Search

Bioinorganic natural product chemistry is a relatively unexplored but rapidly developing field with enormous potential for applications in biology, biotechnology (especially in regards to nanomaterial development, synthesis and environmental cleanup) and biomedicine. In this review the occurrence of metals and metalloids in natural products and their synthetic derivatives are reviewed. A broad overview of the area is provided followed by a discussion on the more common metals and metalloids found in natural sources, and an overview of the requirements for future research. Special attention is given to metal hyperaccumulating plants and their use in chemical synthesis and bioremediation, as well as the potential uses of metals and metalloids as therapeutic agents. The potential future applications and development in the field are also discussed.

A series of novel hybrid 4-aminoquinoline 1,3,5-triazine derivatives was synthesized in a five-steps reaction and evaluated for their in vitro antimalarial activity against chloroquine-sensitive (3D7) and chloroquine-resistant (RKL-2) strains of Plasmodium falciparum. Entire synthetic derivatives showed higher antimalarial activity on the sensitive strain while two compounds, viz., 9a and 9c displayed good activity against both the strains of P. falciparum. The observed activity was further substantiated by docking study on both wild and qradruple mutant type P. falciparum dihydrofolate reductase-thymidylate synthase (pf-DHFR-TS).

La planta cannabis sativa tiene un largo historial de uso en el transcurso de la humanidad y, desde hace varias décadas, se ha retomado el interés por ella debido a su potencial terapéutico relacionado con diversidad de patologías. Sin embargo, el acercamiento a los aspectos toxicológicos, clínicos y terapéuticos de la planta, y sus derivados sintéticos se ha visto limitado, debido a las connotaciones culturales y legales que existen en la actualidad alrededor de su uso. Pues, dichos derivados sintéticos están siendo utilizados con fines recreativos, exponiendo a gran cantidad de personas a riesgos en su salud. En ese sentido, este artículo expondrá algunas generalidades sobre la planta, el sistema endocannabinoide y sus ligandos, su uso como droga de síntesis y su uso terapéutico, principalmente en las enfermedades neurodegenerativas del Parkinson y el Alzheimer. The cannabis sativa plant has a long history of use in the course of humanity and, since a few decades ago, has gained attention because of its therapeutic potential associated with diverse pathologies. However, the study of its toxicological, clinical and therapeutical properties, and its synthetic derivatives, has been limited due to cultural and legal connotations about its use. This is because such synthetic derivatives are being used for recreational purposes, exposing many people to health risks. Thus, this article will present some generalities about the plant, the endocannabinoid system and its ligands, its use as synthetic drug and its therapeutical use, especially in neurodegenerative diseases like Parkinson and Alzheimer.

This paper presents a review on kaurane diterpenes, covering various aspects of chemical and microbiological transformations of native ent-kaurenoic acid, namely, its reactions via COOH groups, double bonds and rearrangements of the carbon skeleton that lead to a wide range of natural and synthetic derivatives with potential biologic activities and can present convenient synthons for the syntheses of other native ent-kauranes.

DNA interactive agents have been used in the clinical setting for the treatment of cancer since the beginning of modern-era chemotherapy. Despite a shift of focus towards molecular targeted therapy, DNA remains a critical macromolecular target for anti-cancer intervention and the next generation of agents must conform to the optimum combination of increased therapeutic activity and reduced off-target toxicity. We evaluate the potential of non-covalent DNA binding small molecules as "gene-control" agents, exploiting inherent or engineered sequence selectivity, to target critical genomic sequences. In addition we review examples of natural products and synthetic derivatives that exert their activity through sequence specific DNA-covalent modification.

Although fungi produce highly structurally diverse metabolites, many of which have served as excellent sources of pharmaceuticals, no fungi-derived agent has been approved as a cancer drug so far. This is despite a tremendous amount of research being aimed at the identification of fungal metabolites with promising anticancer activities. This review discusses the results of clinical testing of fungal metabolites and their synthetic derivatives, with the goal to evaluate how far we are from an approved cancer drug of fungal origin. Also, because in vivo studies in animal models are predictive of the efficacy and toxicity of a given compound in a clinical situation, literature describing animal cancer testing of compounds of fungal origin is reviewed as well. Agents showing the potential to advance to clinical trials are also identified. Finally, the technological challenges involved in the exploitation of fungal biodiversity and procurement of sufficient quantities of clinical candidates are discussed, and potential solutions that could be pursued by researchers are highlighted.

The reaction of 2-oxo-1,2-dihydroquinoline-3-carbonyl chlorides and 2,6-dichloroquinolin-4-amine leads to the formation of N-(2,6-dichloroquinolin-4-yl)-2-oxo-1,2-dihydroquinoline-3-carboxamides. The latter is cyclized to fused [1,6]naphthyridine derivative – 3,13-dichlorobenzo[b]quino[4,3-h][1,6]naphthyridin-6(5H)-one, under heating in polyphosphoric acid at 150°C. The reaction sequence was generalized and was extended to synthetic derivatives. The structures of all synthesized compounds were confirmed by spectral data and elemental analysis.

