Xanthone Inhibitors of Unfolded Protein Response Isolated from Calophyllum caledonicum.

The unfolded protein response (UPR) is a key component of fungal virulence. The prenylated xanthone γ-mangostin isolated from Garcinia mangostana (Clusiaceae) fruit pericarp, has recently been described to inhibit this fungal adaptative pathway. Considering that Calophyllum caledonicum (Calophyllaceae) is known for its high prenylated xanthone content, its stem bark extract was fractionated using a bioassay-guided procedure based on the cell-based anti-UPR assay. Four previously undescribed xanthone derivatives were isolated, caledonixanthones N-Q (3, 4, 8, and 12), among which compounds 3 and 8 showed promising anti-UPR activities with IC50 values of 11.7 ± 0.9 and 7.9 ± 0.3 µM, respectively.

Efficient Semi-Synthesis of Natural δ-( R)-Tocotrienols from a Renewable Vegetal Source.

Recent studies have highlighted the biological potential of tocotrienols, a vitamin E subfamily. The major natural sources of tocotrienols are complex mixtures requiring particularly challenging purification processes. The present study describes efficient semi-synthetic strategies toward relevant δ-( R)-tocotrienol derivatives, using as a starting material δ-( R)-garcinoic acid, the major vitamin E derivative isolated from Garcinia kola nuts, a renewable vegetal source.

Bithiophenic MALDI matrices as valuable leads for the selective detection of alkaloids.

Alkaloids represent a group of biologically most interesting compounds commonly used in modern medicines but also known for exhibiting severe toxic effects. Therefore, the detection of alkaloids is an important issue in quality control of plants, dietary supplements, and herbal pharmaceutical and mostly facilitated by methods such as GC or LC-MS. However, benefitting from the development of selective matrices as well as requiring very little sample preparation, MALDI-MS may also provide a valuable supplement to these standard analytical methods. With this in mind, the present study highlights recent advances in the development of bithiophenic matrix molecules designed for the selective detection of alkaloids. Overall four new bithiophenic matrix molecules (BMs) were tested on different analytes belonging to various chemical families such as alkaloids, curcuminoids, benzopyrones, flavonoids, steroids, and peptides (I). All BMs were further compared to the commercial matrices α-cyano-4-hydroxycinnamic acid (CHCA) and 2,5-dihydroxybenzoic acid (DHB) in terms of their signal response as well as their matrix noise formation (II). Based on these results the most promising candidate, 3-(5'-pentafluorophenylmethylsulfanyl-[2,2']bithiophenyl-5-ylsulfanyl)propionitrile (PFPT3P), was tested on highly complex samples such as the crude extracts of Colchicum autumnale, RYTMOPASC ® solution (a herbal pharmaceutical containing sparteine and rubijervine), as well as strychnine-spiked human plasma (III). For the latter, an evaluation of the limit of detection was performed. Eventually, a simplified protocol for the direct MALDI detection of major alkaloids from pulverized plant material of Atropa belladonna and Senecio vulgaris is presented (IV). Graphical abstract Selective MALDI MATRICES for Alkaloid Detection.

Semisynthetic and Natural Garcinoic Acid Isoforms as New mPGES-1 Inhibitors.

Over the last twenty years, tocotrienol analogues raised great interest because of their higher level and larger domain of biological activities when compared with tocopherols. Amongst the most promising therapeutic application, anti-inflammatory potency has been evaluated through the inhibition of various mediators of inflammation. Here, we worked on the isolation of two natural isoforms of garcinoic acid (i.e., δ and γ) from two different sources, respectively, Garcinia kola seeds and Garcinia amplexicaulis bark. We also developed semisynthetic strategies to access the other two non-natural α- and ß-garcinoic acid isoforms. In the next stage of our work, microsomal prostaglandin E2 synthase was defined as a target to evaluate the anti-inflammatory potential of the four garcinoic acid isomers. Both dimethylated isoforms, ß- and γ-garcinoic acid, exhibited the lowest IC50, 2.8 µM and 2.0 µM, respectively. These results showed that the affinity of tocotrienol analogues to microsomal prostaglandin E2 synthase-1 most probably contributes to the anti-inflammatory potential of this class of derivatives.

Potential of extracts from Saponaria officinalis and Calendula officinalis to modulate in vitro rumen fermentation with respect to their content in saponins.

