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Human-aided invasion of alien species across the world sometimes leads to economic, health or environmental burdens. During invasion process, species encounter new environments and partially escape some ecological constrains they faced in their native range, while they face new ones. The Asian tiger mosquitoAedes albopictusis one of the most iconic invasive species that was introduced in every inhabited continent over a short period of time due to international trade. It has also been shown to be infected by a prevalent and yet disregarded gregarine entomoparasiteAscogregarina taiwanensis. In this study, we aimed at deciphering the global dynamics ofAs. taiwanensisinfection in naturalAe. albopictuspopulations and we further explored factors shaping its distribution. We showed thatAe. albopictuspopulations are highly colonized by severalAs. taiwanesisgenotypes but recently introduced ones are escaping the parasite. We further performed experiments to explain such pattern. First, we hypothesized that founder effects (i.e.population establishment by a small number of individuals) may influence the parasite dynamics. This was confirmed since experimental increase in mosquitoes’ density improves the parasite horizontal transmission to larvae. Furthermore,Ae. albopictuslarvae do not exhibit density dependent prophylaxis to control the parasite meaning that infection is not mitigated when larval density increases. Secondly, we hypothesized that unparasitized mosquitoes were more prompt to found new populations through active flight dispersal. This was, however, unlikely since parasitized mosquitoes tend to be more active than their unparasitized relatives. Finally, we hypothesized that mosquito passive dispersal (i.e.often mediated by human-aided transportation of dried eggs) affects the parasite infectiveness. Our results support this hypothesis since parasite infection decreases over time when dry eggs are stored. This study highlights the importance of global trade on parasitism escape in one of the most invasive vector species on earth.

In the present work, chemical investigation of the aerial parts of Phlomis bovei de Noé an endemic species from Algeria, led to the isolation and identification of seven known compounds including five flavones glycosides: Chrysoeriol 7-O-(3’’-(E et Z)-p-coumaroyl)-β-glucoside (1), terniflorin (apigenin-7-O-(6’’-E-p-coumaroyl)glucoside) (3), apigenin-7-O-(6’’-(5’’’-methoxy-coumaryl) glucoside (4), apigenin 7-O-(3″-p-coumaryl)glucoside (5), hispidulin-7-O-glucuronide (6) and two cinnamic acid derivatives: p-coumaric acid methyl ester (E et Z) (2), chlorogenic acid (7). Compound 4 is described for the first time in the species bovei de Noé, the genus Phlomis and the Lamiaceae family. Structures elucidation was performed by comprehensive 1D and 2D NMR analyses, mass spectrometry and by comparison with literature data. Some pure compounds and extracts have been evaluated for their antioxidant activities through different methods: DPPH and ABTS assays as well as CUPRAC assay. Genotoxic and antigenotoxic activities of pure compounds were also evaluated in-vitro on Escherichia coli PQ37 cells by the SOS Chromotest.

Symbiosis established between actinorhizal plants and

International audience; Symbiosis established between actinorhizal plants and Frankia spp., which are nitrogen-fixing actinobacteria, promotes nodule organogenesis, the site of metabolic exchange. The present study aimed to identify amino acid markers involved in Frankia-Alnus interactions by comparing nodules and associated roots from field and greenhouse samples. Our results revealed a high level of citrulline in all samples, followed by arginine (Arg), aspartate (Asp), glutamate (Glu), γ-amino-n-butyric acid (GABA), and alanine (Ala). Interestingly, the field metabolome approach highlighted more contrasted amino acid patterns between nodules and roots compared with greenhouse samples. Indeed, 12 amino acids had a mean relative abundance significantly different between field nodule and root samples, against only four amino acids in greenhouse samples, underlining the importance of developing “ecometabolome” approaches. In order to monitor the effects on Frankia cells (respiration and nitrogen fixation activities) of amino acid with an abundance pattern evocative of a role in symbiosis, in-vitro assays were performed by supplementing them in nitrogen-free cultures. Amino acids had three types of effects: i) those used by Frankia as nitrogen source (Glu, Gln, Asp), ii) amino acids stimulating both nitrogen fixation and respiration (e.g., Cit, GABA, Ala, valine, Asn), and iii) amino acids triggering a toxic effect (Arg, histidine). In this paper, a N-metabolic model was proposed to discuss how the host plant and bacteria modulate amino acids contents in nodules, leading to a fine regulation sustaining high bacterial nitrogen fixation.

