Design of potent tyrosinase inhibiting N-arylated-4-yl-benzamides bearing 2-aminothiazole-triazole bi-heterocycles: mechanistic insight through enzyme inhibition, kinetics and computational studies.

By using a convergent methodology, a unique series of N-arylated 4-yl-benzamides containing a bi-heterocyclic thiazole-triazole core was synthesized and the structures of these hybrid molecules, 9a-k, were corroborated through spectral analyses. The in vitro studies of these multi-functional molecules demonstrated their potent mushroom tyrosinase inhibition relative to the standard used. The kinetics mechanism was exposed by lineweaver-burk plots which revealed that, 9c, inhibited mushroom tyrosinase non-competitively by forming an enzyme-inhibitor complex. The inhibition constant Ki calculated from Dixon plots for this compound was 0.016 µM. The computational study was also consistent with the experimental results and these molecules disclosed good results of all scoring functions and interactions, which suggested a good binding to mushroom tyrosinase. So, it was predicted from the inferred results that these molecules might be considered as promising medicinal scaffolds for the diseases associated with the over-expression of this enzyme.

Exploring chalcone-sulfonyl piperazine hybrids as anti-diabetes candidates: design, synthesis, biological evaluation, and molecular docking study.

To address the escalating rates of diabetes mellitus worldwide, there is a growing need for novel compounds. The demand for more affordable and efficient methods of managing diabetes is increasing due to the inevitable side effects associated with existing antidiabetic medications. In this present research, various chalcone-sulfonyl piperazine hybrid compounds (5a-k) were designed and synthesized to develop inhibitors against alpha-glucosidase and alpha-amylase. In addition, several spectroscopic methods, including FT-IR, 1H-NMR, 13C-NMR, and HRMS, were employed to confirm the exact structures of the synthesized derivatives. All synthesized compounds were evaluated for their ability to inhibit alpha-glucosidase and alpha-amylase in vitro using acarbose as the reference standard and they showed excellent to good inhibitory potentials. Compound 5k exhibited excellent inhibitory activity against alpha-glucosidase (IC50 = 0.31 ± 0.01 µM) and alpha-amylase (IC50 = 4.51 ± 1.15 µM), which is 27-fold more active against alpha-glucosidase and 7-fold more active against alpha-amylase compared to acarbose, which had IC50 values of 8.62 ± 1.66 µM for alpha-glucosidase and 30.97 ± 2.91 µM for alpha-amylase. It was discovered from the Lineweaver-Burk plot that 5k exhibited competitive inhibition against alpha-glucosidase. Furthermore, cytotoxicity screening assay results against human fibroblast HT1080 cells showed that all compounds had a good level of safety profile. To explore the binding interactions of the most potent compound (5k) with the active site of enzymes, molecular docking research was conducted, and the results obtained supported the experimental data.

Investigations of Limeum Indicum Plant for Diabetes Mellitus and Alzheimer's Disease Dual Therapy: Phytochemical, GC-MS Chemical Profiling, Enzyme Inhibition, Molecular Docking and In-Vivo Studies.

Limeum indicum has been widely utilized in traditional medicine but no experimental work has been done on this herb. The primary objective of this study was to conduct a phytochemical analysis and assess the multifunctional capabilities of aforementioned plant in dual therapy for Alzheimer's disease (AD) and Type 2 diabetes (T2D). The phytochemical screening of ethanol, methanol extract, and their derived fractions of Limeum indicum was conducted using GC-MS, HPLC, UV-analysis and FTIR. The antioxidant capacity was evaluated by DPPH method. The inhibitory potential of the extracts/fractions against α-, ß-glucosidase acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and monoaminine oxidases (MAO-A & B) was evaluated. Results revealed that acetonitrile fraction has highest inhibitory potential against α-glucosidase (IC50=68.47±0.05 µg/mL), methanol extract against ß-glucosidase (IC50=91.12±0.07 µg/mL), ethyl acetate fraction against AChE (IC50=59.0±0.02 µg/mL), ethanol extract against BChE (28.41±0.01 µg/mL), n-hexane fraction against MAO-A (IC50=150.5±0.31 µg/mL) and methanol extract for MAO-B (IC50=75.95±0.13 µg/mL). The docking analysis of extracts\fractions suggested the best binding scores within the active pocket of the respective enzymes. During the in-vivo investigation, ethanol extract produced hypoglycemic effect (134.52±2.79 and 119.38±1.40 mg/dl) after 21 days treatment at dose level of 250 and 500 mg/Kg. Histopathological findings further supported the in-vivo studies.

