scholarly journals Diversity Focused Semisyntheses of Tetronate Polyether Ionophores

Author(s):  
Shaoquan Lin ◽  
Han Liu ◽  
Esben B. Svenningsen ◽  
Christine Pedersen ◽  
Peter Nørby ◽  
...  

The polyether ionophores are complex natural products capable of transporting cations across biological membranes. Many family members possess highly potent antimicrobial activity and a few selected compounds have ability to target particularly aggressive cancer cells. Despite these interesting perspectives, a detailed understanding of the cellular mode-of-action of polyether ionophores is generally lacking. In principle, broad mapping of structure-activity relationships across several biological activities could provide mechanistic insights as well as identification of lead structures but access to structural diversity within the overall class is synthetically very challenging. In this manuscript, we demonstrate that novel polyether ionophores can be constructed by recycling components of highly abundant polyethers. We provide the first examples of synthetically incorporating halogen-functionalized tetronic acids as cation-binding groups into polyether ionophores and we identify analogs with strong anti-bacterial activity and minimal effects on mammalian cells.

Author(s):  
Shaoquan Lin ◽  
Han Liu ◽  
Esben B. Svenningsen ◽  
Christine Pedersen ◽  
Peter Nørby ◽  
...  

The polyether ionophores are complex natural products capable of transporting cations across biological membranes. Many family members possess highly potent antimicrobial activity and a few selected compounds have ability to target particularly aggressive cancer cells. Despite these interesting perspectives, a detailed understanding of the cellular mode-of-action of polyether ionophores is generally lacking. In principle, broad mapping of structure-activity relationships across several biological activities could provide mechanistic insights as well as identification of lead structures but access to structural diversity within the overall class is synthetically very challenging. In this manuscript, we demonstrate that novel polyether ionophores can be constructed by recycling components of highly abundant polyethers. We provide the first examples of synthetically incorporating halogen-functionalized tetronic acids as cation-binding groups into polyether ionophores and we identify analogs with strong anti-bacterial activity and minimal effects on mammalian cells.


2018 ◽  
Vol 42 (13) ◽  
pp. 10676-10688 ◽  
Author(s):  
Doaa R. Ramadan ◽  
Aly A. Elbardan ◽  
Adnan A. Bekhit ◽  
Ayman El-Faham ◽  
Sherine N. Khattab

Several dimerics-triazine Schiff bases displayed more potent anti-bacterial activity compared with ampicillin trihydrate. They revealed significantly low MIC values towards the tested MDR strains and showed a high selectivity index towards antimicrobial activity againstK. pneumoniaeandMRSA1compared to mammalian cells.


Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 4974
Author(s):  
Yu-Pu Juang ◽  
Pi-Hui Liang

Saponins are amphiphilic molecules consisting of carbohydrate and either triterpenoid or steroid aglycone moieties and are noted for their multiple biological activities—Fungicidal, antimicrobial, antiviral, anti-inflammatory, anticancer, antioxidant and immunomodulatory effects have all been observed. Saponins from natural sources have long been used in herbal and traditional medicines; however, the isolation of complexed saponins from nature is difficult and laborious, due to the scarce amount and structure heterogeneity. Chemical synthesis is considered a powerful tool to expand the structural diversity of saponin, leading to the discovery of promising compounds. This review focuses on recent developments in the structure optimization and biological evaluation of synthetic triterpenoid and steroid saponin derivatives. By summarizing the structure–activity relationship (SAR) results, we hope to provide the direction for future development of saponin-based bioactive compounds.


2020 ◽  
Vol 10 (23) ◽  
pp. 8408
Author(s):  
Ngan Tran ◽  
Minh Nguyen ◽  
Khanh PB Le ◽  
Nhi Nguyen ◽  
Quan Tran ◽  
...  

