Effect of Oxylipins, Terpenoid Precursors and Wounding on Soft Corals' Secondary Metabolism as Analyzed via UPLC/MS and Chemometrics

Metabolomics approach of Symphyotrichum squamatum ethanol extract and its nano-Ag formulation protective effect on gastric ulcer via bio-chemical and pathological analyses

ContextGastric ulcer (GU) a widely distributed ailment is associated with many causes, including alcohol consumption.Materials and MethodsChemical profiling of Symphyotrichum squamatum ethanol extract (SSEE) was established via ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC-qTOF-MS) and employed in a silver nano-formulation (SSEE-N-Ag). SSEE and SSEE-N-Ag antiulcer activities were estimated against ethanol-induced rats by biochemical, histological, and metabolomics assessments. Reduced glutathione, total antioxidant capacity and prostaglandin E2 levels and gastric mucosa histopathological examination were analysed. The rats' metabolome changing alongside action pathways were elucidated via metabolite profile coupled to multivariate data analysis.ResultsUPLC-MS profiling of SSEE identified 75 components belonging to various classes. Compared with control, EtOH-treated rats showed decreased of tissue GSH, TAC and PGE2 by 62.32%, 51.85% and 47.03% respectively. SSEE and SSEE-N-Ag administration mitigated biochemical and histopathological alterations. Serum metabolomics analysis revealed for changes in several low molecular weight metabolites with ulcer development. These metabolites levels were restored to normal post-administration of SSEE-N-Ag. SSEE-N-Ag as mediated via modulating numerous metabolic pathways such as lipids, pyrimidine, energy metabolism and phosphatidylinositol signalling. This study provides novel insight for metabolic mechanisms underlying gastric ulcer relieving effect.ConclusionPresent results revealed potential antiulcer effect of SSEE and SSEE-N-Ag by decreasing ulcer-associated syndromes, supporting their anti-ulcerogenic action.

Characterization of lipid droplets from a Taxus media cell suspension and their potential involvement in trafficking and secretion of paclitaxel

Our paper describes the potential roles of lipid droplets of Taxus media cell suspension in the biosynthesis and secretion of paclitaxel and, therefore, highlights their involvement in improving its production. Paclitaxel (PTX) is a highly potent anticancer drug that is mainly produced using Taxus sp. cell suspension cultures. The main purpose of the current study is to characterize cellular LDs from T. media cell suspension with a particular focus on the biological connection of their associated proteins, the caleosins (CLOs), with the biosynthesis and secretion of PTX. A pure LD fraction obtained from T. media cells and characterized in terms of their proteome. Interestingly, the cellular LD in T. media sequester the PTX. This was confirmed in vitro, where about 96% of PTX (C⁰_PTX,_aq [mg L^-1]) in the aqueous solution was partitioned into the isolated LDs. Furthermore, silencing of CLO-encoding genes in the T. media cells led to a net decrease in the number and size of LDs. This coincided with a significant reduction in expression levels of TXS, DBAT and DBTNBT, key genes in the PTX biosynthesis pathway. Subsequently, the biosynthesis of PTX was declined in cell culture. In contrast, treatment of cells with 13-hydroperoxide C18:3, a substrate of the peroxygenase activity, induced the expression of CLOs, and, therefore, the accumulation of cellular LDs in the T. media cells cultures, thus increasing the PTX secretion. The accumulation of stable LDs is critically important for effective secretion of PTX. This is modulated by the expression of caleosins, a class of LD-associated proteins with a dual role conferring the structural stability of LDs as well as regulating lipidic bioactive metabolites via their enzymatic activity, thus enhancing the biosynthesis of PTX.

Metabolomics by UHPLC-Q-TOF Reveals Host Tree-Dependent Phytochemical Variation in Viscum album L

Viscum album L., commonly known as European mistletoe, is a hemi-parasitic plant of the Santalaceae family. The in vitro and in vivo effects of V. album differ, according to its host tree. However, little is known about the host-dependent phytochemical diversity in V. album. In this study, the metabolic profiles of V. album ssp. album from Malus domestica Bork., Quercus robur L., and Ulmus carpinifolia Gled were compared. Leaves, stems, and berries were collected in Switzerland, by the same procedure, in September 2016 and 2017. The methanolic extracts were analyzed by ultra-performance liquid chromatography, coupled to electrospray quadrupole time-of-flight mass spectrometry in positive ionization mode. The data were submitted to partial-least square discriminant analysis (PLS-DA) and the results showed that the V. album ssp. album samples were clustered into three groups, according to the three distinct host trees. Seven compounds, with high VIP scores (variable importance in projection), were responsible for this differentiation. The following four compounds were detected in both the harvest years: arginine, pipecolic acid or lysine, dimethoxycoumarin, and sinapyl alcohol, suggesting their use as host specific V. album biomarkers. The present work highlights the importance of standardized harvest and analytical procedures for the reproducibility of the chemical results of herbal materials.