Novel insight on IRE1 in the regulation of chondrocyte dedifferentiation through ER stress independent pathway.

Inositol-requiring enzyme-1 (IRE1) is the master regulator of the unfolded protein response pathway, associated with the endoplasmic reticulum (ER) in sensing and regulating cell stress. The activity of IRE1 is highly explored and well-characterized in cancer and other cells. However, the IRE1 molecular mechanism in chondrocytes is poorly understood. The present study explored the effect of IRE1 on chondrocytes regarding its chondrogenic gene expression and its correlation with different cellular pathways and cell behavior. Chondrocytes transfected with the cDNA of IRE1 reduced the expression of type II collagen, disrupting chondrocyte differentiation as confirmed by western blotting and immunofluorescence. Upon siRNA treatment, the influence of IRE1 on chondrocyte differentiation is restored by reviving the normal expression of type II collagen. Different molecular pathways were explored to investigate the role of IRE1 in causing chondrocyte dedifferentiation. However, we found no significant correlation, as IRE1 induces dedifferentiation through independent pathways. In response to various endoplasmic reticulum (ER) agonists (2-deoxy-D-glucose), and ER stress antagonists (tauroursodeoxycholic acid and salubrinal), IRE1 overexpression did not affect GRP78/94, as implicated in the pathogenesis of ER stress. Moreover, when IRE1 overexpression was correlated with the inflammation pathway, nuclear factor-kappa B (NFκB), IRE1 substantially increased the expression of p50 while decreasing the expression of nuclear factor kappa light polypeptide alpha (IκBα). These results suggest that IRE1 induces dedifferentiation in chondrocytes by modulating inflammatory pathways that cause dedifferentiation by disrupting type II collagen expression.

Recent Development on Sensing Strategies for Small Molecules Detections.

Sensors play a critical role in the detection and monitoring of various substances present in our environment, providing us with valuable information about the world around us. Within the field of sensor development, one area that holds particular importance is the detection of small molecules. Small molecules encompass a wide range of organic or inorganic compounds with low molecular weight, typically below 900 Daltons including gases, volatile organic compounds, solvents, pesticides, drugs, biomarkers, toxins, and pollutants. The accurate and efficient detection of these small molecules has attracted significant interest from the scientific community due to its relevance in diverse fields such as environmental pollutants monitoring, medical diagnostics, industrial optimization, healthcare remedies, food safety, ecosystems, and aquatic and terrestrial life preservation. To meet the demand for precise and efficient monitoring of small molecules, this summary aims to provide an overview of recent advancements in sensing and quantification strategies for various organic small molecules including Hydrazine, Glucose, Morpholine, Ethanol amine, Nitrosamine, Oxygen, Nitro-aromatics, Phospholipids, Carbohydrates, Antibiotics, Pesticides, Drugs, Adenosine Triphosphate, Aromatic Amine, Glutathione, Hydrogen Peroxide, Acetone, Methyl Parathion, and Thiophenol. The focus is on understanding the receptor sensing mechanism, along with the electrical, optical, and electrochemical response. Additionally, the variations in UV-visible spectral properties of the ligands upon treatment with the receptor, fluorescence and absorption titration analysis for limit of detection (LOD) determination, and bioimaging analysis are discussed wherever applicable. It is anticipated that the information gathered from this literature survey will be helpful for the perusal of innovation regarding sensing strategies.

Synthesis and Computational Exploration of Morpholine Bearing Halogenated Sulfonamides as Potential Tyrosinase Inhibitors.

In the presented work, a new series of three different 4-((3,5-dichloro-2-[(2/4-halobenzyl)oxy]phenyl)sulfonyl)morpholines was synthesized and the structure of these compounds were corroborated by 1 H-NMR & 13 C-NMR studies. The in vitro results established all the three compounds as potent tyrosinase inhibitors relative to the standard. The Kinetics mechanism plots established that compound 8 inhibited the enzyme non-competitively. The inhibition constants Ki calculated from Dixon plots for this compound was 0.0025 µM. Additionally, computational techniques were used to explore electronic structures of synthesized compounds. Fully optimized geometries were further docked with tyrosinase enzyme for inhibition studies. Reasonably good binding/interaction energies and intermolecular interactions were obtained. Finally, drug likeness was also predicted using the rule of five (RO5) and Chemical absorption, distribution, metabolism, excretion, and toxicity (ADMET) characteristics. It is anticipated that current experimental and computational investigations will evoke the scientific interest of the research community for the above-entitled compounds.

