Marine organisms have evolved to survive against predators in complex marine ecosystems via the production of chemical compounds. Soft corals (cnidaria, Anthozoa, octocorallia) are an important source of chemically diverse metabolites with a broad spectrum of biological activities. Herein, we perform a comparative study between high-resolution proton nuclear magnetic resonance (1 H-nMR) and pure shift yielded by chirp excitation (PSYCHE) experiments to analyze the metabolic profile of 24 soft corals from the Colombian Caribbean to correlate chemical fingerprints with their cytotoxic activity against three cancer cell lines (human cervical carcinoma (SiHa), human prostatic carcinoma (PC3) and human lung adenocarcinoma (A549)). All data obtained were explored using multivariate analysis using principal components analysis (pcA) and orthogonal partial least squares (opLS) analysis. the results did not show a significant correlation between clusters using 1 H-nMR data in the pcA and opLS-DA models and therefore did not provide conclusive evidence; on the other hand, a metabolomic analysis of pSYcHe data obtained under the same parameters revealed that when a decoupled experiment is performed, it was possible to establish a statistically valid correlation between the chemical composition of soft corals and their cytotoxic activity against the PC3 cancer cell line, where the asperdiol and plexaurolone markers were putatively identified and related to the cytotoxic activity presented by extracts of Plexaurella sp. and Plexaura kukenthali, respectively. these results increase the speed, effectiveness and reliability of analyses for the study of this type of complex matrices. Metabolomics studies allow a complete analysis of a set of metabolites that are the substrates and products of metabolism driving essential cellular functions in a given biological system 1. This research has applications in different fields, such as pharmacology, environmental sciences, chemotaxonomy, nutrition and medicine 2. Recently, metabolomic approaches have allowed the understanding of complex biological systems and the biochemical composition of organisms that live in diverse environments, such as marine areas 3. Goulitquer et al. demonstrated that metabolites are important links between genotype and phenotype and are important for studying several biological processes and for analyzing interactions between organisms within communities via mass spectrometry (MS)-based metabolomics 4. In addition, Mohamed A. Farag et al. compared metabolomics results obtained with liquid chromatography coupled to mass spectrometry (LC-MS) with those obtained by nuclear magnetic resonance (NMR) to investigate the metabolism of 16 Sarcophyton species in the context of their genetic diversity and growth habitats 3. The importance of studying marine invertebrates lies in their extraordinary ability to produce a broad variety of chemical compounds with unique chemical structures that in most cases have been correlated with significant biological activities, which ...

In the presence of a photomediator such as benzophenone, alkynes with electron-withdrawing groups react with cycloalkanes to give vinyl cycloalkanes. The reaction involves the regiospecific addition of a photochemically generated cycloalkyl radical to the beta-carbon of the alkyne. The stereochemical outcome of the reaction depends on the nature of the photomediator and alkyne used.

Glycosylation analysis of recombinant glycoproteins is of importance for the biopharmaceutical industry and the production of glycoprotein pharmaceuticals. A commercially available lectin array technology was evaluated for its ability to present a reproducible fingerprint of a recombinant CTLY4-IgG fusion glycoprotein expressed in large scale CHO-cell fermentation. The glycosylation prediction from the array was compared to traditional negative mode capillary LC-MS of released oligosaccharides. It was shown that both methods provide data that allow samples to be distinguished by their glycosylation pattern. This included information about sialylation, the presence of reducing terminal galactose β1-, terminal N-acetylglucosamine β1-, and antennary distribution. With both methods it was found that a general trend of increased sialylation was associated with an increase of the antenna and reduced amount of terminal galactose β1-, while N-acetylglucosamine β1- was less affected. LC-MS, but not the lectin array, provided valuable information about the sialic acid isoforms present, including N-acetylneuraminic acid, N-glycolylneuraminic acid and their O-acetylated versions. Detected small amounts of high-mannose structures by LC-MS correlated with the detection of the same epitope by the lectin array.

Collision induced dissociation (CID) fragmentation was compared between reducing and reduced sulfated, sialylated, and neutral O-linked oligosaccharides. It was found that fragmentation of the [M -H] -ions of aldoses with acidic residues gave unique Z-fragmentation of the reducing end GalNAc containing the acidic C-6 branch, where the entire C-3 branch was lost. This fragmentation pathway, which is not seen in the alditols, showed that the process involved charge remote fragmentation catalyzed by a reducing end acidic anomeric proton. With structures containing sialic acid on both the C-3 and C-6 branch, the [M -H] -ions were dominated by the loss of sialic acid. This fragmentation pathway was also pronounced in the [M -2H] 2-ions revealing both the C-6 Z-fragment plus its complementary C-3 C-fragment in addition to glycosidic and cross ring fragmentation. This generation of the Z/C-fragment pairs from GalNAc showed that the charges were not participating in their generation. Fragmentation of neutral aldoses showed pronounced Z-fragmentation believed to be generated by proton migration from the C-6 branch to the negatively charged GalNAc residue followed by charge remote fragmentation similar to the acidic oligosaccharides. In addition, A-type fragments generated by charge induced fragmentation of neutral oligosaccharides were observed when the charge migrated from C-1 of the GalNAc to the GlcNAc residue followed by rearrangement to accommodate the 0,2 A-fragmentation. LC-MS also showed that O-linked aldoses existed as interchangeable α/β pyranose anomers, in addition to a third isomer (25% of the total free aldose) believed to be the furanose form.

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