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Phytochemical investigation of the dichloromethane extract of the leaves of Peltophorum pterocarpum, a tropical ornamental tree, led to the isolation of twelve compounds (1-12). One new derivative of peltogynoid ophioglonin (1) and a new 2-phenoxychromone (2) with its 3'-O-β-D-glucoside derivative (3) are described here for the first time. In addition, nine flavonoid derivatives, including peltogynoid ophioglonin (4), were isolated for the first time from this plant. The structures were determined by spectroscopic and chemical methods. Evaluation of the estrogenic activities of 1, 2, and 4 using different model cell systems revealed that 4 was estrogenic and that 2 was largely inactive. Interestingly, 1 was unable to stimulate the proliferation of breast and endometrial cancer cells but exhibited substantial estrogen receptor α-mediated activation of gene expression. This observation indicates that 1 can be further evaluated for its cancer chemopreventive potential.

TLC autographic assays revealed in the CH(2)Cl(2) extract of Tinospora crispa Miers (Menispermaceae) the presence of three compounds exhibiting antioxidant and radical scavenging properties towards beta-carotene and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical. They were isolated and identified as N-CIS-feruloyltyramine, N-trans-feruloyltyramine and secoisolariciresinol. When tested in dilution assays on the reduction of the DPPH radical, these 3 compounds proved to be more active than the synthetic antioxidant butylhydroxytoluene (BHT). Further investigation of the CH(2)Cl(2) extract led to the isolation of vanillin, syringin, the alkaloid N-formylnornuciferin and the diterpene derivatives borapetosides B and C. In addition, a LC/UV/MS analysis enabled the on-line identification of borapetoside F and N-formylannonain.

Rapid detection of biologically active natural products plays a strategic role in the phytochemical investigation of crude plant extracts. In order to perform an efficient screening of the extracts, both biological assays and HPLC analysis with various detection methods are used. Combined techniques such as HPLC coupled to UV photodiode array detection (LC/UV) and to mass spectrometry (LC/MS or LC/MS/MS) provide useful structural information on the metabolites on-line prior to isolation. The recent introduction of HPLC coupled to nuclear magnetic resonance (LC/NMR) represents a powerful complement to the LC/UV/MS screening. Various plants belonging to the Gentianaceae and Leguminosae families have been analysed by LC/UV, LC/MS, LC/MS/MS, and LC/NMR. The use of all these coupled techniques allows the structural determination of known plant constituents rapidly and with only a minute amount of plant material. With such an approach, the time-consuming isolation of common natural products is avoided and an efficient targeted isolation of compounds presenting interesting chemical or biological features can be performed.

A new method using direct on-line coupling between HPLC and UV-DAD/MS was developed for the rapid detection of aristolochic acid I in plant preparations. The use of both UV-DAD and MS detectors enables this method to be very selective. A ng range detection limit was determined for both UV and MS detections. A quantitative determination of aristolochic acid I in plant preparations was achieved using UV and MS detection. A thin layer chromatography assay was also developed for the preliminary detection of aristolochic acid I in complex mixtures.

The new phloroglucinol derivative 1 has been isolated from the light petroleum ether extract of the aerial parts of Hypericum calycinum. Its structure has been established by means of 1 H- and 13 C-NMR spectroscopy and by nOe, MHQC, and HMBC experiments on its monomethyl ether derivative 3. Compound 1 was fungicidal against Cladosporium cucumerinum in a TLC bioassay. In addition, this new phloroglucinol derivative was also found to exert an interesting antimalarial activity in an in vitro test system

A new method using direct on-line coupling between HPLC, MS and (1 )H-NMR was developed for the detection and identification of pyrrolizidine alkaloids (PAs) in crude extracts of Senecio species. The PAs present in the extracts were separated on a C-18 reversed-phase column with an alkaline acetonitrile-water gradient. Molecular weight information of each peak was obtained by LC/MS and specific fragments were recorded by complementary MS/MS experiments. In order to distinguish isomeric structures of PAs, complementary LC/ (1)H-NMR analyses were performed in both on-flow and stop-flow modes with alkaline acetonitrile-D (2)O and methanol-D (2)O as mobile phases. This approach led to the identification of the known PAs of S. vulgaris; retrorsine, seneciphylline, and senecionine. The method was also applied for the analysis of African Senecio species: S. mariettae and S. venosus. Retrorsine was identified as the main PA in both species. Detection of the PAs in small amounts was achieved by LC/MS. Higher amounts of extracts (mg) had to be injected to obtain good quality on-flow LC/ (1)H-NMR.

