Protective effect of Chresta martii extract against indomethacin-induced gastric lesions in mice.

Chresta martii (Asteraceae) is a plant found in the Xingó region (semi-arid area) in Northeastearn Brazil, and is recognized by the local population as a traditional herb used to treat gastric diseases. This is the first report of the chemical composition, acute toxicity, and gastroprotective effect in mice of the hydroalcoholic extract (HAE) from the aerial parts (leaves and flowers) of Chresta martii. Animals received HAE doses from 10 to 2000 mg/kg, i.p. or 50 to 3000 mg/kg, p.o.) and were observed over 48 h for toxicity signs and mortality; sub-chronic toxicity was evaluated through 14 days treatment with once-daily HAE doses (400 mg/kg, p.o.). The gastroprotective effect of HAE was demonstrated on the indomethacin-induced gastric ulcer model after the administration of extracts. Data comparison of ulcer index averages between saline and HAE (100 or 400 mg/kg, p.o.) groups showed significant (P < 0.01) inhibition (71.73 and 76.72 %, respectively) of indomethacin-induced gastric lesions. Histological analyses showed significant (P < 0.05) inhibition of leukocyte migration in HAE-treated groups. A fingerprint of the HAE obtained by HPLC/UV/MS analysis showed major peaks characteristic of sesquiterpene lactones. Compound 1 was isolated and elucidated as a new natural product. Its capacity to prevent leukocyte chemotaxis was demonstrated in vitro, corroborating the pharmacological effects observed for C. martii HAE.

Antioxidant potential and radical-scavenging effects of flavonoids from the leaves of Psidium cattleianum grown in French Polynesia.

Psidium cattleianum J. Sabine (Myrtaceae) is a traditional medicinal plant in French Polynesia. The leaves and roots possess many medicinal properties. These effects may be correlated with the presence of antioxidant compounds. Seven flavonoids along with a benzoic acid were isolated from the leaves of P. cattleianum. The compounds indicated strong antioxidant and radical-scavenging activities in ALP, DPPH(·), ABTS(·-) and ORAC assays. This study demonstrates that the leaves of P. cattleianum possess main compounds with interesting antioxidant and radical-scavenging activities, as clarified by four biological assays. Our findings may justify the use of these leaves in the traditional medicine of French Polynesia. Among the total eight known compounds, reynoutrin and luteolin were isolated for the first time from the genus Psidium.

Screening medicinal plants for the detection of novel antimalarial products applying the inhibition of ß-hematin formation.

The identification of novel scaffolds for the development of effective and safe treatments to fight malaria is urgently needed. One of the main opportunities is the discovery of new molecules from natural origin. A simple, robust and cost-effective colorimetric assay based on the inhibition of ß-hematin has been adapted to routinely screen plant extracts with the ultimate goal to identify novel antimalarial ingredients. The development of this assay has included a careful optimization of all critical experimental parameters. The ß-hematin assay can be completed in less than one working day, requiring a 96-well UV-vis plate reader and low-cost commercially available reagents using a standard operating protocol. It can be used on its own or in combination with the well-known Plasmodium growth inhibition assay and has the obvious merit to be informative at the early stage of drug discovery regarding the mechanism of action of the actives. A total of 40 diverse natural products and 219 plants extracts were tested. Good correlations in respect with specificity (pure compounds 85%, extracts 93%) and positive predictive value (pure compounds 72%, extracts 50%) were obtained in comparison with Plasmodium growth inhibition assay that was used as the reference assay.

Xanthones from Gentianella amarella ssp. acuta with acetylcholinesterase and monoamine oxidase inhibitory activities.

