Tanjungides A and B: New Antitumoral Bromoindole Derived Compounds from Diazona cf formosa. Isolation and Total Synthesis

Tanjungides A (1) (Z isomer) and B (2) (E isomer), two novel dibrominated indole enamides, have been isolated from the tunicate Diazona cf formosa. Their structures were determined by spectroscopic methods including HRMS, and extensive 1D and 2D NMR. The stereochemistry of the cyclised cystine present in both compounds was determined by Marfey’s analysis after chemical degradation and hydrolysis. We also report the first total synthesis of these compounds using methyl 1H-indole-3-carboxylate as starting material and a linear sequence of 11 chemical steps. Tanjungides A and B exhibit significant cytotoxicity against human tumor cell lines.     

Antioxidant and Antimicrobial Potential of the Bifurcaria bifurcata Epiphytic Bacteria

Surface-associated marine bacteria are an interesting source of new secondary metabolites. The aim of this study was the isolation and identification of epiphytic bacteria from the marine brown alga, Bifurcaria bifurcata, and the evaluation of the antioxidant and antimicrobial activity of bacteria extracts. The identification of epiphytic bacteria was determined by 16S rRNA gene sequencing. Bacteria extracts were obtained with methanol and dichloromethane (1:1) extraction. The antioxidant activity of extracts was performed by quantification of total phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and oxygen radical absorbance capacity (ORAC). Antimicrobial activities were evaluated against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Salmonella enteritidis, Staphylococcus aureus, Saccharomyces cerevisiae and Candida albicans. A total of 39 Bifurcaria bifurcata-associated bacteria were isolated and 33 were identified as Vibrio sp. (48.72%), Alteromonas sp. (12.82%), Shewanella sp. (12.26%), Serratia sp. (2.56%), Citricoccus sp. (2.56%), Cellulophaga sp. (2.56%), Ruegeria sp. (2.56%) and Staphylococcus sp. (2.56%). Six (15.38%) of the 39 bacteria Bifurcaria bifurcata-associated bacteria presented less than a 90% Basic Local Alignment Search Tool (BLAST) match, and some of those could be new. The highest antioxidant activity and antimicrobial activity (against B. subtilis) was exhibited by strain 16 (Shewanella sp.). Several strains also presented high antimicrobial activity against S. aureus, mainly belonging to Alteromonas sp. and Vibrio sp. There were no positive results against fungi and Gram-negative bacteria. Bifurcaria bifurcata epiphytic bacteria were revealed to be excellent sources of natural antioxidant and antimicrobial compounds.     

Chemistry and Biology of Bengamides and Bengazoles,Bioactive Natural Products from Jaspis Sponges

Sponges corresponding to the Jaspidae family have proved to be a prolific source of bioactive natural products. Among these, the bengamides and the bengazoles stand out by virtue of their unprecedented molecular architectures and impressive biological profiles, including antitumor, antibiotic and anthelmintic properties. As a consequence, intense research activity has been devoted to these compounds from both chemical and biological standpoints. This review describes in detail the research into these classes of natural products and the benefits they offer in chemistry and biology.     

Palmitic Acid and Ergosta-7,22-dien-3-ol Contribute to the Apoptotic Effect and Cell Cycle Arrest of an Extract from Marthasterias glacialis L. in Neuroblastoma Cells

We describe the effect of a chemically characterized lipophilic extract obtained from Marthasterias glacialis L. against human breast cancer (MCF-7) and human neuroblastoma (SH-SY5Y) cell lines. Evaluation of DNA synthesis revealed that both cell lines were markedly affected in a concentration-dependent way, the SH-SY5Y cell line being more susceptible. Cell cycle arrest was observed, an effect induced by the sterol, ergosta-7,22-dien-3-ol, present in the extract. Morphological evaluation of treated cells showed the advent of lipid droplets and chromatin condensation compatible with apoptosis, which was confirmed by the evaluation of caspase-3 and -9 activities. Palmitic acid was the main compound responsible for this apoptotic effect by a ceramide-independent mechanism that involved endoplasmic reticulum (ER)-stress with upregulation of CCAAT/-enhancer-binding protein homologous protein (CHOP).     

Nano- and Microdelivery Systems for Marine Bioactive Lipids

There is an increasing body of evidence of the positive impact of several marine lipids on human health. These compounds, which include ω-3 polyunsaturated fatty acids, have been shown to improve blood lipid profiles and exert anti-inflammatory and cardioprotective effects. The high instability of these compounds to oxidative deterioration and their hydrophobicity have a drastic impact in their pharmacokinetics. Thus, the bioavailability of these compounds may be affected, resulting in their inability to reach the target sites at effective concentrations. In this regard; micro/nanoparticles can offer a wide range of solutions that can prevent the degradation of targeted molecules, increase their absorption, uptake and bioavailability. In this work we will present the options currently available concerning micro- and nanodelivery systems for marine lipids; with emphasis on micro/nanoparticles; such as micro/nanocapsules and emulsions. A wide range of bottom-up approaches using casein, chitosan, cyclodextrins, among others; will be discussed.     

Polyunsaturated Aldehydes from Large Phytoplankton of the Atlantic Ocean Surface (42°N to 33°S)

Polyunsaturated aldehydes (PUAs) are organic compounds mainly produced by diatoms, after cell wounding. These compounds are increasingly reported as teratogenic for species of grazers and deleterious for phytoplanktonic species, but there is still scarce information regarding concentration ranges and the composition of PUAs in the open ocean. In this study, we analyzed the spatial distribution and the type of aldehydes produced by the large-sized (>10 μm) phytoplankton in the Atlantic Ocean surface. Analyses were conducted on PUAs released after mechanical disruption of the phytoplankton cells, referred to here as potential PUAs (pPUAs). Results show the ubiquitous presence of pPUA in the open ocean, including upwelling areas, as well as oligotrophic gyres. Total pPUA concentrations ranged from zero to 4.18 pmol from cells in 1 L. Identified PUAs were heptadienal, octadienal and decadienal, with heptadienal being the most common (79% of total stations). PUA amount and composition across the Atlantic Ocean was mainly related to the nitrogen:phosphorus ratio, suggesting nutrient-driven mechanisms of PUA production. Extending the range of trophic conditions considered by adding data reported for productive coastal waters, we found a pattern of PUA variation in relation to trophic status.     

