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3. Antioxidant properties of 4-methylcoumarins in in vitro cell-free systems

Author

Giuseppa Morabito, K. Prasad Ashok, Omidreza Firuzi, Domenico Trombetta, Antonina Saija, Mariateresa Cristani, S. Parmar Virinder, Ferdinando Mancari, Clara Naccari, Luciano Saso, and K. Singh Brajendra

Subjects
hypochlorous, Antioxidant, antioxidant, DPPH, medicine.medical_treatment, Phospholipid, 4-Methylcoumarins, AAPH, Liposome, Hypochlorous, Nitric Oxide, Biochemistry, Redox, chemistry.chemical_compound, Coumarins, Superoxides, cell-free systems, medicine, Structure–activity relationship, Animals, aaph, ABTS, Cell-Free System, Superoxide, 4-methylcoumarins, General Medicine, antioxidants, liposome, Hypochlorous Acid, chemistry, Liposomes, Lipid Peroxidation, Artemia, Fluorescence Recovery After Photobleaching
Abstract

4-Methylcoumarins that possess two hydroxyl groups ortho to each other in the benzenoid ring have shown to have excellent antioxidant and radical-scavenging properties in different experimental models. Furthermore, they cannot be metabolized by the liver P450 monoxygenases and thus cannot form 3,4-coumarin epoxides, which are believed to be mutagenic. Herein, we present a study on the structure activity relationship of eight synthetic 4-methylcoumarins, carried out by employing a series of different chemical cell-free tests. These compounds were tested by means of three assays involving one redox reaction with the oxidant (DPPH assay, ABTS + assay and FRAP). Other assays were employed to evaluate the antioxidant properties of the coumarins under investigation against NO, O2 − and HClO, which are some of the major reactive oxygen and nitrogen species causing damage in the human body. Finally, we have measured the protective capacity of these coumarins against the oxidative damage in a simple biomimetic model of phospholipid membranes. Our results confirm the good antioxidant activity of the 7,8-hydroxy-4-methylcoumarins. In general, their activity is not significantly affected by the introduction of an ethoxycarbonylmethyl or an ethoxycarbonylethyl moiety at the C3 position. A discrete antioxidant activity is retained also by the 7,8-diacetoxy-4-methylcoumarins, although they are less efficient than the corresponding 7,8-dihydroxy compounds. Furthermore, as demonstrated in the brine shrimp toxicity test, none of the tested coumarins significantly affect the larvae viability. Two of the 4-methylcoumarins (7,8-dihydroxy-4-methylcoumarin and 7,8-dihydroxy-3-ethoxycarbonylethyl-4-methylcoumarin), very interestingly, showed strong scavenging activities against the superoxide anion and were also very effective in protecting the lipid bilayer against peroxidation. On the basis of these findings, these 4-methylcoumarins may be considered as potential therapeutic candidates for pathological conditions characterized by free radical overproduction.

Published
2010

5. An Overview of Currently Available Antimalarials

Author

Yu. Gorobets, Nikolay, V. Sedash, Yuriy, K. Singh, Brajendra, Poonam, and Rathi, Brijesh

Abstract

Background: Despite the substantial progress over the time, malaria remains a major public health concern and causing hundreds of thousands of deaths. Resistance to the available antimalarial therapy increases threat to the global public health. Objective: Overview of currently available antimalarials. Method: Literary survey. Results: The summarized data about different types of antimalarial therapies and their efficiency and modes of action. Conclusion: Despite the seemingly large number of the drugs currently available for malaria treatment, this arsenal is limited due to the narrow variation of their mechanism of action.

Published
2017
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6. Potentials of Hydrogels in Cancer Therapy

Author

Prakash Sharma, Prem, Kumar, Ravindra, K Singh, Anil, K Singh, Brajendra, Kumar, Ajay, and Rathi, Brijesh

Abstract

Hydrogels have emerged as an unique and potential transporters for the target drug delivery systems in cancer therapy. Cancer is a terrible disease extracting toll on human health across the world probably due to several drawbacks of the conventional cancer treatments. However, hydrogels facilitate the modern and improved prospects for the treatment of cancer with minimum cytotoxic effects to the healthier cells or tissues. Besides, the easy tailoring associated with the structural features and high biocompatibility of hydrogels have attracted enough attention and offer them as a strong tool for the development of nanomedicine. This review is devoted to update the current studies related to hydrogels and their applications as vectors for cancer chemotherapy.

Published
2014

7. Antioxidant properties of 4-methylcoumarins in in vitro cell-free systems.

Author

Morabito G, Trombetta D, Singh Brajendra K, Prasad Ashok K, Parmar Virinder S, Naccari C, Mancari F, Saija A, Cristani M, Firuzi O, and Saso L

Subjects
Animals, Artemia drug effects, Coumarins pharmacology, Fluorescence Recovery After Photobleaching, Hypochlorous Acid chemistry, Lipid Peroxidation drug effects, Liposomes chemistry, Nitric Oxide chemistry, Superoxides chemistry, Antioxidants chemistry, Antioxidants pharmacology, Cell-Free System, Coumarins chemistry
Abstract

4-methylcoumarins that possess two hydroxyl groups ortho to each other in the benzenoid ring have shown to have excellent antioxidant and radical-scavenging properties in different experimental models. Furthermore, they cannot be metabolized by the liver P450 monoxygenases and thus cannot form 3,4-coumarin epoxides, which are believed to be mutagenic. Herein, we present a study on the structure activity relationship of eight synthetic 4-methylcoumarins, carried out by employing a series of different chemical cell-free tests. These compounds were tested by means of three assays involving one redox reaction with the oxidant (DPPH assay, ABTS.+ assay and FRAP). Other assays were employed to evaluate the antioxidant properties of the coumarins under investigation against NO, O2.- and HClO, which are some of the major reactive oxygen and nitrogen species causing damage in the human body. Finally, we have measured the protective capacity of these coumarins against the oxidative damage in a simple biomimetic model of phospholipid membranes. Our results confirm the good antioxidant activity of the 7,8-hydroxy-4-methylcoumarins. In general, their activity is not significantly affected by the introduction of an ethoxycarbonylmethyl or an ethoxycarbonylethyl moiety at the C3 position. A discrete antioxidant activity is retained also by the 7,8-diacetoxy-4-methylcoumarins, although they are less efficient than the corresponding 7,8-dihydroxy compounds. Furthermore, as demonstrated in the brine shrimp toxicity test, none of the tested coumarins significantly affect the larvae viability. Two of the 4-methylcoumarins (7,8-dihydroxy-4-methylcoumarin and 7,8-dihydroxy-3-ethoxycarbonylethyl-4-methylcoumarin), very interestingly, showed strong scavenging activities against the superoxide anion and were also very effective in protecting the lipid bilayer against peroxidation. On the basis of these findings, these 4-methylcoumarins may be considered as potential therapeutic candidates for pathological conditions characterized by free radical overproduction., (Copyright (c) 2010 Elsevier Masson SAS. All rights reserved.)

Published
2010
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