A dihydrochalcone derivative and further steroidal saponins from Sansevieria trifasciata Prain.

Phytochemical investigation of the aerial parts of Sansevieria trifasciata, one of the most common Dracaenaceae plants, has resulted in the isolation of a new dihydrochalcone derivative named trifasciatine C (1), four previously unreported steroidal saponins as two pairs of inseparable regioisomers: trifasciatosides K/L (2/3), M/N (4/5), together with the known 1,2-(dipalmitoyl)-3-O-ß-D-galactopyranosylglycerol (6), aconitic acid (7), and 1-methyl aconitic acid (8). Their structures were elucidated mainly by extensive spectroscopic analysis (1D and 2D nuclear magnetic resonance) and high-resolution electronspray ionization-mass spectrometry, as well as chemical methods and comparison of their spectral data with those of related compounds. Compounds 2/3 and 4/5 were evaluated for their antiproliferative activity on Hela cells, and no significant effect was observed.

Effects of extracts and compounds from Tricholoma populinum Lange on degranulation and IL-2/IL-8 secretion of immune cells.

Tricholoma populinum Lange is an edible basidiomycete from the family Tricholomataceae. Extracts, fractions, and different metabolites isolated from the fruiting bodies of this mushroom were tested for degranulation-inhibiting activities on RBL-2H3 cells (rat basophils). Dichloromethane extracts decreased degranulation significantly, as did a fraction after column chromatography. In addition, the extract decreased the IL-2 release from Jurkat T cells and the release of IL-8 from HMC-1 human mast cells. The results show the significant effects of extracts of T. populinum on cells of the innate (basophils and mast cells) and adaptive (T cells) immune system and indicate the influence of the mushroom on different immunological processes. As one fraction showed activity, it seems to be possible that it includes an active principle. The compounds responsible for this effect, however, could not be identified as the contents oleic acid (1), ergosterol peroxide (2), and 9,11-dehydroergosterol peroxide (3) showed no effects. Nevertheless, the mushroom could be used for supporting allergy treatment in future studies.

Cytotoxic saponins from the seeds of Pittosporum angustifolium.

Three new acylated R1-barrigenol triterpene glycosides, 1-3, were isolated from the seeds of Pittosporum angustifolium Lodd. together with four known glycosides, 4-7, containing R1- and A1-barrigenol backbones. On the basis of spectroscopic, spectrometric, and chemical analyses the novel compounds were named pittangretosides N-P and established as 21beta-acetoxy-22alpha-angeloyloxy- (1), 21beta-acetoxy-22alpha-(2-acetoxy-2-methylbutyroyloxy)- (2), and 21beta-(2-methylbutyroyloxy)-22alpha-acetoxy-3beta-[beta-D-glucopyranosyl- (1 --> 2)]-[alpha-L-arabinopyranosyl-(1 --> 3)]-[alpha-L-arabinofuranosyl-(1 --> 4)]-beta-D-glucuronopyranosyloxyolean-12-ene-15alpha, 6alpha, 28-triol (3). Evaluation of the in vitro cytotoxicity against three tumour cell lines and one non-tumourigenic cell line revealed antiproliferative effects with IC50 values in a range of 1.74-34.1 microM.

Triterpene glycosides from the leaves of Pittosporum angustifolium.

Phytochemical investigation of the leaves of Pittosporum angustifolium resulted in the isolation and structural elucidation of nine new triterpene saponins, named pittangretosides A-I (1-9), together with a known compound (10). Mainly by NMR and HRESIMS experiments, eight compounds were identified as A1-barrigenol glycosides (1-7, 10), whereas two compounds exhibited an unusual 17,22-seco-backbone of oleanolic acid (8, 9). All compounds were evaluated for their in vitro cytotoxicities against human urinary bladder carcinoma cells (5637). Only compounds with an angeloyl-residue at C-22 of the aglycone (1-4 and 10) showed antiproliferative effects with IC50 values of 4.1, 5.2, 2.1, 17.9, and 2.4 µM, respectively.

Chemical composition and biological activity of Paris quadrifolia L.

