Discovery Of Bioactive Compounds Research Articles

Brazilian Red Propolis Attenuates Inflammatory Signaling Cascade in LPS-Activated Macrophages.

Although previous studies suggested an anti-inflammatory property of Brazilian red propolis (BRP), the mechanisms involved in the anti-inflammatory effects of BRP and its activity on macrophages were still not elucidated. This study aimed to evaluate whether BRP attenuates the inflammatory effect of LPS on macrophages and to investigate its underlying mechanisms. BRP was added to RAW 264.7 murine macrophages after activation with LPS. NO production, cell viability, cytokines profile were evaluated. Activation of inflammatory signaling pathways and macrophage polarization were determined by RT-qPCR and Western blot. BRP at 50 μg/ml inhibited NO production by 78% without affecting cell viability. Cd80 and Cd86 were upregulated whereas mrc1 was down regulated by BRP indicating macrophage polarization at M1. BRP attenuated the production of pro-inflammatory mediators IL-12, GM-CSF, IFN-Ɣ, IL-1β in cell supernatants although levels of TNF- α and IL-6 were slightly increased after BRP treatment. Levels of IL-4, IL-10 and TGF-β were also reduced by BRP. BRP significantly reduced the up-regulation promoted by LPS of transcription of genes in inflammatory signaling (Pdk1, Pak1, Nfkb1, Mtcp1, Gsk3b, Fos and Elk1) and of Il1β and Il1f9 (fold-change rate > 5), which were further confirmed by the inhibition of NF-κB and MAPK signaling pathways. Furthermore, the upstream adaptor MyD88 adaptor-like (Mal), also known as TIRAP, involved in TLR2 and TLR4 signaling, was down- regulated in BRP treated LPS-activated macrophages. Given that BRP inhibited multiple signaling pathways in macrophages involved in the inflammatory process activated by LPS, our data indicated that BRP is a noteworthy food-source for the discovery of new bioactive compounds and a potential candidate to attenuate exhacerbated inflammatory diseases.

Metagenomic Analysis of Upwelling-Affected Brazilian Coastal Seawater Reveals Sequence Domains of Type I PKS and Modular NRPS.

Marine environments harbor a wide range of microorganisms from the three domains of life. These microorganisms have great potential to enable discovery of new enzymes and bioactive compounds for industrial use. However, only ~1% of microorganisms from the environment can currently be identified through cultured isolates, limiting the discovery of new compounds. To overcome this limitation, a metagenomics approach has been widely adopted for biodiversity studies on samples from marine environments. In this study, we screened metagenomes in order to estimate the potential for new natural compound synthesis mediated by diversity in the Polyketide Synthase (PKS) and Nonribosomal Peptide Synthetase (NRPS) genes. The samples were collected from the Praia dos Anjos (Angel’s Beach) surface water—Arraial do Cabo (Rio de Janeiro state, Brazil), an environment affected by upwelling. In order to evaluate the potential for screening natural products in Arraial do Cabo samples, we used KS (keto-synthase) and C (condensation) domains (from PKS and NRPS, respectively) to build Hidden Markov Models (HMM) models. From both samples, a total of 84 KS and 46 C novel domain sequences were obtained, showing the potential of this environment for the discovery of new genes of biotechnological interest. These domains were classified by phylogenetic analysis and this was the first study conducted to screen PKS and NRPS genes in an upwelling affected sample

Identification of epiphytic bacterial communities associated with the brown alga Splachnidium rugosum