Although considerable effort and progress has been made in the search for new anticancer drugs and treatments in the last several decades, cancer remains a major public health problem and one of the major causes of death worldwide. Many sources, including plants, animals, and minerals, are of interest in cancer research because of the possibility of identifying novel molecular therapeutics. Moreover, structure-activity-relationship (SAR) investigations have become a common way to develop naturally derived or semi-synthetic molecular analogues with improved efficacy and decreased toxicity. In 2012, approximately 138 molecules from marine sources, including isolated compounds and their associated analogues, were shown to be promising anticancer drugs. Among these, 62% are novel compounds. In this report, we review the marine compounds identified in 2012 that may serve as novel anticancer drugs.

Leishmaniasis is defined as a cluster of infectious diseases caused by protozoan parasites of the genus Leishmania. It is recognized worldwide as a major health problem, showing high endemicity in developing countries. The present review details this complex group of neglected diseases, with important clinical spectrum and large epidemiological diversity, and discusses the evolution of leishmaniasis treatment and the urgent need for less toxic, more specific and effective drugs against these parasites. Finally, the value of natural products and synthetic derivatives as rich sources of antileishmanial drug candidates is demonstrated, indicating a promising approach for the development of novel therapeutic alternatives.

The absolute configurations of natural esquelane derivatives 1 and 2, the main components of a commercially available fragrance, as well as their synthetic derivatives 3–7 were revised by using the vibrational circular dichroism (VCD) spectroscopy of 2 and 6 in combination with density functional theory calculations at the B3LYP/DGDZVP level of theory. The agreement between the experimental and calculated VCD spectra of these bisnorsesquiterpenes revealed that they are in fact (1S,4R,5S)-esquel-6-en-9-one 1 and (1S,4R,5R)-esquel-7-en-9-one 2 instead of the formerly reported enantiomers. The VCD method was also applied to cacalol acetate 9 in order to verify its absolute configuration, since cacalol 8 was previously used as a comparative motif to determine the absolute configuration of esquelane derivatives.

Background: Neglected tropical diseases are a group of infections caused by microorganisms and viruses that affect mainly poor regions of the world. In addition, most available drugs are associated with long periods of treatment and high toxicity which limits the application and patient compliance. Investment in research and development is not seen as an attractive deal by the pharmaceutical industry since the final product must ideally be cheap, not returning the amount invested. Natural products have always been an important source for bioactive compounds and are advantageous over synthetic compounds when considering the unique structural variety and biological activities. On the other hand, isolation difficulties and low yields, environmental impact and high cost usually limit their application as drug per se. Objective: In this review, the use of natural products as prototypes for the semi-synthesis or total synthesis, as well as natural products as promising hits is covered, specifically regarding compounds with activities against trypanosomatids such as Trypanosoma spp. and Leishmania spp. Methods: Selected reports from literature with this approach were retrieved. Conclusion: As summary, it can be concluded that natural products are an underestimated source for designing novel agents against these parasites.

The flavonoidal alkaloids or flavo alkaloids build a quite special group of natural products, where the typical flavonoid backbone (two aromatic rings are combined with an oxygen heterocycle) is linked with a nitrogen containing moiety too. Several plants, containing flavonoid alkaloids, were applied in the traditional medicine for the treatment of various diseases, e.g., infections, cold, cough, inflammation, icterohepatitis, laryngalgia, etc. In this review, the most important flavonoid alkaloids (ficine, isoficine, capitavine, buchenavianine, aquiledine, isoaquiledine, cheliensisine, lilanine, phyllospadine, lotthanongine, vochysine, dracocephins, drahebephins, davallioside, prolinalin, kopsirachin, uncaringambiriine, etc.) and their isolation, structure elucidation, biosynthesis, biological activity, and syntheses will be detailed. The synthetic derivatives, e.g., the antitumor Flavopiridol (Alvocidib, Sanofi-Tolero) and P276-00 (Piramal) will be discussed too.