International audience; The Asian tiger mosquito Aedes albopictus is a major public health concern because of its invasive success and its ability to transmit pathogens. Given the low availability of treatments against mosquito-borne dis- eases, vector control remains the most suitable strat- egy. The methods used thus far are becoming less effective, but recent strategies have emerged from the study of mosquito-associated microorganisms. Although the role of the microbiota in insect biology does not require further proof, much remains to be deciphered in mosquitoes, especially the contribution of the microbiota to host nutrient metabolism. Mosqui- toes feed on plant nectar, composed of mostly fruc- tose. We used stable isotope probing to identify bacteria and fungi assimilating fructose within the gut of Ae. albopictus. Mosquitoes were fed a 13C-labelled fructose solution for 24 h. Differences in the active microbial community according to the sex of mosqui- toes were highlighted. The bacterium Lelliottia and the fungi Cladosporium and Aspergillus dominated the active microbiota in males, whereas the bacterium Ampullimonas and the yeast Cyberlindnera were the most active in females. This study is the first to investi- gate trophic interactions between Ae. albopictus and its microbiota, thus underscoring the importance of the microbial component in nectar feeding in mosquitoes.

Mosquitoes are considered one of the most important threats worldwide due to their ability to vector pathogens. They are responsible for the transmission of major pathogens such as Malaria, dengue, Zika or Chikungunya. Due to the lack of treatments or prophylaxis against many of the transmitted pathogens and an increasing prevalence of mosquito resistance to insecticides and drugs available, alternative strategies are now being explored. Some of these involve the use of microorganisms as promising agent to limit the fitness of mosquitoes, attract or repel them and decrease the replication and transmission of pathogenic agents. In recent years, the importance of microorganisms colonizing the habitat of mosquitoes has particularly been investigated since they appeared to play major roles in their development and diseases transmission. In this issue we will synthesize researches investigating how microorganisms present within water habitats may influence breeding site selection and oviposition strategy of gravid mosquito females. We will also highlight the impact, effect of such microbes on the fate of females’ progeny during their immature stages with a specific focus on egg hatching, development rate and larvae of pupae survival.

Phytochemical investigation of dichloromethane (DCM) extract from the stems of Paragonia pyramidata var. pyramidata L. Rich. (Bur.) resulted in the isolation and characterization of two new triterpenoids 3β,19β-dihydroxylup-12, 20(29)-diene-28-oic acid (1) and 3β,19β-dihydroxylup-12-en-28-oic acid (2), three known triterpenoids lupeol (3), spinosic acid A (4) and oleanolic acid (5), together with four known steroids (20R)-22E-24-ethylcholesta-4,22-dien-3-one (6), (20R)-24-ethylcholest-4-en-3-one (7), stigmasterol (8) and β-sitosterol (9). HREIMS, GC-MS and NMR experiments including HSQC, HMBC, COSY and NOESY were used for the determination of the structures and NMR spectral assignments. This is the first report about the chemical constituents for this plant.

Three glucosylated resveratrol analogues (piceid, piceatannol glucoside, resveratroloside) were successfully isolated from the crude MeOH extract of the invasive plant species Polygonum cuspidatum by semi-preparative high-speed countercurrent chromatography with a two-phase solvent system composed of cyclohexane-ethyl acetate-methanol-water (1:5:1:5, v/v/v/v). Piceid (23 mg), resveratroloside (17 mg), piceatannol glucoside (15 mg) of purities over 80% were isolated from 500 mg crude MeOH extract in one step. Subsequent passage over a SPE column was used to quickly bring their purities to over 90%. The purities were determined by HPLC analysis and their structures were elucidated by proton nuclear magnetic resonance ((1)H-NMR), HMBC, ESI-MS and HR-MS.