Marine macroalgae host diverse bacterial communities with which they share a complex array of chemical interactions based on the exchange of nutrients, minerals and secondary metabolites. The brown alga Splachnidium rugosum is a rich source of a valuable fucose-containing sulphated polysaccharide (fucoidan). It grows exclusively in the Southern Hemisphere along temperate shores. While growth and development are dependent on specific microbial interactions, the microbiome of S. rugosum has not been characterized. This study reports on the composition and uniqueness of epiphytic bacterial communities associated with S. rugosum. Sporophytes were collected during winter (July 2012) from the Western Cape (−34° 18′ 5.0004″, +18° 48′ 59.0004″), South Africa. Culture-based methods relied on a range of selective marine media including marine agar, nutrient sea water agar, nutrient agar and thiosulfate-citrate-bile-salts-sucrose agar. Epiphytic isolates were identified to species level by 16S rRNA gene sequence analysis and encompassed 39 Gram-negative and 2 Gram-positive bacteria. Isolates were classified as Gamma-Proteobacteria, Alpha-Proteobacteria, Firmicutes or Bacteriodetes. Gamma-Proteobacteria were the most abundant, dominated by Vibrio and Pseudoalteromonas species. Three isolates displayed low sequence identity (˂97 %) with their closest relatives and were grouped into the genera Shewanella, Sphingomonas and Sulfitobacter. All bacterial isolates (41) were screened for anti-microbial activity against indicator strains of Bacillus cereus, Staphylococcus epidermidis, Mycobacterium smegmatis, Micrococcus luteus and Pseudomonas putida. Fifteen isolates (36 %) displayed antimicrobial activity against one or more of the indicator strains. One isolate (Pseudomonas sp.) was active against all strains tested. Splachnidium rugosum is a valuable source for the discovery of bioactive compounds of bacterial origin active against human pathogens.

Gliotoxin Inhibits Proliferation and Induces Apoptosis in Colorectal Cancer Cells.

The discovery of new bioactive compounds from marine natural sources is very important in pharmacological research. Here we developed a Wnt responsive luciferase reporter assay to screen small molecule inhibitors of cancer associated constitutive Wnt signaling pathway. We identified that gliotoxin (GTX) and some of its analogues, the secondary metabolites from marine fungus Neosartorya pseufofischeri, acted as inhibitors of the Wnt signaling pathway. In addition, we found that GTX downregulated the β-catenin levels in colorectal cancer cells with inactivating mutations of adenomatous polyposis coli (APC) or activating mutations of β-catenin. Furthermore, we demonstrated that GTX induced growth inhibition and apoptosis in multiple colorectal cancer cell lines with mutations of the Wnt signaling pathway. Together, we illustrated a practical approach to identify small-molecule inhibitors of the Wnt signaling pathway and our study indicated that GTX has therapeutic potential for the prevention or treatment of Wnt dependent cancers and other Wnt related diseases.

Antileishmanial activity of compounds produced by endophytic fungi derived from medicinal plant Vernonia polyanthes and their potential as source of bioactive substances.

The purpose of this work was to evaluate the antileishmanial activity of endophytic fungi isolated from leaves of Vernonia polyanthes plant and their prospective use in the discovery of bioactive compounds. Sixteen endophytes were isolated by using potato dextrose agar medium and submitted to cultivation in rice medium. The fungal cultures were extracted with ethanol and used as crude extracts for testing their antileishmanial activity. The most active ethanol extract was obtained from P2-F3 strain, which was identified as Cochliobolus sativus by ITS rRNA gene sequence data. Followed by a bioassay-guided fractionation, the cochlioquinone A, isocochlioquinone A and anhydrocochlioquinone A compounds were isolated from the crude extracts and demonstrated to inhibit the parasites. From the present work, it is possible to conclude that endophytic fungi derived from medicinal plant V. polyanthes may be considered promising source for the discovery of bioactive compounds.

Rare Chromones from a Fungal Mutant of the Marine-Derived Penicillium purpurogenum G59.

Three new and rare chromones, named epiremisporine B (2), epiremisporine B1 (3) and isoconiochaetone C (4), along with three known remisporine B (1), coniochaetone A (5) and methyl 8-hydroxy-6-methyl-9-oxo-9H-xanthene-1-carboxylate (6) were isolated from a mutant from the diethyl sulfate (DES) mutagenesis of a marine-derived Penicillium purpurogenum G59. The structures of 2–4 including the absolute configurations were determined by spectroscopic methods, especially by NMR analysis and electronic circular dichroism (ECD) experiments in conjunction with calculations. The absolute configuration of the known remisporine B (1) was determined for the first time. Compounds 2 and 3 have a rare feature that has only been reported in one example so far. The compounds 1–6 were evaluated for their cytotoxicity against several human cancer cell lines. The present work explored the great potential of our previous DES mutagenesis strategy for activating silent fungal pathways, which has accelerated the discovery of new bioactive compounds.