Convergent synthesis, kinetics insight and allosteric computational ascriptions of thiazole-(5-aryl)oxadiazole hybrids embraced with propanamides as alkaline phosphatase inhibitors.

Considering the varied pharmacological prominence of thiazole and oxadiazole heterocyclic moieties, a unique series of bi-heterocyclic hybrids, 8a-h, was synthesized in a convergent manner. The structures of newly synthesized compounds were characterized by 1H-NMR, 13C-NMR, and IR spectral studies. The structure-activity relationship of these compounds was predicted by examining their inhibitory effects against alkaline phosphatase, whereby all these molecules exhibited superb inhibitory potentials relative to the standard used. The kinetics mechanism was determined by Lineweaver-Burk plots which revealed that 8g inhibited the studied enzyme non-competitively by forming an enzyme-inhibitor complex. The inhibition constant Ki calculated from Dixon plots for this compound was 0.42 µM. The allosteric computational study was coherent with the experimental records and these ligands exhibited good binding energy values (kcal mol-1). The hemolytic analysis revealed their mild cytotoxicity towards red blood cell membranes and hence, these molecules have potential to be nontoxic medicinal scaffolds for the treatment of alkaline phosphate-associated ailments.

Design and synthesis of thiadiazole-oxadiazole-acetamide derivatives: Elastase inhibition, cytotoxicity, kinetic mechanism, and computational studies.

Considering the biological significance of 1,3,4-thiadiazole/oxadiazole heterocyclic scaffolds, a novel series of 1,3,4-thiadiazole-1,3,4-oxadiazole-acetamide derivatives (7a-j) was designed and synthesized using molecular hybridization. The inhibitory effects of the target compounds on elastase were evaluated, and all of these molecules were found to be potent inhibitors compared to the standard reference oleanolic acid. Compound 7f exhibited the excellent inhibitory activity (IC50 = 0.06 ± 0.02 µM), which is 214-fold more active than oleanolic acid (IC50 = 12.84 ± 0.45 µM). Kinetic analysis was also performed on the most potent compound (7f) to determine the mode of binding with the target enzyme, and it was discovered that 7f inhibits the enzyme in a competitive manner. Furthermore, the MTT assay method was used to assess their toxicity on the viability of B16F10 melanoma cell lines, and all compounds did not display any toxic effect on the cells even at high concentrations. The molecular docking studies of all compounds also justified with their good docking score and among them, compound 7f had a good conformational state with hydrogen bond interactions within the receptor binding pocket, which is consistent with the experimental inhibition studies.

Evaluation of phytochemicals of Poria cocos against tyrosinase protein: a virtual screening, pharmacoinformatics and molecular dynamics study.

Tyrosinase inhibitors are commonly used in the pharmaceutical and cosmetic industries for skin lightening and hypopigmentation. The current inhibitors of tyrosinase induce strong safety concerns which necessitate the discovery of new inhibitors. Natural compounds are a promising solution to discover potential candidate for anti-melanogenic activity as they possess less safety concerns and high therapeutic effect. The current study aimed to screen and identify potential phytochemicals from Poria cocos for tyrosinase inhibition. The phytochemicals were obtained from the Traditional Chinese Medicine System Pharmacology Database and screened for druglikeness score and toxicity class and then subjected to in-silico virtual screening and molecular dynamics. 7,9-(11)-Dehydropachymic acid established hydrogen interaction with the tyrosinase protein and was found to be highly stable as validated with MD simulations. The pharmacokinetic results showed that this compound has adequate toxicity and ADME profile that can be exploited for anti-melanogenic effects. Our study identified 7,9-(11)-dehydropachymic acid as an efficient candidate for tyrosinase inhibition. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-023-03626-8.

E3 Ubiquitin Ligase Constitutive Photomorphogenic 1 Regulates Differentiation and Inflammation via MAPK Signaling Pathway in Rabbit Articular Chondrocytes.

