experiments. In addition, the naphthalene derivatives 1-5 were evaluated for their in vitro antiprotozoal activity against protozoan parasites belonging to the genera Trypanosoma, Leishmania and Plasmodium. Among the tested compounds, naphthaldehyde 1 showed moderate inhibition of the growth of the parasites, T. brucei, T. cruzi, L. donovani with IC50 values of 19.82, 12.28 and 38.78 microM and displayed cytotoxicity towards rat skeletal myoblasts (L-6 cells) with IC50 of 174.94 microM, while 2 and 3 were found to be comparatively less active to 1. The dimeric quinones 4 and 5 exhibited good activity against T. brucei and L. donovani with IC50 of 1.12 and 8.82 microM and 12.94 and 16.66 microM respectively.     

Antiplasmodial phloroglucinol derivatives from Syncarpia glomulifera

Bioassay guided fractionation of a MeOH extract of the stem bark of Syncarpia glomulifera (Myrtaceae) led to the isolation of the two new phloroglucinol derivatives (±)-rhodomyrtosone F (1) and (±)-calliviminone C (2), the three known triterpenes, betulinic acid (3), ursolic acid-3-acetate (4), and ursolic acid (5), and 1-(2,4,6-trihydroxyphenyl)-1-hexanone (6). Compound 1 exhibited strong antiplasmodial activity, while compounds 2–4 were moderately active and 5 and 6 were inactive in this assay. The structures of 1 and 2 were elucidated based on analyses of their mass spectrometric data, 1D and 2D NMR spectra, and comparison with related compounds.     

An anti-staphylococcal acylphloroglucinol from Hypericum foliosum

An investigation into the antibacterial properties of Hypericum foliosum Aiton. (Guttiferae) has led to the isolation of a new bioactive acylphloroglucinol natural product which by NMR spectroscopy and mass spectrometry was characterised as 1,3,5-trihydroxy-6-[2',3'-epoxy-3'-methyl-butyl]-2-[2'-methyl-butanoyl]-4-[3'-methyl-2'-butenyl]-benzene and is described here for the first time. This metabolite was evaluated against a panel of multidrug-resistant strains of Staphylococcus aureus and minimum inhibitory values ranged from 16 to 32 microg/ml.     

Sinaicinone, a complex adamantanyl derivative from Hypericum sinaicum

The structure of sinaicinone, isolated from the aerial parts of the Egyptian medicinal plant Hypericum sinaicum, has been elucidated by means of spectroscopic data such as UV, IR, MS, 1D and 2D NMR spectra, and chemical degradation. It is a complex adamantanyl derivative with a unique skeleton and oxygenated side chains.     

Antimicrobial and cytotoxic agents from Calophyllum inophyllum

The study of the chemical constituents of the root bark and the nut of Calophyllum inophyllum has resulted in the isolation and characterization of a xanthone derivative, named inoxanthone, 3, together with 12 known compounds: caloxanthones A, 4 and B, 5, macluraxanthone, 6, 1,5-dihydroxyxanthone, 7, calophynic acid, 8, brasiliensic acid, 9 inophylloidic acid, 10, friedelan-3-one, 11, calaustralin, 12, calophyllolide, 13, inophyllums C, 14 and E, 15. Their structures were established on the basis of spectral evidence. Their in vitro cytotoxicity against the KB cell line and their antibacterial activity and potency against a wide range of micro organisms were evaluated.     

Xanthones from Hypericum chinense and their cytotoxicity evaluation

A xanthonolignoid, 2-O-demethylkielcorin, and a phenylxanthone, chinexanthone A, were isolated from stems of Hypericum chinense together with four known xanthonolignoids and seven known xanthones. Their structures were established by spectroscopic analysis, as their optical properties and absolute stereochemistry determined. The cytotoxicities of the isolated xanthone derivatives as well as additional 32 xanthones against a panel of human cancer cell lines were also evaluated.     