Crude extracts of roots and stems of Polygonum cuspidatum Sieb. and Zucc. and Polygonum sachalinensis F. Schmidt ex Maxim from China and Switzerland were analyzed by online HPLC/UV/ESI-MS to ascertain the phytochemical differences between the original and invasive exotic varieties. A total of 36 constituents were identified by comparing their retention times, UV data, mass spectra with those of standards or with literature data. Certain constituents, such as flavanol gallate dimers, were reported for the first time from these species. The relative quantities of the major compounds (emodin glucoside, piceid, resveratroloside and piceatannol glucoside) differed in the samples of the Polygonum species from China and from Switzerland. Phenylpropanoid glucosides were the main constituents of the roots and stems of P. sachalinensis , while the roots of P. cuspidatum were characterized by the presence of stilbenes and anthraquinones.

In order to find some medicinal value for invasive neophytes, inhibition of acetylcholinesterase of Reynoutria sachalinensis F. Schmidt ex Maxim. (Polygonaceae), Polygonum cuspidatum Siebold. Zucc. (Polygonaceae), Heracleum mantegazzianum Sommier Levier (Apiaceae), Buddleja davidii Franch. (Buddlejaceae), and Ambrosia artemisiifolia L. (Asteraceae) was prescreened by a bioautographic TLC assay. Activity was found in the methanol extract of the leaves of the common ornamental bush B. davidii. Its fractionation by centrifugal partition chromatography led to the isolation of linarin as the most active compound. While extracts of Buddleja nitida Benth. (Buddlejaceae) from Panama were inactive, some constituents were identified on the basis of a comparison with B. davidii by HPLC-MS/MS. Structure-activity relationships of linarin and related flavonoids were investigated. For this purpose, fortunellin and tilianin were prepared by methylation reactions. It appears that the structural elements important for acetylcholinesterase inhibition are not only the 4' -OMe group, but also the 7-substituted sugar and the pattern of substitution on the B-ring.

A fruit pulp extract of Detarium microcarpum showed inhibition of the growth of the plant pathogenic fungus Cladosporium cucumerinum and of the enzyme acetylcholinesterase, implicated in Alzheimer's disease. Fractionation of this extract led to the isolation of four new clerodane diterpenes, 3,4-epoxyclerodan-13E-en-15-oic acid ( 1), 5 alpha, 8 alpha-(2-oxokolavenic acid) ( 2), 3,4-dihydroxyclerodan-13E-en-15-oic acid ( 4), and 3,4- dihydroxyclerodan-13Z-en-15-oic acid ( 5). Also isolated were 2-oxokolavenic acid ( 3) and copalic acid ( 6). Structure elucidation of the compounds was carried out by spectroscopic data interpretation and by the X-ray crystallography of 2 and 4. Three of the new clerodane diterpenes ( 1, 2, and 5) showed both antifungal activity and inhibition of acetylcholinesterase, and 3 showed a slight inhibition of this enzyme.

An EtOAc extract of the stem bark of Calophyllum caledonicum (Clusiaceae) yielded thirteen new hydroxylated and/or prenylated xanthone derivatives, namely 5- hydroxy-8-methoxyxanthone (1), 3,5-dihydroxy-1,2-dimethoxyxanthone (2), 1,8-dihydroxy- 6,7-dimethoxyxanthone (3), 5,7-dihydroxy-2,6-dimethoxyxanthone (4), 6,8-dihydroxy-3,7- dimethoxy-xanthone (5), 2,5,6,7,8-pentahydroxyxanthone (6), 1,3,8-trihydroxy-5,7- dimethoxyxanthone (7) and according to a previously adopted nomenclature (3), caledonixanthone G-L. (8-13). The structural elucidation of 1-13 were mainly established on the basis of 1D and 2D NMR and HRMS spectroscopic analysis.