The purpose of this chapter is to review and discuss the literature that has covered the most recent and highly impact researches related with the total synthesis of alkaloids and synthetic products classified as aza-polycycles. After a general introduction, our chapter will be devoted to the recent aspects developed for the stereoselective synthesis of three main aza-polycycles: First, we will refer to the novel synthetic strategies for the preparation of selected pyrrolo[2,1-a]isoquinoline alkaloids and their synthetic derivatives that have included the pharmacophores of known bioactive natural products (nuevamine, jantimine, crispine, and cryptaustoline). In the second place, our interest will focus on methods developed to control the stereochemistry of the C-1 center in the synthesis of 1-phenethyl-1,2,3,4-tetrahydroisoquinoline alkaloids, mainly those ones isolated from Dysoxylum lenticellare: (+)-dysoxyline, (+)-colchiethanamine, (+)-colchiethine, and (+)-homolaudanosine. Then, we will describe the current protocols for the synthesis of aporphine and homoaporphine alkaloids, highlighting and putting in perspective the role of 1-phenethyltetrahydroisoquinolines in the biosynthesis of homoaporphines and how this approach could be taken into account in the future development of strategies for the preparation of analogues to these alkaloids. In the final section, the chemistry of β-carbolines, a group of naturally occurring indole alkaloids that are prevalent in Harmala species but also exist in several marine tunicates, will be analyzed in terms of the methods developed for the total synthesis of these structures, including complete saturated and unsaturated compounds containing one or more chiral center. Additionally, challenging synthetic derivatives that have shown biomedical applications will also be incorporated. We have chosen these aza-polycycles as the main topic for this chapter due to their widely known biological activities and the pharmacological potential of the new derivatives to be discovered, which make them attractive targets for the development of novel approaches for their total synthesis that here we discuss. Besides the synthetic aspects and to increase the practical usefulness of our chapter, in each section we have also included a short, but comprehensive, summary of the diverse biological activities reported and studied for these natural structures in the 2010–2015 period.

Since a decade, there has been a strong consumer demand for more natural products. This has augmented inclination towards substitution of synthetic colorants with natural pigments. Natural pigments not only have the capacity to increase the marketability of products, they also demonstrate valuable biological activities as antioxidants and anticancer agents. There is a long history of exploitation of natural products produced by bacteria as sources of pharmaceutically important, bioactive compounds. Among natural pigments, pigments from microbial sources are potentially suitable alternatives to synthetic pigments. The red pigment prodigiosin (PG) has unusual properties, which have long been documented. The red-pigmented prodiginines are bioactive secondary metabolites produced by both Gram-negative and Gram-positive bacteria. Prodigiosins are characterized by a common pyrrolyl pyrromethene skeleton, and the biological role of these pigments in the producer organisms remains unclear. Bacterial prodigiosins and their synthetic derivatives are effective proapoptotic agents against various cancer cell lines, with multiple cellular targets including multi-drug resistant cells with little or no toxicity towards normal cell lines. However, research into the biology of pigment production will stimulate interest in the bioengineering of strains to synthesize useful prodiginine derivatives. This review article highlights the characteristics and potential applications of prodigiosin pigment from Serratia as prodigiosins are real potential therapeutic drugs.

The electrochemistry and cytotoxicity of marcanine A were investigated by electrochemical, computational and cellular studies. To enable a structure–toxicity-relationship of the natural product, eleven novel synthetic derivatives with different electrochemical properties were synthesized and tested. Derivative 5 revealed a GI50 in the low μM range, being more active than the actual natural product. A clear correlation was found between the experimental and the calculated data. published

In the search for new antimalarials, we used the quinone scaffold of marine secondary metabolites as a chemical starting point to synthesize new thiazinoquinone compounds. Most of synthetic derivatives have shown a significant pharmacological activity and some structural requirements, critical for both the antiplasmodial effect and cytotoxicity, have been evidenced. The redox properties of the prepared compounds have been investigated by computational studies and electrochemical assays, which indicated that a higher antiplasmodial activity of some thiazinoquinones is related to their greater ability to form the semiquinone species and strongly interact with free Fe(III)-protoporphyrin IX.

Sixteen derivatives, eight of which are new compounds, were prepared from cycloartenone (1) and cycloartanone (2), and the cytotoxic activity of 14 of these compounds, together with 1 and 2, was evaluated against a panel of four cell lines. Compound 1 was obtained from the epiphyte plant Tillandsia tenuifolia collected at Salta, Argentina. Due to chemoselectivity and regioselectivity problems observed in the reactions of compound 1, this substance was hydrogenated to compound 2. The attempted transformations were focused on ring A of the cited triterpenes with the aim to verify previous structure-activity relationships obtained from related compounds. The cytotoxicity results of the derivatives showed that only the diosphenol 13 displayed significant activity against all the tested cell lines. These results show that an oxidized side chain, for example an ether bridge between the side chain and ring D, is necessary for the cytotoxic activity of cycloartane derivatives. Fil: Zambrano, Elida Elisabeth. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Salta. Facultad de Ciencias Exactas; Argentina Fil: Casas, Adriana Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Investigaciones sobre Porfirinas y Porfirias. Universidad de Buenos Aires. Centro de Investigaciones sobre Porfirinas y Porfirias; Argentina Fil: Di Venosa, Gabriela Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Investigaciones sobre Porfirinas y Porfirias. Universidad de Buenos Aires. Centro de Investigaciones sobre Porfirinas y Porfirias; Argentina Fil: Uriburu Monasterio, Maria Laura. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Salta. Facultad de Ciencias Exactas; Argentina Fil: Duran, Fernando Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad de Microanálisis y Métodos Físicos en Química Orgánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Unidad de Microanálisis y Métodos Físicos en Química Orgánica; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; Argentina Fil: Palermo, Jorge Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad de Microanálisis y Métodos Físicos en Química Orgánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Unidad de Microanálisis y Métodos Físicos en Química Orgánica; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; Argentina

