A multiplex approach of MS, 1D-, and 2D-NMR metabolomics in plant ontogeny: A case study on Clusia minor L. organs (leaf, flower, fruit, and seed).

INTRODUCTION: The genus Clusia L. is mostly recognised for the production of prenylated benzophenones and tocotrienol derivatives. OBJECTIVES: The objective of this study was to map metabolome variation within Clusia minor organs at different developmental stages. MATERIAL AND METHODS: In total 15 organs/stages (leaf, flower, fruit, and seed) were analysed by UPLC-MS and 1H- and heteronuclear multiple-bond correlation (HMBC)-NMR-based metabolomics. RESULTS: This work led to the assignment of 46 metabolites, belonging to organic acids(1), sugars(2) phenolic acids(1), flavonoids(3) prenylated xanthones(1) benzophenones(4) and tocotrienols(2). Multivariate data analyses explained the variability and classification of samples, highlighting chemical markers that discriminate each organ/stage. Leaves were found to be rich in 5-hydroxy-8-methyltocotrienol (8.5 µg/mg f.w.), while flowers were abundant in the polyprenylated benzophenone nemorosone with maximum level detected in the fully mature flower bud (43 µg/mg f.w.). Nemorosone and 5-hydroxy tocotrienoloic acid were isolated from FL6 for full structural characterisation. This is the first report of the NMR assignments of 5-hydroxy tocotrienoloic acid, and its maximum level was detected in the mature fruit at 50 µg/mg f.w. Seeds as typical storage organ were rich in sugars and omega-6 fatty acids. CONCLUSION: To the best of our knowledge, this is the first report on a comparative 1D-/2D-NMR approach to assess compositional differences in ontogeny studies compared with LC-MS exemplified by Clusia organs. Results derived from this study provide better understanding of the stages at which maximal production of natural compounds occur and elucidate in which developmental stages the enzymes responsible for the production of such metabolites are preferentially expressed.

Comparison of Balanites aegyptiaca parts: metabolome providing insights into plant health benefits and valorization purposes as analyzed using multiplex GC-MS, LC-MS, NMR-based metabolomics, and molecular networking.

Balanites aegyptiaca (L.) Delile (Zygophyllaceae), also known as the desert date, is an edible fruit-producing tree popular for its nutritional and several health benefits. In this study, multi-targeted comparative metabolic profiling and fingerprinting approaches were conducted for the assessment of the nutrient primary and secondary metabolite heterogeneity in different parts, such as leaves, stems, seeds, unripe, and ripe fruits of B. aegyptiaca using nuclear magnetic resonance (NMR), ultra-performance liquid chromatography (UPLC-MS), and gas chromatography mass-spectrometry (GC-MS) based metabolomics coupled to multivariate analyses and in relation to its cytotoxic activities. NMR-based metabolomic study identified and quantified 15 major primary and secondary metabolites belonging to alkaloids, saponins, flavonoids, sugars, and amino and fatty acids. Principal component analysis (PCA) of the NMR dataset revealed α-glucose, sucrose, and isorhamnetin as markers for fruit and stem and unsaturated fatty acids for predominated seeds. Orthogonal projections to latent structure discriminant analysis (OPLS-DA) revealed trigonelline as a major distinctive metabolite in the immature fruit and isorhamnetin as a major distinct marker in the mature fruit. UPLC-MS/MS analysis using feature-based molecular networks revealed diverse chemical classes viz. steroidal saponins, N-containing metabolites, phenolics, fatty acids, and lipids as the constitutive metabolome in Balanites. Gas chromatography-mass spectroscopy (GC-MS) profiling of primary metabolites led to the detection of 135 peaks belonging to sugars, fatty acids/esters, amino acids, nitrogenous, and organic acids. Monosaccharides were detected at much higher levels in ripe fruit and disaccharides in predominate unripe fruits, whereas B. aegyptiaca vegetative parts (leaves and stem) were rich in amino acids and fatty acids. The antidiabetic compounds, viz, nicotinic acid, and trigonelline, were detected in all parts especially unripe fruit in addition to the sugar alcohol d-pinitol for the first time providing novel evidence for B. aegyptiaca use in diabetes. In vitro cytotoxic activity revealed the potential efficacy of immature fruit and seeds as cytotoxic agents against human prostate cancer (PC3) and human colorectal cancer (HCT-116) cell lines. Collectively, such detailed profiling of parts provides novel evidence for B. aegyptiaca medicinal uses.