A new antifungal and radical scavenging 2-hydroxyflavanone, named mosloflavanone, was isolated from the dichloromethane extract of Mosla soochouensis together with the known mosloflavone and moslosooflavone. Structures were established by spectroscopic and chemical methods, as well as X-ray crystallography.

Seven coumarins were isolated from the aerial parts of Tordylium apulum; their structures were established by spectroscopic means. All compounds were tested in vitro for their cytotoxicity against two cell line systems. The antiproliferative effects for three of them were studied at the level of the cell cycle in asynchronous cells of the NSCLC-N6 line with a flow cytometry apparatus.

In the course of a study of medicinal plants from Mali, the root bark of Zanthoxylum zanthoxyloides Lam. (Rutaceae) was investigated. The root bark of this plant is used as a toothbrush by West African people. Phytochemical investigation of the MeOH extract of Zanthoxylum zanthoxyloides Lam. (Rutaceae) led to the isolation of different biologically active compounds. The separation of acetylcholinesterase inhibitors was performed by centrifugal partition chromatography (CPC). The fractions were monitored by direct TLC bioautographic assays. The bio-guided isolation led to the isolation of a new peroxide derivative. In addition, LC/UV/MS analysis performed on the crude MeOH extract allowed on-line identification of some known compounds. The structures of the isolated compounds were elucidated by classical spectroscopic methods including UV, NMR, MS and HR-MS.

Two new acylated secoiridoid glycosides were isolated from the aqueous acetone extract of the whole herb of Gentiana algida. The structures of these new products were established by spectral and chemical methods as 6'-(2,3-dihydroxybenzoyl)sweroside (1) and 6'-(2,3-dihydroxybenzoyl)swertiamarin (2), respectively.

Two anti-inflammatory principles were isolated from the methanol extract of the leaves of Erythrospermum monticolum (Flacourtiaceae). The isolation was based on a guided bioassay of the inhibitory activity on TPA-induced ear edema in mice. These compounds were identified as quercetin 3-O-xylosyl(1-->2) rhamnoside and quercetin 3-O-rhamnoside. In addition, their effects on a chronic topic inflammation model were evaluated.

A chemical and biological screening of 25 species of the Gentianaceae family has been undertaken. Both methanolic and dichloromethane extracts of Swertia calycina exhibited a strong antifungal activity against Cladosporium cucumerinum and Candida albicans. The compound responsible for this activity has been isolated and identified as 2-methoxy-1,4-naphthoquinone. It is the first naphthoquinone to be described in Gentianaceae species. LC-UV and LC-TSP-MS analysis of the crude extracts of Swertia calycina also allowed on-line identification of six known xanthones and secoiridoids.

The hydroalcoholic extract of Tinnevelli senna is widely used as a laxative phytomedicine. In order to improve the knowledge of the chemical composition of this extract, LC/MS and LC/MS(n) studies were performed, allowing the on-line identification of most of the known constituents, i. e., flavonoids, anthraquinones and the typical dianthronic sennosides. However, the identity of four compounds could not be ascertained on-line under the given LC/MS conditions. These substances were isolated and their structures elucidated as kaempferol, the naphthalene derivative tinnevellin 8-glucoside and two new carboxylated benzophenone glucosides.

Phytochemical investigation of the CH2Cl2 extract of Erythrina vogelii led to the isolation of five isoflavonoids. Three prenylated isoflavonoids are new natural compounds. The isolation of the antifungal compounds was monitored by inhibition of the growth of Cladosporium cucumerinum in a direct TLC bioautographic assay, The structures of these compounds were elucidated by spectroscopic techniques.

Cell cultures of Hypericum androsaemum contain an array of prenylated xanthone aglycones and their glucosides, when grown in modified 85 medium in the dark. Derivatives of 1,3,6,7-tetrahydroxyxanthone prevail over compounds with the 1,3,5,6-oxygenation pattern. 1,7-Dihydroxyxanthone was also isolated. Xanthone accumulation parallels cell growth, is repressed by light and strongly influenced by the culture medium used.