peer-reviewed The marine environment is a rich source of chemically diverse, biologically active natural products, and serves as an invaluable resource in the ongoing search for novel antimicrobial compounds. Recent advances in extraction and isolation techniques, and in state-of-the-art technologies involved in organic synthesis and chemical structure elucidation, have accelerated the numbers of antimicrobial molecules originating from the ocean moving into clinical trials. The chemical diversity associated with these marine-derived molecules is immense, varying from simple linear peptides and fatty acids to complex alkaloids, terpenes and polyketides, etc. Such an array of structurally distinct molecules performs functionally diverse biological activities against many pathogenic bacteria and fungi, making marine-derived natural products valuable commodities, particularly in the current age of antimicrobial resistance. In this review, we have highlighted several marine-derived natural products (and their synthetic derivatives), which have gained recognition as effective antimicrobial agents over the past five years (2012–2017). These natural products have been categorized based on their chemical structures and the structure-activity mediated relationships of some of these bioactive molecules have been discussed. Finally, we have provided an insight into how genome mining efforts are likely to expedite the discovery of novel antimicrobial compounds.

Novel emerging drugs of abuse, also referred as new psychoactive substances (NPS), constitute an ever-changing mixture of chemical compounds designed to circumvent legislative controls by means of chemical modifications of previously banned recreational drugs. One of such class, synthetic cathinones, namely β-keto derivatives of amphetamines, has been largely abused over the past decade. A number of new synthetic cathinones are detected each year, either in bulk powders/crystals or in biological matrices. It is therefore important to continuously monitor the supply of new synthetic derivatives and promptly report them. By using complementary analytical techniques (i.e. 1D and 2D NMR, FT-IR, GC-MS, HRMS and HPLC-UV), this study investigates the detection, identification and full characterization of 1-(4-methylphenyl)-2-(methylamino)-pentanone (4-methyl-pentedrone, 4-MPD), 1-(4-fluorophenyl)-2-(pyrrolidin-1-yl)-hexanone (4 F-PHP) and 1-(1,3-benzodioxol-5-yl)-2-(ethylamino)-1-pentanone (bk-EPDP), three emerging cathinone derivatives.

Lapachol (1), β-lapachone (2) and α-lapachone (3) are three well-studied natural products isolated from Tabebuia impetiginosa having most interesting chemodiversity and demonstrating diverse biological effects. Areas covered: The current review summarizes the recent and past discovery of chemotherapeutic agents based on the compounds 1-3. This review presents an overview of patents filed over the past two decades (1997 to 2016) mostly relating to the anticancer effects of these lapachol and lapachone analogues. Expert opinion: The large number of interesting patents published on the therapeutic potential of quinones 1-3 and their synthetic derivatives lends credence to the importance of these molecules. Moreover, these quinones demonstrated potent anticancer effects towards various cancer cell lines and chemical modification of these quinones have led to products displaying enhanced anticancer effects. It is noteworthy that the majority of patents published are on the anticancer effects of quinones 1-3 and their synthetic derivatives along with a limited number of additional biological effects. It is our opinion that in order to get lead compounds, there needs to be a greater focus on the elucidation of the precise mechanism of action of these compounds including SAR and in vivo studies.

Background Mycobacterium abscessus causes a wide range of clinical diseases that are difficult to treat. This microorganism is resistant not only to the classical antituberculosis agents but also to most of the antimicrobials that are currently available, resulting in limited therapeutic options and treatment failure. This scenario stresses the need to search for new drugs with activity against M. abscessus. Objective To evaluate in vitro the antimycobacterial activity and cytotoxicity of rifabutin (RFB 1) and ten derivatives (2-11) against M. abscessus ATCC 19977. Method The minimum inhibitory concentration (MIC) of the molecules was determined by the microdilution broth method according to the guideline described in CLSI. The toxicity evaluation was carried in 96-well microplates, using the cell line J774A.1 (ATCC TIB-67). Result From the eleven molecules tested, RFB 1 and RFB 4 were the compounds showing higher activities against M. abscessus, with MICs of 0.9 and 1.0 µM, respectively. The R1 and R2 moieties seem to have deciding influence over the final activity. Furthermore, N-oxide derivatives 9, 10, and 11 were also active against M. abscessus, with MICs of 7.2 µM, 1.8 µM and 3.8 µM, respectively. An explanatory hypothesis for the better activities of compounds RFB 1, RFB 4, RFB 10 and RFB 11 considers the likely hydrogen bonding between ligands and receptor, balancing the global flexibility and interaction energies. RFB 1 and its most effective derivatives were found to be not toxic. Conclusion Besides RFB 1, its derivatives 4, 10 and 11 show potential for clinical development in the M. abscessus treatment.