Purpurascenines A-C, Azepino-Indole Alkaloids from Cortinarius purpurascens: Isolation, Biosynthesis, and Activity Studies on the 5-HT2A Receptor.

Three previously undescribed azepino-indole alkaloids, named purpurascenines A-C (1-3), together with the new-to-nature 7-hydroxytryptophan (4) as well as two known compounds, adenosine (5) and riboflavin (6), were isolated from fruiting bodies of Cortinarius purpurascens Fr. (Cortinariaceae). The structures of 1-3 were elucidated based on spectroscopic analyses and ECD calculations. Furthermore, the biosynthesis of purpurascenine A (1) was investigated by in vivo experiments using 13C-labeled sodium pyruvate, alanine, and sodium acetate incubated with fruiting bodies of C. purpurascens. The incorporation of 13C into 1 was analyzed using 1D NMR and HRESIMS methods. With [3-13C]-pyruvate, a dramatic enrichment of 13C was observed, and hence a biosynthetic route via a direct Pictet-Spengler reaction between α-keto acids and 7-hydroxytryptophan (4) is suggested for the biosynthesis of purpurascenines A-C (1-3). Compound 1 exhibits no antiproliferative or cytotoxic effects against human prostate (PC-3), colorectal (HCT-116), and breast (MCF-7) cancer cells. An in silico docking study confirmed the hypothesis that purpurascenine A (1) could bind to the 5-HT2A serotonin receptor's active site. A new functional 5-HT2A receptor activation assay showed no functional agonistic but some antagonistic effects of 1 against the 5-HT-dependent 5-HT2A activation and likely antagonistic effects on putative constitutive activity of the 5-HT2A receptor.

Metabolomics characterizes early metabolic changes and markers of tolerant Eucalyptus ssp. clones against drought stress.

EUCALYPTUS: L'Hér. (Myrtaceae) is one of the economically most important and widely cultivated trees for wood crop purposes worldwide. Climatic changes together with the constant need to expand plantations to areas that do not always provide optimal conditions for plant growth highlight the need to assess the impact of abiotic stresses on eucalypt trees. We aimed to unveil the drought effect on the leaf metabolome of commercial clones with differential phenotypic response to this stress. For this, seedlings of 13 clones were grown at well-watered (WW) and water-deficit (WD) conditions and their leaf extracts were subjected to comparative analysis using ultra-high performance liquid chromatography coupled to mass spectrometry (UPLC-MS) and nuclear magnetic resonance spectroscopy (NMR). UPLC-MS and NMR analyses led to the annotation of over 100 molecular features of classes such as cyclitols, phenolics, flavonoids, formylated phloroglucinol compounds (FPCs) and fatty acids. Multivariate data analysis was employed for specimens' classifications and markers identification from both platforms. The results obtained in this work allowed us to classify clones differing in drought tolerance. Classification models were validated using an extra subset of samples. Tolerant plants exposed to water deficit accumulated arginine, gallic acid derivatives, caffeic acid and tannins at higher levels. In contrast, stressed drought-sensitive clones were characterised by a significant reduction in glucose, inositol and shikimic acid levels. These changes in contrasting drought response eucalypt pave ways for differential outcomes of tolerant and susceptible phenotypes. Under optimal growth conditions, all clones were rich in FPCs. These results can be used for early screening of tolerant clones and to improve our understanding of the role of these biomarkers in Eucalyptus tolerance to drought stress.

Lehmanniaside, a new cycloartane triterpene glycoside from Astragalus lehmannianus.

Chemical investigation of the aerial parts of Astragalus lehmannianus Bunge (Leguminosae) led to the isolation and identification of a new cycloartane triterpene glycoside - lehmanniaside (2'-O-acetyl-3-ß-O-D-xylopyranosyl-3ß,6α,16ß,24α-tetrahydroxy-20,25-epoxycycloartane). Its structure was elucidated by means of spectroscopic analysis (HR-MS, 1D and 2D NMR). Bioassays showed that lehmanniaside exhibits weak anthelmintic, antifungal, and cytotoxic activities.