Seed husk extracts of Convolvulus tricolor L. (Convolvulaceae) afforded six compounds, identified for the first time from this plant: isorhamnetin 3-O-beta-D-galactopyranoside (1), isorhamnetin 3-O-beta-D-(6"-acetyl)-galactopyranoside (2), isorhamnetin 3-O-robinobioside (3), 3,4-di-O-caffeoylquinic acid (4), gentisic acid 5-O-glucoside (5), and scopoletin (6). Separation of compounds was carried out by CC and CPC. Structural elucidations were performed by HPLC-UV-DAD, HPLC-ESI/MS (negative mode) and NMR.

International audience; Frankia alni strain ACN14a's genome was scanned for the presence of determinants involved in interactions with its host plant, Alnus spp. One such determinant type is lectin, proteins that bind speciWcally to sugar motifs. The genome of F. alni was found to contain 7 such lectincoding genes, Wve of which were of the ricinB-type. The proteins coded by these genes contain either only the lectin domain, or also a heat shock protein or a serine-threonine kinase domain upstream. These lectins were found to have several homologs in Streptomyces spp., and a few in other bacterial genomes among which none in Frankia EAN1pec and CcI3 and two in strain EUN1f. One of these F. alni genes, FRAAL0616, was cloned in E. coli, fused with a reporter gene yielding a fusion protein that was found to bind to both root hairs and to bacterial hyphae. This protein was also found to modify the dynamics of nodule formation in A. glutinosa, resulting in a higher number of nodules per root. Its role could thus be to permit binding of microbial cells to root hairs and help symbiosis to occur under conditions of low Frankia cell counts such as in pioneer situations.

International audience; Clusiaceae plants display high contents of xanthones and coumarins, the effects of which on endothelium, more particularly on angiogenesis, have not been assessed yet. We screened the capacity of six molecules from Clusiaceae - belonging to xanthones, coumarins and acid chromanes classes - to induce endothelium-dependent relaxation on mice aortic rings. Endothelial nitric oxide (NO) production was assessed in endothelial cell line using electron paramagnetic resonance technique. Then, the capacity of these molecules to induce capillary-like structures of endothelial cells was assessed. Cellular processes implicated in angiogenesis (adhesion, migration and proliferation) and Western blot analyses were then investigated. Among the tested molecules, isocalolongic acid (IA) and 2-deprenylrheediaxanthone (DRX) induced an endothelium-dependent relaxation of the aorta associated with an increase of NO production in endothelial cells. Using in vitro and ex vivo angiogenesis assays, it was shown that IA treatment promoted the formation of capillary-like network. In contrast, DRX prevented the ability of vascular endothelial growth factor (VEGF) to increase the formation of capillary-like network. IA increased endothelial cell proliferation while DRX decreased all cellular processes of angiogenesis. Western blot analysis showed that IA increased VEGF expression whereas DRX decreased ICAM-1 expression. Altogether, these data allowed identifying isolated molecules from Clusiaceae that exhibit a potential activity towards the modulation of endothelium-dependent relaxation involving NO release. Interestingly, they also highlighted paradoxical effects of the two compounds on cellular angiogenic processes, IA being pro-angiogenic and DRX anti-angiogenic.