Two new xanthone glycosides, corymbiferin 3-O-beta-D-glucopyranoside (1) and swertiabisxanthone-I 8'-O-beta- d-glucopyranoside (2), were isolated from Gentianella amarella ssp. acuta, along with eight known xanthones: triptexanthoside C, veratriloside, corymbiferin 1-O-glucoside, swertianolin, norswertianolin, swertiabisxanthone-I, bellidin, and bellidifolin, four of them identified for the first time in G. amarella ssp. acuta. The isolation was conducted mainly by centrifugal partition chromatography, and the structures of the isolated compounds were established on the basis of spectrometric data including 2D NMR and mass spectrometry. Xanthones were weakly active against acetylcholinesterase (AChE), except triptexanthoside C, which inhibited AChE with an IC(50) of 13.8 +/- 1.6 microM. Some compounds were active against monoamine oxidases (MAO): bellidin and bellidifolin showed interesting inhibitory activity of MAO A, while swertianolin, the 8-O-glucopyranoside form of bellidifolin, gave 93.6% inhibition of MAO B activity at 10(-5) M.

3-Farnesyl-2-hydroxybenzoic acid is a new anti-Helicobacter pylori compound from Piper multiplinervium.

A new prenylated salicylic acid derivative, 3-farnesyl-2-hydroxy benzoic acid (1), was isolated from the leaves of Piper multiplinervium C. DC. (Piperaceae). It showed anti-Helicobacter pylori activity (MIC 37.5 microg/ml) and antimicrobial activity at MICs between 2.5 and 5 microg/ml against Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Mycobacterium smegmatis, Pseudomonas aeruginosa and Candida albicans. Its structure was elucidated by means of MS, 1H and 13C NMR. The ethnomedical claim of Piper multiplinervium to treat stomach aches by the Kuna Indians of Panama may be justified by anti-Helicobacter pylori activity of its MeOH extract.

Developments in the application of counter-current chromatography to plant analysis.

Counter-current chromatography is a very versatile separation technique which does not require a solid stationary phase. It relies simply on the partition of a sample between the two phases of an immiscible solvent system. Some of the more recent applications of the method to the separation of plant-derived natural products are described here. Crude plant extracts and semi-pure fractions can be chromatographed, with sample loads ranging from milligrams to grams. Aqueous and non-aqueous solvent systems are used and the separation of compounds with a wide range of polarities is possible. The technique is complementary to other chromatographic methods and is compatible with gradient systems. The possibilities for solvent selection are almost limitless but some guidelines for the choice of successful systems are presented.

On-line identification of the bioactive compounds from Blumea gariepina by HPLC-UV-MS and HPLC-UV-NMR, combined with HPLC-micro-fractionation.

The dichloromethane extract of the aerial parts of Blumea gariepina (Asteraceae) was shown to be active against the phytopathogenic fungus Cladosporium cucumerinum and to inhibit acetylcholinesterase. In order rapidly to identify the active principles, the crude extract was analysed by on-flow HPLC-1H-NMR. HPLC-micro-fractionation was performed and all peaks collected were submitted to assays against C. cucumerinum and acetylcholinesterase. By this means, the biological activities could be efficiently associated with selected HPLC peaks. Complementary on-line structural data for all peaks of interest in the crude extract were obtained from HPLC-MS and from HPLC-UV with post-column addition of UV shift reagents. This chemical screening strategy with integrated bioassays permitted the on-line identification of a number of constituents and gave useful information for an efficient isolation procedure.

HPLC-UV/PAD and HPLC-MS(n) analyses of leaf and root extracts of Vismia guineensis and isolation and identification of two new bianthrones.

In order to evaluate the possible use of the leaves instead of the roots of Vismia guineensis as a new source for the traditional use of this drug, the chemical composition of both organs were compared by HPLC-UV/PAD and HPLC-MS analyses. The leaves are analysed here for the first time. The results show the presence of five major classes of secondary metabolites having specific chromophores: anthraquinones, vismiones, flavonoids, xanthones and benzophenones. The molecular weights and characteristic fragments, compared with previous EI or HPLC-MS literature data, allowed the partial identification of the major peaks in the chromatograms. Six additional isomeric bianthrones and one anthraquinone were detected in the dichloromethane extract of the roots after long storage in solution; the targeted isolation of the bianthrones was performed and enabled the identification of two original C-geranyl derivatives. The chemical compositions of the extracts demonstrated that only a minority of the constituents is shared by both organs. Thus, in order to establish a definitive phytoequivalence, additional pharmacological investigations are required.