Saponins have the potential to favorably modulate rumen fermentation, but there is generally a lack of the chemical structures associated with the described effects. The activity of extracts from Calendula officinalis and Saponaria officinalis in the rumen was evaluated in vitro. The S. officinalis root extract, reduced CH4 production by 8.5% and increased total VFA concentration by 25.2%. C. officinalis and S. officinalis root extracts and the S. officinalis aerial part extract decreased the acetate to propionate ratio from 8.6 to 17.4%, according to the extract. An HPLC-ELSD analysis indicated that the saponin content ranged from 43.6 to 57.6 mg/g of dry matter (DM) in the C. officinalis extracts and from 224.0 to 693.8 mg/g of DM in the S. officinalis extracts, expressed as the hederacoside C equivalent. Identification of the saponin compounds present in the extracts by HPLC-MS(n) suggested that the saponin profile modulated the biological activities, showing the importance of determining the structure of saponins when evaluating extracts.

Polyphenol variability in the fruits and juices of a cider apple progeny.

BACKGROUND: Polyphenols have a favourable antioxidant potential on human health, suggesting that their high content in apple is responsible for the beneficial effects of apple consumption. They are also linked to the quality of apple juices and ciders since they are predominantly responsible for astringency, bitterness and colour. Major phenolic compounds were quantified by liquid chromatography in fruits and juices from a cider apple progeny harvested for 3 years. The total content of procyanidins and their average degree of polymerisation (DPn) were also determined in fruits by phloroglucinolysis. Variability and extraction yield of these compounds were determined. RESULTS: The variability observed in the progeny was representative of the variability observed in many cider apple varieties. Hydroxycinnamic acids were the most extractable group, with an average extraction yield of 67%, whereas flavonols and anthocyanins were the least. CONCLUSION: This study is the first to introduce variability and extraction yields of the main phenolic compounds in both fruits and juices of a cider apple progeny. This dataset will be used for an upcoming QTL mapping study, an original approach that has never been undertaken for cider apple.

Antiangiogenic tocotrienol derivatives from Garcinia amplexicaulis.

Phytochemical investigation of a dichloromethane extract from Garcinia amplexicaulis stem bark led to the isolation of four new tocotrienols (1-4); two known tocotrienols, two triterpenes, and a xanthone were also isolated. Their structures were mainly established using NMR and MS methods. The main compounds isolated, δ-amplexichromanol (1) and γ-amplexichromanol (2), were evaluated on VEGF-induced angiogenesis using a Matrigel assay. Compounds 1 and 2 inhibited in vitro angiogenesis of VEGF-induced human primary endothelial cells in the low nanomolar range. Their capacity to inhibit VEGF-induced proliferation of endothelial cells partially explained this activity, although δ-amplexichromanol (1) also prevented adhesion and migration processes.

Comparison of two methods, UHPLC-UV and UHPLC-MS/MS, for the quantification of polyphenols in cider apple juices.

The aim of this study was to develop faster and more efficient phenotyping methods for in-depth genetic studies on cider apple progeny. The UHPLC chromatographic system was chosen to separate polyphenolic compounds, and quantifications were then simultaneously performed with a UV-PDA detector and an ESI-triple quadrupole mass analyzer (SRM mode). Both quantification methods were validated for 15 major compounds using two apple juice samples, on the basis of linearity, limits of detection and quantification, recovery and precision tests. The comparison between UV and SRM quantifications in 120 different samples of a cider apple progeny showed an excellent correlation for major compounds quantified with both methods. However, an overestimation was revealed for five compounds with the UV detector and the mass analyzer. Co-elution and matrix effects are discussed to explain this phenomenon. SRM methods should therefore be considered with restrictions in some cases for quantification measurements when several phenolic compounds are simultaneously quantified in complex matrices such as apple juices. For both methods, analyses were carried out over short periods of time while maintaining a high quality for the simultaneous quantification of phenolic compounds in apple juice. Each method is relevant for more in-depth genetic studies of the polyphenol content of apple juice.

Fine characterization and microbiota assessment as keys to understanding the positive effect of standardized natural citrus extract on broiler chickens.