International audience; In our continual course toward the valorization of traditionally used endemic flora through the analysis of its chemobiodiversity, the phytochemical analysis of aerial parts of Marrubium deserti de Noé was undertaken. Dichloromethane and methanol extracts led to the isolation of terpenoid derivatives among which two were new labdane diterpenes named marrulibacetal A and desertine, respectively. Six of them were known compounds (a mixture of the isomers cyllenin A and 15-epi-cyllenin A, marrubiin, marrulactone, marrulibacetal and β-stigmasterol) and seven known phenolic compounds were also isolated: apigenin and several 7-O-substituted derivatives (apigenin-7-O-β-neohesperidoside, apigenin-7-O-glucoside, terniflorin and apigenin-7-O-glucuronide) together with two phenylethanoid glucosides (acteoside and forsythoside B). The structures and relative configurations of the new compounds were elucidated by MS and a series of 1D and 2D NMR analyses. Some pure compounds have been evaluated for their antioxidant activities through different methods: DPPH and ABTS assays as well as CUPRAC assay. Genotoxic and antigenotoxic activities of extracts and pure compounds were also evaluated in vitro on Escherichia coli PQ37 cells by the SOS Chromotest. Some of the isolated compounds like phenylethanoid derivatives showed stronger antioxidant capacity than trolox and were also able to significantly inhibit β-galactosidase induction caused by the mutagen agent nitrofurantoin.

International audience; 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 β-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 β-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.

The enantioselective hydrogenation of prochiral ene carbamates, directly derived from 2-tetralone, was completed using a catalytic ruthenium system generated from Ru(COD)(methallyl)2, an optically pure diphosphine and a strong acid containing a non-coordinating counter anion.

Phytochemical investigation of dichloromethane (DCM) extract from the stems of Paragonia pyramidata var. pyramidata L. Rich. (Bur.) resulted in the isolation and characterization of two new triterpenoids 3β,19β-dihydroxylup-12, 20(29)-diene-28-oic acid (1) and 3β,19β-dihydroxylup-12-en-28-oic acid (2), three known triterpenoids lupeol (3), spinosic acid A (4) and oleanolic acid (5), together with four known steroids (20R)-22E-24-ethylcholesta-4,22-dien-3-one (6), (20R)-24-ethylcholest-4-en-3-one (7), stigmasterol (8) and β-sitosterol (9). HREIMS, GC-MS and NMR experiments including HSQC, HMBC, COSY and NOESY were used for the determination of the structures and NMR spectral assignments. This is the first report about the chemical constituents for this plant.

International audience; The actinorhizal symbiosis is a major contributor to the global nitrogen budget, playing a dominant role in ecological successions following disturbances. The mechanisms involved are still poorly known but there emerges the vision that on the plant side, the kinases that transmit the symbiotic signal are conserved with those involved in the transmission of the Rhizobium Nod signal in legumes. However, on the microbial side, complementation with Frankia DNA of Rhizobium nod mutants failed to permit identification of symbiotic genes. Furthermore, analysis of three Frankia genomes failed to permit identification of canonical nod genes and revealed symbiosis-associated genes such as nif, hup, suf and shc to be spread around the genomes. The present review explores some recently published approaches aimed at identifying bacterial symbiotic determinants.

International audience; Polygonum sachalinensis is a widespread invasive plant in Europe. Chemical profiles of its different organs were studied by HPLC-UV-ESI/MS. Seven major constituents quercetin-3-O-β-D-galactopyranoside, quercetin-3-O-arabinopyranoside, lapathoside D, N-trans-feruloyltyramine, lapathoside C, hydropiperoside, and vanicoside B were isolated and identified. The free radical-scavenging, α/β-glucosidase, and acetylcholinesterase inhibitory activities of crude MeOH extracts and isolated compounds were studied. The structure\textendashactivity relationships were discussed. The chemical profiles revealed flavonoids and phenylpropanoids are the major compounds of all the organs of this plant. Quercetin-3-O-arabinopyranoside, lapathoside D, N-trans-feruloyltyramine, lapathoside C and hydropiperoside were isolated from this species for the first time. In the α-glucosidase bioassay, quercetin-3-O-β-D-galactopyranoside, lapathoside D and N-trans-feruloyltyramine demonstrated stronger activities than the positive reference acarbose. The trend in scavenging power showed no relation to enzyme inhibition in the test models.

