Recent Advances in the Discovery and Development of Plant-Derived Natural Coumarins and their Analogues as Anti Human Immunodeficiency Virus—Type 1 (HIV-1) Agents
TL;DR: The aim of this review is to summarize research findings for herbal medicines, especially coumarins, which are endowed with the ability to inhibit HIV.
Abstract: The acquired immunodeficiency syndrome (AIDS) is a result of human immunodeficiency virus (HIV) infection which leads to severe suppression of immune functions. AIDS is a real threat to the health of mankind, and the search for effective therapies is still of great importance. However, besides the high cost, there are adverse effects and limitations associated with chemotherapy applied. Thus, herbal medicines are frequently used as an alternative therapy by individuals living with HIV. Numerous plant-derived compounds have been evaluated for inhibitory effects on HIV replication, and many coumarins have been found to inhibit different steps in HIV replication cycle. The aim of this review is to summarize research findings for herbal medicines, especially coumarins, which are endowed with the ability to inhibit HIV.
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TL;DR: In this article, a review of antibiotic resistance strategies produced by multidrug-resistant bacteria and phytochemicals from different classes with documented antimicrobial action against resistant bacteria, either alone or in combination with traditional antibiotics is presented.
Abstract: Microbial resistance has progressed rapidly and is becoming the leading cause of death globally. The spread of antibiotic-resistant microorganisms has been a significant threat to the successful therapy against microbial infections. Scientists have become more concerned about the possibility of a return to the pre-antibiotic era. Thus, searching for alternatives to fight microorganisms has become a necessity. Some bacteria are naturally resistant to antibiotics, while others acquire resistance mainly by the misuse of antibiotics and the emergence of new resistant variants through mutation. Since ancient times, plants represent the leading source of drugs and alternative medicine for fighting against diseases. Plants are rich sources of valuable secondary metabolites, such as alkaloids, quinones, tannins, terpenoids, flavonoids, and polyphenols. Many studies focus on plant secondary metabolites as a potential source for antibiotic discovery. They have the required structural properties and can act by different mechanisms. This review analyses the antibiotic resistance strategies produced by multidrug-resistant bacteria and explores the phytochemicals from different classes with documented antimicrobial action against resistant bacteria, either alone or in combination with traditional antibiotics.
48 citations
TL;DR: The objective of this review is to evaluate data on coumarins’ potent activity with respect to the inhibition of HIV-reverse transcriptase, HIV-integrase or HIV-protease.
Abstract: Considerable progress has been made in recent years in the field of drug development against HIV. Many different kinds of natural products, including coumarins, have been found to be active in anti-HIV models and are thus undergoing further investigation. This review demonstrates the variety of coumarins with unique mechanisms of action in the different stages of HIV replication. The discovery and development of coumarins as anti-HIV agents has expanded in the past two decades. Most of the studies have been focused on the inhibitory activity of reverse transcriptase, but anti-integrase and antiprotease activities were also described. The objective of this review is to evaluate data on coumarins’ potent activity with respect to the inhibition of HIV-reverse transcriptase, HIV-integrase or HIV-protease. Recent requirements for potential anti-HIV agents increasingly require adequate definition of the mechanism of action as well as definition of toxic effects and this also applies to natural as well as synthe...
21 citations
Cites background from "Recent Advances in the Discovery an..."
...1 μM* RT [4,5]...
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...3 μM¶,# RT [4,5]...
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...2 μM*,‡,§ RT [4,5]...
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...The coumarins represent a unique class of non-nucleoside reverse transcriptase inhibitors (NNRTIs) [4,5]....
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...Imperatorin 100 μg/ml** RT [4,5]...
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TL;DR: The cerium Ce(III, lanthanum La(III), and neodymium Nd(III) complexes were synthesized and studied for the first time for cytotoxicity (on MT-2 cells) and as anti-HIV agents under acute and chronic infection.
