scholarly journals Antiprotozoal and Antitumor Activity of Natural Polycyclic Endoperoxides: Origin, Structures and Biological Activity

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 686
Author(s):  
Valery M. Dembitsky ◽  
Ekaterina Ermolenko ◽  
Nick Savidov ◽  
Tatyana A. Gloriozova ◽  
Vladimir V. Poroikov
Keyword(s):  
Antitumor Activity ◽  
Confidence Level ◽  
Clinical Medicine ◽  
Marine Invertebrates ◽  
Antiprotozoal Activity ◽  
Strong Activity ◽  
The Third ◽  
Intracellular Parasites ◽  
Antitumor Properties ◽  
Pharmacological Potential

Polycyclic endoperoxides are rare natural metabolites found and isolated in plants, fungi, and marine invertebrates. The purpose of this review is a comparative analysis of the pharmacological potential of these natural products. According to PASS (Prediction of Activity Spectra for Substances) estimates, they are more likely to exhibit antiprotozoal and antitumor properties. Some of them are now widely used in clinical medicine. All polycyclic endoperoxides presented in this article demonstrate antiprotozoal activity and can be divided into three groups. The third group includes endoperoxides, which show weak antiprotozoal activity with a reliability of up to 70%, and this group includes only 1.1% of metabolites. The second group includes the largest number of endoperoxides, which are 65% and show average antiprotozoal activity with a confidence level of 70 to 90%. Lastly, the third group includes endoperoxides, which are 33.9% and show strong antiprotozoal activity with a confidence level of 90 to 99.6%. Interestingly, artemisinin and its analogs show strong antiprotozoal activity with 79 to 99.6% confidence against obligate intracellular parasites which belong to the genera Plasmodium, Toxoplasma, Leishmania, and Coccidia. In addition to antiprotozoal activities, polycyclic endoperoxides show antitumor activity in the proportion: 4.6% show weak activity with a reliability of up to 70%, 65.6% show an average activity with a reliability of 70 to 90%, and 29.8% show strong activity with a reliability of 90 to 98.3%. It should also be noted that some polycyclic endoperoxides, in addition to antiprotozoal and antitumor properties, show other strong activities with a confidence level of 90 to 97%. These include antifungal activity against the genera Aspergillus, Candida, and Cryptococcus, as well as anti-inflammatory activity. This review provides insights on further utilization of polycyclic endoperoxides by medicinal chemists, pharmacologists, and the pharmaceutical industry.

Oxford Assess and Progress: Clinical Medicine

2019 ◽  
Keyword(s):  
Correct Answer ◽  
Clinical Medicine ◽  
The Other ◽  
The Third

Maximise your exam success with this essential revision guide. The third edition of Oxford Assess and Progress: Clinical Medicine features over 550 Single Best Answer questions. Packed with questions written by practicing clinicians and educators, this revision tool is an authoritative guide on core clinical topics and professional themes. Each question is accompanied by extensive feedback which explains not only the rationale of the correct answer, but why the other options are incorrect. Further reading resources and cross-references to the Oxford Handbook of Clinical Medicine have been fully updated to expand your revision further. Progess to exam success with the third edition of Oxford Assess and Progress: Clinical Medicine.

scholarly journals Sulfated and Sulfur-Containing Steroids and Their Pharmacological Profile

Marine Drugs ◽  
2021 ◽  
Vol 19 (5) ◽  
pp. 240
Author(s):  
Tatyana A. Pounina ◽  
Tatyana A. Gloriozova ◽  
Nick Savidov ◽  
Valery M. Dembitsky
Keyword(s):  
Antitumor Activity ◽  
Confidence Level ◽  
Biological Activities ◽  
Marine Sponges ◽  
Bioactive Lipids ◽  
Pharmacological Profile ◽  
Wide Range ◽  
Sulfated Steroids ◽  
Strong Antitumor Activity ◽  
Sulfur Containing