Non-mycorrhizal endophytic fungi from orchids.

Orchidaceae is one of the largest flowering plant families of the plant kingdom. The habitats of orchids are highly diverse, ranging from tree bark and damp forest floors to rock crevices, sandy dunes and semi-arid deserts. The diversity of endophytes (internal symbiotic fungi) associated with orchids is enormous. Most studies of endophytic fungi from orchids in the past have focused on mycorrhizal endophytes (internal symbiotic fungi associated with plant roots). There has, however, been an increasing trend to study nonmycorrhizal endophytes from orchids because of their physiological roles and their potential as sources of novel bioactive compounds. This review discusses the methods used in the isolation and identification of endophytic fungi from orchids, their diversity and host-specificity, their significance in orchid conservation and cultivation, and their potential application in the discovery of bioactive compounds.

Draft genome sequence of Paenibacillus algorifonticola sp. nov., an antimicrobial-producing strain.

Paenibacillus algorifonticola sp. nov. is isolated from a cold spring sample from Xinjiang Uyghur Autonomous Region (China), a novel strain that can produce antimicrobial substance against human pathogenic bacteria and fungi, including Staphylococcus aureus and Candida albicans. Here we report a 7.60-Mb assembly of its genome sequence and other useful information, including the coding sequences (CDSs) responsible for the biosynthesis of antibacterial factors, anaerobic respiration and several immune-associated reactions. Also, prospective studies on P.algorifonticola sp. nov. in the cold spring might offer a potential source for the discovery of bioactive compounds with medical value. The data repository is deposited on the website http://www.ncbi.nlm.nih.gov/nuccore/LAQO00000000 and the accession number is LAQO00000000.

Discovery of novel bioactive natural product-like compounds based on diversity-enhanced reactions

Diversity-enhanced reaction (DER), a non-selectivity and non-specificity reaction, is proposed to increase the diversified chemical structures of natural products for drug discovery (Fig. 1). We have applied this method to quickly synthesize a number of BB1608-like derivatives (Scheme 1). 2 underwent DER to afford a mixture. Separation and derivatization provided 3 – 12, Compounds 3 – 12 were evaluated for their anticancer and antiviral activities. The development of more complex DER is in progress. [The work described in this paper was supported by HKBU Interdisciplinary Research Matching Scheme (RC-IRMS/12 – 13/03) and Natural Science Foundation of China (No. 21402166)].

Anti-quorum Sensing Effetcs of Ethanolic Crude Extract of Anethum graveolens L.

In the recent years, effort to interfere with the quorum sensing (QS) has taken researchers consideration into the discovery and identification of bioactive compounds secreted by prokaryotes and eukaryotes. In this research, the anti-QS activity of thirty one plant species was detected through the inhibition of the QS related behaviors, violacein pigmentation in Chromobacterium violaceum CV026 and plant tissue maceration in Pectobacterium carotovorum. The results revealed that the arial parts extract of seven plant species interfered quorum sensing phenotypes in bacteria which amoung them, the dill (Anethum graveolens L.) extract effectively inhibited violacein production in CV026 and singificantly reduced tissue maceration in test plants. The result substantiates that the dill extract has decreased (>13 mm) violacein production in biosensor besides possessing slight antimicrobial property (<7.5 mm). Both potato tubers and calla-lily slices inoculated with Pcc-extract showed significant reduction in tissue maceration, while the tubers and slices inoculated with Pcc and Pcc-DMSO were strongly macerated. GC-MS analysis of the A. graveolens extract indicated that the oil was consisted eight phytocompounds of which the Eugenol (49.62 %) as major component. This results suggest that plants have mimic quorum-sensing signals which could be serving as potential sources to disrupt quorum sensing in associated bacteria.

Top-down Targeted Metabolomics Reveals a Sulfur-Containing Metabolite with Inhibitory Activity against Angiotensin-Converting Enzyme in Asparagus officinalis.