Summary There is increasing interest in developing cationic host defense peptides (HDPs) and their synthetic derivatives as antimicrobial, immunomodulatory, and anti-biofilm agents. These activities are often evaluated without considering biologically relevant concentrations of salts or serum; furthermore certain HDPs have been shown to aggregate in vitro . Here we examined the effect of aggregation on the immunomodulatory activity of a synthetic innate defense regulator peptide, 1018 (VRLIVAVRIWRR-NH 2 ). A variety of salts and solutes were screened to determine their influence on 1018 aggregation, revealing that this peptide "salts out" of solution in an anion-specific and concentration-dependent manner. Furthermore, the immunomodulatory activity of 1018 was found to be inhibited under aggregation-promoting conditions. A series of 1018 derivatives were synthesized with the goal of disrupting this self-assembly process. Indeed, some derivatives exhibited reduced aggregation while maintaining certain immunomodulatory functions, demonstrating that it is possible to engineer optimized synthetic HDPs to avoid unwanted peptide aggregation.

Esculetin, synonymous with 6,7-dihydroxycoumarin, is the main active ingredient of the traditional Chinese medicine Cortex Fraxini. The twig skin or trunk bark of Cortex Fraxini are used by herb doctors as a mild, bitter liver and gallbladder meridians’ nontoxic drug as well as dietary supplement. Recently, with a variety of novel esculetin derivatives being reported, the molecular mechanism research as well as clinical application of Cortex Fraxini and esculetin are becoming more attractive. This mini-review will consolidate what is known about the biological activities, the mechanism of esculetin and its synthetic derivatives over the past decade in addition to providing a brief synopsis of the properties of esculetin.

Biotin/(strept)avidin self-assembly is a powerful platform for nanoscale fabrication and capture with many different applications in science, medicine, and nanotechnology. However, biotin/(strept)avidin self-assembly has several well-recognized drawbacks that limit performance in certain technical areas and there is a need for synthetic mimics that can either become superior replacements or operational partners with bio-orthogonal recognition properties. The goal of this tutorial review is to describe the recent progress in making high affinity synthetic association partners that operate in water or biological media. The review starts with a background summary of biotin/(strept)avidin self-assembly and the current design rules for creating synthetic mimics. A series of case studies are presented that describe recent success using synthetic derivatives of cyclodextrins, cucurbiturils, and various organic cyclophanes such as calixarenes, deep cavitands, pillararenes, and tetralactams. In some cases, two complementary partners associate to produce a nanoscale complex and in other cases a ditopic host molecule is used to link two partners. The article concludes with a short discussion of future directions and likely challenges.

Antimicrobial natural preparations involving cinnamon, storax and propolis have been long used topically for treating infections. Cinnamic acids and related molecules are partly responsible for the therapeutic effects observed in these preparations. Most of the cinnamic acids, their esters, amides, aldehydes and alcohols, show significant growth inhibition against one or several bacterial and fungal species. Of particular interest is the potent antitubercular activity observed for some of these cinnamic derivatives, which may be amenable as future drugs for treating tuberculosis. This review intends to summarize the literature data on the antimicrobial activity of the natural cinnamic acids and related derivatives. In addition, selected hybrids between cinnamic acids and biologically active scaffolds with antimicrobial activity were also included. A comprehensive literature search was performed collating the minimum inhibitory concentration (MIC) of each cinnamic acid or derivative against the reported microorganisms. The MIC data allows the relative comparison between series of molecules and the derivation of structure-activity relationships.

Naturally occurring aromatic abietane diterpenoids (dehydroabietanes) exhibit a wide range of biological activities. A number of synthetic studies aimed at modifying the abietane skeleton in order to obtain new potential chemotherapeutic agents have been reported. In this study, the biological activities of synthetic derivatives of aromatic abietane diterpenoids are reviewed.

Apoptosis is a critical defense mechanism against the formation and progression of cancer and exhibits distinct morphological and biochemical traits. Targeting apoptotic pathways becomes an intriguing strategy for the development of chemotherapeutic agents particularly if the process is selective to cancer cells. Marine natural products have become important sources in the discovery of antitumour drugs, especially when recent technological and methodological advances have increased the scope of investigations of marine organisms. A high number of individual compounds from diverse organisms have induced apoptosis in several tumour cell lines via a number of mechanisms. Here, we review the effects of selected marine natural products and their synthetic derivatives on apoptosis signalling pathways in association with their pharmacological properties. Providing an outlook into the future, we also examine the factors that contribute to new discoveries and the difficulties associated with translating marine-derived compounds into clinical trials.