A study of the components of Paris quadrifolia was undertaken to identify compounds with potential influence on cardiac cells, since previous reports suggested a cardiotoxic risk of this plant. Compounds isolated and identified included one new steroidal saponin, (23S,24S)-spirosta-5,25(27)-diene-1beta,3beta,21,23,24-pentol-1-O-beta-D-apiofuranosyl-(1-->3)-alpha-L-rhamnopyranosyl-(1-->2)-[beta-D-xylopyranosyl-(1-->3)]-beta-D-glucopyranoside 21-O-beta-D-apiofuranoside 24-O-beta-D-fucopyranoside (1), demonstrating quite unusual structural features, as well as the known compounds 26-O-beta-D-glucopyranosyl-(25R)-5-en-furost-3beta,17alpha,22alpha,26-tetraol-3-O-alpha-L-rhamnopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->4)-[alpha-L-rhamnopyranosyl--(1-->2)]-beta-D-glucopyranoside (2), pennogenin 3-O-alpha-L-rhamnopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->4)-[alpha-L-rhamnopyranosyl-(1-->2)]-beta-D-glucopyranoside (3), 7-O-beta-D-glucopyranosyl-kaempferol-3-O-beta-D-glucopyranosyl-(1-->2)-beta-D-galactopyranoside (4), kaempferol-3-O-beta-D-glucopyranosyl-(1-->2)-beta-D-galactopyranoside (5), 5-hydroxyecdysterone (6), and 20-hydroxyecdysone (7). The pennogenin derivative 3 showed strong cardiotoxic effects in an in vitro cellular model system, whereas the respective furostanol derivative 2 was inactive.

Major constituents and cytotoxic effects of Ajuga chamaecistus ssp. tomentella.

The n-butanolic fraction of a methanolic extract (80%) from aerial parts of Ajuga chamaecistus ssp. tomentella was analysed using different chromatographic methods. Column (CC) and high-performance liquid chromatography (HPLC) were used for isolation and purification. 13C, H NMR, H-H COSY, HSQC, HMBC, and ESI-MS were employed for identification of the compounds isolated from this fraction. The structures of the compounds were determined to be cis-melilotoside (1), trans-melilotoside (2), lavandulifolioside (3), 20-hydroxyecdysone (4), leonoside B (5), martynoside (6), ajugalactone (7), makisterone A (8), and 24-dehydroprecyasterone (9). This is the first report on the presence of cis- and trans-melilotoside in Ajuga species. Cytotoxic evaluation of the n-butanolic fraction, cis- and trans-melilotoside against cancer (T47D, HT-29, and Caco-2) and normal (NIH 3T3) cell lines by the mitochondrial tetrazolium test (MTT) showed no cytotoxic effects up to 400 microg/mL. The results of this study suggest that melilotoside, phenylethyl glycosides, and phytoecdysteroids are the main constituents of the n-butanolic fraction of Ajuga chamaecistus ssp. tomentella.

New phenolic compounds of Acmella ciliata.

The phytochemical analysis of a butanolic fraction of Acmella ciliata Kunth. afforded a total of 15 hydrophilic compounds. Seven flavonol 3-O-glycosides were isolated, including two new natural products, quercetin-3-O-(3-O-acetyl-beta-D-glucuronopyranoside) and quercetin-3-O-(2- O-acetyl-alpha-L-rhamnopyranosyl-(1--> 6)-beta-D-glucopyranoside). Furthermore, a variety of caffeoylquinic acid derivatives could be identified using ESI-MS and NMR-spectroscopy.

New cucurbitane-type triterpenoids from Bryonia aspera.

Phytochemical investigation of the chloroform extract of BRYONIA ASPERA roots resulted in the isolation and structure elucidation of two new cucurbitacins (1, 2) together with eight known cucurbitane derivatives (6-13), the pentacyclic triterpene bryonolic acid (5) and two hydroxybenzoic acid amides (3, 4). Their structures were elucidated by spectroscopic analysis, including 2D NMR techniques.

Extracts of Cynomorium songaricum protect SK-N-SH human neuroblastoma cells against staurosporine-induced apoptosis potentially through their radical scavenging activity.

In traditional Chinese medicine a number of herbs are used to alleviate the symptoms of aging, among them the stems of Cynomorium songaricum, Cynomoriaceae. This study evaluated the protective effect of different extracts of C. songaricum on staurosporine-induced apoptotic cell death in SK-N-SH neuroblastoma cells. Staurosporine (100 nm) reduced cell viability to about 55%. The ethyl acetate fraction of C. songaricum significantly attenuated staurosporine-induced cell death at concentrations of 100 and 10 microg/mL. On the other hand, the dichloromethane as well as water fractions showed no protective effects. In order to further analyse the protective mode of action, the superoxide anion scavenging activity of two extracts was evaluated in a xanthine/xanthine oxidase system. In this system, the EtOAc extract showed a good scavenging activity (IC(50) value 2.9 microg/mL) without inhibition of xanthine oxidase. In conclusion, the results prove the neuroprotective activity of C. songaricum extracts in vitro, thus supporting its traditional use.