The review focuses on sulfated steroids that have been isolated from seaweeds, marine sponges, soft corals, ascidians, starfish, and other marine invertebrates. Sulfur-containing steroids and triterpenoids are sourced from sedentary marine coelenterates, plants, marine sediments, crude oil, and other geological deposits. The review presents the pharmacological profile of sulfated steroids, sulfur-containing steroids, and triterpenoids, which is based on data obtained using the PASS program. In addition, several semi-synthetic and synthetic epithio steroids, which represent a rare group of bioactive lipids that have not yet been found in nature, but possess a high level of antitumor activity, were included in this review for the comparative pharmacological characterization of this class of compounds. About 140 steroids and triterpenoids are presented in this review, which demonstrate a wide range of biological activities. Therefore, out of 71 sulfated steroids, thirteen show strong antitumor activity with a confidence level of more than 90%, out of 50 sulfur-containing steroids, only four show strong antitumor activity with a confidence level of more than 93%, and out of eighteen epithio steroids, thirteen steroids show strong antitumor activity with a confidence level of 91% to 97.4%.

THE INFLUENCE OF THE TYPE OF GREASE ON THE SYNERGY OF ITS COMPOSITION WITH PTFE POWDER AND COPPER POWDER

Tribologia ◽  
2016 ◽  
Vol 265 (1) ◽  
pp. 45-55 ◽  
Author(s):  
Stanisław KRAWIEC ◽  
Michał KRAWIEC ◽  
Tadeusz LEŚNIEWSKI
Keyword(s):  
Synergistic Effect ◽  
Copper Powder ◽  
Confidence Level ◽  
Solid Lubricants ◽  
Test Results ◽  
Extreme Pressure ◽  
The Third ◽  
Student’S T ◽  
Student’S T Test ◽  
Lubricating Properties

Studies of the influence of the type of grease on the synergistic effect of its compositions with PTFE powder and of copper during the lubrication of steel sliding pairs working in mixed friction area of were presented. Two greases, car grease 1S with a lithium thickener and grease STP with calcium thickener, were adopted for analysis. As fillers in the two lubricants, powders of two solid lubricants were PTFE and copper were used. Three lubricating compositions were tested for each of the adopted greases. Two compositions contained one filler of 5% by weight, and the third composition contained the two fillers in the same proportion (5% each). The lubricating properties of the adopted compositions were evaluated based on an experiment conducted with the use of a four–ball extreme pressure tester according to the standard PN-76/ C04147. The effectiveness of the analysed lubricants was evaluated according to four criterion values (wear of the balls d, fusion point Fz, limit wear load Goz, and wear index Ih). The results were statistically handled at the confidence level of 95% using Student’s t-test. The developed test results are shown graphically. Appropriate conclusions were drawn.

Contemporaneous Faulting and of Sandbody Control in PN Oilfield

2013 ◽  
Vol 411-414 ◽  
pp. 3117-3120
Author(s):  
Zhan Dong Li ◽  
Sai Liu ◽  
Hai Xiang Zhang
Keyword(s):  
Structural Feature ◽  
Control Function ◽  
Sedimentary Environment ◽  
Growth Index ◽  
Activity Period ◽  
Distance Curve ◽  
Strong Activity ◽  
The Third ◽  
Overall Performance ◽  
Fault Growth

This paper investigates the structural feature of X area in PN oilfield and expounds the control function which contemporaneous faults do to the sandstone bodies. Considering the research of the fault growth index, the fault stretching rate and the stretching rate, it can be sure that the activities of a contemporaneous fault happen mainly in the period of Qingshankou Fm the period of Yaojia Fm~ nen the first or the second segments and also the third or the fourth segments. According to the thickening of the weight at each unit time in P reservoir, the strong activity period of contemporaneous faults located in PI3 time unit. Through researches on the distance curve of fault throw and of the ancient fault throw, the growth of contemporaneous faults has an overall performance that it has multi-episodic activity of faults in vertical and different sections on different locations in horizontal. Summarized two kinds of sandbody control methods:The way using downthrown block of contemporaneous fault and sectioning the growing point. The downthrown block of contemporaneous fault method has the same evolutionary series with stratigraphic deposition; the type of sandbody control depends on the evolution of sedimentary environment.

scholarly journals Synthesis and antitumor properties of some new 3-R-6-(5-arylfuran-2-yl-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazoles

2021 ◽  
pp. 37-49
Author(s):  
І. І. Мирко ◽  
Ю. І. Горак ◽  
Т. І. Чабан ◽  
І. В. Драпак ◽  
В. С. Матійчук
Keyword(s):  
Antitumor Activity ◽  
Antitumor Agents ◽  
Condensed System ◽  
Highly Active ◽  
Therapeutic Program ◽  
Composition And Structure ◽  
Antitumor Properties ◽  
High Antitumor Activity ◽  
Derivatives Of ◽  
Potential Antitumor