Extracts from several plants of the family Bignoniaceae from Panama were submitted to a rapid DPPH TLC test for the detection of radical-scavenging activity. The MeOH extract of the stems of Jacaranda caucana, a tree that grows from Costa Rica to Colombia, was selected due to its interesting activity and the lack of phytochemical studies on the polar extract. This extract was partitioned between ethyl acetate, butanol, and water. The EtOAc fraction afforded two new phenylethanoid glycosides (1, 2), along with protocatechuic acid, acteoside, and jionoside D. Further purifications yielded isoacteoside and martynoside. The BuOH fraction afforded a new rhamnosyl derivative of sisymbrifolin (8), a neolignan. The structures were determined by means of spectrometric methods, including 1D and 2D NMR experiments and MS analysis.

Chemical investigation of the methanol extract from the leaves of Arrabidaea patellifera, a Bignoniaceae from Panama, afforded mangiferin, isomangiferin, and six new derivatives (3′-O-p-hydroxybenzoylmangiferin, 3′-O-trans-coumaroylmangiferin, 6′-O-trans-coumaroylmangiferin, 3′-O-trans-cinnamoylmangiferin, 3′-O-trans-caffeoylmangiferin, and 3′-O-benzoylmangiferin). All these compounds had antioxidant and radical-scavenging activities, and four of them were relatively active in vitro against Plasmodium falciparum. The structures were determined by spectrometric and chemical methods, including 1D and 2D NMR experiments and MS analysis.

International audience; Seven xanthones, the new vieillardiixanthones B and C (1) and (7), pancixanthones A (2), B (3), 1,6-dihydroxyxanthone (6), pyranojacareubin and 5,6-O-dimethyl-2-deprenylrheediaxanthone together with two benzophenones, clusiachromene (4) and 3-geranyl-2,4,6-trihydroxybenzophenone (5) were isolated from the stem bark of the neocaledonian Garcinia vieillardii. 2, 5 and 6 showed a significant antileishmanial activity against the promastigote forms of Leishmania mexicana and L. infantum and against the amastigote forms of L. infantum.

The dicholoromethane extract of Pseudocedrela kotschyi root demonstrated marked antileishmanial properties in preliminary screening of extracts from 21 species commonly used in Malian traditional medicine. Phytochemical investigation of the active extract yielded three novel phragmalin-type limonoid orthoacetates (1-3), named kotschyins A-C, and the known compounds 7-deacetylgedunin (4) and 7-deacetyl-7-oxogedunin (5). The structures of 1-3 were elucidated by analytical methods including 1D- and 2D-NMR spectroscopy together with MS spectroscopy. The relative configurations of 1-3 were assigned on the basis of NOE correlations. The extract and the isolated compounds were tested for their antiprotozoal activities against Leishmania donovani, Trypanosoma brucei rhodesiense, Trypanosoma cruzi, and Plasmodium falciparum as well as for cytotoxicity toward the L-6 cell line. The crude extract and the two gedunin derivatives exhibited good in vitro activity against all of these parasites.

Sixteen crude extracts from six Panamanian plants of the family Bignoniaceae were submitted to rapid TLC tests against DPPH and acetylcholinesterase. Pithecoctenium crucigerum (L.) A.H. Gentry, which showed interesting activity against DPPH, has been studied. The chemical investigation of the methanol extract from the stems afforded the iridoid glycoside theviridoside and three derivatives (6 '-O-cyclopropanoyltheviridoside, 10-O-hydroxybenzoyltheviridoside and 10-O-vanilloyltheviridoside), along with five known phenyl-ethanoid glycosides (verbascoside, isoverbascoside, forsythoside B, jionoside D and leucosceptoside B. These last compounds were all active against DPPH. The structures were determined by means of spectrometric and chemical methods, including 1 and 2D NMR experiments and MS analysis. (c) 2007 Elsevier Ltd. All rights reserved.

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 novel furoquinolines, named sarcodifurine A (1) and B (2) were isolated from the leaves of Sarcomelicope follicularis (Rutaceae). The structures were elucidated on the basis of spectroscopical data, especially 2D-HMBCand HMQC NMR experiments. The relative configurations were unambiguously determined by single-crystal X-Ray diffraction analyses.