Constitutive photomorphogenic 1 (COP1), is an E3 ubiquitin ligase that plays a role in the regulation of various cellular processes including cell growth, differentiation, and survival in mammals. In certain conditions such as overexpression or loss of function, COP1 acts either as an oncogenic protein or as a tumor suppressor by targeting specific proteins for ubiquitination-mediated degradation. However, the precise role of COP1 has not been well studied in primary articular chondrocytes. In this study, we investigated the role of COP1 in chondrocyte differentiation. Western blotting and reverse transcription-polymerase chain reaction analysis demonstrated that COP1 overexpression reduced type II collagen expression, promoted cyclooxygenase 2 (COX-2) expression, and reduced sulfated proteoglycan synthesis, as detected by Alcian blue staining. Upon siRNA treatment, revived type II collagen, sulfated proteoglycan production, and decreased COX-2 expression. Phosphorylation of p38 kinase and ERK-1/-2 signaling pathways was regulated by COP1 upon cDNA and siRNA transfection in chondrocytes. The inhibition of the p38 kinase and ERK-1/-2 signaling pathways with SB203580 and PD98059 ameliorated the expression of type II collagen and COX-2 in transfected chondrocytes, thus suggesting that COP1 regulates differentiation and inflammation in rabbit articular chondrocytes via the p38 kinase and ERK-1/-2 signaling pathway.

Synthesis and discovery of potential tyrosinase inhibitor of new coumarin-based thiophenyl-pyrazolylthiazole nuclei: In vitro evaluation, cytotoxicity, kinetic, and computational studies.

A well-known key enzyme in melanogenesis and hyperpigmentation is tyrosinase. The present study introduces a novel series of thiophenyl-pyrazolylthiazole-coumarin hybrids (6a-6h) as tyrosinase inhibitors. The in-vitro tyrosinase inhibition results indicated that all compounds have strong tyrosinase inhibitory activity, particularly compound 6g (IC50  = 0.043 ± 0.006 µM), was identified as the most active compound compared to the positive control (kojic acid, IC50  = 18.521 ± 1.162 µM). Lineweaver-Burk plots were employed to analyze the kinetic mechanism, and compound 6g formed an enzyme-inhibitor complex by inhibiting tyrosinase non-competitively. Furthermore, all compounds demonstrated excellent antioxidant activity against DPPH. MTT assay was used to screen the cytotoxicity of all compounds on B16F10 melanoma cells, and they had no toxic effect on the cells. The binding affinity of compounds with tyrosinase was also investigated using molecular docking, and the ligands displayed good binding energy values. These molecules could be a promising lead for skin pigmentation and associated diseases as nontoxic pharmacological scaffolds.

Synthesis, kinetic studies and in-silico investigations of novel quinolinyl-iminothiazolines as alkaline phosphatase inhibitors.

Deposition of hydroxyapatite (HA) or alkaline phosphate crystals on soft tissues causes the pathological calcification diseases comprising of end-stage osteoarthritis (OA), ankylosing spondylitis (AS), medial artery calcification and tumour calcification. The pathological calcification is symbolised by increased concentration of tissue non-specific alkaline phosphatase (TNAP). An efficient therapeutic strategy to eradicate these diseases is required, and for this the alkaline phosphatase inhibitors can play a potential role. In this context a series of novel quinolinyl iminothiazolines was synthesised and evaluated for alkaline phosphatase inhibition potential. All the compounds were subjected to DFT studies where N-benzamide quinolinyl iminothiazoline (6g), N-dichlorobenzamide quinolinyl iminothiazoline (6i) and N-nitrobenzamide quinolinyl iminothiazoline (6j) were found as the most reactive compounds. Then during the in-vitro testing, the compound N-benzamide quinolinyl iminothiazoline (6g) exhibited the maximum alkaline phosphatase inhibitory effect (IC50 = 0.337 ± 0.015 µM) as compared to other analogues and standard KH2PO4 (IC50 = 5.245 ± 0.477 µM). The results were supported by the molecular docking studies, molecular dynamics simulations and kinetic analysis which also revealed the inhibitory potential of compound N-benzamide quinolinyl iminothiazoline (6g) against alkaline phosphatase. This compound can be act as lead molecule for the synthesis of more effective inhibitors and can be suggested to test at the molecular level.

Synthesis, anticancer evaluation, and molecular docking studies of thiazolyl-pyrazoline derivatives.