Structural Elucidation of an Atropisomeric Entcassiflavan-(4ß→8)-Epicatechin Isolated from Dalbergia monetaria L.f. Based on NMR and ECD Calculations in Comparison to Experimental Data.

A rare dihydoxyflavan-epicatechin proanthocyanidin, entcassiflavan-(4ß→8)-epicatechin, was isolated from Dalbergia monetaria, a plant widely used by traditional people from the Amazon to treat urinary tract infections. The constitution and relative configuration of the compound were elucidated by HR-MS and detailed 1D- and 2D-NMR measurements. By comparing the experimental electronic circular dichroism (ECD) spectrum with the calculated ECD spectra of all 16 possible isomers, the absolute configuration, the interflavan linkage, and the atropisomers could be determined.

Dissecting coffee seeds metabolome in context of genotype, roasting degree, and blending in the Middle East using NMR and GC/MS techniques.

With a favored taste and various bioactivities, coffee has been consumed as a daily beverage worldwide. The current study presented a multi-faceted comparative metabolomics approach dissecting commercially available coffee products in the Middle East region for quality assessment and functional food purposes using NMR and GC/MS platforms. NMR metabolites fingerprinting led to identification of 18 metabolites and quantification (qNMR) of six prominent markers for standardization purposes. An increase of ß-ethanolamine (MEA) reported for the first time, 5-(hydroxymethyl) furfural (5-HMF), concurrent with a reduction in chlorogenic acid, kahweol, and sucrose levels post roasting as revealed using multivariate data analyses (MVA). The diterpenes kahweol and cafestol were identified in green and roasted Coffea arabica, while 16-O-methyl cafestol in roasted C. robusta. Moreover, GC/MS identified a total of 143 metabolites belonging to 15 different chemical classes, with fructose found enriched in green C. robusta versus fatty acids abundance, i.e., palmitic and stearic acids in C. arabica confirming NMR results. These potential results aided to identify novel quality control attributes, i.e., ethanolamine, for coffee in the Middle East region and have yet to be confirmed in other coffee specimens.

Antioxidant capacity and fragmentation features of C-glycoside isoflavones by high-resolution electrospray ionization tandem mass spectrometry using collision-induced and high-energy collisional dissociation techniques.

The rapid annotation and identification by mass spectrometry techniques of flavonoids remains a challenge, due to their structural diversity and the limited availability of reference standards. This study applies a workflow to characterize two isoflavonoids, the orobol-C-glycosides analogs, using high-energy collisional dissociation (HCD)- and collision-induced dissociation (CID)-type fragmentation patterns, and also to evaluate the antioxidant effects of these compounds by ferric reducing antioxidant power (FRAP), 2,2'-azino-bis(3-ethylbenzothiazolin acid) 6-sulfonic acid (ABTS), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) methods. By the CID-type fragmentation, in positive mode and at all high-resolution mass spectrometry (HRMS) multiple stage, there were shown differences in the annotation of the compounds, mainly concerning some ratios of relative abundance. At CID-MS2 20 eV, the compounds could be efficiently characterized, because they present distinct base peaks [M + H]+ and [M + H-H2 O]+ for the orobol-8-C- and orobol-6-C-glycoside, respectively. Similarly, by the HCD-type fragmentation, in HRMS2 stage, differences between orobol analogs in both mode of ionization were observed. However, the HR HCD-MS2 at 80 eV, in positive mode, generated more ions and each isomer presented different base peaks ions, [0,2X]+ for the orobol-8-C-glycoside and [0,3X]+ for the orobol-6-C-glycoside. By the DPPH, the 8-C-derivative showed a very close value compared with the standard rutin and, in the ABTS method, a higher radical-scavenging activity. In both methods, the EC50 of orobol-8-C-glycoside was almost twice better compared with orobol-6-C-glycoside. In FRAP, both C-glycosides showed a good capacity as Fe+3 reducing agents. We could realize that combined MS techniques, highlighting the positive mode of ionization, can be used to evaluate the isoflavones analogs being useful to differentiate between the isomeric flavones; therefore, these data are important to mass spectrometry dereplication studies become more efficient. HIGHLIGHTS: The MS2, in positive mode of ionization, at low CID energies (15 and 20 eV) and at high HCD energies (50 eV), was suitable to characterize orobol 8 and 6-C-derivatives. Positive mode of ionization was effective to rapid annotation of each orobol C-glycoside. The orobol C-derivatives showed high radical scavenging effects. Orobol-8-C-glycoside showed higher antioxidant capacity.

