Constrained saccharides: a review of structure, biology, and synthesis

2018 ◽  
Vol 35 (3) ◽  
pp. 220-229 ◽  
Author(s):  
Jacob Rodriguez ◽  
Sloane O'Neill ◽  
Maciej A. Walczak
Keyword(s):  
Natural Products ◽  
Biological Properties ◽  
Conformationally Restricted ◽  
Oligosaccharide Chain

Conformationally restricted natural products containing hydrocarbon tethers attached to an oligosaccharide chain display intriguing structural and biological properties.

Synthesis of new cyclopeptide analogues of the miuraenamides

2021 ◽  
Vol 18 ◽  
Author(s):  
Sarah Kappler ◽  
Andreas Siebert ◽  
Uli Kazmaier
Keyword(s):  
Natural Products ◽  
Biological Properties ◽  
Amide Bond ◽  
Side Chain ◽  
Aromatic Side Chain ◽  
Highly Active ◽  
C Terminus ◽  
Terminal Amino ◽  
High Cytotoxicity ◽  
Derivatives Of

Introduction: Miuraenamides belong to marine natural compounds with interesting biological properties. Materials and Methods: They initiate polymerization of monomeric actin and therefore show high cytotoxicity by influencing the cytoskeleton. New derivatives of the miuraenamides have been synthesized containing a N-methylated amide bond instead of the more easily hydrolysable ester in the natural products. Results: Incorporation of an aromatic side chain onto the C-terminal amino acid of the tripeptide fragment also led to highly active new miuraenamides. Conclusion: We could show that the ester bond of the natural product miuraenamide can be replaced by an N-methyl amide. The yields in the cyclization step are high and generally much better that with the corresponding esters. On the other hand, the biological activity of the new amide analogs are lower compared to the natural products, but the activity can significantly be increased by incorporation of a p-nitrophenyl group at the C-terminus of the peptide fragment.

The [4.3.0] piperidine alkaloids: architectures, biology, biosyntheses and the complete details of the asymmetric syntheses of streptazone A and abikoviromycin

Synlett ◽  
2021 ◽  
Author(s):  
Gustav J. Wørmer ◽  
Thomas Bjørnskov Poulsen
Keyword(s):  
Natural Products ◽  
Biological Properties ◽  
Piperidine Alkaloids ◽  
Complete Coverage ◽  
Asymmetric Syntheses ◽  
Concise Overview ◽  
Michael Acceptors

Piperidine alkaloids continue to challenge the synthetic community by featuring densely functionalized scaffolds which often requires careful chemical orchestration. Streptazone A and abikoviromycin are small and highly functionalized piperidine alkaloids both accommodating Michael acceptors and a labile epoxide. These moieties are loaded into a [4.3.0] bicyclic core also present in other structurally related natural products including the well-known piperidine alkaloid streptazolin. Herein, we cover ring-closing strategies employed in prior streptazolin syntheses, provide a concise overview of structures, biological properties and biosyntheses of selected [4.3.0] piperidine alkaloids, and finally we disclose a complete coverage of our recent asymmetric syntheses of streptazone A and abikoviromycin.

scholarly journals Special Issue: The Antioxidant Capacities of Natural Products

Molecules ◽  
2019 ◽  
Vol 24 (3) ◽  
pp. 492 ◽  
Author(s):  
Susana Cardoso
Keyword(s):  
Oxidative Stress ◽  
Natural Products ◽  
Biological Properties ◽  
Industrial Applications ◽  
Special Issue ◽  
Antioxidant Capacities

Antioxidants are under the research spotlight because of their potential to prevent oxidative stress as well as for their versatile biological properties that grant them multiple industrial applications [...]