The molecular hybridization of thiazole and pyrazoline heterocyclic structures with diverse activities appears to be an interesting strategy for developing new anticancer compounds. This study presents the synthesis of eleven new thiazolyl-pyrazoline derivatives (7a-k) and the evaluation of their in-vitro anti-proliferative activities against human lung carcinoma (A549) and human melanoma cancer (A375) cell lines through MTT assay. In comparison to the positive reference drug erlotinib (IC50 = 34.16 µM in A549 and IC50 = 25.85 µM in A375), four compounds (7e, 7h, 7j, and 7k) were identified as the most active against both cell lines (especially compound 7k with IC50 = 20.28 µM in A549 and 16.08 µM in A375). Additionally, these potent compounds were selected to be investigated for their anti-metastasis and anti-inflammatory properties via inhibition of the expression of matrix metalloproteinase 2, 9 (MMP-2, 9) and cyclooxygenase 2 (COX-2). In A549 cells, upon exposure to compounds 7e and 7j, COX-2 expression is decreased, whereas compounds 7e, 7j, and 7k reduced COX-2 expression in A375 cell lines. Molecular docking studies were carried out to show the possible interactions of synthesized compounds with the predicted active site of the COX-2 protein. The results revealed that compounds 7e and 7j can bind well to the active site of COX-2 protein. Collectively, compounds 7e, 7j, and 7k are all promising candidates for further research towards the development of novel anticancer agents.

Synthesis, carbonic anhydrase inhibition, anticancer activity, and molecular docking studies of 1,3,4-oxadiazole derivatives.

In this work, we have synthesized various organic compounds possessing 1,3,4-oxadiazole as a core structure and the structure of the newly synthesized target compounds has been revealed using different analytical approaches such as FT-IR, LCMS, and NMR (proton and carbon), respectively. The in vitro carbonic anhydrase potentials of these synthesized 17 different analogues were investigated. The result suggests that compound 7g, a 3-pyridine substituted analogue with an IC50 of 0.1 µM, was found to have the most potent carbonic inhibitory activity (11-fold more active) than the positive control (acetazolamide) with an IC50 of 1.1 ± 0.1 µM. Besides, among the series 7(a-q) approved in the identification of four potent carbonic anhydrase inhibitors with the IC50 standards varies from 0.1 to 1.0 ± 0.1 µM. Additionally, the non-competitive behaviour for potent compound 7g was analysed using the Lineweaver-Burk plot from the kinetic study. Furthermore, the anticancer activity of all the synthesized compounds screened against B16F10 melanoma cells using the MTT assay method. Additionally, the molecular docking studies revealed that 7g inhibitor shows good binding energy as well as good binding interaction pattern along with enzyme.

Design, Synthesis, Kinetic Analysis and Pharmacophore-Directed Discovery of 3-Ethylaniline Hybrid Imino-Thiazolidinone as Potential Inhibitor of Carbonic Anhydrase II: An Emerging Biological Target for Treatment of Cancer.

Carbonic anhydrases (CA), having Zn2+ metal atoms, are responsible for the catalysis of CO2 and water to bicarbonate and protons. Any abnormality in the functioning of these enzymes may lead to morbidities such as glaucoma and different types of cancers including brain, renal and pancreatic carcinomas. To cope with the lack of presence of a promising therapeutic agent against these cancers, searching for an efficient and suitable carbonic anhydrase inhibitor is crucial. In the current study, ten novel 3-ethylaniline hybrid imino-thiazolidinones were synthesized and characterized by FTIR, NMR (1H, 13C), and mass spectrometry. Synthesis was carried out by diethyl but-2-ynedioate cyclization and different acyl thiourea substitutions of 3-ethyl amine. The CA (II) enzyme inhibition profile for all synthesized derivatives was determined. It was observed that compound 6e demonstrated highest inhibition of CA-II with an IC50 value of 1.545 ± 0.016 µM. In order to explore the pharmacophoric properties and develop structure activity relationship, in silico screening was performed. In silico investigations included density functional theory (DFT) studies, pharmacophore-guided model development, molecular docking, molecular dynamic (MD) simulations, and prediction of drug likeness scores. DFT investigations provided insight into the electronic characteristics of compounds, while molecular docking determined the binding orientation of derivatives within the CA-II active site. Compounds 6a, 6e, and 6g had a reactive profile and generated stable protein-ligand interactions with respective docking scores of -6.12, -6.99, and -6.76 kcal/mol. MD simulations were used to evaluate the stability of the top-ranked complex. In addition, pharmacophore-guided modeling demonstrated that compound 6e produced the best pharmacophore model (HHAAARR) compared to standard brinzolamide. In vitro and in silico investigations anticipated that compound 6e would be an inhibitor of carbonic anhydrase II with high efficacy. Compound 6e may serve as a potential lead for future synthesis that can be investigated at the molecular level, and additional in vivo studies are strongly encouraged.