Abstract: The cerium Ce(III), lanthanum La(III), and neodymium Nd(III) complexes with 4-hydroxy-3-(3-oxo-1-phenylbutyl)-2H-1-benzopyran-2-one (warfarin) (W) and 3,3'-benzylidenebis[4-hydroxycoumarin] (1) were synthesized and studied for the first time for cytotoxicity (on MT-2 cells) and as anti-HIV agents under acute and chronic infection. The complexes were characterized by different physicochemical methods: mass spectrometry, (1)H NMR, (13)C NMR, and IR spectroscopy. The spectra of the complexes were interpreted on the basis of comparison with the spectrum of the free ligands. Anti-HIV effect of the complexes/ligands was measured in MT-2 cells by microtiter infection assay. Detection of endogenous reverse transcriptase (RT) activity and RT processivity by PCR indicative for proviral DNA synthesis demonstrated that anti-HIV activity has not been linked to early stages of viral replication. No effect on late steps of viral replication has been found using cells chronically producing HIV-1(LAI) virus. La(W) demonstrated anti-HIV activity (IC50=21.4 muM) close to maximal nontoxic concentration. Nd(W), Ce(1), and Nd(1) demonstrated limited anti-HIV potency, so none of the complexes seems appropriate to be used in clinic. Further targeting of HIV-1 inhibition by La(W) is under progress.
20 citations
Cites background from "Recent Advances in the Discovery an..."
...Coumarins and bicoumarins are widely spread in nature [1, 2]....
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07 Mar 2011
TL;DR: In this article, a new reaction in phosphorus chemistry, namely, the interaction of 2,2,2-trihalobenzo-1, 3, 2-dioxaphospholes with aryl(alkyl)acetylenes, leads to the formation of benzo[e]-1,2oxaphosphinine derivatives, or “phosphacoumarins.
Abstract: The account covers a new reaction in phosphorus chemistry, namely, the interaction of 2,2,2-trihalobenzo-1,3,2-dioxaphospholes with aryl(alkyl)acetylenes, which leads to the formation of benzo[e]-1,2-oxaphosphinine derivatives, or “phosphacoumarins.” The easy formation of a P-C bond and phosphoryl group, the ipso-substitution of the oxygen atom by the carbon one, and selective chlorination para to endocyclic oxygen are realized under mild conditions in this reaction. The ipso-substitution of a tertiary butyl group and a bromine atom also takes place in some cases.
11 citations
TL;DR: In this article, the minor isomer was formed as a result of substitution of the oxygen atom in the ortho position with respect to one tert-butyl group of the initial phosphole.
Abstract: 2,2,2-Tribromo-4,6-di-tert-butylbenzo-1,3,2λ5-dioxaphospholedioxaphosphole reacted with a terminal alkyne, pent-1-yne, to give a mixture of two isomeric 1,2-benzoxaphosphinine derivatives, 6,8- and 5,7-di-tert-butyl-2-bromo-4-propylbenzo-1,2λ5-oxaphosphinin-2-oxides, at a ratio of 5.9: 1. The regioselectivity of substitution of oxygen in the dioxaphosphole fragment by carbon differs from that observed previously in the reaction with 4,6-di-tert-butyl-2,2,2-trichlorobenzo-1,3,2λ5-dioxaphosphole: the minor isomer was formed as a result of substitution of the oxygen atom in the ortho position with respect to one tert-butyl group of the initial phosphole.
3 citations
References
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TL;DR: Levels of (+)-calanolide A in human plasma were higher than would have been predicted from animal studies, yet the safety profile remained benign, and although raw plasma drug levels were higher in women than in men, when doses were normalized for body mass, the pharmacokinetic profiles were virtually identical with those observed for males.
Abstract: (+)-Calanolide A is a novel, naturally occurring, nonnucleoside inhibitor of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase first isolated from a tropical tree (Calophyllum lanigerum) in the Malaysian rain forest. Previous studies have demonstrated that (+)-calanolide A has specific activity against the reverse transcriptase of HIV-1 and a favorable safety profile in animals. In addition, (+)-calanolide A exhibits a unique HIV-1 resistance profile in vitro. The safety and pharmacokinetics of (+)-calanolide A was examined in four successive single-dose cohorts (200, 400, 600, and 800 mg) in healthy, HIV-negative volunteers. In this initial phase I study, the toxicity of (+)-calanolide A was minimal in the 47 subjects treated. Dizziness, taste perversion, headache, eructation, and nausea were the most frequently reported adverse events. These events were not all judged to be related to study medication nor were they dose related. While 51% of subjects reported mild and transient dizziness, in many cases this appeared to be temporally related to phlebotomy. Calculation of the terminal-phase half-life (t1/2) was precluded by intrasubject variability in the 200-, 400-, and 600-mg dose cohorts but was approximately 20 h for the 800-mg dose group. (+)-Calanolide A was rapidly absorbed following administration, with time to maximum concentration of drug in plasma (Tmax) values occurring between 2.4 and 5.2 h postdosing depending on the dose. Plasma levels of (+)-calanolide A at all dosing levels were quite variable; however, both the mean concentration in plasma (Cmax), and the area under the plasma concentration-time curve increased proportionately in relation to the dose. Although raw plasma drug levels were higher in women than in men, when doses were normalized for body mass, the pharmacokinetic profiles were virtually identical with those observed for males. In general, levels of (+)-calanolide A in human plasma were higher than would have been predicted from animal studies, yet the safety profile remained benign. In conclusion, this study demonstrated the safety and favorable pharmacokinetic profile of single doses of (+)-calanolide A in healthy, HIV-negative individuals.