The objective of this study was to investigate the effect and composition of a standardized natural citrus extract (SNCE) on both broiler chickens' growth performances and intestinal microbiota. A total of 930 one-day-old males were randomly assigned to three dietary treatments: a control treatment (CTL) in which broiler chickens were fed with a standard diet and two citrus treatments in which broiler chickens were fed with the same standard diet supplemented with 250 ppm and 2,500 ppm of SNCE, respectively. Each dietary treatment was composed of 10 experimental units (pen) of 31 broiler chickens each. Growth performances such as feed consumption, body weight, and feed conversion ratio (FCR) were recorded weekly until day 42. Litter quality was also weekly recorded while mortality was daily recorded. One broiler chicken was randomly selected from each pen (10 chickens/group) and ceca samples were collected for microbiota analysis at day 7 and 42. Chromatographic methods were used to determine molecules that enter into the composition of the SNCE. Results from the characterization of SNCE allowed to identify pectic oligosaccharides (POS) as a major component of the SNCE. In addition, 35 secondary metabolites, including eriocitrin, hesperidin, and naringin, were identified. The experiment performed on broiler chickens showed that the final body weight of broiler chickens fed diets supplemented with SNCE was higher than those fed the CTL diets (P < 0.01). Broiler cecal microbiota was impacted by age (P < 0.01) but not by the dietary supplementation of SNCE. Results indicate that SNCE allowed enhancing chickens' performances without any modulation of the cecal microbiota of broiler chickens. The characterization of SNCE allowed to identify compounds such as eriocitrin, naringin, hesperidin, and POS. Thus, opening new horizons for a better understanding of the observed effect on broiler chickens' growth performances.

Citrus extracts are increasingly being used in animal nutrition to enhance animal growth performances. Most of the available studies indicate an effect of these extracts on microbiota. However, citrus extracts can vary a lot. Indeed, the composition of citrus extract depends on parameters such as the citrus species, the extraction methods, and the inclusion rate. This variation is very important to take into consideration before using a citrus extract. The objective here was to evaluate a commercially available standardized natural citrus extract in terms of composition and effect on broiler chickens' performances and microbiota. Results showed that standardized natural citrus extract positively affects the final weight of broilers, but no effect was observed on chickens' caecal microbiota. The characterization of the standardized natural citrus extract reveals pectic oligosaccharides as major compounds as well as 35 others molecules. Most of these compounds are well described for their beneficial effect on animals' performances and health. In conclusion, the standardized natural citrus extract showed beneficial effects on broilers' performances. These effects are not correlated with broilers microbiota modulation and may be explained by the composition of the product.

An accurate, cost-effective and simple colorimetric method for the quantification of total triterpenoid and steroidal saponins from plant materials.

Saponins are heterosides widely distributed in the plant kingdom. Their properties are used in many industrial sectors, such as food, cosmetics, agriculture, and pharmaceuticals, and their use is increasing due to the market trend to use natural ingredients. Although many techniques exist to quantify saponins (e.g., gravimetric, foaming, spectrophotometric or chromatographic), none of these allow simultaneous accurate, rapid and inexpensive analysis of both triterpenoid and steroidal saponins. A new colorimetric method constituted of p-anisaldehyde and sulfuric acid was developed and avoids all of the above disadvantages. Parameters used in this method allow a similar molar absorptivity for steroidal and triterpenoid saponins with high specificity in complex matrices reducing the sample preparation step and allowing quantification of saponins blends.

Development of a quantification method for routine analysis of glucosinolates and camalexin in brassicaceous small-sized samples by simultaneous extraction prior to liquid chromatography determination.

Glucosinolates and camalexin are secondary metabolites that, as phytoanticipins and phytoalexins, play a crucial role in plant defence. The present work proposes an improved analytical method for routine analysis and quantification of glucosinolates and camalexin in brassicaceous small-sized samples by using the very specific desulfation process of glucosinolates analysis and the specificity of fluorescence detection for camalexin analysis. The approach is based on a simultaneous ultrasound-assisted extraction followed by a purification on an anion-exchange column. Final analyses are conducted by HPLC-UV-MS for desulfo-glucosinolates and HPLC coupled to a fluorescence detector (HPLC-FLD) for camalexin. The method is linear for glucosinolates (50-3500 µM) and camalexin (0.025-5 µg.mL-1) with an LOD/LOQ of 3.8/12.6 µM and 0.014/0.046 µg.mL-1 respectively. The method demonstrated adequate precision, accuracy and trueness on certified reference rapeseed. A practical application of our approach was conducted on different Brassicaceae genera (Barbarea vulgaris, Brassica nigra, Capsella bursa-pastoris, Cardamine hirsuta, Coincya monensis, Sinapis arvensis, and Sisymbrium officinale) and Arabidopsis thaliana genotypes (Columbia and Wassilewskija). Futhermore, different plant organs (seeds and leaves) were analysed, previously inoculated or not with the pathogenic fungus Alternaria brassicicola.

A Descriptive Chemical Composition of Concentrated Bud Macerates through an Optimized SPE-HPLC-UV-MS2 Method-Application to Alnus glutinosa, Ribes nigrum, Rosa canina, Rosmarinus officinalis and Tilia tomentosa.

