Manganese distribution in the Mn-hyperaccumulator Grevillea meisneri from New Caledonia.

New Caledonian endemic Mn-hyperaccumulator Grevillea meisneri is useful species for the preparation of ecocatalysts, which contain Mn-Ca oxides that are very difficult to synthesize under laboratory conditions. Mechanisms leading to their formation in the ecocatalysts are unknown. Comparing tissue-level microdistribution of these two elements could provide clues. We studied tissue-level distribution of Mn, Ca, and other elements in different tissues of G. meisneri using micro-X-Ray Fluorescence-spectroscopy (µXRF), and the speciation of Mn by micro-X-ray Absorption Near Edge Structure (µXANES), comparing nursery-grown plants transplanted into the site, and similar-sized plants growing naturally on the site. Mirroring patterns in other Grevillea species, Mn concentrations were highest in leaf epidermal tissues, in cortex and vascular tissues of stems and primary roots, and in phloem and pericycle-endodermis of parent cluster roots. Strong positive Mn/Ca correlations were observed in every tissue of G. meisneri where Mn was the most concentrated. Mn foliar speciation confirmed what was already reported for G. exul, with strong evidence for carboxylate counter-ions. The co-localization of Ca and Mn in the same tissues of G. meisneri might in some way facilitate the formation of mixed Ca-Mn oxides upon preparation of Eco-CaMnOx ecocatalysts from this plant. Grevillea meisneri has been successfully used in rehabilitation of degraded mining sites in New Caledonia, and in supplying biomass for production of ecocatalysts. We showed that transplanted nursery-grown seedlings accumulate as much Mn as do spontaneous plants, and sequester Mn in the same tissues, demonstrating the feasibility of large-scale transplantation programs for generating Mn-rich biomass.

HPLC-ELSD Quantification and Centrifugal Partition Chromatography Isolation of 8-O-Acetylharpagide from Oxera coronata (Lamiaceae).

INTRODUCTION: Iridoid glycosides possess highly functionalised monoterpenoid aglycon with several contiguous stereocentres. For the most common, they are often present in quantities reaching several percentage of the fresh plant weight, and thus they may be regarded as starting material for the synthesis of a number of new chiral and bioactive molecules. OBJECTIVE: To quantify and to isolate 8-O-acetylharpagide (AH) from several extracts of Oxera coronata R.P.J. de Kok, a Lamiaceae species endemic to New Caledonia, using HPLC-ELSD (evaporative light scattering detector) and centrifugal partition chromatography (CPC). METHODOLOGY: Oxera coronata produces high amounts of AH in leaves, twigs and fruits. Water and methanol extracts of these plant parts were prepared. The content of AH in each extract was quantified by HPLC-ELSD, using acetonitrile-water (+0.1% formic acid) gradient elution. The HPLC method was validated for precision, linearity, limit of detection (LOD), limit of quantification (LOQ) and accuracy. A ternary solvent system ethyl acetate/n-propanol/water (3:2:5, v/v/v) was selected and applied to recover the target compound using Spot CPC from the leaves aqueous extract. RESULTS: HPLC-ELSD analysis followed by CPC purification led to the efficient isolation of AH from O. coronata leaves aqueous extract. CONCLUSION: HPLC-ELSD has proven to be a well-adapted detection and quantification method for iridoid glycosides, while CPC confirmed to be an efficient technique for the isolation of polar compounds. Copyright © 2016 John Wiley & Sons, Ltd.

New Caledonia: A Hot Spot for Valuable Chemodiversity Part 3: Santalales, Caryophyllales, and Asterids.

The flora of New Caledonia encompasses more than 3000 plant species and an endemism of almost 80%. New Caledonia is even considered as one of the 34 'hot spots' for biodiversity. Considering the current global loss of biodiversity and the fact that several drugs and pesticides become obsolete, there is an urgent need to increase sampling and research on new natural products. In this context, here, we reviewed the chemical knowledge available on New Caledonian native flora from economical perspectives. We expect that a better knowledge of the economic potential of plant chemistry will encourage the plantation of native plants for the development of a sustainable economy which will participate in the conservation of biodiversity. This review is divided into three parts, and the third part which is presented here summarizes the scientific literature related to the chemistry of endemic santalales, caryophyllales, and asterids. We show that the high rate of endemism is correlated with the originality of phytochemicals encountered in New Caledonian plants. A total of 176 original natural compounds have been identified from these plants, whereas many species have not been investigated so far. We also discuss the economic potential of plants and molecules with consideration of their medicinal and industrial perspectives. This review finally highlights several groups, such as Sapotaceae, that are unexplored in New Caledonia despite the high chemical interest in them. These plants are considered to have priority in future chemical investigations.

New Caledonia: A ' Hot Spot' for Valuable Chemodiversity: Part 2: Basal Angiosperms and Eudicot Rosids.

