Extracts of Cynomorium songaricum protect human neuroblastoma cells from beta-amyloid25-35 and superoxide anion induced injury.

In Traditional Chinese Medicine a number of herbs are used to alleviate age-related diseases including memory impairment and dementia, among them stems of Cynomorium songaricum, Cynomoriaceae. In this study, we evaluated the protective effect of different extracts of aerial parts of C. songaricum on amyloid-beta peptide (Abeta) and hypoxanthine/xanthine oxidase induced cell death in SK-N-SH neuroblastoma cells. Abeta (20 microM) as well as superoxide anions generated by the hypoxanthine/xanthine oxidase system both reduced cell viability to about 60%. The methanolic extract of C. songaricum attenuated Abeta induced cell death at concentrations of 100 and 10 microg/ml, an even stronger effect was observed for the ethyl acetate fraction obtained from the crude methanolic extract. On the other hand, the dichloromethane as well as water fractions showed no protective effects. In order to further analyze the protective mode of action, the ability of extracts to protect against superoxide anions induced cell death was also evaluated. In this system, cell viability could again be restored by methanol and ethyl acetate extracts, the latter showingsignificant protective effects even at concentrations as low as 0.1 microg/ml.

Enhancement of cytotoxicity of ribosome-inactivating-protein type I by saponinum album is not based on stimulation of phagocytosis.

Saponinum album, a mixture of triterpenoic saponins derived from Gypsophila species, led to an increased internalization of agrostin, a ribosome-inactivating-protein (RIP) type I in U-937 cells differentiated with interferon-gamma or phorbol myristate acetate. Treatment with agrostin only showed no cytotoxicity. It was hypothesized that saponinum album stimulated phagocytosis and by that the uptake of agrostin. For this purpose phagocytosis experiments with Alexa-Fluor-488-labelled 1-microm amino-latex beads and FITC-labelled Escherichia coli (K-12 strain) were performed. The results indicated no stimulation of phagocytosis by treatment with saponinum album.

Phenolic glycosides from Exostema mexicanum leaves.

Phytochemical investigation of the leaves of Exostema mexicanum led to the isolation of two novel acylated flavonol glycosides 6, 7 and three glycosides 1-4 structurally belonging to the group of 4-phenylcoumarins. One of them, 5-O-beta-D-glucopyranosyl-4'-hydroxy-7-methoxy-4-phenylcoumarin (2), turned out to be new. Furthermore, the 4-phenylcoumarin aglycone 3'-hydroxy-4',5,7-trimethoxy-4-phenylcoumarin (5) was obtained. The in vitro cytotoxicity of 3-5 against the cell line ECV-304 was evaluated; the aglycone 5 was highly cytotoxic, whereas the glycosidic compounds 3 and 4 were inactive.

New prenylated benzoic acid derivatives of Piper hispidum.

Three new 4-hydroxy-benzoic acid derivatives, 4-methoxy-3,5-bis-(3-hydroxy-3-methyl-1-butenyl)benzoate, 3-hydroxy-2-(1-hydroxy-1-methylethyl)-2,3-dihydrobenzofuran-5-carboxylic acid, and 3-hydroxy-2-(1-hydroxy-1-methylethyl)-2,3-dihydrobenzofuran-5-carboxylic acid methyl ester together with eight known compounds, have been isolated from the stems of Piper hispidum. Their structures were elucidated by a detailed spectroscopic analysis. In addition, the cytotoxicity of seven isolated compounds has been evaluated, revealing a moderate activity for three derivatives of dillapiole.

Cytotoxicity of plants used in traditional medicine in Yemen.

Twenty-five extracts obtained from 14 plant species used in the traditional medicine in Yemen have been screened for cytotoxic activity against human ECV-304 cells. Extracts of Dracaena cinnabari, Eucalyptus camaldulensis, Euclea divinorum, Euphorbia cactus, Pulicaria crispa, and Withania somnifera displayed a remarkable activity.

N1,N10-ditigloylspermidine, a novel alkaloid from the seeds of Ipomoea nil.

A novel spermidine alkaloid, N1,N10-ditigloylspermidine (1), has been isolated from the seeds of Ipomoea nil (L.) Roth (Convolvulaceae). Structural elucidation was achieved by EIMS, HRMS, 1H NMR, and 13C NMR spectroscopy.

Merrekentrones A-D, ipomeamarone-like furanosesquiterpenes from Merremia kentrocaulos.

Four new furanosesquiterpenes, merrekentrones A (1), B (2), C (3), and D (4), were isolated from the roots and rootstocks of Merremia kentrocaulos. Their structures were elucidated on the basis of spectroscopic data interpretation. In contrast to ipomeamarone (5), the well-known phytoalexin of Ipomoea batatas, 1-4 seem to be normal plant constituents. Merrekentrone A (1) was also detected in the roots of M. guerrichii and M. aurea.

