Natural Product Chemistry Research Articles

The Natural Product Chemistry of Terpenoids - a Tribute to the Remarkable Legacy of Academician Pavel Vlad

The purpose of this paper is to put forward concisely some of the most valuable scientific contributions of academician Pavel Vlad and his disciples to the field of natural product chemistry of terpenoids. Under the guidance and with direct contribution of academician Pavel Vlad, new approaches to determining the absolute configuration of a series of labdanic diterpenoids and of converting them into bi-, tri- and tetra- cyclic compounds have been designed. Novel universal methods for synthesizing tetrahydrofurans from 1,4-glycols, olefins from tertiary alcoholic acetates, as well as dienones by means of photodehydrogenation of unsaturated cyclic ketons have been developed by academician Pavel Vlad.

Chemistry and Pharmacological Activity of Sesquiterpenoids from the Chrysanthemum Genus.

Plants from the Chrysanthemum genus are rich sources of chemical diversity and, in recent years, have been the focus of research on natural products chemistry. Sesquiterpenoids are one of the major classes of chemical constituents reported from this genus. To date, more than 135 sesquiterpenoids have been isolated and identified from the whole genus. These include 26 germacrane-type, 26 eudesmane-type, 64 guaianolide-type, 4 bisabolane-type, and 15 other-type sesquiterpenoids. Pharmacological studies have proven the biological potential of sesquiterpenoids isolated from Chrysanthemum species, reporting anti-inflammatory, antibacterial, antitumor, insecticidal, and antiviral activities for these interesting molecules. In this paper, we provide information on the chemistry and bioactivity of sesquiterpenoids obtained from the Chrysanthemum genus which could be used as the scientific basis for their future development and utilization.

Ethnobotany, Phytochemistry and Pharmacology of Pericopsis laxiflora (Baker) Meeuwen (Leguminosae) – A Review

Pericopsis laxiflora (Family Leguminosae) is a medicinal plant that is ubiquitous especially in the tropical and savannah regions. There are many reports on folkloric and traditional medicinal uses that include haemorrhoids, rheumatism, abdominal pain treatment, diarrhoea, and dysentery, fever, skin diseases and jaundice. Peer-reviewed articles were gathered by consulting the databases of Scopus, Medline, Web of Science, PubMed, Science Direct and Google Scholar. Phytochemical investigations have revealed many bioactive compounds such as β-carboline derivative and tryptamine derivative. The plant has been examined on the basis of the in vitro, in vivo or clinical evaluations and shown to possess major pharmacological activities. These include anti-trypanosomal, antimicrobial, antibacterial, antioxidant and anti-malarial activities. In the present review, an attempt has been made to congregate the traditional, phytochemical and pharmacological studies performed on Pericopsis laxiflora. Comprehensive safety and efficacy studies must be conducted on the plant. Generally, there are knowledge gaps that must be filled. Thus this review is intended for practitioners and researchers in the fields of ethnopharmacology, natural product chemistry and drug discovery related research.

Future direction of agrochemical development for plant disease in China

AbstractThe growth of the global population poses a huge challenge to food security. The continuous application of crop protection products has many negative effects including increased pesticide resistance, accumulation of residues, and ecological damage. The challenge for the future is to develop agrochemicals with that are effective, with a high degree of selectivity, environmental friendliness, a low use rate, and cost‐effectiveness. Cutting‐edge developments in natural product chemistry, asymmetric synthesis, and rational drug design, as well as an increasing knowledge of the mechanisms that induce plant immunity, have provided potential solutions. In this review, we discuss the comprehensive use of emerging technologies that will help to tackle these current challenges and issues, highlighting the discovery of novel crop production products and their beneficial properties.

Presence of Bromotyrosine Alkaloids in Marine Sponges Is Independent of Metabolomic and Microbiome Architectures.

