Liquid–liquid phase separation (LLPS) is a biological phenomenon wherein a metastable and concentrated droplet phase of biomolecules spontaneously forms. A link may exist between LLPS of proteins and ...the disease-related process of amyloid fibril formation; however, this connection is not fully understood. Here, we investigated the relationship between LLPS and aggregation of the C-terminal domain of TAR DNA-binding protein 43, an amyotrophic lateral sclerosis–related protein known to both phase separate and form amyloids, by monitoring conformational changes during droplet aging using Raman spectroscopy. We found that the earliest aggregation events occurred within droplets as indicated by the development of β-sheet structure and increased thioflavin-T emission. Interestingly, filamentous aggregates appeared outside the solidified droplets at a later time, suggestive that amyloid formation is a heterogeneous process under LLPS solution conditions. Furthermore, the secondary structure content of aggregated structures inside droplets is distinct from that in de novo fibrils, implying that fibril polymorphism develops as a result of different environments (LLPS versus bulk solution), which may have pathological significance.
•A novel series of hydrazide-hydrazones derivatives (1–12) were synthesized and characterizations.•The antioxidant and AChE inhibition potentials of the targeted compounds were examined.•Compound 3 ...exhibit best antioxidant activity according to DPPH and FRAP methods.•Compound 5 exhibit best inhibitory effect against AChE.
The design and synthesis of hydrazone derivatives are increasing in popularity day by day due to the significant biological activities of this scaffold. In the present study, twelve novel isonicotinic hydrazide-hydrazone analogues were synthesized by the condensation reaction of isonicotinic hydrazide with benzaldehyde possessing sulfonate moiety. The structures of the novel compounds have been characterized in detail using spectroscopic techniques. All compounds have shown inhibitory effects against the AChE enzyme at rates ranging from 21.00 to 59.48%. Among them, compound 5 has exhibited the best inhibitory effect of 59.48% against AChE at a concentration of 0.1 mM. Furthermore, to determine how effective the novel compounds are as antioxidants, FRAP and DPPH studies were also carried out. FRAP values in compounds 1–12 were found to range from 26.989–3415.556 µmol FeSO4.7H2O/mg. They also displayed moderate antioxidant potential in the range of SC50=0.03–87.32 mg/mL compared with the control Trolox (SC50 =0.004) in DPPH radical scavenging activities. It was seen that the AChE inhibition percentages of the compounds were in the range of 23.04–58.10% at 0.1 mM concentration. This is the first research on the synthesis, antioxidant and enzyme inhibition properties of these compounds.
In this work, we put forward a hypothesis about the decisive role of multivalent nonspecific interactions in the early stages of PML body formation. Our analysis of the PML isoform sequences showed ...that some of the PML isoforms, primarily PML-II, are prone to phase separation due to their polyampholytic properties and the disordered structure of their C-terminal domains. The similarity of the charge properties of the C-terminal domains of PML-II and PML-VI isoforms made it possible for the first time to detect migration of PML-VI from PML bodies to the periphery of the cell nucleus, similar to the migration of PML-II isoforms. We found a population of “small” (area less than 1 µm2) spherical PML bodies with high dynamics of PML isoforms exchange with nucleoplasm and a low fraction of immobilized proteins, which indicates their liquid state properties. Such structures can act as “seeds” of functionally active PML bodies, providing the necessary concentration of PML isoforms for the formation of intermolecular disulfide bonds between PML monomers. FRAP analysis of larger bodies of toroidal topology showed the existence of an insoluble scaffold in their structure. The hypothesis about the role of nonspecific multiple weak interactions in the formation of PML bodies is further supported by the change in the composition of the scaffold proteins of PML bodies, but not their solidification, under conditions of induction of dimerization of PML isoforms under oxidative stress. Using the colocalization of ALT-associated PML bodies (APBs) with TRF1, we identified APBs and showed the difference in the dynamic properties of APBs and canonical PML bodies.
Introduction: From time immemorial, different parts of Cassia tora (Jue ming zi) have found application in Chinese medicine. There is a reputation for the therapeutic properties of the plant's ...leaves, seeds, and roots. The objective of this study is to ascertain the antioxidant properties and bioactive compounds found in Cassia tora leaf. Materials and method: Phytochemical and antioxidant studies were carried out using standard analytical techniques. Bioactive compounds were analysed using GC FID. Results: Results of the quantitative phytochemical analysis of the methanolic fraction of Cassia tora leaves indicated the presence of saponins (71,760±943.2µg/ml), terpenoids (47,466.70±46.2µg/ml), tannins (21,253.30±46.2µg/ml), flavonoids (14,682.70±40.3µg/ml), phenols (30,986.70±46.2µg/ml), steroids (13,557.30±24.4µg/ml), alkaloids (9770.67±9.2µg/ml), glycosides (5434.67±139.8µg/ml). Using ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and total antioxidant capacity (TAC) to analyze the antioxidant properties of the methanolic fraction of Cassia tora leaves, it was discovered that the higher the scavenging power of the fraction, the lower the concentration of the standard (ascorbic acid). In comparison to the standard (ascorbic acid), the fraction had the maximum antioxidant capacity at 6.86mg/ml. Total antioxidant power in the fraction ranged from 1.78mg/ml to 16mg/ml. Twenty (20) bioactive chemicals were found in the methanol fraction of Cassia tora leaves, according to the results of the gas chromatography flame ionization detector (GC-FID) investigation. Conclusion: The findings of this current study demonstrate that the leaves of Cassia tora are rich in numerous bioactive compounds and are natural sources of antioxidants.
