Current Chemical Biology - Volume 17, Issue 1, 2023

Background: Lignins are phenylpropanoid polymers with complex composition and structures and crucial components in plant cell walls. Lignins are biosynthesized from oxidative polymerization of 4-hydroxycinnamyl alcohols, but differ in the degree of methoxylation. Objective: This review makes an endeavour to identify the gaps in our understanding of lignin modulation and gain insights into their relevance to abiotic stress tolerance. Methods: Critical review of the recent literature to understand the regulation of lignin, the major biopolymer involved in a multitude of functions. Results: Lignin contributes to the growth of tissues, and organs that give mechanical protection or lodging resistance and also responds to multiple biotic and abiotic stresses. The quantity and quality of accumulation of lignin is dependent on the type of plant species and abiotic stress. In this review, we briefly discuss the biosynthesis, modulation of lignin by diverse transcription factors and its role in salt, drought and temperature stress tolerance. Conclusion: We need to explore many areas to gain comprehensive knowledge about the secondary cell wall deposition of monolignols, and their transport, leading to lignin accumulation which imparts biotic and abiotic stress tolerance to plants.

The development of novel small molecules with effective catalytic antioxidant properties is highly sought after. A wide array of structurally diverse selenium- and tellurium-containing glutathione peroxidase mimics have been studied over the past two decades. Within this arena, organotellurium compounds generally exhibit higher catalytic properties with respect to selenium-containing analogues. Different mechanisms accounting for the thiol-peroxidase-like activity of various classes of organotellurium derivatives have been proposed. This review documents developments in this area and provides an overview of the catalytic mechanisms proposed for the various classes of telluriumcontaining thiol-peroxidase-like-catalysts.

Introduction: Acinetobacter baumannii is an opportunistic bacterium capable of causing nosocomial infections resistant to a wide range of antibiotics. Herbal medicines could become the source of novel therapies for antibiotic-resistant bacteria. This review paper aimed to survey the effectiveness of medicinal plants in treating infections caused by A. baumannii. Methods: The relevant data was obtained by systematically searching PubMed, ISI Web of Science, Scopus, Science Direct, and Google Scholar databases with the specific keywords of medicinal plants (including extracts and essential oils) and bacterial infections (including A. baumannii). Results: The present review identified 23 studies published between 2009 and 2021 that discussed the effectiveness of medicinal plants in inhibiting the growth of A. baumannii. In these studies, 28 medicinal plants were found effective against infection caused by A. baumannii in vivo. Conclusion: The results of this review indicated that to develop a therapeutic strategy for treating bacterial infections, especially A. baumannii, based on medicinal plants, extensive studies were required to determine their cytotoxicity and therapeutic dosage before they could be used as an alternative to antibiotics.

Aims and Objective: The aim of this study was to evaluate the antifungal, dyeing activity and optimization of carotenoid production by Rhodosporidium babjevae. Background: Rhodosporidium red yeast is one of the natural alternative sources of carotenoids. Carotenoids are produced by a wide variety of bacteria, algae, fungi ,and plants. These pigments serve a vital function as antioxidant protectors and have lately caught a lot of attention because of their positive impact on human health. Methods: In this experimental-laboratory study, Rhodosporidium was isolated from different environmental sources in Isfahan. After carotenoid extraction based on the Davis method from Rhodosporidium, cell biomass, and the total amount of carotenoids were measured, and the carotenoid light absorption spectrum was determined. To optimize carotenoid production, one-factor and Taguchi methods evaluated incubation time factors, pH, nitrogen, and carbon source. Then, yeast carotenoid antifungal activity, minimum inhibitory concentration (MIC),and minimum fungicidal concentration (MFC) were determined. The stability of dye against washing, rubbing, and light was investigated to evaluate the carotenoid dyeing activity. Results: The optimum condition for carotenoid production was 96 hours of incubation, 2 g L^-1 peptone, pH 5.5, and 30 g L^-1 glucose. The optimal conditions of Taguchi were performed, and production of 11.67 mg L^-1 was obtained. The carotenoid pigment isolated from Rhodosporidium babjevae showed no anti-candida properties but has antifungal activity against A. flavus and A. niger. Woolen fabric had washing fastness of 2 and cotton fabric had a washing fastness of 3. The staining grade on woolen and cotton fabrics was 4. The grade of color fastness of woolen and cotton fabrics against dry rubbing was 5, while the grade of color fastness against wet rubbing was 2 and 4, respectively. Conclusion: Based on the results, Rhodosporidium babjevae carotenoid is a suitable option for dyeing woolen and cotton fabrics with antifungal properties that can be used in industry. It is hoped that it can be used for the commercial production of carotenoids.