Cloning and expression analysis of mevalonate kinase and phosphomevalonate kinase genes associated with the MVA pathway in Santalum album

Sandalwood (Santalum album L.) is highly valued for its fragrant heartwood and extracted oil. Santalols, which are the main components of that oil, are terpenoids, and these are biosynthesized via the mevalonic acid (MVA) pathway. Mevalonate kinase (MK) and phosphomevalonate kinase (PMK) are key enzymes in the MVA pathway. Little is known about the genes that encode MK and PMK in S. album or the mechanism that regulates their expression. To isolate and identify the functional genes involved in santalol biosynthesis in S. album, an MK gene designated as SaMK, and a PMK gene designated as SaPMK, were cloned from S. album. The sequences of these genes were analyzed. A bioinformatics analysis was conducted to assess the homology of SaMK and SaPMK with MK and PMK genes from other plants. The subcellular localization of SaMK and SaPMK proteins was also investigated, as was the functional complementation of SaMK and SaPMK in yeast. Our results show that the full-length cDNA sequences of SaMK and SaPMK were 1409 bp and 1679 bp long, respectively. SaMK contained a 1381 bp open reading frame (ORF) encoding a polypeptide of 460 amino acids and SaPMK contained a 1527 bp ORF encoding a polypeptide of 508 amino acids. SaMK and SaPMK showed high homology with MK and PMK genes of other plant species. Functional complementation of SaMK in a MK-deficient mutant yeast strain YMR208W and SaPMK in a PMK-deficient mutant yeast strain YMR220W confirmed that cloned SaMK and SaPMK cDNA encode a functional MK and PMK, respectively, mediating MVA biosynthesis in yeast. An analysis of tissue expression patterns revealed that SaMK and SaPMK were constitutively expressed in all the tested tissues. SaMK was highly expressed in young leaves but weakly expressed in sapwood. SaPMK was highly expressed in roots and mature leaves, but weakly expressed in young leaves. Induction experiments with several elicitors showed that SaMK and SaPMK expression was upregulated by methyl jasmonate. These results will help to further study the role of MK and PMK genes during santalol biosynthesis in S. album.

Marine and terrestrial endophytic fungi: a mine of bioactive xanthone compounds, recent progress, limitations, and novel applications

Endophytic fungi are a kind of fungi that colonizes living plant tissues presenting a myriad of microbial adaptations that have been developed in such a hidden environment. Owing to its large diversity and particular habituation, they present a golden mine for research in the field of drug discovery. Endophytic fungal communities possess unique biocatalytic machinery that furnishes a myriad of complex natural product scaffolds. Xanthone compounds are examples of endophytic secondary metabolic products with pronounced biological activity to include: antioxidant, antimicrobial, anti-inflammatory, antithrombotic, antiulcer, choleretic, diuretic, and monoamine oxidase inhibiting activity.The current review compiles the recent progress made on the microbiological production of xanthones using fungal endophytes obtained from both marine and terrestrial origins, with comparisons being made among both natural resources. The biosynthesis of xanthones in endophytic fungi is outlined along with its decoding enzymes. Biotransformation reactions reported to be carried out using different endophytic microbial models are also outlined for xanthones structural modification purposes and the production of novel molecules.A promising application of novel computational tools is presented as a future direction for the goal of optimizing microbial xanthones production to include establishing metabolic pathway databases and the in silico analysis of microbial interactions. Metagenomics methods and related bioinformatics platforms are highlighted as unexplored tools for the biodiversity analysis of endophytic microbial communities that are difficult to be cultured.

A Brief Review on New Naturally Occurring Cembranoid Diterpene Derivatives from the Soft Corals of the Genera Sarcophyton, Sinularia, and Lobophytum Since 2016

This work reviews the new isolated cembranoid derivatives from species of the genera Sarcophyton, Sinularia, and Lobophytum as well as their biological properties, during 2016–2018. The compilation permitted to conclude that much more new cembranoid diterpenes were found in the soft corals of the genus Sarcophyton than in those belonging to the genera Lobophytum or Sinularia. Beyond the chemical composition, the biological properties were also reviewed, namely anti-microbial against several Gram-positive and Gram-negative bacteria and fungi, anti-inflammatory and anti-tumoral against several types of cancer cells. In spite of the biological activities detected in almost all samples, there is a remarkable diversity in the results which may be attributed to the chemical variability that needs to be deepened in order to develop new molecules with potential application in medicine.

Marine natural products

Covering: January to December 2017This review covers the literature published in 2017 for marine natural products (MNPs), with 740 citations (723 for the period January to December 2017) referring to compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, mangroves and other intertidal plants and microorganisms. The emphasis is on new compounds (1490 in 477 papers for 2017), together with the relevant biological activities, source organisms and country of origin. Reviews, biosynthetic studies, first syntheses, and syntheses that led to the revision of structures or stereochemistries, have been included. Geographic distributions of MNPs at a phylogenetic level are reported.