Propolis samples used for the present study were collected in Transylvania. Our study had the purpose to investigate the amount of total polyphenols and the correlation that it may exist between the ...mentioned class of compounds and antioxidant properties. Polyphenolic profile was determined using Folin-Ciocalteu colorimetric method, while antioxidant activity was investigated by means of free radical scavenging activity (DPPH assay) and ferric reducing antioxidant power (FRAP assay). The content in polyphenols for analyzed propolis samples ranged between 24.46 and 62.39 g standard mixture/ 100 g propolis. All propolis samples showed antioxidant activity. The correlation between polyphenolic profile of propolis and its antioxidant properties was found to be positive.
Signaling by receptors from the transforming growth factor-β (TGF-β) superfamily plays critical roles in multiple physiological and pathological processes. Their signaling requires complex formation ...between type I and type II receptors with Ser/Thr kinase activity, whereby the type II receptor phosphorylates and activates the relevant type I receptor(s), which transduces downstream signaling. It is therefore important to study complex formation among receptors from this family. In the current chapter, we use the type I (ALK5) and type II TGF-β receptors (TβRI and TβRII) as an example for measuring complex formation among cell-surface receptors in live cells by patch-FRAP, a variation of fluorescence recovery after photobleaching (FRAP).
Crataegus species (hawthorn) have been commonly used in traditional medicine, especially for the treatment of congestive heart failure. Many studies confirmed that they are rich in polyphenols, thus ...exhibiting strong antioxidant activity, which contribute to the beneficial effects of hawthorn on the cardiovascular system. In the market, there are many herbal medicinal products based on hawthorn, which consumption as adjuvant therapy in heart-related issues is supported by European Medicines Agency. Since there is a global trend of making homemade herbal preparations, this study aimed to compare whether there is a difference in polyphenol profile and antioxidant potential between homemade and commercial ethanol extracts of hawthorn. Polyphenol profile was evaluated by determination of total phenolic and flavonoid contents, and by quantitative analysis of selected polyphenols by liquid chromatography? mass spectrometry/mass spectrometry. Antioxidant potential was examined by 2,2-diphenyl-1-picrylhydrazyl, ferric ion reducing antioxidant power and lipid peroxidation inhibition assays. The results of this study suggest that homemade ethanol extracts of hawthorn flowers, leaves and fruits are just as good source of polyphenols and antioxidants as commercial ones, and their utilization should be supported. Furthermore, hawthorn extracts made of leaves and flowers are better source of bioactive polyphenols and have higher antioxidant activity compared with the same of fruits, regardless of the method of preparation.
The initial steps in preclinical drug developing research concern the synthesis of new compounds for specific therapeutic use which needs to be confirmed by in vitro and then in vivo testing.
Nine ...thiazolidinone derivatives (numerically labeled 1–9) classified as follows: 1,3-thiazole-based compounds (1 and 2); 1,3,4-thiadiazole based compounds (3 and 4); substituted 5-benzylideno-2-adamantylthiazol3,2-b1,2,4triazol-6(5H)ones (5–8); and an ethylaminothiazole-based chalcone (9), were tested for antioxidant activity (AOA) by using three in vitro assays: DPPH (1,1-diphenyl-2-picrylhydrazyl scavenging capacity test); FRAP (ferric reducing antioxidant power test); and TBARS (thiobarbituric acid reactive substances test). Compounds 1–4 and 9 in particular are newly synthesized compounds. Also, traditional antioxidants Vitamins E and C and α-lipoic acid (α-LA) were tested.
The results of DPPH testing: Vitamin C 94.35%, Vitamin E 2.99% and α-LA 1.57%; compounds: 4 33.98%; 2 18.73%; 1 15.62%; 5 6.59%; 3 4.99%; 6–9 demonstrated almost no AOA. The results of TBARS testing (% of LPO inhibition): Vitamin C 62.32%; Vitamin E 36.29%; α-LA 51.36%; compounds: 1 62.11%; 5 66.71%; 9 60.93%; 4, 6 and 7 demonstrated ∼50%; 3 and 8 displayed ∼38%; 2 23.51%. By FRAP method, Vitamins E and C showed equal AOA, ∼100%, unlike α-LA (no AOA), and AOA of the tested compounds (expressed as a fraction of the AOA of Vitamin C) were: 2 and 4–75%; 8, 3 and 1–45%; 5–7 and 9–27%.
Different red-ox reaction principles between these assays dictate different AOA outcomes for a single compound. Vitamin C appeared to be the superior antioxidant out of the traditional antioxidants; and compound 4 was superior to other tested thiazolidinone derivatives. Vitamin C appeared to be the superior antioxidant out of the traditional antioxidants; and compound 4 was superior to other tested thiazolidinone derivatives. Phenyl-functionalized benzylidene, amino-carbonyl functional domains and chelating ligand properties of the thiazolidinone derivatives correlated with AOA.
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•9 thiazolidinone derivatives were tested for antioxidant activity (AOA).•Used in vitro assays: DPPH radical scavenging capacity test, FRAP and TBARS.•Accomplished AOA were compared to vitamins C and E and α-lipoic acid.•Different AOA for a single compound depends on its structure and test principles.•Chelating effect, phenoxy (in benzylidene) and amino-carbonyl groups determine AOA.