The discovery of bioactive natural compounds containing sulfur, which is crucial for inhibitory activity against angiotensin-converting enzyme (ACE), is a challenging task in metabolomics. Herein, a new S-containing metabolite, asparaptine (1), was discovered in the spears of Asparagus officinalis by targeted metabolomics using mass spectrometry for S-containing metabolites. The contribution ratio (2.2%) to the IC50 value in the crude extract showed that asparaptine (1) is a new ACE inhibitor.

Dereplication of known nucleobase and nucleoside compounds in natural product extracts by capillary electrophoresis-high resolution mass spectrometry.

Nucleobase and nucleoside compounds exist widely in various organisms. An often occurring problem in the discovery of new bioactive compounds from natural products is reisolation of known nucleobase and nucleoside compounds. To resolve this problem, a capillary electrophoresis-high resolution mass spectrometry (CE-HR-MS) method providing both rapid separation and accurate mass full-scan MS data was developed for the first time to screen and dereplicate known nucleobase and nucleoside compounds in crude extracts of natural products. Instrumental parameters were optimized to obtain optimum conditions for CE separation and electrospray ionization-time-of-flight mass spectrometry (ESI-TOF/MS) detection. The proposed method was verified to be precise, reproducible, and sensitive. Using this method, known nucleobase and nucleoside compounds in different marine medicinal organisms including Syngnathus acus Linnaeus; Hippocampus japonicus Kaup and Anthopleura lanthogrammica Berkly were successfully observed and identified. This work demonstrates that CE-HR-MS combined with an accurate mass database may be used as a powerful tool for dereplicating known nucleobase and nucleoside compounds in different types of natural products. Rapid dereplication of known nucleobase and nucleoside compounds allows researchers to focus on other leads with greater potential to yield new substances.

Natural products as leads in schistosome drug discovery.

Schistosomiasis is a neglected parasitic tropical disease that claims around 200,000 human lives every year. Praziquantel (PZQ), the only drug recommended by the World Health Organization for the treatment and control of human schistosomiasis, is now facing the threat of drug resistance, indicating the urgent need for new effective compounds to treat this disease. Therefore, globally, there is renewed interest in natural products (NPs) as a starting point for drug discovery and development for schistosomiasis. Recent advances in genomics, proteomics, bioinformatics, and cheminformatics have brought about unprecedented opportunities for the rapid and more cost-effective discovery of new bioactive compounds against neglected tropical diseases. This review highlights the main contributions that NP drug discovery and development have made in the treatment of schistosomiasis and it discusses how integration with virtual screening (VS) strategies may contribute to accelerating the development of new schistosomidal leads, especially through the identification of unexplored, biologically active chemical scaffolds and structural optimization of NPs with previously established activity.

Evaluation of Antibiotic Biosynthetic Potential of Actinomycete Isolates to Produce Antimicrobial Agents

Aim: To assess the antibiotic biosynthetic potential of actinomycete isolates from rhizospheric soil samples collected from Ngaka Modiri Molema district in North West Province of South Africa. Study Design : Th e analysis of biosynthetic gene clusters through PCR - based approach presents a useful foundation for the discovery of bioactive compounds.

Nephroprotective effects of ferulic acid, Z-ligustilide and E-ligustilide isolated from Angelica sinensis against cisplatin toxicity in vitro

Cisplatin (CisPt), a chemotherapeutic drug applied against solid tumors, is highly detrimental to the kidney. The risk of acute kidney injury implies adequate patient hydration to ensure sufficient diuresis; this strategy, now implemented in clinical practice, remains however incompletely satisfactory. New pharmacological approaches relying on the discovery of bioactive compounds need to be developed.Based on previous studies reporting renoprotective activities for extracts of Angelica sinensis (Oliv.) Diels roots, three of its major active compounds, ferulic acid, Z-ligustilide and E-ligustilide, were investigated for possible alleviation of CisPt-induced nephrotoxicity. Five phenomena involved in acute kidney injury and subsequent fibrosis were investigated: (i) modulation of cell survival via reduction of the apoptosis rate; (ii) reduction of oxidative stress; (iii) improvement of tubular regeneration capacities through proliferation and migration; (iv) limitation of extracellular matrix and collagen deposition; and (v) prevention of the dedifferentiation processes via the β-catenin pathway.Ferulic acid emerged as the most potent compound for alleviating cell death and collagen deposition, and for enhancing cell regeneration capacities. It also partially inhibited the β-catenin pathway, but was ineffective in lowering oxidative stress. Z- and E-ligustilides, however, were effective for limiting the oxidative stress, but only moderately affected other parameters. Ferulic acid appears to be a promising nephroprotective drug lead deserving further preclinical investigation.