Concentrated bud macerates (CBMs) are obtained from meristematic tissues such as buds and young shoots by maceration in a solvent composed of glycerin, water and ethanol (1/1/1/, v/v). Their traditional utilization in gemmotherapy has gained interest in the past years, and the knowledge of their chemical characterization can provide commercial arguments, particularly to secure their quality control. Therefore, an optimized method for phytochemical analysis including glycerol removal by a preliminary solid phase extraction (SPE) followed by compound identification using high performance liquid chromatography coupled with ultra-violet and tandem mass detectors (HPLC-UV-MS2) was developed. This method was applied on 5 CBMs obtained from Alnus glutinosa, Ribesnigrum, Rosmarinus officinalis, Rosa canina and Tilia tomentosa in order to determinate their chemical composition. Their antioxidant effects were also investigated by radical scavenging activity assays (DPPH and ORAC). Glycerol removal improved the resolution of HPLC chemical profiles and allowed us to perform TLC antioxidant screening. Our approach permitted the identification of 57 compounds distributed in eight major classes, three of them being common to all macerates including nucleosides, phenolic acids and glycosylated flavonoids. Quantification of the later class as a rutin equivalent (RE) showed a great disparity between Rosa canina macerate (809 mg RE/L), and the other ones (from 175 to 470 mg RE/L). DPPH and ORAC assays confirmed the great activity of Rosa canina (4857 and 6479 µmol TE/g of dry matter, respectively). Finally, phytochemical and antioxidant analysis of CBMs strengthened their phytomedicinal interest in the gemmotherapy field.

Standardized Natural Citrus Extract dietary supplementation influences sows' microbiota, welfare, and preweaning piglets' performances in commercial rearing conditions.

We investigated the effect of the Standardized Natural Citrus Extract (SNCE; Nor-Spice AB, Nor-Feed SAS, France) on the microbiota of the sows and on the weight gain of their piglets. Fifty sows were randomly divided into two groups: a control group (23 sows) with a standard diet and a SNCE group (27 sows) with a standard diet supplemented with 2,500 ppm of SNCE. Supplementation occurred 10 d before and 5 d after farrowing. Fecal samples from 16 sows (8 randomly selected sows of each dietary treatment) were collected for the fecal microbiota analysis 5 d after farrowing. The supplementation of SNCE increases the amount of cultivable Lactobacillus threefold in vitro. Microbial DNA was extracted from the fecal samples for sequencing of the 16S rRNA gene. The SNCE, which affected the microbiota as a discriminant analysis, was able to separate the microbial communities of the eight sows that received SNCE from the three control sows with 21 Operational Taxonomic Units (area under the ROC curve = 96%). SNCE also reduced the interval between farrowing and the first dejection of the sow and increased their feed intake (P-value < 0.05). Furthermore, feeding the sows with SNCE improved the weight gain of the piglets in the first week of life. These results show that SNCE supplementation allows to enhance zootechnical performances of peripartum' sows, possibly due to the modulation of the microbiota transmitted to the piglets.

Cytotoxic and antiplasmodial xanthones from Pentadesma butyracea.

Four new xanthones, butyraxanthones A-D (1-4), were isolated from the stem bark of Pentadesma butyracea, together with six known xanthones (5-10) and a triterpenoid (lupeol). The structures of 1-4 were established by spectroscopic methods. Compounds 1-10 were tested in vitro for antiplasmodial activity against a Plasmodium falciparum chloroquine-resistant strain and for cytotoxicity against a human breast cancer cell line (MCF-7). Nearly all of these xanthones exhibited good antiplasmodial activity, and some of them also demonstrated potent cytotoxicity.

Mycolactone as Analgesic: Subcutaneous Bioavailability Parameters.