A new ursane-type triterpene oxoglucopyranoside from Crossopteryx febrifuga.

A new saponin, 3-O-ß-d-3-oxo-glucopyranosyl-ursa-12,20(30)-diene-27,28-dioic acid (1), was isolated from the methanol extract of stem bark of Crossopteryx febrifuga together with the known 3ß-d-glucopyranosyl-ursa-12,20(30)-diene-27,28-dioic acid (2), shanzhiside methyl ester (3), shanzhiside (4), ß-sitosterol (5), ß-sitosterol-3-O-ß-d-glucopyranoside (6), ursa-12,20(30)-diene-27,28-dioic acid (7), hederagenin (8), and oleanolic acid (9). The structures were established by comprehensive interpretation of their spectral data 1D- (1H and 13C), 2D-NMR (1H-1H COSY, HMQC, HMBC), spectroscopic, and electrospray ionisation time-of-flight mass spectrometry analysis. The isolated compounds and extracts were screened for their antibacterial properties. Although the EtOAc and n-BuOH extracts exhibited considerable antibacterial activity against Pseudomonas aeruginosa with minimum inhibitory concentration (MIC) value of 32 µg/mL, compounds 2 and 8 showed moderate activity against Enterococcus faecalis with MIC values of 256 and 128 µg/mL, respectively. The new compound (1) exhibited a moderate antibacterial activity against Staphylococcus aureus with an MIC value of 512 µg/mL.

Flavonol Glycosides and Cytotoxic Steroidal Saponins from Furcraea tuberosa (Agavaceae).

Phytochemical analysis of the mature fruits of Furcraea tuberosa (Agavaceae) resulted in the isolation of a new bisdesmosidic spirostanol saponin (1), along with eight known steroidal glycosides (2-9), one known phenolic carboxylic acid ester (10) and three known flavonol glycosides (11-13). The structures of these compounds were assigned using a combination of ID and 2D NMR techniques including ¹H, ¹³C, COSY, TOCSY, HSQC and HMBC NMR, and confirmed by mass spectrometry. Thus the new saponin was elucidated as (25R)-6α-(ß-D-glucopyranosyloxy)-5α-spirostane-3ß-Ο-[(6-Ο-hexadecanoyl)-ß-D- glucopyranoside]. The literature survey revealed that most of the steroidal saponins isolated have shown potent cytotoxic effects against various human cancer cell lines and the results are herein reviewed.

Ipangulines and minalobines, chemotaxonomic markers of the infrageneric Ipomoea taxon subgenus Quamoclit, section Mina.

A comprehensive GC-MS analysis of 8 Ipomoea species belonging to the subgenus Quamoclit, section Mina revealed that the members of this taxon form combinations of two necine bases with rare necic acids resulting in unique pyrrolizidine alkaloids. The occurrence and diversity of these metabolites show remarkable variations: Some species, especially Ipomoea hederifolia and Ipomoea lobata, are able to synthesize a large number of alkaloids whereas others, especially Ipomoea coccinea and Ipomoea quamoclit, are poor synthesizers with only a few compounds. However, these metabolites are apparently chemotaxonomic markers of this infrageneric taxon in general. They represent either esters of (-)-platynecine (altogether 48 ipangulines and 4 further esters including results of a previous study) or esters of (-)-trachelanthamidine, an additional novel structural type called minalobines (altogether 21 alkaloids). Both types are characterized by section-specific rare necic acids, e.g., ipangulinic/isoipangulinic acid, phenylacetic acid. The alkaloids of Ipomoea cholulensis, I. coccinea, I. hederifolia, Ipomoea neei, and Ipomoea quamoclit were mono and diesters of platynecine. Minalobines turned out to be metabolites of I. lobata (Cerv.) Thell. (syn.: Mina lobata Cerv.) lacking ipangulines. The major alkaloid of this species, minalobine R, has been isolated and identified as 9-O-(threo-2-hydroxy-2-methyl-3-phenylacetoxy-butyryl)-(-)-trachelanthamidine on the basis of spectral data. Apparently only two of the species included in this study, Ipomoea cristulata and Ipomoea sloteri, are able to synthesize both, ipangulines as well as minalobines. Minalobine O could be isolated as a major alkaloid of I. cristulata, its structure has been established as 9-O-(erythro-2-hydroxy-2-methyl-3-tigloyloxy-butyryl)-(-)-trachelanthamidine on the basis of spectral data.