91 citations
TL;DR: The results with isolates selected in cell culture indicate that the carboxanilide compounds interact with the RT at two vulnerable sites, selecting UC-resistant virus isolates with the Y-to-C mutation at position 181 (Y181C) or the L100I substitution.
Abstract: A series of compounds related to the nonnucleoside reverse transcriptase (RT) inhibitor (NNRTI) oxathiin carboxanilide (UC84) were evaluated for activity against the human immunodeficiency virus (HIV) to determine structural requirements for anti-HIV activity. Twenty-seven compounds representative of the more than 400 Uniroyal Chemical Company (UC) compounds were evaluated for structure-activity relationships. Several of the compounds evaluated were highly active, with 50% effective concentrations in the nanomolar range and therapeutic indices of > 1,000. Highly synergistic anti-HIV activity was observed for each compound when used in combination with 3'-azido-3'-deoxythymidine; additive to slightly synergistic interactions were observed with the compounds used in combination with dideoxycytidine. In combination with the NNRTI costatolide, only UC38 synergistically inhibited HIV type 1. Residues in the RT which, when mutated, impart resistance to the virus isolates selected in cell culture, against virus variants with site-directed mutations, and against RTs containing defined single amino acid changes. The mutations included changes in RT amino acids 100, 101, 103, 106, 108, and 181. The results with isolates selected in cell culture indicate that the carboxanilide compounds interact with the RT at two vulnerable sites, selecting UC-resistant virus isolates with the Y-to-C mutation at position 181 (Y181C) or the L100I substitution. A resistant virus isolate containing both Y181C combination with calanolide A, an NNRTI which retains activity against virus with the single Y181C mutation, UC10 rapidly selected a virus isolate with the K103N mutation. The merits of selecting potential candidate anti-HIV agents to be used in rational combination drugs design as part of an armamentarium of highly active anti-HIV compounds are discussed.
73 citations
Journal Article•
TL;DR: The study substantially supports the conclusion that calanolide A represents a novel subclass of nonnucleoside RT inhibitor which merits consideration for anti-HIV drug development.
Abstract: Calanolide A, recently discovered in extracts from the tropical rainforest tree, Calophyllum lanigerum, is a novel inhibitor of the human immunodeficiency virus (HIV) type 1. The compound is essentially inactive against strains of the less common HIV type 2. The present study focused on the further characterization of the selective antiviral activity and mechanism of action of calanolide A. The compound inhibited a wide variety of laboratory strains of HIV type 1, with EC50 values ranging from 0.10 to 0.17 microM. The compound similarly inhibited promonocytotropic and lymphocytotropic isolates from patients in various stages of HIV disease, as well as drug-resistant strains. Viral life-cycle studies indicated that calanolide A acted early in the infection process, similar to the known HIV reverse transcriptase (RT) inhibitor 2', 3'-dideoxycytidine. In enzyme inhibition assays, calanolide A potently and selectively inhibited recombinant HIV type 1 RT but not cellular DNA polymerases or HIV type 2 RT within the concentration range tested. Serial passage of the virus in host cells exposed to increasing concentrations of calanolide A yielded a calanolide A resistant virus strain. RT from the resistant virus was not inhibited by calanolide A but retained sensitivity to other nonnucleoside as well as nucleoside RT inhibitors, including 3'-azido-2',3'-dideoxythymidine triphosphate and nevirapine. The study substantially supports the conclusion that calanolide A represents a novel subclass of nonnucleoside RT inhibitor which merits consideration for anti-HIV drug development.
71 citations
TL;DR: Results indicate that the various subgroups of HIV-1-specific inhibitors interact differently with HIV- 1 RT, suggesting important potential implications for drug combination therapeutic strategies.
70 citations
TL;DR: Comparison of the structure and activity of 1 with those of ten related compounds indicated that the dihydroseselin type of pyranocoumarin possessing a 4'-isovaleryl group is important to suksdorfin's enhanced anti-HIV activity.
69 citations