The antimalarial activity of 22 xanthones against chloroquino-resistant strains of Plasmodium falciparum was evaluated. Natural caloxanthone C (1), demethylcalabaxanthone (2), calothwaitesixanthone (3), calozeyloxanthone (4), dombakinaxanthone (5), macluraxanthone (6), and 6-deoxy-gamma-mangostin (7) were isolated from Calophyllum caledonicum. 1,6-dihydroxyxanthone (8), pancixanthone A (9), isocudraniaxanthone B (10), isocudraniaxanthone A (11), 2-deprenylrheediaxanthone B (12) and 1,4,5-trihydroxyxanthone (13) were isolated from Garcinia vieillardii. Moreover, synthetic compounds (14-22) are analogues or intermediates of xanthones purified from Calophyllum caledonicum (Oger J.M., Morel C., Helesbeux J.J., Litaudon M., Seraphin D., Dartiguelongue C., Larcher G., Richomme P., Duval O. 2003. First 2-Hydroxy-3-Methylbut-3-Enyl substituted xanthones isolated from Plants: structure elucidation, synthesis and antifungal activity. Natural Product Research 17(3), 195-199; Helesbeux J.J., Duval O., Dartiguelongue C., Seraphin D., Oger J.M., Richomme P., 2004. Synthesis of 2-hydroxy-3-methylbut-3-enyl substituted coumarins and xanthones as natural products. Application of the Schenck ene reaction of singlet oxygen with ortho-prenylphenol precursors. Tetrahedron 60(10), 2293-2300). The relationship between antimalarial activity and molecular structure of xanthones has also been explored. The most potent xanthones (2), (3) and (7) (IC50 = c.a. 1.0 microg/mL) are 1,3,7 trioxygenated and prenylated on the positions 2 and 8.

Two new xanthones, 6-O-methyl-2-deprenylrheediaxanthone B (1) and vieillardixanthone (2), were isolated from the stem bark of Garcinia vieillardii, as were four known compounds (4-7). The structures of 1 and 2 were determined by means of spectroscopic analysis and chemical derivatization. Each isolate was tested for its antioxidant properties based on a scavenging activity study using the stable 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical.

Two new xanthones, caledonixanthone M 1 and caloxanthone L 2, and one new acid, caledonic acid 6 were isolated from the hexane-soluble extract of the stem bark of Calophyllum caledonicum. In the course of this phytochemical study, seven other known compounds - calothwaitesixanthone, calozeyloxanthone, allanxanthone, isoapetalic acid 3, calolongic acid 4, apetalic acid 5 and isocalolongic acid 7 - were isolated. Their antifungal activity against the growth of the human pathogenic fungus Aspergillus fumigatus was then investigated. The results indicated that the crude extract, calolongic acid 4 and isocalolongic acid 7 exhibited strong inhibitory effects with MIC (80) values of 8, 4, 2 microg/mL, respectively. Besides, calolongic acid 4, its lactone derivative 4a and isocalolongic acid 7 markedly reduced the respiration of pea seed mitochondria.

N-(Alk-1-en-1-yl)carbamates bearing an endocyclic carbon-carbon double bond have been prepared by the reaction of unsubstituted carbamates with tetrahydronaphthalen-2-one and chroman-2-one derivatives in the presence of a catalytic amount of 4-methylbenzene-1-sulfonic acid.

Cyclic enamides were prepared in one step from tetralone and chromanone derivatives and primary amides under acidic conditions. The enantioselective hydrogenation of these enamides bearing an endocyclic trisubstituted carbon-carbon double bond was performed at room temperature in the presence of ruthenium catalysts. On the one hand, the nature of the amide group had little influence on the enantioselectivity of the hydrogenation when mononuclear precatalysts were used. On the other hand, the presence of a coordinating atom at some specific position on the tetralone and chromanone skeleton led to a dramatic decrease of the enantiomeric excesses.