Rare Glutamic Acid Methyl Ester Peptaibols from Sepedonium ampullosporum Damon KSH 534 Exhibit Promising Antifungal and Anticancer Activity.

Fungal species of genus Sepedonium are rich sources of diverse secondary metabolites (e.g., alkaloids, peptaibols), which exhibit variable biological activities. Herein, two new peptaibols, named ampullosporin F (1) and ampullosporin G (2), together with five known compounds, ampullosporin A (3), peptaibolin (4), chrysosporide (5), c(Trp-Ser) (6) and c(Trp-Ala) (7), have been isolated from the culture of Sepedonium ampullosporum Damon strain KSH534. The structures of 1 and 2 were elucidated based on ESI-HRMSn experiments and intense 1D and 2D NMR analyses. The sequence of ampullosporin F (1) was determined to be Ac-Trp1-Ala2-Aib3-Aib4-Leu5-Aib6-Gln7-Aib8-Aib9-Aib10-GluOMe11-Leu12-Aib13-Gln14-Leuol15, while ampullosporin G (2) differs from 1 by exchanging the position of Gln7 with GluOMe11. Furthermore, the total synthesis of 1 and 2 was carried out on solid-phase to confirm the absolute configuration of all chiral amino acids as L. In addition, ampullosporin F (1) and G (2) showed significant antifungal activity against B. cinerea and P. infestans, but were inactive against S. tritici. Cell viability assays using human prostate (PC-3) and colorectal (HT-29) cancer cells confirmed potent anticancer activities of 1 and 2. Furthermore, a molecular docking study was performed in silico as an attempt to explain the structure-activity correlation of the characteristic ampullosporins (1-3).

Sugar Containing Compounds and Biological Activities of Lagochilus setulosus.

Phytochemical investigation of the methanolic extract obtained from the aerial parts of Lagochilus setulosus (Lamiaceae) afforded the new compound 1-methoxy-3-O-ß-glucopyranosyl-α-l-oliose (1) together with five known glycosides, namely sitosterol-3-O-ß-glucoside (2), stigmasterol-3-O-ß-glucoside (3), pinitol (4), 6ß-hydroxyl-7-epi-loganin (5), and chlorotuberoside (6). The structures of these compounds were elucidated by extensive spectroscopic analyses, especially HR-MS, 1D and 2D NMR spectroscopy. The in vitro cytotoxic activity of the methanolic extract and the isolated compounds was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and crystal violet (CV) staining assays. In addition, the antifungal activities of the components were evaluated against Botrytis cinerea, Septoria tritici, and Phytophthora infestans. The anthelmintic potential was determined against Caenorhabditis elegans nematodes. Neither the extract nor the isolated compounds showed promising activity in all the bioassays.

A single cytochrome P450 oxidase from Solanum habrochaites sequentially oxidizes 7-epi-zingiberene to derivatives toxic to whiteflies and various microorganisms.