Structural diversity oriented synthesis to explore the living world

Structural diversity oriented synthesis aims to fulfill the unoccupied tridimensional "chemical space" gap left by traditional chemical libraries. Through the development of novel synthetic strategies relying on divergent reactions, chemist is now able to realize in only two or three steps such library that ensures the access of a large number of products having a good quality in term of structural diversity. A few examples are presented to illustrate how this can be done in the context of increasing molecular complexity and diversity devoted to the discovery and optimization of bioactive compounds.

The Tribe Caesalpinieae (Fabaceae): An Updated Review on Pharmacological Aspects

Caesalpinieae tribe is one of the largest archaic tribes of subfamily Caesalpinioideae, family Fabaceae. Caesalpinieae tribe includes 9 subtribes that have more than 47 genera, including several valuable medicinal plants. Extracts of different plants of Caesalpinieae tribe were reported to possess a wide range of pharmacological activities, including anti-oxidant, anti-bacterial, anti-inflammatory, cytotoxic, anti-diabetic, antifungal, hepatoprotective, gastroprotective, analgesic, anti-arthritic, anti-filarial, antimalarial, anthelmintic, amoebicidal, diuretic, anti-psoriatic, anti-estrogenic, anti-fertility, wound-healing, anxiolytic, cardioprotective, immunomodulatory, anti-HIV activities. Thus, Caesalpinieae tribe includes several plants with a potential for exploitation as a source for plant-based pharmaceutical products. The present review could form a sound basis for further investigation in the potential discovery of new natural bioactive compounds and provide preliminary information for future research.

MCR synthesis of a tetracyclic tetrazole scaffold

Scaffold diversity is key in the ongoing exercise of discovery of novel bioactive compounds using high throughput screening (HTS). Based on the Ugi tetrazole synthesis we have designed novel bi- and tri-cyclic scaffolds featuring interesting pharmacophore properties. The compounds of the scaffold (B) are synthesizable in large diversity and numbers in two steps using (hetero)phenylethylamines, HN3, oxo components and iscyanoacetaldehyde(dimethylacetale). The chemistry is amenable to parallel synthesis and is used to enhance and fill the screening decks of the European Lead factory (ELF). Here, we are reporting full experimental details, scope and limitations of the reaction, cheminformatic analysis and the 3D structures of selected compounds.

Increased bioassay sensitivity of bioactive molecule discovery using metal-enhanced bioluminescence

We report the use of bioluminescence signal enhancement via proximity to deposited silver nanoparticles for bioactive compound discovery. This approach employs a whole-cell bioreporter harboring a plasmid-borne fusion of a specific promoter incorporated with a bioluminescence reporter gene. The silver deposition process was first optimized to provide optimal nanoparticle size in the reaction time dependence with fluorescein. The use of silver deposition of 350 nm particles enabled the doubling of the bioluminescent signal amplitude by the bacterial bioreporter when compared to an untouched non-silver-deposited microtiter plate surface. This recording is carried out in the less optimal but necessary far-field distance. SEM micrographs provided a visualization of the proximity of the bioreporter to the silver nanoparticles. The electromagnetic field distributions around the nanoparticles were simulated using Finite Difference Time Domain, further suggesting a re-excitation of non-chemically excited bioluminescence in addition to metal-enhanced bioluminescence. The possibility of an antiseptic silver effect caused by such a close proximity was eliminated disregarded by the dynamic growth curves of the bioreporter strains as seen using viability staining. As a highly attractive biotechnology tool, this silver deposition technique, coupled with whole-cell sensing, enables increased bioluminescence sensitivity, making it especially useful for cases in which reporter luminescence signals are very weak.

ChemInform Abstract: Peptides Come Round: Using SICLOPPS Libraries for Early Stage Drug Discovery

AbstractReview: 45 refs.