Ever since the discovery of cyclodextrins, a family of cyclic oligosaccharides based on α (1 → 4) linkage among glucopyranose subunits, these versatile supramolecular hosts have received tremendous attention for scientific explorations. Due to their property of forming host-guest type inclusion complex, cyclodextrins and their synthetic derivatives exhibit wide range of utilities in different areas viz. pharmaceuticals, drug delivery systems, cosmetics, food and nutrition, textile and chemical industry etc.The purpose of this review is to highlight properties, advantages, recent studies and versatile benefits of cyclodextrins and to re-strengthen their prospective applications in novel directions for future research.This article summarizes a variety of applications of cyclodextrins in various industrial products, technologies, analytical and chemical processes and recent industrial advancements by extensively literature search on various scientific databases, Google and websites of various associated pharmaceutical industries and patenting authorities across the world.Due to possibility of multidimensional changes in physical and chemical properties of molecules upon inclusion complexation in cyclodextrins, these compounds are of great commercial interest and may offer solution to many of the scientific problems of the current world.

The 26S proteasome has many important roles in the biological functions of the cells, and proteasome inhibitors have multiple and complex activities on cells. These compounds can be natural or synthesized. Most synthetic derivatives have been rationally designed, synthesized and optimized to obtain the best selectivity and increase the activity. The design of chemical entities with desired molecular identification, which plays an important role in biological systems, is provided by pharmacophore modeling. Indeed, pharmacophore models can be established either in a ligand-based manner or in a receptor-based manner.The authors discuss the application of pharmacophore modeling techniques to proteasome inhibitors development. Furthermore, the article reviews the classification of the currently discovered proteasome inhibitors where the principal mechanism of action and clinical application are represented.In the era of new drug development, database of compounds should be thoroughly evaluated with a combination of methods that consider both pharmacophore- and ligand-based virtual screening. The concept of pharmacophore helps to discover new active compounds and to evaluate their activity. The nature of proteasome inhibitor pharmacophore affects the secondary active-site specificity; indeed, increasing specificity decreases the cytotoxicity of the proteasome inhibitors. It is hypothesized that the balanced simultaneous modulation of a few druggable targets may have superior efficacy and fewer side effects than single-target or combination therapies for the treatment of human cancers. The discovery of new compounds should aim to find more active compounds that improve the compliance of patients.

Molecules with antibiotic properties, produced by various microbes, have been around long before mankind recognized their usefulness in preventing and treating bacterial infections. Bacteria have therefore been exposed to selection pressures from antibiotics for very long times, however, generally only on a micro-scale within the immediate vicinity of the antibiotic-producing organisms. In the twentieth century we began mass-producing antibiotics, mainly synthetic derivatives of naturally produced antibiotic molecules, but also a few entirely synthetic compounds. As a consequence, entire bacterial communities became exposed to unprecedented antibiotic selection pressures, which in turn led to the rapid resistance development we are facing today among many pathogens. We are, rightly, concerned about the direct selection pressures of antibiotics on the microbial communities that reside in or on our bodies. However, other environments, outside of our bodies, may also be exposed to antibiotics through different routes, most often unintentionally. There are concerns that increased selection pressures from antibiotics in the environment can contribute to the recruitment of resistance factors from the environmental resistome to human pathogens. This paper attempts to 1) provide a brief overview of environmental exposure routes of antibiotics, 2) provide some thoughts about our current knowledge of the associated risks for humans as well as ecosystems, and 3) indicate management options to reduce risks.

Structures of plant furanolabdanoids and synthetic schemes for a series of furanolabdanoids (coronarins A and E, hedychenone, acuminolide and 17-O-acetylacuminolide) from the available diterpenoids sclareol and larixol were reviewed. Attention was focused on transformations of available furanolabdanoids. Data on the biological activity of native metabolites and their synthetic derivatives were presented.

Recently, the methylene-cycloakylacetate (MCA) scaffold has been reported as a potential pharmacophore for neurite outgrowth activity. In this work, natural diterpenes that embed MCA fragments are reviewed, as they are major components of Halimium viscosum: ent-halimic acid, the prototype for these bioactive compounds. Herein, structures, sources, and activities for the natural diterpenes, as well as their synthetic derivatives of interest, are reviewed.

The mosquito Aedes aegypti (Diptera, Culicidae) is the vector of yellow and dengue fever. In this study, chemometric tools, such as, Principal Component Analysis (PCA), Consensus PCA (CPCA), and Partial Least Squares Regression (PLS), were applied to a set of fifty five active compounds against Ae. aegypti larvae, which includes terpenes, cyclic alcohols, phenolic compounds, and their synthetic derivatives. The calculations were performed using the VolSurf+ program. CPCA analysis suggests that the higher weight blocks of descriptors were SIZE/SHAPE, DRY, and H2O. The PCA was generated with 48 descriptors selected from the previous blocks. The scores plot showed good separation between more and less potent compounds. The first two PCs accounted for over 60% of the data variance. The best model obtained in PLS, after validation leave-one-out, exhibited q(2) = 0.679 and r(2) = 0.714. External prediction model was R(2) = 0.623. The independent variables having a hydrophobic profile were strongly correlated to the biological data. The interaction maps generated with the GRID force field showed that the most active compounds exhibit more interaction with the DRY probe.