Secretions from glandular trichomes potentially protect plants against a variety of aggressors. In the tomato clade of the Solanum genus, glandular trichomes of wild species produce a rich source of chemical diversity at the leaf surface. Previously, 7-epi-zingiberene produced in several accessions of Solanum habrochaites was found to confer resistance to whiteflies (Bemisia tabaci) and other insect pests. Here, we report the identification and characterisation of 9-hydroxy-zingiberene (9HZ) and 9-hydroxy-10,11-epoxyzingiberene (9H10epoZ), two derivatives of 7-epi-zingiberene produced in glandular trichomes of S. habrochaites LA2167. Using a combination of transcriptomics and genetics, we identified a gene coding for a cytochrome P450 oxygenase, ShCYP71D184, that is highly expressed in trichomes and co-segregates with the presence of the zingiberene derivatives. Transient expression assays in Nicotiana benthamiana showed that ShCYP71D184 carries out two successive oxidations to generate 9HZ and 9H10epoZ. Bioactivity assays showed that 9-hydroxy-10,11-epoxyzingiberene in particular exhibits substantial toxicity against B. tabaci and various microorganisms including Phytophthora infestans and Botrytis cinerea. Our work shows that trichome secretions from wild tomato species can provide protection against a wide variety of organisms. In addition, the availability of the genes encoding the enzymes for the pathway of 7-epi-zingiberene derivatives makes it possible to introduce this trait in cultivated tomato by precision breeding.

Nuclear Magnetic Resonance Metabolomics Approach for the Analysis of Major Legume Sprouts Coupled to Chemometrics.

Legume sprouts are a fresh nutritive source of phytochemicals of increasing attention worldwide owing to their many health benefits. Nuclear magnetic resonance (NMR) was utilized for the metabolite fingerprinting of 4 major legume sprouts, belonging to family Fabaceae, to be exploited for quality control purposes. Thirty-two metabolites were identified belonging to different classes, i.e., fatty acids, sugars, amino acids, nucleobases, organic acids, sterols, alkaloids, and isoflavonoids. Quantitative NMR was employed for assessing the major identified metabolite levels and multivariate data analysis was utilized to assess metabolome heterogeneity among sprout samples. Isoflavones were detected exclusively in Cicer sprouts, whereas Trigonella was characterized by 4-hydroxyisoleucine. Vicia sprouts were distinguished from other legume sprouts by the presence of L-Dopa versus acetate abundance in Lens. A common alkaloid in all sprouts was trigonelline, detected at 8-25 µg/mg, suggesting its potential role in legume seeds' germination. Trigonelline was found at highest levels in Trigonella sprouts. The aromatic NMR region data (δ 11.0-5.0 ppm) provided a better classification power than the full range (δ 11.0-0.0 ppm) as sprout variations mostly originated from secondary metabolites, which can serve as chemotaxonomic markers.

Anthelmintic and antimicrobial activities of three new depsides and ten known depsides and phenols from Indonesian lichen: Parmelia cetrata Ach.

An extensive phytochemical study of a foliose lichen from Indonesia, Parmelia cetrata, resulted in the successful isolation of 13 phenol and depside derivatives (1-13) including the previously unreported depsides 3'-hydroxyl-5'-pentylphenyl 2,4-dihydroxyl-6-methylbenzoate (7), 3'-hydroxyl-5'-propylphenyl 2,4-dihydroxyl-6-methylbenzoate (8) and 3'-hydroxyl-5'-methylphenyl 2-hydroxyl-4-methoxyl-6-propylbenzoate (9). The anti-infective activity of isolated compounds was evaluated against the gram-negative bacterium Aliivibrio fischeri and the nematode Caenorhabditis elegans. 2,4-Dihydroxyl-6-pentylbenzoate (5) and lecanoric acid (6) induced growth inhibition of A. fischeri with inhibition values of 49% and 100% at a concentration of 100 µM, respectively. The antibacterial activity might be due to their free carboxyl group. A phenolic group at C4 also contributed to the antimicrobial activity of the depsides as shown for compounds 7 and 8, which caused 89% and 96% growth inhibition at 100 µM, respectively. Lecanoric acid (6) in addition possesses significant anthelmintic effects causing 80% mortality of C. elegans at 100 µg/mL.

PSYCHE-A Valuable Experiment in Plant NMR-Metabolomics.