This study aimed to screen the anticancer and antioxidant potential and antimicrobial activity of methanol, petroleum ether, chloroform, ethyl acetate, butanol of Euphorbia hirta Linn. extracts (EH-Me, EH-PE, EH-Ch, EH-EA and EH-Bu, respectively). The results of 2,2-diphenyl-1-pycrylhydrazyl (DPPH) radical scavenging assay and lipid peroxidation inhibition assay showed that EH-EA was the strongest antioxidant (IC50 = 10.33 ± 0.01 µg/mL; IC50 = 1.48 ± 0.12 µg/mL, respectively) compared to all other extracts. In the antimicrobial activity of the extracts against eight strains of Gram-positive and Gram-negative bacteria using the agar disc diffusion method, we found the EH-EA to be the best antimicrobial agent. Anticancer activities of those extracts were examined by sulforhodamine B (SRB) in vitro cytotoxicity assay on two cancer cell lines, including lung cancer cells NCI-H460 and liver cancer cells Hep G2. EH-EA at concentration of 100 μg/mL has significant inhibitory activity the growth of lung cancer cells NCI-H460 and liver cancer cells Hep G2 compared to all other extracts. Our results suggest that E. hirta Linn. extracts possess significant biological activities, including antimicrobial, antioxidant, and moderate anticancer properties. Our results show that this plant could be a good source for natural antioxidants and a possible pharmaceutical supplement. Among five analyzed extracts, EH-EA extract has the strongest activities, and should be used to determine phytochemicals and mechanisms of these activities.


2019 ◽  
Vol 14 (6) ◽  
pp. 1934578X1985822
Author(s):  
Tao Wu ◽  
Osafo Raymond Kwaku ◽  
Hai-Zhou Li ◽  
Chong-Ren Yang ◽  
Long-Jiao Ge ◽  
...  

The term ginseng refers to the dried roots of several plants belonging to the genus Panax of the Araliaceae family. The 3 major commercial ginsengs are Panax notoginseng (Burk.) F.H. Chen (Notoginseng), P. ginseng C.A. Meyer (Ginseng), and P. quinquefolius L. (American ginseng), which have been used as herbal medicines. Over 18,000 papers on ginsengs have been published on the basis of their structural diversity and biological activities. Many reviews have summarized the phytochemistry, pharmacology, and clinical use of ginsengs, but the structure-activity relationship (SAR) of ginsenosides from ginsengs in autophagy is unavailable. Herein, we review the structural diversity of ginsenosides, especially the ones in notoginseng, and the SAR in autophagic activity is discussed in detail.


Biomedicines ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 342 ◽  
Author(s):  
Natalya N. Besednova ◽  
Boris G. Andryukov ◽  
Tatyana S. Zaporozhets ◽  
Sergey P. Kryzhanovsky ◽  
Tatyana A. Kuznetsova ◽  
...  

The increasing drug resistance of pathogenic microorganisms raises concern worldwide and necessitates the search for new natural compounds with antibacterial properties. Marine algae are considered a natural and attractive biotechnological source of novel antibiotics. The high antimicrobial activity of their polyphenolic compounds is a promising basis for designing innovative pharmaceuticals. They can become both a serious alternative to traditional antimicrobial agents and an effective supplement to antibiotic therapy. The present review summarizes the results of numerous studies on polyphenols from algae and the range of biological activities that determine their biomedical significance. The main focus is put on a group of the polyphenolic metabolites referred to as phlorotannins and, particularly, on their structural diversity and mechanisms of antimicrobial effects. Brown algae are an almost inexhaustible resource with a high biotechnological potential for obtaining these polyfunctional compounds. An opinion is expressed that the effectiveness of the antibacterial activity of phlorotannins depends on the methods of their extraction aimed at preserving the phenolic structure. The use of modern analytical tools opens up a broad range of opportunities for studying the metabolic pathways of phlorotannins and identifying their structural and functional relationships. The high antimicrobial activity of phlorotannins against both Gram-positive and Gram-negative bacteria provides a promising framework for creating novel drugs to be used in the treatment and prevention of infectious diseases.


Author(s):  
Shaochen Li ◽  
Min Lv ◽  
Shaoyong Zhang ◽  
Hui Xu

: Derivatives of monosaccharides and oligosaccharides play the important roles in biological processes. Monosaccharides are the single carbohydrate building blocks, such as glucose, xylose, and fructose. Oligosaccharides are composed of 2–10 monosaccharides including disaccharides and trisaccharides. Moreover, monosaccharides, oligosaccharides and their derivatives are vital molecules with various biological properties including anticancer activity, antiviral activity, insecticidal activity, antimicrobial activity, and antioxidant activity. This review covers a survey of structural modifications, biological activities, and mechanisms of action of monosaccharides, oligosaccharides and their derivatives. Additionally, their structure–activity relationships are also concluded.