Traditional medicine in north Côte-d'Ivoire: screening of 50 medicinal plants for antibacterial activity.

Sixty-seven crude ethanol extracts from 50 plants (31 families), which are used in North Côte-d'Ivoire as traditional remedies for bacterial diseases, were screened for in vitro activity against Gram negative (Escherichia coli and Pseudomonas aeruginosa) and Gram positive (Staphylococcus aureus, Enterococcus faecalis, Streptococcus pyogenes and Bacillus subtilis) bacteria. Thirty-one extracts showed antibacterial activity only on Gram positive bacteria. Of these, 10 extracts from 10 plant species had a promising level of activity against bacteria including strains resistant to antibiotics such as aminosides, penicillin M, macrolides, lincosamide and streptrogramin B. The most active was Erythrina senegalensis DC (Fabaceae) followed by Bobgunnia madagascariensis (Desv.) J.H. Kirkbr. & Wiersema (Caesalpinaceae), Waltheria lanceolata R. Br. ex Mast. (Sterculiaceae), Uapaca togoensis Pax. (Euphorbiaceae), Ximenia americana L. (Olacaceae), Khaya senegalensis (Ders.) A. Juss. (Meliaceae), Lannea acida A. Rich. (Anacardiaceae), Cissus populnea Guill. & Perr. (Vitaceae), Keetia hispida (Benth.) Bridson (Rubiaceae) and Ficus thonningii (Miq.) A. Rich. (Moraceae). This is the first report of the antibacterial potency of these 10 plant species on a range of bacteria. The results provided evidence that some of the studied plants might indeed be potential sources of new antibacterial agents, also against some antibiotic-resistant strains.

Heliotropamide, a novel oxopyrrolidine-3-carboxamide from Heliotropium ovalifolium.

Heliotropamide (1), a new alkaloid with a novel oxopyrrolidine-3-carboxamide central moiety, has been isolated as the major product of the dicholoromethane extract of Heliotropium ovalifolium aerial parts. Its structure was elucidated by spectrometric methods including ESI-HR, EI, D/CI mass spectrometry, (1)H, (13)C, and 2D NMR experiments, and chemical derivatization. Neither heliotropamide nor its acetylated derivative (1a) showed any antifungal activity against Cladosporium cucumerinum and Candida albicans, antibacterial activity against Bacillus subtilis, radical-scavenging properties in the DPPH test, or inhibitory potential toward acetylcholinesterase.

Structural investigations of isomeric oxidised forms of hyperforin by HPLC-NMR and HPLC-MSn.

The prenylated phloroglucinol hyperforin, thought to be an essential component for the anti-depressant activity of St. John's Wort (Hypericum perforatum), is unstable. The facile oxidative degradation of hyperforin poses serious problems for standardisation, and may also dramatically affect the pharmacological activity of the extracts. Hyperforin was dissolved in hexane and stored at room temperature for 3 days and yielded various closely related degradation products which, although difficult to isolate on the preparative scale, have been analysed by on-flow and stop-flow HPLC-NMR and HPLC-MS/MS. From on-line spectroscopic data, and with the aid of complementary in-mixture standard NMR two-dimensional correlation experiments, the different oxidised forms of hyperforin were found to be phloroglucinol derivatives in which a hydroxy-dihydrofuran ring is formed involving the enol OH at C-7 or C-9 (tautomeric form) and the prenyl chain at C-8 of the core nucleus of hyperforin. The strategy followed for the on-line identification of these constituents is discussed.

In vitro cytotoxicity of 11 Panamanian plants.

Thirty-five crude extracts from 11 Panamanian plants, distributed in 10 genera and five families, were evaluated for their in vitro cytotoxicity. Four extracts exhibited an inhibition of cellular growth at IC(50) values lower than 25 microg/ml which was considered a significant activity.