Essential oil composition of Hypericum L. species from Southeastern Serbia and their chemotaxonomy

The essential oils of the aerial parts of nine species of Hypericum (Hypericum barbatum, Hypericum hirsutum, Hypericum linarioides, Hypericum maculatum, Hypericum olympicum, Hypericum perforatum, Hypericum richeri, Hypericum rumeliacum and Hypericum tetrapterum), collected from different locations in Southeast Serbia, were obtained by steam distillation and analyzed by GC and GC–MS. The essential oils investigated were characterized by a high content of non-terpene compounds and a low content of monoterpenes. The contents of non-terpenes, monoterpenes and sesquiterpenes in oils of the species H. barbatum, H. richeri and H. rumeliacum (section Drosocaprium) were similar and these oils were characterized by high contents of fatty acids. The oils of H. hirsutum and H. linarioides (section Taeniocarpium) contained a high percentage of n-nonane. There were similarities in contents of non-terpenes and sesquiterpenes in oils of species that belong to the section Hypericum (H. maculatum, H. perforatum and H. tetrapterum). The oil of H. olympicum differed from others by higher terpene content. A comparison was also carried out of the chemical composition of the essential oils from flower, leaf and stem of H. perforatum and it revealed that the highest concentration of non-terpene compounds was found in the flower and stem oil, while a high concentration of sesquiterpenes was characteristic for leaf oil. There were significant differences in the concentrations of the same compounds in the essential oils of H. maculatum, H. olympicum and H. perforatum, collected in different years from the same location which could be explained by seasonal differences. All data were statistically processed with principal component analysis and cluster analysis. The main conclusion from the above data is that genetic and environmental factors both play a role in determining the composition of essential oils of the Hypericum species studied.     

Xanthone derivatives from Cratoxylum cochinchinense roots

Two xanthones and two caged-prenylated xanthones, named cochinchinones A-D, respectively, and a synthetically known caged-prenylated xanthone, together with seven known compounds were isolated from the roots of Cratoxylum cochinchinense (Lour.) Blume. Their structures were assigned on the basis of analyses of spectroscopic data. Some of the compounds exhibited effective antioxidative properties.     

Two benzophenone O-arabinosides and a chromone from Hypericum annulatum

Two benzophenone O-arabinosides, annulatophenonoside (1) and acetylannulatophenonoside (2) were isolated from the methanol extract of the herb of Hypericum annulatum. The structures of the benzophenones were established as 2-O-alpha-L-arabinofuranosyl-3',5',6-trihydroxy-4-methoxybenzophenone (1) and 2-O-alpha-L-3"-acetylarabinofuranosyl-3',5',6-trihydroxy-4-methoxybenzophenone (2) based on spectral and chemical evidence. A chromone, 5,7-dihydroxy-3-methylchromone (3) was isolated from the chloroform extract. Although it has been previously synthesized it is encountered in a plant source for the first time. Co-occurrence of the two new benzophenone O-arabinosides along with the biogenetically related 1,5,7-trihydroxy-3-methoxyxanthone was not found.     

国产金丝桃属(藤黄科)新植物

描述了采集于湖北巴东县的金丝桃属Hypericum L.的3个新分类群,即湖北小连翘H. hubeiense L. H. Wu &; D. P. Yang、恩施小连翘H. enshiense L. H. Wu &; F. S. Wang和长萼小连翘H. erectum Thunb. ssp. longisepalum L. H. Wu &; D. P. Yang。湖北小连翘与H. asahinae Makino相似,表现在叶无柄,基部心形抱茎,花萼和花瓣上具黑色腺条;区别在于叶近边缘腺体全为黑色,叶片上部无腺体     

Marsdenosides A-H, polyoxypregnane glycosides from Marsdenia tenacissima

Eight polyoxypregnane glycosides, marsdenosides A-H, were isolated from the CHCl(3)-soluble fraction of the ethanolic extract of the stem of Marsdenia tenacissima, along with six known glycosides and two known polyoxypregnane aglycones. Three polyoxypregnanes, 12beta-O-2-methylbutyryl-tenacigenin A, 11alpha,12beta-di-O-acetyltenacigenin B, and 11alpha-O-tigloyltenacigenin B were also obtained. Their structures were established on the basis of spectroscopic analysis and chemical evidence.