Calystegines as chemotaxonomic markers in the Convolvulaceae.

An extended GC-MS study of 129 convolvulaceous species belonging to 29 genera (all 12 tribes) including the results of a previous survey (65 spp.) revealed the occurrence of one to six polyhydroxy alkaloids of the nortropane type (calystegines) in 62 species belonging to 22 genera of all tribes except the unique parasitic Cuscuteae. The large genus Ipomoea turned out to comprise calystegine-positive species in at least eight out of ten sections checked. The number of the calystegines used as reference compounds has been increased from seven (previous survey) to 11 (present study). Furthermore, the results concerning these additional four alkaloids could also be completed for all species of the previous survey. The plant material (epigeal vegetative parts and/or roots, flowers, fruits/seeds) was obtained from collections in the wild from a wide range of tropical, subtropical, and temperate locations of all continents as well as from cultivation in the greenhouse. All plant organs turned out to be potential locations for the occurrence of these metabolites though they are detectable often only in certain organs of a given species. Three genera (Cuscuta, Operculina, Polymeria) might have lost the ability to synthesize these plesiomorphic characters in the course of the evolution since the examination of several different organs and/or provenances of five species each failed to show calystegines as constituents. Nevertheless, the present data clearly demonstrate that the occurrence of calystegines is an almost consistent trait in the Convolvulaceae in principle, from basal to most advanced tribes.

Chemotaxonomy of the pantropical genus Merremia (Convolvulaceae) based on the distribution of tropane alkaloids.

The occurrence and distribution of tropane and biogenetically related pyrrolidine alkaloids in 18 Merremia species of paleo-, neo-, and pantropical occurrence have been studied. The extensive GC-MS study included members of almost all sections of the genus and has been carried out with epigeal vegetative parts as well as with roots. It comprises altogether 74 tropanes and 13 pyrrolidines including nicotine. Along with datumetine known already from a solanaceous species, the study led to the isolation (from M. dissecta and M. guerichii, respectively) and structure elucidation (spectral data) of four novel 3alpha-acyloxytropanes, merresectines A-D: 3alpha-(4-methoxybenzoyloxy)nortropane (A), 3alpha-kurameroyloxytropane (B), 3alpha-nervogenoyloxytropane (C), 3alpha-[4-(beta-D-glucopyranosyloxy)-3-methoxy-5-(3-methyl-2-butenyl)benzoyloxy]tropane (beta-d-glucoside of D). Moreover, the novel 3alpha,6beta-di-(4-methoxybenzoyloxy)tropane (merredissine) has been isolated from M. dissecta and structurally elucidated. In addition the structures of datumetine and merresectine A could be confirmed by synthesis. Spectral data for two known 3alpha-acyloxytropanes (merresectine E beta-D-glucoside, 4'-dihydroconsabatine) and one known 3beta-acyloxytropane (concneorine) are documented for the first time. The structures of three further merresectines (F-H) have been determined by mass spectrometry. Furthermore, the linkage (2',3- and 2',4-, respectively) of two position isomer N-methylpyrrolidinylhygrines was proven by synthesis. The results of the study contribute to the solution of infrageneric taxonomic problems. Whereas all species yield pyrrolidine alkaloids without suitably differentiating results the diverging occurrence of tropane alkaloids leads to three groups of sections: (1) taxa free of tropanes, (2) taxa with simple tropanes, and (3) taxa with merresectines in addition to simple tropanes.

Naghibione; A Novel Sesquiterpenoid with Antiplasmodial Effect from Dorema hyrcanum Koso-Pol. Root, a Plant Used in Traditional Medicine.