ABSTRACTMarine sponge holobionts are prolific sources of natural products. One of the most geographically widespread classes of sponge-derived natural products is the bromotyrosine alkaloids. A distinguishing feature of bromotyrosine alkaloids is that they are present in phylogenetically disparate sponges. In this study, using sponge specimens collected from Guam, the Solomon Islands, the Florida Keys, and Puerto Rico, we queried whether the presence of bromotyrosine alkaloids potentiates metabolomic and microbiome conservation among geographically distant and phylogenetically different marine sponges. A multi-omic characterization of sponge holobionts revealed vastly different metabolomic and microbiome architectures among different bromotyrosine alkaloid-harboring sponges. However, we find statistically significant correlations between the microbiomes and metabolomes, signifying that the microbiome plays an important role in shaping the overall metabolome, even in low-microbial-abundance sponges. Molecules mined from the polar metabolomes of these sponges revealed conservation of biosynthetic logic between bromotyrosine alkaloids and brominated pyrrole-imidazole alkaloids, another class of marine sponge-derived natural products. In light of prior findings postulating the sponge host itself to be the biosynthetic source of bromotyrosine alkaloids, our data now set the stage for investigating the causal relationships that dictate the microbiome-metabolome interconnectedness for marine sponges in which the microbiome may not contribute to natural product biogenesis.IMPORTANCE Our work demonstrates that phylogenetically and geographically distant sponges with very different microbiomes can harbor natural product chemical classes that are united in their core chemical structures and biosynthetic logic. Furthermore, we show that independent of geographical dispersion, natural product chemistry, and microbial abundance, overall sponge metabolomes tightly correlate with their microbiomes.

Methods for Identifying Microbial Natural Product Compounds that Target Kinetoplastid RNA Structural Motifs by Homology and De Novo Modeled 18S rRNA.

The development of novel anti-infectives against Kinetoplastids pathogens targeting proteins is a big problem occasioned by the antigenic variation in these parasites. This is also a global concern due to the zoonosis of these parasites, as they infect both humans and animals. Therefore, we need not only to create novel antibiotics, but also to speed up the development pipeline for these antibiotics. This may be achieved by using novel drug targets for Kinetoplastids drug discovery. In this study, we focused our attention on motifs of rRNA molecules that have been created using homology modeling. The RNA is the most ambiguous biopolymer in the kinetoplatid, which carries many different functions. For instance, tRNAs, rRNAs, and mRNAs are essential for gene expression both in the pro-and eukaryotes. However, all these types of RNAs have sequences with unique 3D structures that are specific for kinetoplastids only and can be used to shut down essential biochemical processes in kinetoplastids only. All these features make RNA very potent targets for antibacterial drug development. Here, we combine in silico methods combined with both computational biology and structure prediction tools to address our hypothesis. In this study, we outline a systematic approach for identifying kinetoplastid rRNA-ligand interactions and, more specifically, techniques that can be used to identify small molecules that target particular RNA. The high-resolution optimized model structures of these kineoplastids were generated using RNA 123, where all the stereochemical conflicts were solved and energies minimized to attain the best biological qualities. The high-resolution optimized model’s structures of these kinetoplastids were generated using RNA 123 where all the stereochemical conflicts were solved and energies minimized to attain the best biological qualities. These models were further analyzed to give their docking assessment reliability. Docking strategies, virtual screening, and fishing approaches successfully recognized novel and myriad macromolecular targets for the myxobacterial natural products with high binding affinities to exploit the unmet therapeutic needs. We demonstrate a sensible exploitation of virtual screening strategies to 18S rRNA using natural products interfaced with classical maximization of their efficacy in phamacognosy strategies that are well established. Integration of these virtual screening strategies in natural products chemistry and biochemistry research will spur the development of potential interventions to these tropical neglected diseases.

Integrated analytical workflow for chromatographic profiling and metabolite annotation of a cytotoxic Phorbas amaranthus extract

Phorbas is a widely studied genus of marine sponge and produce structurally rich cytotoxic metabolites. Still, only few studies have assessed metabolites present in Brazilian species. To circumvent redundancy, in this work, we applied and herein report the use of a scouting liquid chromatographic system associate to the design of experiment produced by the DryLab® software to obtain a fast and efficient chromatographic separation of the active hexane fraction, further enabling untargeted high-resolution mass spectrometry (HRMS) data. To this end, a crude hydroalcoholic extract of the sponge Phorbas amaranthus collected in Brazilian coast was prepared and partitioned. The cytotoxicity of the crude extract and the fractions was evaluated using tumor cell culture models. Fragmentation pathways assembled from HRMS data allowed the annotation of 18 known Phorbas metabolites, while 17 metabolites were inferred based on Global Natural Product Social Molecular Networking (GNPS), matching with a further 29 metabolites annotated through molecular subnetwork. The workflow employed demonstrates that chromatographic method development can be accelerated by the use of automated scouting systems and DryLab®, which is useful for profiling natural product libraries, as well as data curation by molecular clusters and should be incorporated to the tools of natural product chemists.

