scholarly journals Lyngbouilloside and Related Macrolides from Marine Cyanobacteria

2013 ◽  
Vol 8 (7) ◽  
pp. 1934578X1300800
Author(s):  
Abdelatif ElMarrouni ◽  
Amandine Kolleth ◽  
Raphael Lebeuf ◽  
Julian Gebauer ◽  
Sébastien Prevost ◽  
...  
Keyword(s):  
Natural Products ◽  
Biological Activities ◽  
Marine Cyanobacteria ◽  
The Past

Lyngbouilloside and the related macrolides lyngbyaloside lyngbyaloside B and lyngbyaloside C have attracted a lot of attention over the past decade due to their intriguing architecture their natural scarcity and their potential biological activities. This review aims to showcase the various strategies that have been used to access these natural products.

scholarly journals Modern Synthetic Methods for the Stereoselective Construction of 1,3-Dienes

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 249
Author(s):  
Raquel G. Soengas ◽  
Humberto Rodríguez-Solla
Keyword(s):  
Organic Chemistry ◽  
Natural Products ◽  
Functional Group ◽  
Biological Activities ◽  
Synthetic Methods ◽  
Bond Forming ◽  
Drug Candidates ◽  
The Past ◽  
Wide Range

The 1,3-butadiene motif is widely found in many natural products and drug candidates with relevant biological activities. Moreover, dienes are important targets for synthetic chemists, due to their ability to give access to a wide range of functional group transformations, including a broad range of C-C bond-forming processes. Therefore, the stereoselective preparation of dienes have attracted much attention over the past decades, and the search for new synthetic protocols continues unabated. The aim of this review is to give an overview of the diverse methodologies that have emerged in the last decade, with a focus on the synthetic processes that meet the requirements of efficiency and sustainability of modern organic chemistry.

scholarly journals Imidazole: Having Versatile Biological Activities

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Amita Verma ◽  
Sunil Joshi ◽  
Deepika Singh
Keyword(s):  
Natural Products ◽  
Nucleic Acid ◽  
Biological Activities ◽  
Imidazole Ring ◽  
Heterocyclic Ring ◽  
Heterocyclic Chemistry ◽  
The Past ◽  
Poorly Soluble ◽  
Anti Hiv ◽  
Imidazole Compounds

Imidazoles have occupied a unique position in heterocyclic chemistry, and its derivatives have attracted considerable interests in recent years for their versatile properties in chemistry and pharmacology. Imidazole is nitrogen-containing heterocyclic ring which possesses biological and pharmaceutical importance. Thus, imidazole compounds have been an interesting source for researchers for more than a century. The imidazole ring is a constituent of several important natural products, including purine, histamine, histidine, and nucleic acid. Being a polar and ionisable aromatic compound, it improves pharmacokinetic characteristics of lead molecules and thus is used as a remedy to optimize solubility and bioavailability parameters of proposed poorly soluble lead molecules. There are several methods used for the synthesis of imidazole-containing compounds, and also their various structure reactions offer enormous scope in the field of medicinal chemistry. The imidazole derivatives possess extensive spectrum of biological activities such as antibacterial, anticancer, antitubercular, antifungal, analgesic, and anti-HIV activities. This paper aims to review the biological activities of imidazole during the past years.

scholarly journals ESPECTROSCOPIA COMPUTACIONAL APLICADA AO REASSINALAMENTO ESTRUTURAL DE MOLÉCULAS QUIRAIS: HELIANNUOL L

2020 ◽  
Author(s):  
Jordana T. Brito ◽  
Lucas H. Martorano ◽  
Ana Carolina F. de Albuquerque ◽  
Carlos Magno Rocha Ribeiro ◽  
Rodolfo Goetze Fiorot ◽  
...  
Keyword(s):  
Natural Products ◽  
Theoretical Calculations ◽  
Chemical Shifts ◽  
Biological Activities ◽  
Great Effort ◽  
The Past ◽  
Spectral Interpretation ◽  
Combined Use ◽  
Helianthus Annus