Mycobacterium ulcerans is the bacillus responsible for Buruli ulcer, an infectious disease and the third most important mycobacterial disease worldwide, after tuberculosis and leprosy. M. ulcerans infection is a type of panniculitis beginning mostly with a nodule or an oedema, which can progress to large ulcerative lesions. The lesions are caused by mycolactone, the polyketide toxin of M. ulcerans. Mycolactone plays a central role for host colonization as it has immunomodulatory and analgesic effects. On one hand, mycolactone induces analgesia by targeting type-2 angiotensin II receptors (AT2R), causing cellular hyperpolarization and neuron desensitization. Indeed, a single subcutaneous injection of mycolactone into the mouse footpad induces a long-lasting hypoesthesia up to 48 h. It was suggested that the long-lasting hypoesthesia may result from the persistence of a significant amount of mycolactone locally following its injection, which could be probably due to its slow elimination from tissues. To verify this hypothesis, we investigated the correlation between hypoesthesia and mycolactone bioavailability directly at the tissue level. Various quantities of mycolactone were then injected in mouse tissue and hypoesthesia was recorded with nociception assays over a period of 48 h. The hypoesthesia was maximal 6 h after the injection of 4 µg mycolactone. The basal state was reached 48 h after injection, which demonstrated the absence of nerve damage. Surprisingly, mycolactone levels decreased strongly during the first hours with a reduction of 70 and 90% after 4 and 10 h, respectively. Also, mycolactone did not diffuse in neighboring skin tissue and only poorly into the bloodstream upon direct injection. Nevertheless, the remaining amount was sufficient to induce hypoesthesia during 24 h. Our results thus demonstrate that intact mycolactone is rapidly eliminated and that very small amounts of mycolactone are sufficient to induce hypoesthesia. Taken together, our study points out that mycolactone ought to be considered as a promising analgesic.

Sesquiterpenes from aerial parts of Ferula vesceritensis.

From the dichloromethane extract of aerial parts of Ferula vesceritensis (Apiaceae), 11 sesquiterpene derivatives were isolated. Among them five were compounds designated as 10-hydroxylancerodiol-6-anisate, 2,10-diacetyl-8-hydroxyferutriol-6-anisate, 10-hydroxylancerodiol-6-benzoate, vesceritenone and epoxy-vesceritenol. The six known compounds were identified as feselol, farnesiferol A, lapidol, 2-acetyl-jaeschkeanadiol-6-anisate, lasidiol-10-anisate and 10-oxo-jaesckeanadiol-6-anisate. All the structures were determined by extensive spectroscopic studies including 1D and 2D NMR experiments and mass spectroscopy analysis. Two of the compounds, the sesquiterpene coumarins farnesiferol A and feselol, bound to the model recombinant nucleotide-binding site of an MDR-like efflux pump from the enteropathogenic protozoan Cryptosporidium parvum.

Endogenous metabolites of vitamin E limit inflammation by targeting 5-lipoxygenase.

Systemic vitamin E metabolites have been proposed as signaling molecules, but their physiological role is unknown. Here we show, by library screening of potential human vitamin E metabolites, that long-chain ω-carboxylates are potent allosteric inhibitors of 5-lipoxygenase, a key enzyme in the biosynthesis of chemoattractant and vasoactive leukotrienes. 13-((2R)-6-hydroxy-2,5,7,8-tetramethylchroman-2-yl)-2,6,10-trimethyltridecanoic acid (α-T-13'-COOH) can be synthesized from α-tocopherol in a human liver-on-chip, and is detected in human and mouse plasma at concentrations (8-49 nM) that inhibit 5-lipoxygenase in human leukocytes. α-T-13'-COOH accumulates in immune cells and inflamed murine exudates, selectively inhibits the biosynthesis of 5-lipoxygenase-derived lipid mediators in vitro and in vivo, and efficiently suppresses inflammation and bronchial hyper-reactivity in mouse models of peritonitis and asthma. Together, our data suggest that the immune regulatory and anti-inflammatory functions of α-tocopherol depend on its endogenous metabolite α-T-13'-COOH, potentially through inhibiting 5-lipoxygenase in immune cells.

Normal phase HPLC-based activity profiling of non-polar crude plant extracts - acetylcholinesterase inhibiting guttiferones from Montrouziera cauliflora as a case study.

The study describes bioactive compounds as inhibitors of acetylcholinesterase (AChE), from the stem bark extract of Montrouziera cauliflora, selected among 19 dichloromethane extracts from Clusiaceae species. Our work focused on the development of an original normal phase HPLC microfractionation strategy to rapidly assess highly active zones from this crude active non-polar plant extract. Two different microfraction collection methods were evaluated for the assessment of the AChE inhibition. Two guttiferones and a tocotrienol were directly isolated among five compounds identified off-line by NMR after upscaling the fractionation and their AChE inhibition was evaluated. The strengths and weaknesses of the two microfractionation collection methods for HPLC-AChE activity-based profiling are discussed.

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.

Antifungal diterpenes from Hypoestes serpens (Acanthaceae).

Two new diterpenes, fusicoserpenol A and dolabeserpenoic acid A, with antifungal activity, were isolated from leaves of Hypoestes serpens (Acanthaceae). Their structures were elucidated by means of spectrometric methods including 1D and 2D NMR experiments and MS analysis. X-ray crystallographic analysis confirmed the structure of fusicoserpenol A and established the relative configuration.