Early Detection of Cyanobacterial Blooms and Associated Cyanotoxins using Fast Detection Strategy

Fast detection of cyanobacteria and cyanotoxins is achieved using a Fast Detection Strategy (FDS). Only 24 h are needed to unravel the presence of ...

University of Naples Federico II

The study of the secondary metabolites contained in the organic extract of Caribbean sponge Smenospongia aurea led to the isolation of smenothiazole A (3) and B (4), hybrid peptide/polyketide compounds. Assays performed using four solid tumor cell lines showed that smenothiazoles exert a potent cytotoxic activity at nanomolar levels, with selectivity over ovarian cancer cells and a pro-apoptotic mechanism. 

Isolation and assessment of the in vitro anti-tumor activity of smenothiazole A and B, chlorinated thiazole-containing peptide/polyketides from the Caribbean sponge, Smenospongia aurea.

Glycosylinositol phosphorylceramides (GIPCs) show a great structural diversity, but all share a small number of core structures, with a glucosamine, a mannose, or a glucuronic acid as the first sugar linked to the inositol. The Caribbean sponge  was shown to consistently contain zeamide (), the first example of a new class of GIPCs, in which the inositol is glycosylated by a d-arabinose. The structure of zeamide was determined by spectroscopic analysis (NMR, MS, ECD) and microscale chemical degradation. The 6--β-d-arabinopyranosyl--inositol (d-Ara(1β→6)Ins) core motif of zeamide is unprecedented not only among GIPCs, but also in any natural glycoconjugate.

Zeamide, a Glycosylinositol Phosphorylceramide with the Novel Core Arap(1β→6)Ins Motif from the Marine Sponge Svenzea zeai.

Smenamides are an intriguing class of peptide/polyketide molecules of marine origin showing antiproliferative activity against lung cancer Calu-1 cells at nanomolar concentrations through a clear pro-apoptotic mechanism. To probe the role of the activity-determining structural features, the 16--analogue of smenamide A and eight simplified analogues in the 16- series were prepared using a flexible synthetic route. The synthetic analogues were tested on multiple myeloma (MM) cell lines showing that the configuration at C-16 slightly affects the activity, since the 16--derivative is still active at nanomolar concentrations. Interestingly, it was found that the truncated compound , mainly composed of the pyrrolinone terminus, was not active, while compound , essentially lacking the pyrrolinone moiety, was 1000-fold less active than the intact substance and was the most active among all the synthesized compounds.

Smenamide A Analogues. Synthesis and Biological Activity on Multiple Myeloma Cells.

The organic extract of the Caribbean sponge  has been shown to contain an array of novel chlorinated secondary metabolites derived from a mixed PKS-NRPS biogenetic route such as the smenamides. In this paper, we report the presence of a biogenetically different compound known as smenopyrone, which is a polypropionate containing two γ-pyrone rings. The structure of smenopyrone including its relative and absolute stereochemistry was determined by spectroscopic analysis (NMR, MS, ECD) and supported by a comparison with model compounds from research studies. Pyrone polypropionates are unprecedented in marine sponges but are commonly found in marine mollusks where their biosynthesis by symbiotic bacteria has been hypothesized and at least in one case demonstrated. Since pyrones have recently been recognized as bacterial signaling molecules, we speculate that smenopyrone could mediate inter-kingdom chemical communication between  and its symbiotic bacteria.

Isolation of Smenopyrone, a Bis-γ-Pyrone Polypropionate from the Caribbean Sponge .

Fast Detection Strategy for Cyanobacterial blooms and associated Cyanotoxins (FDSCC) is a multidisciplinary strategy that allows early detection, in 24 man-hours, of cyanobacteria and related cyanotoxins in water and bivalve samples. This approach combines the advantages of remote/proximal sensing with those of analytical/bioinformatics analyses, namely, LC-HRMS-based molecular networking. The detection of Lyngbyatoxin A, a lipophilic cyanotoxin, in all analyzed water samples and in bivalves, commonly used as food, was the proof of the reliability of the new method.

A Fast Detection Strategy for Cyanobacterial blooms and associated cyanotoxins (FDSCC) reveals the occurrence of lyngbyatoxin A in campania (South Italy).

Covering: up to 2019This review covers the current status of the quantum mechanical prediction of chiroptical properties, such as electronic CD and optical rotation, as needed for stereochemical assignments in new natural products. The reliability of the prediction of chiroptical properties is steadily increasing, with a parallel decrease in the required computational resources. Now, quantum mechanical calculations for a medium-sized natural product can be reliably performed by natural product chemists on a mainstream PC. This review is aimed to guide natural product chemists through the numerous steps involved in such calculations. Through a concise, but comprehensive, discussion of the current computational practice, enriched by a few illustrative examples, this review provides readers with the theoretical background and practical knowledge needed to select the most appropriate parameters for performing the calculations, to anticipate possible problems, and to critically evaluate the reliability of their computational results. Common reasons for mistakes are also discussed; in particular, the importance of the correct evaluation of conformational ensembles of flexible molecules (an aspect often overlooked in current research) is stressed.

Computational prediction of chiroptical properties in structure elucidation of natural products.

Thirteen nitrogen-containing molecules (/ and -) were isolated from the Indonesian sponge , highlighting the richness of this organism as a source of alkaloids. Their structures were elucidated using one- and two-dimensional NMR spectroscopy and HR-ESI-MS, while the stereochemistry of the diketopiperazines was established using Marfey's method. All compounds were screened in our standard bioactivity assays, including antibacterial, antikinases, and amyloid β-42 assays. The most interesting bioactivity result was obtained with the known acanthocyclamine A (), which revealed for the first time a specific  antimicrobial activity and an inhibitory effect on amyloid β-42 production induced by aftin-5 and no cytotoxicity at the dose of 26 µM. These results highlight the potentiality of a bipiperidine scaffold as a promising skeleton for preventing or reducing the production of amyloid β-42, a key player in the initiation of Alzheimer's disease.

A Collection of Bioactive Nitrogen-Containing Molecules from the Marine Sponge .

Caribbean sponges of the genus  are a prolific source of chlorinated secondary metabolites. The use of molecular networking as a powerful dereplication tool revealed in the metabolome of  two new members of the smenamide family, namely smenamide F () and G (). The structure of smenamide F () and G () was determined by spectroscopic analysis (NMR, MS, ECD). The relative and the absolute configuration at C-13, C-15, and C-16 was determined on the basis of the conformational rigidity of a 1,3-disubstituted alkyl chain system (i.e., the C-12/C-18 segment of compound (). Smenamide F () and G () were shown to exert a selective moderate antiproliferative activity against cancer cell lines MCF-7 and MDA-MB-231, while being inactive against MG-63.

Germana Esposito

TheBlueChemistryLab,
Department of Pharmacy,
TheBlueChemistryLab, Department of Pharmacy

University of Naples Federico II

Early Detection of Cyanobacterial Blooms and Associated Cyanotoxins using Fast Detection Strategy

Germana Esposito

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}TheBlueChemistryLab,Department of Pharmacy,TheBlueChemistryLab, Department of Pharmacy

University of Naples Federico II

Early Detection of Cyanobacterial Blooms and Associated Cyanotoxins using Fast Detection Strategy

TheBlueChemistryLab,
Department of Pharmacy,
TheBlueChemistryLab, Department of Pharmacy