1H-NMR is a very reproducible spectroscopic method and, therefore, a powerful tool for the metabolomic analysis of biological samples. However, due to the high complexity of natural samples, such as plant extracts, the evaluation of spectra is difficult because of signal overlap. The new NMR "Pure Shift" methods improve spectral resolution by suppressing homonuclear coupling and turning multiplets into singlets. The PSYCHE (Pure Shift yielded by Chirp excitation) and the Zangger-Sterk pulse sequence were tested. The parameters of the more suitable PSYCHE experiment were optimized, and the extracts of 21 Hypericum species were measured. Different evaluation criteria were used to compare the suitability of the PSYCHE experiment with conventional 1H-NMR. The relationship between the integral of a signal and the related bin value established by linear regression demonstrates an equal representation of the integrals in binned PSYCHE spectra compared to conventional 1H-NMR. Using multivariate data analysis based on both techniques reveals comparable results. The obtained data demonstrate that Pure Shift spectra can support the evaluation of conventional 1H-NMR experiments.

Characterization of Antibacterial Proanthocyanidins of Dalbergia monetaria, an Amazonian Medicinal Plant, by UHPLC-HRMS/MS.

Dalbergia monetaria is an Amazonian plant whose bark is widely used to treat urinary tract infections. This paper describes a bio-guided study of ethanolic extracts from the bark and leaves of D. monetaria, in a search for metabolites active against human pathogenic bacteria. In vitro assays were performed against 10 bacterial strains, highlighting methicillin-sensitive Staphylococcus aureus and methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa. Fractioning of the extracts was performed using instrumental and classical techniques, and samples were characterized by UHPLC-HRMS/MS. Ethyl acetate fractions from bark and leaves showed similar antibacterial activities. EAFB is enriched in isoflavone C-glucosides and EAFL enriched in proanthocyanidins. Subfractions from EAFL presented higher activity and showed a complex profile of proanthocyanidins constructed by (epi)-cassiaflavan and (epi)-catechin units, including dimers, trimers and tetramers. The fragmentation pattern emphasized the neutral loss of cassiaflavan units by quinone-methide fission. Fraction SL7-6, constituted by (ent)-cassiaflavan-(ent)-cassiaflavan-(epi)-catechin isomers, showed the lowest MIC against the S. aureus and P. aeruginosa with values corresponding to 64 and 32 µg/mL, respectively. Cassiaflavan-proanthocyanidins have not been found previously in another botanical genus, except in Cassia, and the traditional medicinal use of D. monetaria might be related to the antibacterial activity of proanthocyanidins characterized in the species.

Foliar Application of Chitosan Increases Tomato Growth and Influences Mycorrhization and Expression of Endochitinase-Encoding Genes.

Nowadays, applying bio-organic fertilizer (e.g., chitosan, Ch) or integrating beneficial microorganisms (e.g., arbuscular mycorrhizal fungi, AMF) are among the successful strategies to promote plant growth. Here, the effect of two application modes of Ch (foliar spray or root treatment) and Ch-derived nanoparticles (NPs) on tomato plants colonized with the AMF Rhizophagus irregularis were analyzed, thereby focusing on plant biomass, flowering and mycorrhization. An increase of shoot biomass and flower number was observed in arbuscular mycorrhizal (AM) plants sprayed with Ch. The interaction with AMF, however, was reduced as shown by decreased mycorrhization rates and AM-specific gene expression. To get insights into Ch effect on mycorrhization, levels of sugars, jasmonates, abscisic acid, and the expression of two chitinase-encoding genes were determined in mycorrhizal roots. Ch had no effect on sugar and phytohormone levels, but the reduced mycorrhization was correlated with down- and upregulated expression of Chi3 and Chi9, respectively. In contrast, application of NPs to leaves and Ch applied to the soil did not show any effect, neither on mycorrhization rate nor on growth of mycorrhizal plants. Concluding, Ch application to leaves enhanced plant growth and flowering and reduced interaction with AMF, whereas root treatment did not affect these parameters.

A piperic acid CoA ligase produces a putative precursor of piperine, the pungent principle from black pepper fruits.