A series of 4-methoxybenzoylhydrazones 1–30 was synthesized and the structures of the synthetic derivatives elucidated by spectroscopic methods. The compounds showed a varying degree of antiglycation activity, with IC50 values ranging between 216.52 and 748.71 µM, when compared to a rutin standard (IC50 = 294.46 ± 1.50 µM). Compounds 1 (IC50 = 216.52 ± 4.2 µM), 3 (IC50 = 289.58 ± 2.64 µM), 6 (IC50 = 227.75 ± 0.53 µM), 7 (IC50 = 242.53 ± 6.1) and 11 (IC50 = 287.79 ± 1.59) all showed more activity that the standard, and these compounds have the potential to serve as possible leads for drugs to inhibit protein glycation in diabetic patients. A preliminary SAR study was performed.

A large number of bioactive pentacyclic triterpenoids have been shown to have multiple biological activities. This study was conducted to evaluate the inhibitory activities of 6 newly synthesized and novel pentacyclic triterpenoids against enterovirus 71 (EV71). The parent compound, ursolic acid (UA), showed the greatest inhibitory activity against EV71, while oleanolic acid (OA), asiatic acid (AA), and synthetic derivatives of 18-β-glycyrrhetinic acid (GA) and OA also exhibited inhibitory effects, although to lesser extents. The results suggest these compounds show potential for further optimization as antiviral candidates for treatment of EV71 infections.

Marine organisms have been found to be a very rich source of bioactive molecules. Among marine organisms, sponges have been proven to be excellent producers of secondary metabolites. More than 5,300 compounds have been isolated from sponges with around 200 new molecules reported each year. Bromopyrrole alkaloids constitute a family of exclusively marine alkaloids and represent a fascinating example of the large variety of compounds formed by marine sponges which exhibit different biological activities such as antifeedent, anti-biofilm, anticancer, antiinflammatory, antimicrobial, immunomodulatory, analgesic, antiserotonergic, antiangiogenic, antihistaminic, chitinase inhibitor and actimyosin ATPase activator. More than 140 derivatives with different structures and biological activities, have been isolated from more than 20 different sponges. Most of these alkaloids share a key building block, pyrrole-imidazole with oroidin being their underlying structural motif. In this review detailed account of isolation and medicinal application of marine bromopyrrole alkaloids and their synthetic derivatives are discussed.

Transient receptor potential (TRP) channels represent interesting molecular target structures involved in a number of different physiological and pathophysiological systems. In particular, TRPA1 channel is involved in nociception and in sensory perception of many pungent chemesthetic compounds, which are widespread in spices and food plants, including Perilla frutescens. A natural compound from P. frutescens (isoegomaketone) and 16 synthetic derivatives of perillaketone have been prepared and tested in vitro on rTRPA1 expressed in HEK293 cells and their potency, efficacy and desensibilisation activity measured. Most derivatives proved to be high potency agonists of TRPA1, with a potency higher than most natural agonists reported in the literature. These furylketones derivatives, represent a new class of chemical structures active on TRPA1 with many potential applications in the agrifood and pharmaceutical industry.

The spasmolytic activity of diterpenoid alkaloids of various structural types that were isolated from plants of the genera Aconitum, Delphinium, and Consolida and their synthetic derivatives was studied in vitro using the barium-chloride contraction model of isolated sections of rat and rabbit small intestine. The structure–activity relationship of the spasmolytic activity was analyzed.

Chrysin is one of flavones constituents of Orocylumineicum vent. It has been a hot spot as a potential chemopreventive agent and as a natural molecule with numerous biological activities such as antioxidant, antitumor, antiviral, anti-hypertension, anti-diabetic, antibacterial, and so on in recent years. Because of its poor solubility, small intestinal absorption, and the rapid metabolism of glycosylation, a large number of efforts had been made by domestic and foreign researchers on designing its analogs and conjugates to obtain compounds with improved efficacy and selectivity for developing more active drugs for clinic. This article reviews the current research of studying on chrysin derivatives including their properties and possible applications. Additionally, this article also presents the basic information concerning chemical reactivity of chrysin, relevant to the synthesis of its derivatives.

A new model of lung cell membrane chromatography has been established by using a lung cell membrane stationary phase (CMSP), in which lung cell membranes were immobilized on activated silica by the adsorption. Retention characteristics of 2-methoxyestradiol (2-ME) and its synthetic derivatives were investigated under the chromatographic conditions described. The affinities of 2-ME and its synthetic derivatives were expressed by k′ values. The affinity of drugs in the lung cell membrane was consistent with the results of cytotoxicity in vitro. The study indicated that 2-ME had the property of adsorption on the membrane of the lung.