In the past, structure determination of natural products was an arduous process depending almost entirely on chemical synthesis, mainly by derivatization and degradation processes, taking years of effort. Recently, structural elucidation of natural products has undergone a revolution. Nowadays, with the combined use of different advanced spectroscopic methods, it became possible to completely assign the structure of natural products using small amounts of sample. However, despite the extraordinary ongoing advances in spectroscopy, the mischaracterization of natural products has been and remains a recurrent problem, especially in the presence of several chiral centers. The misinterpretation of NMR data has resulted in frequent reports addressing the issue of structural reassignment. In this context, a great effort has been devoted to the development of quantum chemical calculations to predict NMR parameters, and thus achieve a more accurate spectral interpretation. In this work, we applied a protocol for theoretical calculations of 1H NMR chemical shifts in order to establish the correct and unequivocal structure of Helianuol L, a member of the Heliannuol’s class, isolated from Helianthus annus. These secondary metabolites present a broad spectrum of biological activities, including the allelochemical activity, making them promising candidates as natural agrochemicals. It is worth mentioning, however, that the process of elucidating the structure of Heliannuol L was based on structural correlations with molecules already known in the literature, where few stereochemical analyses were performed. In this way, based on the fact that other compounds of the Heliannuol’s class had their structure previously reassigned, the verification of the proposed structure of Heliannuol L becomes of great importance.

Recent Advances in the Synthesis of Thiadiazoles

Synlett ◽  
2019 ◽  
Vol 30 (18) ◽  
pp. 2041-2050
Author(s):  
Yan Xiao ◽  
Song Sun ◽  
Jin-Tao Yu ◽  
Jiang Cheng
Keyword(s):  
Natural Products ◽  
Broad Spectrum ◽  
Biological Activities ◽  
Pharmaceutical Compounds ◽  
Antifungal Drugs ◽  
The Past ◽  
Recent Advances

Thiadiazole moieties are present in many natural products and pharmaceutical compounds that possess a broad spectrum of biological activities, serving as antidepressant, anxiolytic, antimicrobial, antitubercular, antiinflammatory, antidiabetic, anticancer, antihypertensive, or antifungal drugs. Many excellent methods have been reported for accessing such frameworks. In this review, we summarize advances made within the past ten years in the synthesis of various types of thiadiazole.1 Introduction2 Synthesis of Thiadiazoles2.1 Synthesis of 1,2,3-Thiadiazoles2.1.1 Synthesis of 1,2,3-Thiadiazoles from Diazo/Azide Compounds2.1.2 Synthesis of 1,2,3-Thiadiazoles from Sulfonyl Hydrazines or N-Tosylhydrazones2.2 Synthesis of 1,2,4-Thiadiazoles2.2.1 Synthesis of 1,2,4-Thiadiazoles from Thioamides or their Derivatives2.2.2 Synthesis of 1,2,4-Thiadiazoles from Amidines or 2-Aminopyridines2.3 Synthesis of 1,3,4-Thiadiazoles2.4 Synthesis of 1,2,5-Thiadiazoles3 Conclusion

scholarly journals ANTI-ULCER AGENTS: A PHARMACOLOGICAL UPDATE OF THE PAST TEN YEARS

2019 ◽  
pp. 37-41
Author(s):  
SUDIP KUMAR MANDAL ◽  
SUBHOJIT DAWN ◽  
ANINDYA BOSE
Keyword(s):  
Natural Products ◽  
Proton Pump Inhibitors ◽  
Proton Pump ◽  
Biological Activities ◽  
Mangifera Indica ◽  
Aloe Vera ◽  
Zingiber Officinale ◽  
Ocimum Sanctum ◽  
Cell Hyperplasia ◽  
The Past

New anti-ulcer substances are still vitally necessary for the people of countries such as India and South Africa to avoid high cost of the most prescribed marketed anti-ulcer drugs (proton-pump inhibitors). New candidate against gastric ulcer is also necessary to avoid the potential problem (enterochromaffin-like cell hyperplasia may be induced) associated with the long-term use of synthetic proton-pump inhibitors. However, the search for the novel entity against ulceration is challenging because of the complexity of the ulcer process and its role in host defense to infections. Nature is the source of remedies for the humankind. Among the different biological activities of the natural products that have been published till date, anti-ulcer is one of the most reported effects. Some single natural products such as curcumin, 1-hydroxy-3,7,8-trimethoxyxanthone, cinnamic acid, thymol, epoxycarvone, and menthol; single synthetic products such as, 4,6-diaryl-3, 4-dihydropyrimidin-2(1H)-thiones, 1,4-dihydropyrimidine derivatives, and dihydropyrimidinone and piperidine hybrids; plant products such as Aloe vera, Mangifera indica, Zingiber officinale, Azadirachta indica, Psidium guava, Carica papaya, Panax ginseng, Terminalia chebula, Ocimum sanctum, Daucus carota, and Mimosa pudica, Alpinia galangal; nutraceuticals such as garlic, cauliflower, banana, honey, cucumber, and cod liver oil with anti-ulcer effects have been discussed in this review. A complete review of literature was conducted using different databases on ScienceDirect, Scopus, PubMed, and Google Scholar. This review is a genuine attempt to explore the past 10 years’ pharmacological update of some anti-ulcer agents.