Some Dorema species are used in Persian traditional medicine. In the present study the total extract from the roots of Dorema hyrcanum Koso-Pol. was investigated for its in-vitro (pLDH assay) and in-vivo (Peters' 4-days suppressive test) antiplasmodial effects and assessed for cytotoxicity against the normal cell line MDBK (MTT test). The IC50 values for a chloroquine- sensitive (3D7) and a chloroquine- resistant (K1) strain of Plasmodium falciparum were 28.64 and 9.79 µg/mL, respectively. The inhibition percentage of the rodent parasite, Plasmodium berghei, on day 4 in mice was 77.9% and IC50 value on Madin-Darby bovine kidney cells (MDBK cells) was 59.84 µg/mL. The total extract was subjected to a bioassay-guided fractionation protocol based on the in-vivo model which resulted in the isolation of an acetophenon (compound 1), one new sesquiterpenoid; naghibione (compound 2) and two known sesquiterpenoid derivatives (compounds 3, 4). Their structures were elucidated by spectroscopic analysis, including 1D and 2D NMR experiments and ESI-MS. All compounds were evaluated for in-vivo antiplasmodial effect and the results revealed that naghibione showed good suppression activity, inhibiting 68.1 % of the parasite growth.

Ipobscurines C and D: macrolactam-type indole alkaloids from the seeds of Ipomoea obscura.

Separation of the methanolic seed extract of Ipomoea obscura afforded five indole alkaloids, three of them (ipobscurines B-D) being new natural products of a unique structural type characterized as serotonin hydroxycinnamic acid amide-type conjugates with a second phenylpropanoid moiety forming an ether with the 5-OH position of the indole nucleus. Due to an oxidative phenolic coupling between the two phenylpropanoid moieties of the supposed precursor ipobscurine B two 21-membered macrolactams with a phenol ether partial structure are formed: the trans-cis isomers ipobscurines C and D. Their structures were established on the basis of spectral data. Moreover, total synthesis of the racemic erythro- and threo-ipobscurine B 4',4"-dimethyl ethers and the comparison with the corresponding derivative of natural (-)-ipobscurine B proved an erythro configuration of the latter.

Antiplasmodial activity of sesquilignans and sesquineolignans from Bonamia spectabilis.

Phytochemical re-investigation of the aerial parts of Bonamia spectabilis (Convolvulaceae) led to the isolation of four minor tetrahydrofuran-type sesquilignans (bonaspectins E-H) together with the known neolignan virolongin A and the known lignan rel-(7S,8R,7'R,8'R)-3,3',4,4',5,5'-hexamethoxylignan. Their structures were established on the basis of spectral data. These six compounds as well as further seven lignanoids from B. spectabilis, characterised previously, were tested for their antiplasmodial activity against a chloroquine-sensitive strain (PoW) and a chloroquine-resistant clone (Dd2) of Plasmodium falciparum. Bonaspectin C 4"-O-glucoside, its aglycone, and bonaspectin D 4"-O-glucoside revealed the highest antiplasmodial activities (IC50 values: 1.3, 2.0, 6.5 microM [PoW]; 1.7, 4.6, 3.7 microM [Dd2], respectively).

Sipaucins A-C, sesquiterpenoids from Siparuna pauciflora.

The phytochemical investigation of the leaves of Siparuna pauciflora yielded three novel sesquiterpenoids: the germacrane sipaucin A, the elemane sipaucin B and sipaucin C, comprising a new type of carbon skeleton. In addition, four known aporphine alkaloids-nor-boldine, boldine, laurotetanine, and N-methyl-laurotetanine-were obtained. The evaluation of the antiplasmodial activity of the isolated compounds against two strains of Plasmodium falciparum (PoW, Dd2) showed a moderate activity of nor-boldine.

Cornutins C-L, neo-clerodane-type diterpenoids from Cornutia grandifolia var. intermedia.

Ten novel neo-clerodane diterpenoids, named cornutins C-L, have been isolated from the leaves of Cornutia grandifolia var. intermedia. Their structures have been elucidated by detailed spectroscopic analysis. In addition, the in vitro antiplasmodial activity of four isolated compounds (cornutin C-F) has been evaluated, revealing only a marginal activity.

Antiplasmodial activity of naphthoquinones and one anthraquinone from Stereospermum kunthianum.

A lipophilic extract of the root bark of Stereospermum kunthianum revealed antiplasmodial activity in vitro. Bioassay-guided fractionation led to the isolation of four novel naphthoquinones (sterekunthals A and B, pyranokunthones A and B) and one novel anthraquinone (anthrakunthone) together with the known naphthoquinone pinnatal. The structures of the novel compounds were determined by comprehensive analyses of their 1D and 2D NMR data. The antiplasmodial activities and toxicity against the endothelial cell line ECV-304 of the isolated compounds have been assessed.