Multitargeted Effects of Vitexin and Isovitexin on Diabetes Mellitus and Its Complications.

Background Till date, there is no known antidote to cure diabetes mellitus despite the discovery and development of diverse pharmacotherapeutic agents many years ago. Technological advancement in natural product chemistry has led to the isolation of analogs of vitexin and isovitexin found in diverse bioresources. These compounds have been extensively studied to explore their pharmacological relevance in diabetes mellitus. Aim of the Study. The present review was to compile results from in vitro and in vivo studies performed with vitexin and isovitexin derivatives relating to diabetes mellitus and its complications. A systematic online literature query was executed to collect all relevant articles published up to March 2020. Results In this piece, we have collected data and presented it in a one-stop document to support the multitargeted mechanistic actions of vitexin and isovitexin in controlling diabetes mellitus and its complications. Conclusion Data collected hint that vitexin and isovitexin work by targeting diverse pathophysiological and metabolic pathways and molecular drug points involved in the clinical manifestations of diabetes mellitus. This is expected to provide a deeper understanding of its actions and also serve as a catapult for clinical trials and application research.

A different kind of Nierenstein reaction. The Chemical Society’s mistreatment of Maximilian Nierenstein

ABSTRACT Between 1920 and 1922, the University of Bristol biochemist, Maximilian Nierenstein, published four papers in a series exploring the structure of catechin in the Journal of the Chemical Society. The Society then abruptly refused to accept any more of his papers on catechin, or any other subject. It provided him with no reasons for the embargo until 1925. It then transpired that Nierenstein was boycotted because it was deemed that he had not responded adequately to criticisms of his work made by his rival in catechin research, the German natural products chemist, Karl Freudenberg. It was not until 1929 that, as a result of a petition by a group of his former Bristol pupils and friends, that Nierenstein was again permitted to publish in the Society’s journal. The paper explores the Chemical Society’s treatment of Nierenstein in detail, sheds new light on his career and his reaction to the Society’s unprecedented boycott, examines some of the structural chemistry involved in the disputes, and discusses whether Nierenstein’s research deserves the label of ‘bad science’.

Compostos bioativos: Uma contribuição para o ensino de Funções Orgânicas no curso de Licenciatura em Química

No ensino da química, percebe-se que os alunos, muitas vezes, não conseguem aprender, não são capazes de associar o conteúdo estudado com seu cotidiano, tornando-se desinteressados pelo tema. Com isso, surge a necessidade de contextualizar o conteúdo abordado em sala de aula com o cotidiano do discente facilitando, assim, na aprendizagem. O tema funções orgânicas é um assunto de fundamental importância na Química, no qual os alunos ainda encontram dificuldades, devido a memorização de conceitos e classificações. Pensando nisso, o presente trabalho tem como objetivo, apresentar uma análise dos resultados obtidos a partir da abordagem contextualizada do estudo de funções orgânicas presentes em compostos bioativos existentes em compostos naturais. Foi aplicado aula expositiva/interativa, discussões e questionários, com a finalidade de analisar os conhecimentos dos alunos acerca do tema e facilitar o processo de aprendizagem. A identificação das funções orgânicas abordada de uma maneira contextualizada propiciou aos alunos uma visão sobre como a química dos produtos naturais está presente no nosso cotidiano e, com isso, facilitou a aprendizagem do conteúdo sobre funções orgânicas, mostrando a influência da contextualização no ensino de química na melhoria da aprendizagem.

Isolation of artelasticine for student practice in low-resource laboratory settings

The isolation of secondary metabolites can be used by students for laboratory activities in the natural product chemistry course. The laboratory experience of isolating secondary metabolites will be useful for students to isolate secondary metabolites in other plant species whose chemical content has never been reported. In this laboratory the student isolated artelasticine from Artocarpus scortechinii. Students learn about extraction, fractionation, purification, and structural elucidation through the natural product chemistry laboratory activities. Various chromatography techniques are used to obtain pure artelasticine compounds. The artelasticine structure was determined based on UV, IR, 1H-NMR and 13C-NMR spectroscopic data. The laboratory method allowed students to readily understand the process of isolating artelasticine.