Click Reactions in Chemistry of Triterpenes - Advances Towards Development of Potential Therapeutics

2018 ◽  
Vol 25 (5) ◽  
pp. 636-658 ◽  
Author(s):  
Jan Pokorny ◽  
Lucie Borkova ◽  
Milan Urban
Keyword(s):  
Biological Activities ◽  
Synthetic Approach ◽  
Clinical Use ◽  
New Approach ◽  
Click Reactions ◽  
Drug Candidates ◽  
The Past ◽  
Low Toxicity ◽  
New Compounds ◽  
Potential Therapeutics

Triterpenoids are natural compounds with a large variety of biological activities such as anticancer, antiviral, antibacterial, antifungal, antiparazitic, antiinflammatory and others. Despite their low toxicity and simple availability from the natural resources, their clinical use is still severely limited by their higher IC50 and worse pharmacological properties than in the currently used therapeutics. This fact encouraged a number of researchers to develop new terpenic derivatives more suitable for the potential clinical use. This review summarizes a new approach to improve both, the activity and ADME-Tox properties by connecting active terpenes to another modifying molecules using click reactions. Within the past few years, this synthetic approach was well explored yielding a lot of great improvements of the parent compounds along with some less successful attempts. A large quantity of the new compounds presented here are superior in both activity and ADME-Tox properties to their parents. This review should serve the researchers who need to promote their hit triterpenic structures towards their clinical use and it is intended as a guide for the chemical synthesis of better drug candidates.

Anti-Inflammatory Properties of Plant Derived Natural Products – A Systematic Review

2019 ◽  
Vol 26 (24) ◽  
pp. 4506-4536 ◽  
Author(s):  
Iris E. Allijn ◽  
René P. Brinkhuis ◽  
Gert Storm ◽  
Raymond M. Schiffelers
Keyword(s):  
Systematic Review ◽  
Natural Products ◽  
Positive Control ◽  
Therapeutic Effects ◽  
Reference Compound ◽  
Individual Molecular Species ◽  
The Past ◽  
Anti Inflammatory ◽  
The Individual ◽  
Natural Medicines

Traditionally, natural medicines have been administered as plant extracts, which are composed of a mixture of molecules. The individual molecular species in this mixture may or may not contribute to the overall medicinal effects and some may even oppose the beneficial activity of others. To better control therapeutic effects, studies that characterized specific molecules and describe their individual activity that have been performed over the past decades. These studies appear to underline that natural products are particularly effective as antioxidants and anti-inflammatory agents. In this systematic review we aimed to identify potent anti-inflammatory natural products and relate their efficacy to their chemical structure and physicochemical properties. To identify these compounds, we performed a comprehensive literature search to find those studies, in which a dose-response description and a positive control reference compound was used to benchmark the observed activity. Of the analyzed papers, 7% of initially selected studies met these requirements and were subjected to further analysis. This analysis revealed that most selected natural products indeed appeared to possess anti-inflammatory activities, in particular anti-oxidative properties. In addition, 14% of the natural products outperformed the remaining natural products in all tested assays and are attractive candidates as new anti-inflammatory agents.