Oxidation of phenosafranin and an excess of aniline gave a novel hydroxylated derivative of pseudo-mauveine. N-Methyl- p-toluidine and bis(4-methylphenyl)amine are efficient building blocks for making mauveine-related chromophores. Their oxidation with K2Cr2O7 is believed to form nitrogen centred radicals which then couple with an aromatic amine by homolytic aromatic substitution of hydrogen. The N-methyl substituent and the p-methyl sub-stituents are essential for the reaction to proceed. N-Methyl substituted chromophores were not demethylated in the reaction or by oxidation with K2Cr2O7 in dilute H2SO4. N-Nitroso-bis(4-methylphenyl)amine rearranges smoothly to the orange compound, (2-nitro-4-methylphenyl)-4-methylphenylamine, when a solution in CH2Cl2 is treated with montmorillonite at room temperature for 24 h. 2,4-Dimethylaniline has been used to make a mauveine homologue. The colour of silk dyed with mauveine chromophores has been compared to the colour of silk dyed with authentic 1862 mauveine.

Ligustrazine, a natural product from Rhizoma Chuanxiong containing a pyrazine ring, has been widely used in China for treatment of heart diseases. Because of its remarkable effects but rapid metabolism, studies on structural modification of ligustrazine have attracted much attention. Ligustrazine synthetic derivatives reported in recent decades can be divided into ethers, esters, amides and piperazines, olefins, and others. These derivatives are mainly derived from four primary intermediates. The lack of a comprehensive and recent review on this topic prompted us to gather more new information. This paper is a compilation of almost all of the 304 synthetic ligustrazine derivatives we encountered; the information included is expected to be of benefit to further studies of ligustrazine.

The emergence of multidrug-resistant Staphylococcus aureus coupled with a declining output of new antibiotic treatment options from the pharmaceutical industry is a growing worldwide healthcare problem. Multidrug efflux pumps are known to play a role in antibiotic and biocide resistance in S. aureus. These membrane transporters are capable of extruding drugs and other structurally unrelated compounds, hence decreasing intracellular concentration and increasing survival. Coadministration of efflux pump inhibitors (EPIs) with antibiotics that are pump substrates could increase intracellular drug levels, thus bringing renewed efficacy to existing antistaphylococcal agents. Numerous EPIs have been identified or synthesized over the past two decades; these include existing pharmacologic drugs, naturally occurring compounds, and synthetic derivatives thereof. This review describes the current progress in EPI development for use against S. aureus.

Cancer continues to be a major public health problem despite the efforts that have been made in the search for novel drugs and treatments. The current sources sought for the discovery of new molecules are plants, animals and minerals. During the past decade, the search for anticancer agents of marine origin to fight chemo-resistance has increased greatly. Each year, several novel anticancer molecules are isolated from marine organisms and represent a renewed hope for cancer therapy. The study of structure-function relationships has allowed synthesis of analogues with increased efficacy and less toxicity. In this report, we aim to review 42 compounds of marine origin and their derivatives that were published in 2011 as promising anticancer compounds.

Artemisinin and synthetic derivatives of dihydroartemisinin are known to possess various biological activities. Post-functionalization of dihydroartemisinin with triazole heterocycles has been proven to lead to enhanced therapeutic potential. By using our newly developed triazolization strategy, a library of unexplored fused and 1,5-disubstituted 1,2,3-triazole derivatives of dihydroartemisinin were synthesized in a single step. All these newly synthesized compounds were characterized and evaluated for their anti-HIV (Human Immunodeficiency Virus) potential in MT-4 cells. Interestingly; three of the synthesized triazole derivatives of dihydroartemisinin showed activities with half maximal inhibitory concentration (IC50) values ranging from 1.34 to 2.65 µM. ispartof: Molecules vol:22 issue:2 pages:303- ispartof: location:Switzerland status: published

Cancer is a major problem of public health and one of the main causes of death around the globe. According to World Health Organization, the prevalence of this disease is rising, however, more rapidly in Africa, Asia, and Central and South America that account for about 70% of cancer deaths in the world. The chemotherapy is one of the ways to treat this disease and the advances in anticancer drugs have improved patient care. Plants have been used to treat different diseases since ancient times. Among the anticancer drugs, about 50% come from natural products as isolated or semisynthetic or related synthetic compounds and plants represent important source of these substances. Taxol, vinca alkaloids, camptothecin, and podophyllotoxins, as well as their semisynthetic or synthetic derivatives, are the most important anticancer drugs obtained from plants. In this chapter, we review the importance of plants as source of drugs and describe these anticancer compounds. The continuing search for antitumor agents from plants is extremely necessary to find the possible ways to have safe and more effective treatment for this health problem.

Derivatives are the functional form that speculative capital assumes in markets. The notional amount of derivatives in 2015, as reported by the Bank for International Settlement, was $550 trillion. That number does not include the synthetic derivatives, so it grossly – by a factor of many multiples – underestimates the size of capital earmarked for derivatives-type trading. Speculative capital operating as derivatives is the glue that holds the financial markets together. This chapter explains the nature of that mechanism. We offer no policy recommendations, only a description of the conditions that prevail in the markets and the potential effects of disturbing them through regulation.