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Biogenic Synthesis of Nanoparticulate Materials for Antiviral Applications
Published in Devarajan Thangadurai, Saher Islam, Charles Oluwaseun Adetunji, Viral and Antiviral Nanomaterials, 2022
Kah Hon Leong, Jit Jang Ng, Lan Ching Sim, Pichiah Saravanan, Chaomeng Dai, Bo Tan
The bacteria mediated technique in synthesizing nanoparticles is either intracellular or extracellular. This technique can be performed using cell-free extracts, derivative bacteria components, supernatant, and biomass. However, the extracellular method is beneficial compared to the intracellular method because of the simple recovery of the nanoparticles. The mechanism of each biosynthesis is different due to the different organic substances used as the reducing agent during the synthesis process. Various organic substances are used as reducing agents, such as reductase, peptides, c-type cytochromes, exopolysaccharide, and cofactors (Xu et al. 2020). Besides this technique, various enzymes have also been incorporated to synthesize nanoparticles, such as lactate dehydrogenase and nitrate reductase and peptides with special amino acid (Ali et al. 2019). Moreover, some organic substances can use a stabilizer and capping agents to prevent the nanoparticle from aggregating (Galvez et al. 2019). The bacteria mediated technique is simple, environmentally friendly, and yields high efficacy.
Cellular Radiation Damage
Published in Kedar N. Prasad, Handbook of RADIOBIOLOGY, 2020
Reactivity of free radicals: Because free radicals contain unpaired electrons, they are very reactive and can oxidize or reduce the biological molecules within the cell. The free radicals OH. and are oxidizing agents, whereas H. is a reducing agent. Free radicals can damage molecules such as DNA, RNA, and proteins as well as membranes. Free radicals have been implicated in the etiology of cancer as well as in neurodegenerative diseases.
The Modification of Methionine
Published in Roger L. Lundblad, Chemical Reagents for Protein Modification, 2020
It is possible to convert methionine sulfoxide to methionine under relatively mild conditions7 thus providing for the reversibility of the oxidative reactions described above (Figure 6). This can be accomplished through both nonenzymatic and enzymatic methods. The nonenzymatic approaches have, in general, proved to be of greater value. A systematic study has shown that of four reducing agents tested, mercaptoacetic acid, β-mercaptoethanol, dithiothreitol, and N-methylmercaptoacetamide, the latter reagent, N-methylmercaptoacetamide was the most effective. The reactions demonstrated little pH dependence but did not proceed well at concentrations of acetic acid above 50% (v/v). Complete regeneration of methionine could be accomplished with 0.7 to 2.8 M reagent at 37° for 21 h. An enzymatic system for the reduction of methionine sulfoxide has been reported.8
Evaluation and clinical comparison studies on liposomal and non-liposomal ascorbic acid (vitamin C) and their enhanced bioavailability
Published in Journal of Liposome Research, 2021
Sreerag Gopi, Preetha Balakrishnan
The blend of liposomal formulation of vitamin C with squeezed orange did not change its organoleptic qualities and indicated microbiological solidness after sanitization and capacity at 4 °C for 37 days (Marsanasco et al. 2011). A polyelectrolyte delivery system for vitamin C was accomplished by successive deposition of positive chitosan and negative sodium alginate onto the surface of anionic nanoliposomes, which demonstrated that liposomes can give a potential platform for tailored design of carriers for nutrients or preservatives to enhance both the shelf-life and safety of food matrices (Liu et al. 2017). Chitosan-coated nano-size liposomes were made from phosphatidylcholine (pc) and cholesterol (chol) and were promising vitamin C carriers with a great loading efficiency and payload with 15-week storage over 85% vitamin C was protected against oxidation (Liu and Park 2010). Vitamin C (ascorbic acid) is better considered as a true vitamin because in humans cannot be able to synthesis it. Vitamin C acts as a reducing agent since it exhibits a number of enzymatic/non-enzymatic effect and its ability to donate electrons. Vitamins also perform as a co-factor for a number of enzymes, including collagen hydroxylation, and prevent oxidative damage to DNA and intracellular proteins. In plasma, it increases endothelium-dependent vasodilatation and lowers extracellular oxidants from neutrophils. Insufficiency in vitamin C results in the potentially fatal disease scurvy, low invulnerability which can be cured only by administering right dose of vitamin C (Hemilä and Chalker 2020, Van der Velden 2020).
Emerging glucagon-like peptide 1 receptor agonists for the treatment of obesity
Published in Expert Opinion on Emerging Drugs, 2021
Mathies M. Jepsen, Mikkel B. Christensen
The need for safe and effective weight reducing agents is apparent. However, based on previous safety concerns and market withdrawals, there is also a strong clinical and regulatory focus on prevention of hard clinical endpoints such as major cardiovascular events and death, but potentially also prevention of obesity-associated conditions outlined above. Of all the above-mentioned approved obesity drugs, only liraglutide has shown effects on cardiovascular events, cardiovascular mortality and overall mortality – and this was documented in a population with established atherosclerotic cardiovascular disease and type 2 diabetes. A beneficial cardiovascular effect seems to apply to all long acting GLP-1 receptor agonists and associate with weight loss and effects on glycemic control [16]. Besides prevention of hard endpoints, current research goals in GLP-1-based obesity treatment focus on improving convenience and/or efficacy either by enabling oral administration or enhancing and prolonging effects by structural modifications. The structural modifications may also confer affinity for other hormonal receptors with therapeutic anti-obesity potential, e.g. receptors for GIP, glucagon, and amylin.
Evaluation of hepatorenal protective activity of Moringa oleifera on histological and biochemical parameters in cadmium intoxicated rats
Published in Toxin Reviews, 2019
The antioxidant activity of Moringa is mainly due to its content of many phenolic compounds as previously mentioned (Karthivashan et al. 2013). These phenolic compounds are multifactorial defenders against oxidative stress. This is because they can act as reducing agents via singlet oxygen scavengers and hydrogen atom donators with subsequent stabilization of the produced free radicals forming stable compounds that do not initiate or propagate oxidation. In addition, the involvement of the anti-inflammatory and analgesic activities of such phenolic compounds in both plants in the protective mechanisms cannot be neglected. Further, phenolic compounds including flavonoids can protect the cells against emptying reduced glutathione (GSH) via activating the activity of glutathione reductase as well as increasing the activities of other antioxidant enzymes which are ultimately helpful in renal and hepatic protection (Adeyemi and Elebiyo 2014).