New conformationally restricted analog of the immunosuppressory mini-domain of HLA-DQ and its biological properties

Peptides ◽  
2000 ◽  
Vol 21 (12) ◽  
pp. 1849-1858 ◽  
Author(s):  
Zbigniew Szewczuk ◽  
Andrzej Wilczyński ◽  
Marcin Dyba ◽  
Inga Petry ◽  
Ignacy Z Siemion ◽  
...  
Keyword(s):  
Biological Properties ◽  
Conformationally Restricted ◽  
Hla Dq

scholarly journals Neuroprotective Strategies for Neurological Disorders by Natural Products: An update

2019 ◽  
Vol 17 (3) ◽  
pp. 247-267 ◽  
Author(s):  
Muneeb U. Rehman ◽  
Adil Farooq Wali ◽  
Anas Ahmad ◽  
Sheeba Shakeel ◽  
Saiema Rasool ◽  
...  
Keyword(s):  
Natural Products ◽  
Large Scale ◽  
Biological Properties ◽  
In Vivo Studies ◽  
Preclinical Models ◽  
Neuroprotective Effects ◽  
Neuroprotective Strategies ◽  
Inflammatory Processes

Nature has bestowed mankind with surplus resources (natural products) on land and water. Natural products have a significant role in the prevention of disease and boosting of health in humans and animals. These natural products have been experimentally documented to possess various biological properties such as antioxidant, anti-inflammatory and anti-apoptotic activities. In vitro and in vivo studies have further established the usefulness of natural products in various preclinical models of neurodegenerative disorders. Natural products include phytoconstituents, like polyphenolic antioxidants, found in herbs, fruits, nuts, vegetables and also in marine and freshwater flora. These phytoconstituents may potentially suppress neurodegeneration and improve memory as well as cognitive functions of the brain. Also, they are known to play a pivotal role in the prevention and cure of different neurodegenerative diseases, such as Alzheimer’s disease, epilepsy, Parkinson’s disease and other neuronal disorders. The large-scale neuro-pharmacological activities of natural products have been documented due to the result of either the inhibition of inflammatory processes, or the up-regulation of various cell survival proteins or a combination of both. Due to the scarcity of human studies on neuroprotective effects of natural products, this review focuses on the various established activities of natural products in in vitro and in vivo preclinical models, and their potential neuro-therapeutic applications using the available knowledge in the literature.

scholarly journals Exploring the Chemistry of Natural Products and Biological Properties of Mimosa Linnaeus Genus (FABACEAE-MIMOSOIDADE)

2019 ◽  
Vol 11 (3) ◽  
pp. 970-1010 ◽  
Author(s):  
Nayana Bruna Nery Monção ◽  
Bruno Quirino Araújo ◽  
Antônia Maria d as Graças Lopes Citó
Keyword(s):  
Natural Products ◽  
Biological Properties

scholarly journals Uncovering Novel Peptide Chemistry from Bacterial Natural Products

2021 ◽  
Vol 75 (6) ◽  
pp. 543-547
Author(s):  
Florian Hubrich ◽  
Alessandro Lotti ◽  
Thomas A. Scott ◽  
Jörn Piel
Keyword(s):  
Natural Products ◽  
Bioactive Peptides ◽  
Biological Activities ◽  
Biological Properties ◽  
Post Translational Modifications ◽  
Peptide Chemistry ◽  
Chemical Structures ◽  
Therapeutic Value ◽  
Modified Peptides ◽  
Unique Chemical

Nature has evolved a remarkable array of biosynthetic enzymes that install diverse chemistries into natural products (NPs), bestowing them with a range of important biological properties that are of considerable therapeutic value. This is epitomized by the ribosomally synthesized and post-translationally modified peptides (RiPPs), a class of peptide natural products that undergo extensive post-translational modifications to produce structurally diverse bioactive peptides. In this review, we provide an overview of our research into the proteusin RiPP family, describing characterized members and the maturation enzymes responsible for their unique chemical structures and biological activities. The diverse enzymology identified in the first two proteusin pathways highlights the enormous potential of the RiPP class for new lead structures and novel pharmacophore-installing maturases as biocatalytic tools for drug discovery efforts.