The flora of New Caledonia encompasses more than 3000 plant species and almost 80% are endemic. New Caledonia is considered as a 'hot spot' for biodiversity. With the current global loss of biodiversity and the fact that several drugs and pesticides become obsolete, there is an urgent need to increase sampling and research on new natural products. In this context, we review the chemical knowledge available on New Caledonian native flora from economical perspectives. We expect that a better knowledge of the economic potential of plant chemistry will encourage the plantation of native plants for the development of a sustainable economy which will participate in the conservation of biodiversity. In the second part of this review, we focus on the results exposed in 60 scientific articles and describe the identification of 225 original compounds from basal angiosperms and eudicot rosids. We discuss the economic potential of plants and molecules from medicinal and industrial perspectives. This review also highlights several plants and groups, such as Amborella sp., Piperaceae, or Phyllanthaceae, that are unexplored in New Caledonia despite their high chemical interest. Those plants are considered to have priority in future chemical investigations.

Triterpenes from the exudate of Gardenia urvillei.

A cycloartane gardurvilleic acid, three 3,4-seco-cycloartanes securvienol, secodienurvilleic acid, securvitriol, a 3,4;9,10-seco-cycloartane gardheptlactone, two dammaranes urvilone, urvilol, along with eight known cycloartanes and 3,4-seco-cycloartanes and four known dammaranes have been isolated from the bud exudate of Gardenia urvillei, an endemic tree to the New Caledonian dry forest. Two other dammarane derivatives have been obtained by semisynthesis. The structures of the original compounds were determined by spectroscopic methods and chemical correlations. In association with previously published data, the description of oxidized side-chains in position 17 are now available for two couples of diastereoisomers. Evaluation of anti-parasite activity and cytotoxicity has shown noticeable results for some of the isolated triterpenes.

New Caledonia: A 'Hot Spot' for Valuable Chemodiversity. Part 1: Gymnosperms.

The flora of New Caledonia encompasses more than 3,000 species and almost 80% of them are endemic. New Caledonia is considered as a 'hot spot' for biodiversity. With the current global loss of biodiversity, and the fact that several drugs and pesticides are becoming obsolete, there is an urgent need to increase sampling and research on new natural products. In this context, we review the chemical information available on New Caledonian native flora from economical perspectives. We expect that a better knowledge of the economic potential will encourage the plantation of native plants for the development of a sustainable economy which will participate in the conservation of biodiversity. In the first part of this review, we discuss the results reported in 18 scientific articles on the chemicals isolated from 23 endemic conifers of New Caledonia. Several bioactive and original products, such as neocallitropsene or libocedrins, have been isolated from these conifers. This review also highlights several groups, such as Podocarpus spp., that are unexplored in New Caledonia despite the fact that they have been described in other countries to contain a wide range of original bioactive compounds. Those plants are considered as priority for future chemical investigations.

A tocotrienol series with an oxidative terminal prenyl unit from Garcinia amplexicaulis.

Ten tocotrienol derivatives, i.e., amplexichromanols (1-10), were isolated from stem bark of Garcinia amplexicaulis Vieill. ex Pierre collected in Caledonia. The structures of the compounds 1-5 were determined to be chromanol derivatives substituted by a polyprenyl chain oxidized in terminal position. The remaining compounds 6-10 are the corresponding dimeric derivatives. Eleven known compounds, including xanthones, tocotrienol derivatives, triterpenes and phenolic compounds, were also isolated. Their structures were mainly determined using one and two-dimensional NMR and mass spectroscopy analysis. The compounds and some amplexichromanol molecules formerly isolated from G. amplexicaulis exhibited significant antioxidant activity against lipid peroxidation and in the ORAC assay.

Antiviral chlorinated daphnane diterpenoid orthoesters from the bark and wood of Trigonostemon cherrieri.

The chemical study of the bark and the wood of Trigonostemon cherrieri, a rare endemic plant of New Caledonia, led to the isolation of a series of highly oxygenated daphnane diterpenoid orthoesters (DDO) bearing an uncommon chlorinated moiety: trigocherrins A-F and trigocherriolides A-D. Herein, we describe the isolation and structure elucidation of the DDO (trigocherrins B-F and trigocherriolides A-D). We also report the antiviral activity of trigocherrins A, B and F (1, 2 and 6) and trigocherriolides A, B and C (7-9) against various emerging pathogens: chikungunya virus (CHIKV), Sindbis virus (SINV), Semliki forest virus (SFV) and dengue virus (DENV).

Alkylated flavanones from the bark of Cryptocarya chartacea as dengue virus NS5 polymerase inhibitors.

An in vitro screening of New Caledonian plants allowed the selection of several species with a significant dengue virus NS5 RNA-dependent RNA polymerase (RdRp) inhibiting activity. The chemical investigation of Cryptocarya chartacea led to the isolation of a series of new mono- and dialkylated flavanones named chartaceones A-F (1-6), along with pinocembrin. They were isolated as racemic mixtures and characterized using extensive one- and two-dimensional NMR spectroscopy. Four diastereomers of chartaceone A (1) were separated using chiral HPLC, and their absolute configurations were established by comparison of their experimental and calculated ECD spectra. The dialkylated flavanones, chartaceones C-F (3-6), exhibited the most significant NS5 RdRp inhibiting activity, with IC(50) ranging from 1.8 to 4.2 µM. Chartaceones represent a new class of non-nucleosidic inhibitors of the DENV NS5 RdRp.