Andinermals A-C, antiplasmodial constituents from Andira inermis.

Bioassay-guided fractionation of the leaves from Andira inermis was undertaken as part of a screening program to verify the traditional use of herbal remedies against malaria. Among the isolated phenolic compounds three novel 2-arylbenzofuran-3-carbaldehydes, andinermal A-C, were obtained together with a new flavanonol glycoside, taxifolin-3-O-(3"-O-trans-cinnamoyl)-alpha-L-rhamnopyranoside.

In vitro antiplasmodial activity of 4-phenylcoumarins from Exostema mexicanum.

The stem bark of Exostema mexicanum (Rubiaceae) is used in Latin American folk medicine as a quinine substitute for malaria treatment. Bioassay-guided fractionation of lipophilic and hydrophilic extracts from the stem bark and branches yielded two previously undescribed 4-phenylcoumarins: 4',8-dihydroxy-5,7-dimethoxy-4-phenylcoumarin (exomexin A) and 3',4'-dihydroxy-5,7,8-trimethoxy-4-phenylcoumarin (exomexin B). Together with five known derivatives the in vitro activities against a chloroquine-sensitive strain (poW) and a chloroquine-resistant strain (Dd2) of Plasmodium falciparum have been evaluated. The most lipophilic compound, 4',5,7,8-tetramethoxy-4-phenylcoumarin (O-methylexostemin) revealed the strongest antiplasmodial activity (IC50 values: 3.6 microg/ml [poW], 1.6 microg/ml [Dd2]).

Antiplasmodial activity of isoflavones from Andira inermis.

The stem bark and seeds of Andira inermis, Fabaceae, are employed as a purgative, vermifuge, and febrifuge. In particular, the powdered bark is claimed to be efficacious in intermittent fever. Bioassay-guided fractionation of lipophilic extracts from the stems and leaves yielded six isoflavones: biochanin A, calycosin, formononetin, genistein, pratensein, and prunetin. Calycosin (3', 7-dihydroxy-4'-methoxyisoflavone) and genistein (4',5, 7-trihydroxyisoflavone) have been shown to possess in vitro activity against the chloroquine-sensitive strain poW and the chloroquine-resistant clone Dd2 of Plasmodium falciparum.

Sipandinolide: a butenolide including a novel type of carbon skeleton from Siparuna andina.

From a lipophilic extract of leaves of Siparuna andina (Monimiaceae), which exhibited antiplasmodial activity in vitro, two new compounds have been isolated: sipandinolide (1), a compound with a novel type of carbon skeleton and (-)-cis-3-acetoxy-4',5,7-trihydroxyflavanone (2). Their structures were established by spectroscopic methods; 2 showed moderate antiplasmodial activity whereas 1 was inactive.

Bonaspectins and neobonaspectins, first sesquilignans and sesquineolignans from a convolvulaceous species.

Four new tetrahydrofuran-type sesquilignans, named bonaspectin A, bonaspectin B, bonaspectin C 4''-beta-glucoside and bonaspectin D 4''-beta-glucoside, as well as two new 8.O.4'-type sesquineolignans, named neobonaspectin A and B, were isolated from the aerial vegetative parts of Bonamia spectabilis (Convolvulaceae), together with the known compound rel-(7S,8S,7'R,8'R)-3,3',4,4',5,5'-hexamethoxy-7.O.7',8.8'-lignan. Their structures were established on the basis of spectral data.

Iseluxine: a novel isoquinolinone alkaloid from Iseia luxurians.

A novel isoquinolinone alkaloid, iseluxine (1), has been isolated from the epigeal parts of Iseia luxurians (MORIC.) O'DONELL (Convolvulaceae), a climber indigenous to the tropical Americas. Structural elucidation was achieved by HRMS, 1H NMR, 13C NMR, and HMBC spectroscopy. N- and/or O-methyl derivatives of 1 are already known from certain Magnoliidae families, e.g., the Fumariaceae, the Lauraceae, or the Papaveraceae. Iseluxine, the "missing link" in the biosynthesis of these methyl derivatives from dopamine, is the first isoquinolinone alkaloid characterized by a catechol substructure.

In vitro antiplasmodial activity of Central American medicinal plants.

The in vitro antiplasmodial activities of 14 plant species traditionally used in Central America for the treatment of malaria or fever were evaluated. Lipophilic extracts of Piper hispidum, Siparuna andina, S. pauciflora, S. tonduziana, and Xylopia cf. frutescens, proved to be active against both a chloroquine-sensitive and a resistant strain of Plasmodium falciparum. IC50 values ranged between 3.0 microg/ml and 21.9 microg/ml; however, moderate cytotoxicity of active extracts was observed. Bioactivity-guided fractionation of Piper hispidum yielded 2',4, 6'-trihydroxy-4'-methoxydihydrochalcone (asebogenin) as an active compound.