scholarly journals Update on Medicinal Plants with Potency onMycobacterium ulcerans

2015 ◽  
Vol 2015 ◽  
pp. 1-16 ◽  
Author(s):  
Patrick Valere Tsouh Fokou ◽  
Alexander Kwadwo Nyarko ◽  
Regina Appiah-Opong ◽  
Lauve Rachel Tchokouaha Yamthe ◽  
Mark Ofosuhene ◽  
...  
Keyword(s):  
Natural Products ◽  
Chemical Composition ◽  
Medicinal Plants ◽  
Infectious Diseases ◽  
Biological Properties ◽  
Mycobacterium Ulcerans ◽  
Herbal Remedies ◽  
Community Based ◽  
Remote Areas ◽  
Inhibitory Potential

Mycobacterium ulceransdisease has been a serious threat for people living in rural remote areas. Due to poverty or availability of traditional medicine these populations rely on herbal remedies. Currently, data on the anti-Mycobacterium ulceransactivity of plants, so far considered community-based knowledge, have been scientifically confirmed, concomitantly with some medicinal plants used to treat infectious diseases in general. Products derived from plants usually responsible for the biological properties may potentially controlMycobacterium ulceransdisease; numerous studies have aimed to describe the chemical composition of these plant antimicrobials. Thus, the present work provides the first compilation of medicinal plants that demonstrated inhibitory potential onMycobacterium ulcerans. This work shows that the natural products represent potential alternatives to standard therapies for use as curative medicine forMycobacterium ulceransdisease.

Synthetic Approaches for Building Tricyclic Cage-like Motifs Found in Indoxamycins

2020 ◽  
Vol 24 ◽  
Author(s):  
Saqlain Haider ◽  
Ikhlas A. Khan ◽  
Hanfeng Ding ◽  
Amar G. Chittiboyina
Keyword(s):  
Natural Products ◽  
Michael Addition ◽  
Claisen Rearrangement ◽  
Biological Activities ◽  
Cascade Reactions ◽  
Biological Properties ◽  
Starting Material ◽  
Central Core ◽  
Chemical Transformations ◽  
One Pot

Abstract:: Indoxamycins A-F, a novel class of polyketides, were isolated from the saline culture of marine-derived actinomyces by Sato et al. in 2009. Intriguing stereochemical complexity involving tricyclic [5.5.6] cage-like structures with six consecutive chiral centers challenged many organic chemists. Chemical ingenuity, implementation of pioneered reactions along with fine chemical transformations allowed not only the rapid construction of the central core but also allowed minor structural revision and paved the information to delineate the absolute stereostructures of these complex polyketide marine natural products. To achieve the central core structure in indoxamycins A-F, reactions like the Ireland- Claisen rearrangement, an enantioselective 1,6-enyne reductive cyclization, and one-pot cascade reactions of 1,2- addition/oxa-Michael/methylenation were employed. Using the chiral pool approach, the readily available R-carvone was employed as a cost-effective starting material to achieve the concise total syntheses of (-)-indoxamycins A and B, in which Pauson-Khand, Cu-catalyzed Michael addition and tandem retro-oxa-Michael addition/1,2-addition/oxa-Michael addition reactions were employed. The antipodes, (+)-indoxamycins can be easily accessed by simply switching to S-carvone as the starting material. Synthetically prepared indoxamycins A-F are devoid of antiproliferative properties which disagrees with the work reported by Sato and co-workers for (-)-indoxamycins A and F. Nevertheless, ready access to such complex natural products allows probing the untapped potential biological activities of these polyketides including cytotoxicity. A concise overview of interesting, key chemical transformations including named reactions in establishing the architecture of indoxamycins was compiled to inspire organic chemists and help reinvigorate the development of novel strategies for the asymmetric synthesis as well as the development of novel derivatives of indoxamycins with unique physicochemical and biological properties.

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