Background: Germanium is a biologically active trace element, and it is present in almost all organs and tissues. Its biological activity was revealed in the 20^th century. However, the study on the possibility of using germanium for medical purposes was first undertaken by the Japanese scientist Dr. Kazuhiko Asai in 1940. In 1965, academician M.G.Voronkov and colleagues synthesized tricyclic esters of triethanolamine germanium with the general formula XGe(OCH2CH2)3N and studied their biological activity. However, the adaptogenic properties of these compounds have not been sufficiently studied. In this regard, there is an urgent need to study the adaptogenic properties of these drugs. Objective: As the resistance of the organism to stress factors primarily depends on energy metabolism, the aim of our work was to study the influence of stress and 1- (germatran-1-il) –oxyethylamine (GM) on the functional state of mitochondria. Methods: The functional state of mitochondria was studied as per the rate of mitochondria respiration by the level of lipid peroxidation and fatty acid composition of mitochondrial membranes by chromatography technique. Results: It was shown that the drug in concentrations of 10^-5, 10^-6, and 10^-11M reduced the intensity of LPO in the membranes of "aged" mitochondria. This may serve as evidence regarding the presence of anti-stress properties in the drug. Injection of GM at a dose of 10^-5 mol/kg to rats prevented the activation of LPO in the membranes of the liver mitochondria in conditions of acute hypobaric hypoxia. Restricting lipid peroxidation, GM prevented changes in the content of C18 and C22 fatty acids in mitochondrial membranes, which probably contributed to maintaining the bioenergetic characteristics of mitochondria at the control level. Conclusion: It is assumed that the anti-stress activity of the drug is associated with its antioxidant properties and its effect on the complex I of the mitochondrial respiratory chain.

Background: We report the synthesis and antioxidant evaluation of 1-organoselanylnaphthalen- 2-ols. The title compounds were selectively prepared through the selenofunctionalization of 2-naphthol derivatives using benzeneseleninic acids as a selenium source. Objective: We aimed at synthesizing 1-organoselanyl-naphthalen-2-ol by functionalizing 2-naphthol with arylseleninic acids using glycerol as the solvent and further evaluating the pharmacological activity. Methods: The products were synthesized at 70°C using glycerol as a solvent in an oil bath. Reactive species (RS) tests, DPPH radical scavenging activity assay, and ABTS+ radical scavenging activity assay were performed. A statistical analysis of the data was performed. Results and Discussion: A total of fifteen 1-organoselanyl-naphthalen-2-ols were selectively obtained in yields of 58-95% in 0.25-48 h of reaction. Additionally, all the synthesized seleno-derivatives exhibited antioxidant activity, as revealed by their ability to scavenge DPPH and ABTS+ radicals and reduce the reactive species (RS) levels. Conclusion: The synthesis of 1-arylselanyl-naphthalen-2-ols was developed under mild reaction conditions using benzeneseleninic acid derivatives in reactions with 2-naphthol. All synthesized 2- naphthol derivatives exhibited antioxidant activity, as revealed by their DPPH and ABTS+ radical scavenging activity and reduced RS levels.

Background: Resveratrol (RSV), a polyphenolic compound, is reported to have antiaggregation properties against Amyloid-beta peptides. It is, therefore, significant to understand the mechanism of inhibition of Aβ1-42 peptide aggregation by the RSV at the molecular level. We have used Molecular docking along with Molecular dynamics (MD) simulation techniques to address the role of RSV in the inhibition of Aβ1-42 peptide aggregation. Objective: To understand the role of Resveratrol on the Aβ1-42 peptide aggregation. Methods: In this computational study, we have docked the RSV to Aβ1-42 peptide using Molecular Docking software and then performed MD simulation for the Aβ1-42 peptide monomer Aβ1-42 peptide- RSV complex using the AMBER force field. From the analysis of MD trajectories, we obtained salient structural features and determined the Binding Free Energy(BFE) and Per-residue Energy Decomposition Analysis (PRED) using MM-PBSA/GBSA method. Results: The secondary structure and the conformational analysis obtained from MD trajectories show that the binding of RSV with the Aβ1-42 peptide monomer causes an increase in the helical content in the structure of the Aβ1-42 peptide. The BFE and PRED results show a high binding affinity (GBtotal=- 11.07 kcal mol^-1; PBtotal= -1.82 kcal mol^-1) of RSV with Aβ1-42 peptide. Also, we found the RSV to interact with crucial residues (Asp 23 and Lys 28) of the Aβ1-42 peptide. These residues play a significant role in facilitating the formation of toxic amyloid oligomers and amyloid fibrils. The salt bridge interaction between these residues D23-K28 was found to be destabilized in the Aβ1-42 peptide when it is complexed with RSV. Conclusion: In summary, it can be concluded that Resveratrol greatly aids the prevention of Aβ1-42 peptide aggregation. Therefore, it can be considered a possible drug candidate for therapeutic strategies for Alzheimer’s disease.