Structural and Bioactive Studies of Halogenated Constituents from Sponges

2020 ◽  
Vol 27 (14) ◽  
pp. 2335-2360 ◽  
Author(s):  
Chao Li ◽  
Dayong Shi
Keyword(s):  
Microbial Communities ◽  
Organic Compounds ◽  
Biological Activities ◽  
Marine Sponges ◽  
Nitrogen Compounds ◽  
Halogenated Organic Compounds ◽  
Bioactive Natural Products ◽  
The Past ◽  
Tyrosine Derivatives ◽  
Polyunsaturated Lipids

: Marine organisms are abundant sources of bioactive natural products. Among metabolites produced by sponges and their associated microbial communities, halogenated natural compounds accounted for an important part due to their potent biological activities. The present review updates and compiles a total of 258 halogenated organic compounds isolated in the past three decades, especially brominated derivatives derived from 31 genera of marine sponges. These compounds can be classified as the following classes: brominated polyunsaturated lipids, nitrogen compounds, brominated tyrosine derivatives and other halogenated compounds. These substances were listed together with their source organisms, structures and bioactivities. For this purpose, 84 references were consulted.

Pyrone-derived Marine Natural Products: A Review on Isolation, Bio-activities and Synthesis

2020 ◽  
Vol 24 (4) ◽  
pp. 354-401 ◽  
Author(s):  
Keisham S. Singh
Keyword(s):  
Natural Products ◽  
Marine Natural Products ◽  
Marine Fungi ◽  
Kojic Acid ◽  
Biological Activities ◽  
Biological Significance ◽  
Pyrone Ring ◽  
Enol Ethers ◽  
Bioactive Natural Products ◽  
Marine Metabolites

Marine natural products (MNPs) containing pyrone rings have been isolated from numerous marine organisms, and also produced by marine fungi and bacteria, particularly, actinomycetes. They constitute a versatile structure unit of bioactive natural products that exhibit various biological activities such as antibiotic, antifungal, cytotoxic, neurotoxic, phytotoxic and anti-tyrosinase. The two structure isomers of pyrone ring are γ- pyrone and α-pyrone. In terms of chemical motif, γ-pyrone is the vinologous form of α- pyrone which possesses a lactone ring. Actinomycete bacteria are responsible for the production of several α-pyrone compounds such as elijopyrones A-D, salinipyrones and violapyrones etc. to name a few. A class of pyrone metabolites, polypropionates which have fascinating carbon skeleton, is primarily produced by marine molluscs. Interestingly, some of the pyrone polytketides which are found in cone snails are actually synthesized by actinomycete bacteria. Several pyrone derivatives have been obtained from marine fungi such as Aspergillums flavus, Altenaria sp., etc. The γ-pyrone derivative namely, kojic acid obtained from Aspergillus fungus has high commercial demand and finds various applications. Kojic acid and its derivative displayed inhibition of tyrosinase activity and, it is also extensively used as a ligand in coordination chemistry. Owing to their commercial and biological significance, the synthesis of pyrone containing compounds has been given attention over the past years. Few reviews on the total synthesis of pyrone containing natural products namely, polypropionate metabolites have been reported. However, these reviews skipped other marine pyrone metabolites and also omitted discussion on isolation and detailed biological activities. This review presents a brief account of the isolation of marine metabolites containing a pyrone ring and their reported bio-activities. Further, the review covers the synthesis of marine pyrone metabolites such as cyercene-A, placidenes, onchitriol-I, onchitriol-II, crispatene, photodeoxytrichidione, (-) membrenone-C, lihualide-B, macrocyclic enol ethers and auripyrones-A & B.

Single Heterocyclic Compounds as Monoamine Oxidase Inhibitors: From Past to Present

2020 ◽  
Vol 20 (10) ◽  
pp. 908-920 ◽  
Author(s):  
Su-Min Wu ◽  
Xiao-Yang Qiu ◽  
Shu-Juan Liu ◽  
Juan Sun
Keyword(s):  
Monoamine Oxidase ◽  
Heterocyclic Compounds ◽  
Biological Activities ◽  
The Past ◽  
Structure Activity ◽  
Receptor Interactions ◽  
Heterocyclic Derivatives ◽  
Inhibitory Activities ◽  
Leading Compounds ◽  
Heterocyclic Moiety

Inhibitors of monoamine oxidase (MAO) have shown therapeutic values in a variety of neurodegenerative diseases such as depression, Parkinson’s disease and Alzheimer’s disease. Heterocyclic compounds exhibit a broad spectrum of biological activities and vital leading compounds for the development of chemical drugs. Herein, we focus on the synthesis and screening of novel single heterocyclic derivatives with MAO inhibitory activities during the past decade. This review covers recent pharmacological advancements of single heterocyclic moiety along with structure- activity relationship to provide better correlation among different structures and their receptor interactions.

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