[History of a plant: the example of Echinacea]. / Geschichte einer Pflanze am Beispiel von Echinacea.

In comparison with other medicinal plants, the history of use of Echinacea is relatively short. The plant originates from North America and was employed by the indigenous Indians. The first archaeological evidence dates from the 18th century. Included in the name Echinacea or purple coneflower are several species of the Asteraceae family: Echinacea purpurea (L.) Moench, Echinacea angustifolia DC. and Echinacea pallida (Nutt.) Nutt. Information about the use of the plant from traditional healers ranges from external application for wounds, burns and insect bites to the chewing of roots for toothache and throat infections, and internal application for pain, coughs, stomach cramps and snake bites. The interest of white settlers was also drawn to this medicinal plant. The first Echinacea preparation, known as Meyers Blood Purifier, arrived on the market around 1880, with rheumatism, neuralgia and rattlesnake bites as indications. At the beginning of the 20th century, Echinacea was the most frequently used plant preparation in the USA. Commercial cultivation was started in Germany around 1939. The introduction and cultivation of Echinacea in Switzerland by A. Vogel was around 1950. Chemists and pharmacologists became interested in Echinacea and many constituents are now known, such as polysaccharides, echinacoside, cichoric acid, ketoalkenes and alkylamides. The extracts exhibit immunostimulant properties and are mainly used in the prophylaxis and therapy of colds, flu and septic complaints. Although there are over 400 publications concerning the plant and dozens of preparations of Echinacea n the market, the true identity of the active principles still remains open.

Triterpenoid saponins from the roots of Silene cucubalus.

A new triterpenoid saponin was isolated from the roots of Silene cucubalus and its structure was determined on the basis of one- and two-dimensional NMR spectroscopy as gypsogenin 3-O-beta-xylopyranosyl-(1-->3)-[beta-galactopyranosyl-(1-->2)]-beta-glucuronopyranoside. A known saponin, quillaic acid 3-O-beta-xylopyranosyl-(1-->3)-[beta-galactopyranosyl-(1-->2)]-beta-glucuronopyranoside, was also isolated.

Antifungal, antioxidant and larvicidal activities of compounds isolated from the heartwood of Mansonia gagei.

Eleven compounds isolated from the heartwood of Mansonia gagei were tested for their antifungal activities against Cladosporium cucumerinum and Candida albicans, as well as for their larvicidal activities against Aedes aegypti and radical scavenging properties in a DPPH assay. Mansonone C (4) was found to be the most interesting compound with antifungal activities against Cladosporium cucumerinum and Candida albicans as well as for its larvicidal properties against Aedes aegypti. Mansonone E (5) was active against Cladosporium cucumerinum and Candida albicans. Two coumarin derivatives, mansorin A (1) and mansorin B (2) were also found to be active against Cladosporium cucumerinum, while mansonone N (9) was the only isolated product to show radical scavenging properties.

Detection of aristolochic acid in Chinese phytomedicines and dietary supplements used as slimming regimens.

Over the last 10 years, numerous cases of intoxications, leading for the most part to end-stage renal failure, have been reported after consumption of slimming regimens made of Chinese herbal preparations. These intoxications were associated with species of the Aristolochia genus, such as Aristolochia fangchi (Aristolochiaceae), known to contain very nephrotoxic and carcinogenic metabolites named aristolochic acids. Several commercial dietary supplements, teas and phytomedicines used as slimming regimens were analysed for their aristolochic acid I content. A preliminary detection of this toxic compound was made by thin-layer chromatography. The presence of aristolochic acid I in these preparations was confirmed by a HPLC/UV-DAD/MS analysis. A quantitative determination of aristolochic acid I was also achieved in the incriminated preparations using both UV and MS detection. Out of 42 analysed preparations, four were found to contain aristolochic acid I and two were suspected to contain aristolochic acid derivatives. Immediate removal of these products from the Swiss market was called for.