Biosynthetic Modularity Rules in the Bisintercalator Family of Antitumor Compounds

Diverse actinomycetes produce a family of structurally and biosynthetically related non-ribosomal peptide compounds which belong to the chromodepsipeptide family. These compounds act as bisintercalators into the DNA helix. They give rise to antitumor, antiparasitic, antibacterial and antiviral bioactivities. These compounds show a high degree of conserved modularity (chromophores, number and type of amino acids). This modularity and their high sequence similarities at the genetic level imply a common biosynthetic origin for these pathways. Here, we describe insights about rules governing this modular biosynthesis, taking advantage of the fact that nowadays five of these gene clusters have been made public (thiocoraline, triostin, SW-163 and echinomycin/quinomycin). This modularity has potential application for designing and producing novel genetic engineered derivatives, as well as for developing new chemical synthesis strategies. These would facilitate their clinical development.     

Maritime Halophyte Species from Southern Portugal as Sources of Bioactive Molecules

Extracts of five halophytes from southern Portugal (Arthrocnemum macrostachyum, Mesembryanthemum edule, Juncus acutus, Plantago coronopus and Halimione portulacoides), were studied for antioxidant, anti-inflammatory and in vitro antitumor properties. The most active extracts towards the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical were the methanol extracts of M. edule (IC₅₀ = 0.1 mg/mL) and J. acutus (IC₅₀ = 0.4 mg/mL), and the ether extracts of J. acutus (IC₅₀ = 0.2 mg/mL) and A. macrostachyum (IC₅₀ = 0.3 mg/mL). The highest radical scavenging activity (RSA) against the 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical was obtained in the ether extract of J. acutus (IC₅₀ = 0.4 mg/mL) and H. portulacoides (IC₅₀ = 0.9 mg/mL). The maximum total phenolic content (TPC) was found in the methanol extract of M. edule (147 mg gallic acid equivalents (GAE)/g) and in the ether extract of J. acutus (94 mg GAE/g). Significant decreases in nitric oxide (NO) production were observed after incubation of macrophages with lipopolysaccharide (LPS) and the chloroform extract of H. portulacoides (IC₅₀ = 109 µg/mL) and the hexane extract of P. coronopus (IC₅₀ = 98.0 µg/mL). High in vitro cytotoxic activity and selectivity was obtained with the ether extract of J. acutus. Juncunol was identified as the active compound and for the first time was shown to display selective in vitro cytotoxicity towards various human cancer cells.     

Diazaquinomycins E–G,Novel Diaza-Anthracene Analogs from a Marine-Derived Streptomyces sp.

As part of our program to identify novel secondary metabolites that target drug-resistant ovarian cancers, a screening of our aquatic-derived actinomycete fraction library against a cisplatin-resistant ovarian cancer cell line (OVCAR5) led to the isolation of novel diaza-anthracene antibiotic diazaquinomycin E (DAQE; 1), the isomeric mixture of diazaquinomycin F (DAQF; 2) and diazaquinomycin G (DAQG; 3), and known analog diazaquinomycin A (DAQA; 4). The structures of DAQF and DAQG were solved through deconvolution of X-Ray diffraction data of their corresponding co-crystal. DAQE and DAQA exhibited moderate LC₅₀ values against OVCAR5 of 9.0 and 8.8 μM, respectively. At lethal concentrations of DAQA, evidence of DNA damage was observed via induction of apoptosis through cleaved-PARP. Herein, we will discuss the isolation, structure elucidation, and biological activity of these secondary metabolites.     

Developing scoring functions for soil quality to assess land suitability for irrigated wheat in Southern Algeria

Efficient land-use management could be optimized through appropriate advice regarding land suitability and achieving a reasonable yield while preserving soil and environmental conditions. The main objective of this study was to determine and define those locations capable of wheat cultivation with irrigation in the municipality of N’goussa (Southern Algeria). Expert opinion (EO) method was used for selecting minimum soil data set (MDS_-EO), where six influencing soil properties (sand, pH, salinity, organic matter, gypsum and lime) and other three key parameters (slope, land use/land cover, and proximity to roads and electricity network) were considered important for irrigated wheat cultivation in the study area. Indicators were weighted according to principal component analysis (PCA) loadings and summed. PCA revealed that the selected nine indicators are appropriate for accounting 73.63% of the total variance. Two maps of land suitability were created here (expressed as a soil quality index within a range from 0 to 1) from multivariate analysis and already known standard scoring functions (SSFs) by using two data sets (pure and scored). The distribution of soil quality index (IQI) showed that above 70% of the land was moderately (MS) to highly suitable (HS) for irrigated wheat. The estimation accuracy of soil quality classes has been evaluated using random forests (RF), having as a dependent variable the final class of land suitability used in each map. It was determined that estimation accuracy could reach 60% (pure data set) and 65% (scored data set) at 0.5 cut-off value for soil quality classes. Final prioritizing according to ranks of sensitivity index (SI) and efficiency ratio (ER) showed that IQI obtained from scored data set is the most suitable approach in soil quality assessment of arid areas. Therefore, it could be applied in southern Algeria for land management, integrated planning and environmental assessments.