Metal ion chelation and anti-glycation properties of polysaccharides of Phyllanthus amarus plant

The study was conducted to investigate the in vitro anti-glycation activity of Phyllanthus amarus plant extract. The above plant has been used for centuries for its useful health benefits in variety of inflammatory diseases. In current study, antioxidant, metal chelating and ferric ion reducing and antiglycation property was studied for the polysaccharides isolated from Phyllanthus amarus plant extract. At 25 μg/mL sugar concentration and Vitamin C, gave 57 % and 65 % inhibition in hydroxyl radical scavenging assay and in Antiglycation assay the extract and vitamin C showed 65% and 87% respectively. It also had metal ion chelating (PAPE 74%, Ascorbic acid 88%) and ferric ion reducing activity showed by PAPE IS about 68% when compared to standard metal ion chelator EDTA 90%. It inhibited fructosamine formation by 52% after 3 days of incubation. The above studies gave an opinion that the inhibition of glycation exhibited by extract was due to its free radical scavenging property but also due to the modification in the amino or carbonyl groups resulted in the inhibition of fructosamine formation. The polysaccharides of the extract may be donating the hydrogen atom to the free radical, and exhibiting the antioxidant activity. So polysaccharide isolated from Phyllanthus amarus plant may use in preventing many free radicals induced diseases and also in delaying or preventing complications of diabetes.

8-Hydroxyquinoline Glycoconjugates Containing Sulfur at the Sugar Anomeric Position—Synthesis and Preliminary Evaluation of Their Cytotoxicity

One of the main factors limiting the effectiveness of many drugs is the difficulty of their delivery to their target site in the cell and achieving the desired therapeutic dose. Moreover, the accumulation of the drug in healthy tissue can lead to serious side effects. The way to improve the selectivity of a drug to the cancer cells seems to be its conjugation with a sugar molecule, which should facilitate its selective transport through GLUT transporters (glucose transporters), whose overexpression is seen in some types of cancer. This was the idea behind the synthesis of 8-hydroxyquinoline (8-HQ) derivative glycoconjugates, for which 1-thiosugar derivatives were used as sugar moiety donors. It was expected that the introduction of a sulfur atom instead of an oxygen atom into the anomeric position of the sugar would increase the stability of the obtained glycoconjugates against untimely hydrolytic cleavage. The anticancer activity of new compounds was determined based on the results of the MTT cytotoxicity tests. Because of the assumption that the activity of this type of compounds was based on metal ion chelation, the effect of the addition of copper ions on cell proliferation was tested for some of them. It turned out that cancer cells treated with glycoconjugates in the presence of Cu2+ had a much slower growth rate compared to cells treated with free glycoconjugates in the absence of copper. The highest cytotoxic activity of the compounds was observed against the MCF-7 cell line.

Carnosine and Lung Disease

Carnosine (β-alanyl-L-histidine) is a small dipeptide with numerous activities, including antioxidant effects, metal ion chelation, proton buffering capacity, and inhibitory effects on protein carbonylation and glycation. Carnosine has been mostly studied in organs where it is abundant, including skeletal muscle, cerebral cortex, kidney, spleen, and plasma. Recently, the effect of supplementation with carnosine has been studied in organs with low levels of carnosine, such as the lung, in animal models of influenza virus or lipopolysaccharide-induced acute lung injury and pulmonary fibrosis. Among the known protective effects of carnosine, its antioxidant effect has attracted increasing attention for potential use in treating lung disease. In this review, we describe the in vitro and in vivo biological and physiological actions of carnosine. We also report our recent study and discuss the roles of carnosine or its related compounds in organs where carnosine is present in only small amounts (especially the lung) and its protective mechanisms.

Fluorophoric [2]rotaxanes: post-synthetic functionalization, conformational fluxionality and metal ion chelation

Fluorophoric [2]rotaxanes form an exciplex upon interpenetration and the exciplex signals are used to monitor the chelation properties of the interlocked systems.