Black pepper (Piper nigrum L.) is known for its high content of piperine, a cinnamoyl amide derivative regarded as largely responsible for the pungent taste of this widely used spice. Despite its long history and worldwide use, the biosynthesis of piperine and related amides has been enigmatic up to now. In this report we describe a specific piperic acid CoA ligase from immature green fruits of P. nigrum. The corresponding enzyme was cloned and functionally expressed in E. coli. The recombinant enzyme displays a high specificity for piperic acid and does not accept the structurally related feruperic acid characterized by a similar C-2 extension of the general C6-C3 phenylpropanoid structure. The enzyme is also inactive with the standard set of hydroxycinnamic acids tested including caffeic acid, 4-coumaric acid, ferulic acid, and sinapic acid. Substrate specificity is corroborated by in silico modelling that suggests a perfect fit for the substrate piperic acid to the active site of the piperic acid CoA ligase. The CoA ligase gene shows its highest expression levels in immature green fruits, is also expressed in leaves and flowers, but not in roots. Virus-induced gene silencing provided some preliminary indications that the production of piperoyl-CoA is required for the biosynthesis of piperine in black pepper fruits.

Improved Stability and Tunable Functionalization of Parallel ß-Sheets via Multicomponent N-Alkylation of the Turn Moiety.

In contrast to the myriad of methods available to produce α-helices and antiparallel ß-sheets in synthetic peptides, just a few are known for the construction of stable, non-cyclic parallel ß-sheets. Herein, we report an efficient on-resin approach for the assembly of parallel ß-sheet peptides in which the N-alkylated turn moiety enhances the stability and gives access to a variety of functionalizations without modifying the parallel strands. The key synthetic step of this strategy is the multicomponent construction of an N-alkylated turn using the Ugi reaction on varied isocyano-resins. This four-component process assembles the orthogonally protected turn fragment and incorporates handles serving for labeling/conjugation purposes or for reducing peptide aggregation. NMR and circular dichroism analyses confirm the better-structured and more stable parallel ß-sheets in the N-alkylated peptides compared to the non-functionalized variants.

Nor-guanacastepene pigments from the Chilean mushroom Cortinarius pyromyxa.

For the first time, the pigment composition of basidiocarps from the Chilean mushroom Cortinarius pyromyxa was studied under various aspects like phylogeny, chemistry and antibiotic activity. A molecular biological study supports the monotypic position of C. pyromyxa in subgenus Myxacium, genus Cortinarius. Four undescribed diterpenoids, named pyromyxones A-D, were isolated from fruiting bodies of C. pyromyxa. Their chemical structures were elucidated based on comprehensive one- and two-dimensional NMR spectroscopic analysis, ESI-HRMS measurements, as well as X-ray crystallography. In addition, the absolute configurations of pyromyxones A-D were established with the aid of JH,H, NOESY spectra and quantum chemical CD calculation. The pyromyxones A-D possess the undescribed nor-guanacastane skeleton. Tested pyromyxones A, B, and D exhibit only weak activity against gram-positive Bacillus subtilis and gram-negative Aliivibrio fischeri as well as the phytopathogenic fungi Botrytis cinerea, Septoria tritici and Phytophthora infestans.

Comparative metabolome-based classification of Senna drugs: a prospect for phyto-equivalency of its different commercial products.

INTRODUCTION: The demand to develop efficient and reliable analytical methods for the quality control of nutraceuticals is on the rise, together with an increase in the legal requirements for safe and consistent levels of its active principles. OBJECTIVE: To establish a reliable model for the quality control of widely used Senna preparations used as laxatives and assess its phyto-equivalency. METHODS: A comparative metabolomics approach via NMR and MS analyses was employed for the comprehensive measurement of metabolites and analyzed using chemometrics. RESULTS: Under optimized conditions, 30 metabolites were simultaneously identified and quantified including anthraquinones, bianthrones, acetophenones, flavonoid conjugates, naphthalenes, phenolics, and fatty acids. Principal component analysis (PCA) was used to define relative metabolite differences among Senna preparations. Furthermore, quantitative 1H NMR (qHNMR) was employed to assess absolute metabolites levels in preparations. Results revealed that 6-hydroxy musizin or tinnevellin were correlated with active metabolites levels, suggesting the use of either of these naphthalene glycosides as markers for official Senna drugs authentication. CONCLUSION: This study provides the first comparative metabolomics approach utilizing NMR and UPLC-MS to reveal for secondary metabolite compositional differences in Senna preparations that could readily be applied as a reliable quality control model for its analysis.