Drug Discovery Insights from Medicinal Beetles in Traditional Chinese Medicine.

Traditional Chinese medicine (TCM) was the primary source of medical treatment for the people inhabiting East Asia for thousands of years. These ancient practices have incorporated a wide variety of materia medica including plants, animals and minerals. As modern sciences, including natural products chemistry, emerged, there became increasing efforts to explore the chemistry of this materia medica to find molecules responsible for their traditional use. Insects, including beetles have played an important role in TCM. In our survey of texts and review articles on TCM materia medica, we found 48 species of beetles from 34 genera in 14 different families that are used in TCM. This review covers the chemistry known from the beetles used in TCM, or in cases where a species used in these practices has not been chemically studied, we discuss the chemistry of closely related beetles. We also found several documented uses of beetles in Traditional Korean Medicine (TKM), and included them where appropriate. There are 129 chemical constituents of beetles discussed.

Genome Sequence of Streptomyces sp. Strain HB-N217, Isolated from the Marine Sponge Forcepia sp.

The genome sequence of the Forcepia sponge-derived bacterium Streptomyces sp. strain HB-N217 was determined, with approximately 8.25 Mbp and a G+C content of 72.1%. Thirty biosynthetic gene clusters that bear the capability to produce secondary metabolites were predicted. The results will aid marine natural product chemistry and sponge-microbe association studies.

Chemical Research on Antitumor Isoquinoline Marine Natural Products and Related Compounds.

The biologically active, naturally occurring 1,2,3,4-tetrahydroisoquinoline-quinone (THIQ) family members isolated from Actinomycetes and marine organisms have been studied thoroughly over the past five decades. Among them, marine natural products along with their reduced compounds, such as renieramycins and ecteinascidins, have attracted interest due to their fantastic structures and meager availability in nature as well as their potent antitumor profiles. As part of our search for new anticancer metabolites through the isolation and characterization of anticancer THIQ compounds from Thai marine animals, we have developed a fascinating THIQ natural product chemistry and medicinal chemistry based on knowledge of the chemistry of saframycin antibiotics as well as their isolation, characterization, transformation, partial synthesis, and total synthesis. This review mainly presents our contributions during 1999-2019 to the field of research on biologically active renieramycin along with ecteinascidin marine natural products.

The Three Pillars of Natural Product Dereplication. Alkaloids from the Bulbs of Urceolina peruviana (C. Presl) J.F. Macbr. as a Preliminary Test Case.

The role and importance of the identification of natural products are discussed in the perspective of the study of secondary metabolites. The rapid identification of already reported compounds, or structural dereplication, is recognized as a key element in natural product chemistry. The biological taxonomy of metabolite producing organisms, the knowledge of metabolite molecular structures, and the availability of metabolite spectroscopic signatures are considered as the three pillars of structural dereplication. The role and the construction of databases is illustrated by references to the KNApSAcK, UNPD, CSEARCH, and COCONUT databases, and by the importance of calculated taxonomic and spectroscopic data as substitutes for missing or lost original ones. Two NMR-based tools, the PNMRNP database that derives from UNPD, and KnapsackSearch, a database generator that provides taxonomically focused libraries of compounds, are proposed to the community of natural product chemists. The study of the alkaloids from Urceolina peruviana, a plant from the Andes used in traditional medicine for antibacterial and anticancer actions, has given the opportunity to test different approaches to dereplication, favoring the use of publicly available data sources.

Sublimation for Enrichment and Identification of Marker Compounds in Fruits

In this article, we describe the benefits of sublimation for natural product and food chemistry. The direct sublimation of substances from dried plant powders has not received much attention in research in the past, just like the sublimation of substances from dried plant extracts. We used sublimation to study dried sea buckthorn berry powders and dried sea buckthorn berry extracts. The results of the powder sublimations were compared to that of dried chokeberry, wolfberry, and European cornel powder. 52 marker substances of which 27 are specific for sea buckthorn were found in the sea buckthorn powder sublimates using LC/MS. The majority of them are not described in the literature and were obtained by direct sublimation. Accordingly, sublimation can help to identify new plant constituents. Our identification method was validated by the analysis of four commercially available fruit powders. The sea buckthorn powder showed an almost 80% correlation with the determined marker substances, whereas the other fruit powders did not achieve more than 38% correlation. The sublimates of sea buckthorn extracts show additional marker substances compared to the fruit powder sublimate, and we think that both techniques can be used to fight food fraud.