On-line identification of the antifungal constituents of Erythrina vogelii by liquid chromatography with tandem mass spectrometry, ultraviolet absorbance detection and nuclear magnetic resonance spectrometry combined with liquid chromatographic micro-fractionation.

In our continuing search for new antifungal agents of plant origin, the investigation of Erythrina vogelii Hook. f. (Leguminosae), a plant used in the traditional medicine of Ivory Coast to treat various infectious ailments, was undertaken. In order to rapidly identify the active principles, the crude extract was analysed by low-flow LC-1H nuclear magnetic resonance spectrometry (NMR) which gave a sensitive detection of all the main peaks. LC microfractionation was performed just after LC-NMR detection and all peaks collected were submitted to antifungal bioautography assays against Cladosporium cucumerinum. By this means, the antifungal activity could be efficiently linked to three of the LC peaks. In order to obtain complementary on-line structural information for all peaks of interest, high-resolution LC-MS-MS together with LC-UV with post-column addition of UV shifts reagents was undertaken on the crude extract. This chemical screening strategy with integrated antifungal bioassays has permitted the on-line identification of numerous constituents and has given useful information for an efficient peak-guided isolation procedure.

Isolation and structure elucidation of an isoflavone and a sesterterpenoic acid from Henriettella fascicularis.

A new isoflavone, 4',5,7-trihydroxy-6,8-dimethylisoflavone (1), and a new sesterterpenoic acid (2), together with five known compounds, lichexanthone (3), (-)-pinoresinol (4), betulinic acid, palmitic acid, and beta-sitosterol, were isolated from a dichloromethane extract of the branches of Henriettella fascicularis. Their structures were established by extensive spectroscopic methods. An attempt to determine the absolute stereochemistry of (2E,6S)-6-[(1R,5Z,3aS,9R,10Z,12aR)-1,2,3,3a,4,7,8,9,12,12a-decahydro-9-hydroxy-3a,6,10-trimethylcyclopentanocycloundecen-1-yl]-2-methylhept-2-enoic acid (2) was performed by single-crystal X-ray analysis, using Cu Kalpha radiation. Compound 1 showed significant competitive binding to estrogen receptor beta and moderate antiestrogenic activity with cultured Ishikawa cells.

Evaluation of the antimicrobial potential of medicinal plants from the Ivory Coast.

A total of 148 crude ethanol extracts from 115 plant species were tested in vitro against Gram-negative strains (Escherichia coli, Pseudomonas aeruginosa) and the Gram-positive Staphylococcus aureus and Enterococcus faecalis. Moreover, they were submitted to antifungal assays against Candida albicans and Cladosporium cucumerinum, a human and a plant pathogenic microorganism, respectively, known to be good indicators of antifungal activity. No activity was detected against the Gram-negative bacteria, while 14.8% and 10.8% of the extracts showed Gram-positive bactericidal or bacteriostatic effects on S. aureus and E. faecalis, respectively. An antifungal activity was observed with 15 extracts (10.1%). Two species were particularly active against the fungi: Dioscorea minutiflora and Erythrina vogelii. The young tubers of D. minutiflora contain metabolites with a specific effect on fungi and were not active against the bacteria. On the other hand, E. vogelii was highly effective against the Gram-positive bacteria and the fungi.

A rapid TLC bioautographic method for the detection of acetylcholinesterase and butyrylcholinesterase inhibitors in plants.

A simple and rapid bioautographic enzyme assay on TLC plates has been developed for the screening of acetylcholinesterase and butyrylcholinesterase inhibition by plant extracts. Enzyme activity was detected by the conversion of naphthyl acetate into naphthol and the formation of the corresponding purple-coloured diazonium dye with Fast Blue B salt. Inhibitors of cholinesterases produced white spots on the dye-coloured background of the TLC plates. The alkaloids galanthamine and physostigmine, which are known inhibitors of acetylcholinesterase, were used to determine the sensitivity of the assay. Various plant extracts were tested using the bioassay.