One of the promising methods of creating antitumor drugs is the screening of potential antitumor agents among synthesized compounds. Nitrogen-based heterocycle analogues are an extremely important class of organic substances that are widely used in medical chemistry. [1,2,4]Triazolo[3,4-b][1,3,4] thiadiazoles are among the little-studied and hard-to-reach members of this class of compounds. The aim of our work was to synthesize some new 3-R-6-(5-arylfuran-2-yl-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazoles, as well as the study of their antitumor activity. The objects of study were 3-R-6-(5-arylfuran-2-yl-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazoles. The composition and structure of the synthesized compounds were confirmed by the data of elemental analysis and 1H NMR spectroscopy. The antitumor activity of the synthesized compounds was studied in the framework of the international scientific program of the National Cancer Institute (Bethesda, Maryland, USA) DTP NCI (Developmental Therapeutic Program). The synthesis of 11 derivatives of 3-R-6-(5-arylfuran-2-yl-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazoles was carried out. These substances are obtained by the interaction of 5-arylfuran-2-carboxylic acids with 5-substituted 4-amino-4H-1,2,4-triazolo-3-thiols. Primary screening revealed individual 3-R-6-(5-arylfuran-2-yl-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazoles, which showed pronounced selective antitumor activity. The most active among the tested compounds were 3 d, 3 e and 3 j, which were further investigated during secondary screening. The results of these studies confirm the high antitumor activity of these compounds. The proposed approaches and the developed synthesis protocols made it possible to obtain a series of new 3-R-6-(5-arylfuran-2-yl-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazoles. The results of studies of the antitumor activity of the synthesized compounds made it possible to single out 3 highly active compounds with high antitumor activity, which gives reason to consider this condensed system as a promising molecular framework for the design of potential antitumor agents.

scholarly journals The natural product biosynthetic potential of Red Sea nudibranch microbiomes

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10525
Author(s):  
Samar M. Abdelrahman ◽  
Nastassia V. Patin ◽  
Amro Hanora ◽  
Akram Aboseidah ◽  
Shimaa Desoky ◽  
...  
Keyword(s):  
Antitumor Activity ◽  
16S Rrna ◽  
Microbial Communities ◽  
Natural Product ◽  
Red Sea ◽  
High Throughput Sequencing ◽  
Marine Invertebrates ◽  
Gene Clusters ◽  
Rrna Gene ◽  
Biosynthetic Gene

Background Antibiotic resistance is a growing problem that can be ameliorated by the discovery of novel drug candidates. Bacterial associates are often the source of pharmaceutically active natural products isolated from marine invertebrates, and thus, important targets for drug discovery. While the microbiomes of many marine organisms have been extensively studied, microbial communities from chemically-rich nudibranchs, marine invertebrates that often possess chemical defences, are relatively unknown. Methods We applied both culture-dependent and independent approaches to better understand the biochemical potential of microbial communities associated with nudibranchs. Gram-positive microorganisms isolated from nudibranchs collected in the Red Sea were screened for antibacterial and antitumor activity. To assess their biochemical potential, the isolates were screened for the presence of natural product biosynthetic gene clusters, including polyketide synthase (PKS) and non-ribosomal peptide synthetase (NRPS) genes, using PCR. The microbiomes of the nudibranchs were investigated by high-throughput sequencing of 16S rRNA amplicons. Results In screens against five model microorganisms, 51% of extracts displayed antimicrobial activity against more than one organism, and 19% exhibited antitumor activity against Ehrlich’s ascites carcinoma. Sixty-four percent of isolates contained PKS and NRPS genes, suggesting their genomes contain gene clusters for natural product biosynthesis. Thirty-five percent were positive for more than one class of biosynthetic gene. These strains were identified as belonging to the Firmicutes and Actinobacteria phyla via 16S rRNA gene sequencing. In addition, 16S rRNA community amplicon sequencing revealed all bacterial isolates were present in the uncultured host-associated microbiome, although they were a very small percentage of the total community. Taken together, these results indicate that bacteria associated with marine nudibranchs are potentially a rich source of bioactive compounds and natural product biosynthetic genes.

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