2020 ◽  
Vol 26 (1) ◽  
pp. 138-159 ◽  
Author(s):  
Yanfei Ban ◽  
Tianshuang Xia ◽  
Rui Jing ◽  
Yaoli Guo ◽  
Yiya Geng ◽  
...  

Plants of the genus Vitex (Verbenaceae) are mainly distributed throughout tropical and temperate regions, and many Vitex plants have been traditionally used in folk medicine. Plants of this genus are a rich source of diterpenoids, which not only displayed versatile structural diversity with potential chemotaxonomical significance but also exhibited a wide range of biological activities, mainly including in vitro cytotoxic, antiinflammatory, antimicrobial, hormone level-regulating and antiangiogenic activities. Recently, a series of bioactive diterpenoids, with interesting carbon skeletons, have been reported and gathered considerable interest. This article systematically reviewed diterpenoids isolated from the genus Vitex that appeared in the literature up to December 2018, critically highlighting their structural diversity and pharmacological activities. Up to now, a total of 154 diterpenoids with diverse structures have been isolated and identified from Vitex plants. The authors also summarized the reported structure-activity relationships of those well explored Vitex diterpenoids. Finally, the authors discussed the challenges and potential applications of these diterpenoids in the future.


Marine Drugs ◽  
2020 ◽  
Vol 18 (7) ◽  
pp. 368
Author(s):  
Hanan I. Althagbi ◽  
Walied M. Alarif ◽  
Khalid O. Al-Footy ◽  
Ahmed Abdel-Lateff

The curiosity and attention that researchers have devoted to alkaloids are due to their bioactivities, structural diversity, and intriguing chemistry. Marine-derived macrocyclic alkaloids (MDMAs) are considered to be a potential source of drugs. Trabectedin, a tetrahydroisoquinoline derivative, has been approved for the treatment of metastatic soft tissue sarcoma and ovarian cancers. MDMAs displayed potent activities that enabled them to be used as anticancer, anti-invasion, antimalarial, antiplasmodial, and antimicrobial. This review presents the reported chemical structures, biological activities, and structure–activity relationships of macrocyclic alkaloids from marine organisms that have been published since their discovery until May 2020. This includes 204 compounds that are categorized under eight subclasses: pyrroles, quinolines, bis-quinolizidines, bis-1-oxaquinolizidines, 3-alkylpiperidines, manzamines, 3-alkyl pyridinium salts, and motuporamines.


2020 ◽  
Vol 14 (4) ◽  
pp. 2525-2541
Author(s):  
Kalidoss Rajendran ◽  
Shanmugam Poornima ◽  
Ponmurugan Ponnusamy

Substances which are normally secondary metabolites in a lichen are known to possess various medicinal properties but little is known about the biological activities of compounds present in these mycobiont culture extract. The objectives of the present study were isolation and optimization of growth conditions of the mycelia from Parmotrema austrosinense and assess the antiproliferative and antimicrobial activities of acetone extracts. The extraction of bioactive compound from mycobiont culture was achieved by using acetone and standard Soxhlet extraction procedures. The culture extract was subjected to silica gel column chromatography and detection of compound in thin layer chromatography. HPLC, UV vis, IR spectra, microcrystallization and NMR were done for the purified compound. The antimicrobial activity in the extracts were assayed using the standard disc diffusion and broth microdilution protocol against microbial strains. The lecanoric acid in the extracts was purified and MTT method was applied to assess antiproliferative activity against DLA cancer cells. The culture extract containing lecanoric acid exhibited antimicrobial activity against the test strains with the Minimum Inhibitory Concentrations varied between 0.83±0.28 and 2.3±1.5 mg mL−1. The lecanoric acid inhibited the growth of DLA cancer cells with inhibitory concentration (IC50) of about 42±1.5 µg mL−1. Conclusion: The result of the present study suggests that this compound might possess potent antitumor property and should be further analysed using appropriate animal model and clinical trials.


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