Xanthine oxidase is a key enzyme associated with the incidence of hyperuricemia-related disorders. Repeated chromatography of the enzyme inhibitory part of the water extract of the twigs and leaves of Brandisia hancei (Scrophulariaceae) gave a flavone luteolin, an iridoid glycoside mussaenoside, two beta-sitosterol glycosides daucosterol and beta-sitosterol gentiobioside, and five phenylethanoids arenarioside, brandioside, acteoside, 2'-O-acetylacteoside and isoacteoside. Luteolin and isoacteoside inhibited the xanthine oxidase (XO, EC 1.2.3.2) with the IC50 values at 7.83 and 45.48 microM, respectively. Isoacteoside was found to be the first phenylethanoid that decreased substantially the formation of uric acid by inhibiting competitively xanthine oxidase (Ki value: 10.08 microM). Furthermore, the study suggested that the caffeoylation of the 6'-hydroxyl group of the phenylethanoids was essential for the enzyme inhibitory action.

In addition to beta-sitosterol and alpha-amyrin detected in all the investigated species, the extract of the aerial parts of Artemisia giraldii var. giraldii gave stigmasterol, daucosterol, sesamine, luteolin, eupafolin, hispidulin, eupatilin, belamcanidin, pinitol, artemin, ridentin, and a new antifungal monoterpene (named santolinylol) while that of the aerial parts of A. mongolica afforded sesamine, eupafolin, eupatilin, matricarin, and a new germacranolide (3-oxo-11 alpha H-germacra-1(10)E,4Z-dien-12,6 alpha-olide), and that of the aerial parts of A. vestita yielded stigmasterol, daucosterol, umbelliferone, scopolin, scoparone, and isoscopoletin-O-glucoside. Pinitol, first reisolated from Artemisia genus, was shown to inhibit the growth of the human pathogenic fungi Candida albicans, Aspergillus flavus, A. niger, Geotrichun candidum, Trichophyton rubrum, and Epidermophyton floccosum. Umbelliferone was also active against Candida tropicalis, A. flavus, G. candidum, T. rubrum, and E. floccosum. The flavones hispidulin and belamcanidin were almost equally inhibitory to the growth of A. flavus, G. candidum, T. rubrum, and E. floccosum, and santolinylol to C. albicans, A. flavus, A. niger, G. candidum, T. rubrum, and E. floccosum. In addition, ridentin was active against the growth of the plant pathogenic fungus Cladosporium cucumerinum.

Species of the genus Epilobium (Onagraceae) have been investigated for their activity against 5 alpha-reductase and aromatase, two enzymes which are involved in the aetiology of benign prostatic hyperplasia (BPH). Activity-guided fractionation has led to the identification of two macrocyclic ellagitannins, oenothein A (1) and oenothein B (2), as the main constituents responsible for the inhibition of the two enzymes. Quantitation of oenothein B in 10 different species of Epilobium has shown that amounts of up to 14% in the crude plant extracts are possible.

Bioactivity-guided fractionation has led to the isolation of two larvicidal diterpenes, active against the yellow fever-transmitting mosquito Aedes aegypti, from a dichloromethane root extract of Melantheria albinervia (Asteraceae), a plant from Zimbabwe. These diterpenes were identified as ent-kaur-16-en-19-oic acid and 9(11),16-kauradien-19-oic acid. The diterpenes were also weakly active against Bacillus subtilis.

Four compounds including a flavone, an acetylenic lactone, a prenylated coumarin, and a 3-methyl ether flavone were isolated from the dichloromethane leaf extract of Baccharis pedunculata (Mill.) Cabr. (Asteraceae). The latter three compounds were identified to be responsible for the antifungal activity against some human pathogenic and phytopathogenic fungi. The most active compound, lachnophyllum lactone, an acetylenic lactone, showed a very high toxicity (LD50 2 micrograms/ml) against human keratinocytes.

The detection limits in two bioautographic assays have been determined for a series of antifungal compounds, including clinically used antimycotics, fungicidal agrochemicals, and various classes of secondary plant metabolites. Target organisms were the filamentous fungus Cladosporium cucumerinum and the yeast Candida albicans. For clinical agents and agrochemicals, the detection limits in the two assays reflected to a certain extent their known spectrum of activity. Most of the plant-derived compounds tested showed a positive response in both assays, but with detection limits varying by a factor up to tenfold. For screening purposes, it is thus advisable to use both tests, as some activities would otherwise go undetected. The MIC values of these substances were determined in order to verify a possible correlation with the detection limit in the bioautographic assays.

The naphthylisoquinoline alkaloids dioncophylline A (1) and 5'-O-demethyl-8-O-methyl-7-epi-dioncophylline A (2) represent a new structural type of molluscicidal compounds and the active principle of extracts of the tropical lianas Ancistrocladus abbreviates and Triphyophyllum peltatum. The activity of 1 was further improved by derivatization.