My 60-Year Love Affair with Natural Products.

The author describes his 60-year career in studying the chemistry of natural products, which includes structural, synthetic, and biosynthetic studies of natural products ranging from insect pigments, antibiotics, and fecal mutagens to taxol and other anticancer natural products as well as antimalarial natural products. One of the compounds discussed, napabucasin, is now an anticancer drug in phase III clinical trials.

Extraction and Isolation of bioactive compounds from Lantana camara leaves by column Chromatographic techniques

The biological active compounds that are present in plants referred as phytochemicals. These phytochemicals derived from different parts of plants such as leaves, barks, seed, seed coat, flowers, roots and pulps and thereby used as sources of direct medicinal agents. Phytochemistry describes the large number of secondary metabolic compounds present in the plants. The plants are the reservoirs of naturally occurring chemical compounds and of structurally diverse bioactive molecules. Chromatographic techniques have significant role in natural products chemistry as well as contribute dramatically in the discovery of novel and innovative compounds of pharmaceutical and biomedical importance. The study absorbed on visual demonstration of fractionation and isolation of Lantana camara leaves of secondary metabolites using column-chromatographic techniques. Isolation of bioactive compounds using column-chromatographic involves: a) Preparation of sample; b) Packing of column; c) Pouring of sample into the column; d) Elution of fractions e) Analysis of each fractions using thin layer chromatography. However, depending on nature of research, compounds can be further purified using Gas chromatography and Mass spectrometry (GC-MS), infrared spectroscopy (IR) and high performance liquid chromatography (HPLC) and nuclear magnetic resonance (NMR) spectral analyses.

Next-generation microbial drugs developed from microbiome's natural products.

Scientists working in natural products chemistry have been enticed by the current advancements being made in the discovery of novel "magic bullets" from microbes homed to all conceivable environments. Even though researchers continue to face challenges funneling the novel bioactive compounds in the global therapeutic industries, it seems most likely that the discovery of some "hit molecules" with significant biomedical applications is not that far. We applaud novel natural products for their ability to combat the spread of superbugs and aid in the prevention of currently observed antibiotic resistance. This in-depth investigation covers a wide range of microbiomes with a proclivity for synthesizing novel compounds to combat the spread of superbugs. Furthermore, we use this opportunity to explore various groups of secondary metabolites and their biosynthetic pathways in various microbiota found in mammals, insects, and humans. This systematic study, when taken as a whole, offers detail understanding on the biomedical fate of various groups of compounds originated from diverse microbiomes. For gathering all information that has been uncovered and released so far, we have also presented the huge diversity of microbes that are associated with humans and their metabolic products. To conclude, this concrete review suggests novel ideas that will prove immensely helpful in reducing the danger posed by superbugs while also improving the efficacy of antibiotics.

Editorial Note for Natural Products Chemistry & Research

I am pleased to introduce that the journal of Natural Products Chemistry & Research deals with chemical compounds found in nature that usually has a pharmacological or biological activity for use in pharmaceutical drug discovery and drug design. Natural Products Chemistry & Research emphasizes articles related to the study of chemistry and biochemistry of naturally occurring compounds or the biology of living systems from which they are obtained. Natural Products Journal is at higher echelons that enhance the intelligence and information dissemination on topics closely related to Natural Products. They provide a unique forum dedicated to scientists to express their research articles, review articles, case reports and short communications on an array of Natural Products research. The Natural Products Peer Reviewed Journal is proficiently supported by universally prominent Editorial Board members. Natural Products journal impact factor is mainly calculated based on the number of articles that undergo a double blind peer review process by competent Editorial Board so as to ensure excellence, essence of the work and number of citations received for the same published articles. Abstracts and full texts of all articles published by Natural Products Open Access articles are freely accessible to everyone immediately after publication.