Modification of Polyacrylonitrile Fibers by Coupling to Thiosemicarbazones

This work reports the modification of Polyacrylonitrile (PAN) fibers by coupling to thiosemicarbazones to achieve the biological activity for the applications in the food product packaging. After modification, seven thiosemicarbazone compounds were synthesized. The as-synthesized thiosemicarbazone compounds were bonded to PAN fibers via covalent coupling, which was confirmed using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy. The mean graft efficiency of the compounds was about 1.92%, and the antibacterial efficiency was 88.6% and 45.1% against Staphylococcus aureus (S-aureus) bacteria. All the seven thiosemicarbazone compounds exerted excellent tyrosinase activity, low cytotoxicity, excellent metal ion chelation ability, and anti-bacterial behavior against both gram-positive and negative bacteria. The mechanical properties of the fibers have been maintained without significant damage after the chemical modification. The break strength test and elongation at the break test were done to measure the fracture strength of the modified fibers. Overall, the promising properties of the modified PAN fibers show potential applications in food packaging materials for fruits and vegetables, which require long-term anti-browning effects during their transportation and storage.

Wasted Ganoderma tsugae Derived Chitosans for Smear Layer Removal in Endodontic Treatment

The objective of this study is to investigate the synergistic effects of acid etching and metal-ion chelation in dental smear layer removal using wasted Ganoderma tsugae derived chitosans. The wasted Ganoderma tsugae fruiting body was used to prepare both acid-soluble fungal chitosan (FCS) and alkali-soluble polysaccharide (ASP). To explore the effective irrigant concentration for smear layer removal, a chelating effect on ferrous ions was conducted. Specimens of various concentrations of EDTA, citric acid, and polysaccharide solutions were reacted with FerroZine™ then the absorbance was examined at 562 nm by a UV-visible spectrophotometer to calculate their metal chelating capability. Twenty extracted premolars were instrumented and individually soaked in the solutions of 15 wt% EDTA, 10 wt% citric acid, 0.04 wt% ASP, 0.04 wt% FCS, and normal saline were randomly divided into five groups (N=4). Next, each tooth was cleaved longitudinally and examined by scanning electron microscopy (SEM) to assay the effectiveness of smear layer removal. The chelating capability for EDTA, FCS, and ASP showed no significant difference over the concentration of 0.04 wt% (p > 0.05). The SEM results showed that 0.04 wt% FCS solution was effective in smear layer removal along the canal wall. These results indicated that Ganoderma tsuage derived FCS in acid solutions could be a potential alternative as a root canal irrigant solution due to its synergistic effect.

In vitro antioxidant, 𝛼-amylase and 𝛼-glucosidase activities of methanol extracts from three Momordica species

<p>Antioxidant based drug preparations are used in the prevention and management of complex diseases which include atherosclerosis, stroke, diabetes, alzheimer’s disease and cancer. Diabetes mellitus is a metabolic disorder of glucose metabolism. The management of blood glucose level is the hallmark in the treatment of this ailment, which may be achieved through the use of oral hypoglycemic drugs such as biguanides, insulin secretagogues, and 𝛼-amylase and glucosidase inhibitors. Although several biological activities had been reported for <em>Momordica</em> <em>foetida </em>and <em>Momordica</em> <em>charantia</em>; it appears there is limited information on the biological activity of <em>Momordica</em> <em>cissoides</em>. The purpose of this study is to compare the antioxidant, 𝛼-amylase and 𝛼-glucosidase inhibitory activities of <em>Momordica</em> <em>charantia </em>(M1), <em>Momordica</em> <em>foetida </em>(M2)<em>, </em>and <em>Momordica</em> <em>cissoides</em> (M3) to establish a chemotaxonomic relationship between them. The antioxidant activities measured by DPPH scavenging properties, metal ion chelation, hydrogen peroxide scavenging and ABTS revealed that <em>M. foetida</em> had the highest inhibition potential, followed by <em>M. charantia</em> and the least being <em>M. cissoides</em>. In contrast, the antioxidant activities measured by FRAP, the total phenolic content , flavonoids and tannins revealed that <em>M. cissoides</em> had the best antioxidant potential, while <em>M. foetida</em> had the least activity. The comparative α-amylase and glucosidase inhibitory studies performed demonstrated that the extracts of <em>M.cissoides </em>had the highest inhibitory potentials. Thus, the plant can be used in the management of diabetes.</p>