Potent Alkaline Phosphatase Inhibitors, Pyrazolo-Oxothiazolidines: Synthesis, Biological Evaluation, Molecular Docking, and Kinetic Studies.

To develop new alkaline phosphatase inhibitors (ALP), a series of pyrazolo-oxothiazolidine derivatives were synthesized and biologically assessed, and the results showed that all of the synthesized compounds significantly inhibited ALP. Specifically, compound 7g displayed the strongest inhibitory activity (IC50 = 0.045 ± 0.004 µM), which is 116-fold more active than monopotassium phosphate (IC50 = 5.242 ± 0.472 µM) as a standard reference. The most potent compound among the series (7g) was checked for its mode of binding with the enzyme and shown as non-competitively binding with the target enzyme. The antioxidant activity of these compounds was examined to investigate the radical scavenging effect. Moreover, the MTT assay method was performed to evaluate their toxic effects on the viability of MG-63 human osteosarcoma cells, and all compounds have no toxic effect on the cells at 4 µM. Computational research was also conducted to examine the binding affinity of the ligands with alkaline phosphatase, and the results revealed that all compounds showed good binding energy values within the active site of the target. Therefore, these novel pyrazolo-oxothiazolidine derivatives might be employed as promising pharmacophores for potent and selective alkaline phosphatase inhibitors.

Analysis of 1-Aroyl-3-[3-chloro-2-methylphenyl] Thiourea Hybrids as Potent Urease Inhibitors: Synthesis, Biochemical Evaluation and Computational Approach.

Urease is an amidohydrolase enzyme that is responsible for fatal morbidities in the human body, such as catheter encrustation, encephalopathy, peptic ulcers, hepatic coma, kidney stone formation, and many others. In recent years, scientists have devoted considerable efforts to the quest for efficient urease inhibitors. In the pharmaceutical chemistry, the thiourea skeleton plays a vital role. Thus, the present work focused on the development and discovery of novel urease inhibitors and reported the synthesis of a set of 1-aroyl-3-[3-chloro-2-methylphenyl] thiourea hybrids with aliphatic and aromatic side chains 4a-j. The compounds were characterized by different analytical techniques including FT-IR, 1H-NMR, and 13C-NMR, and were evaluated for in-vitro enzyme inhibitory activity against jack bean urease (JBU), where they were found to be potent anti-urease inhibitors and the inhibitory activity IC50 was found in the range of 0.0019 ± 0.0011 to 0.0532 ± 0.9951 µM as compared to the standard thiourea (IC50 = 4.7455 ± 0.0545 µM). Other studies included density functional theory (DFT), antioxidant radical scavenging assay, physicochemical properties (ADMET properties), molecular docking and molecular dynamics simulations. All compounds were found to be more active than the standard, with compound 4i exhibiting the greatest JBU enzyme inhibition (IC50 value of 0.0019 ± 0.0011 µM). The kinetics of enzyme inhibition revealed that compound 4i exhibited non-competitive inhibition with a Ki value of 0.0003 µM. The correlation between DFT experiments with a modest HOMO-LUMO energy gap and biological data was optimal. These recently identified urease enzyme inhibitors may serve as a starting point for future research and development.

The Inhibitory Effect of Polyphenon 60 from Green Tea on Melanin and Tyrosinase in Zebrafish and A375 Human Melanoma Cells.

Polyphenon 60 (PP60) from green tea has long been used as an antioxidant, anticancer, antimicrobial, and antimutagenic. Aim of the Study. To investigate tyrosinase inhibition-related kinetic mechanism and antimelanogenesis potential of PP60. Materials and Methods. The effect of PP60 on melanin and tyrosinase was evaluated in A375 melanoma cells and zebrafish embryos. The melanoma cells were treated with 20, 40, and 60 µg/mL of PP60, and tyrosinase expression was induced by using L-DOPA. The western blot method was used for the evaluation of tyrosinase expression. Cell lysates were prepared from treated and untreated cells for cellular tyrosinase and melanin quantification. Furthermore, zebrafish embryos were treated with 20, 40, and 60 µg/mL of PP60 and reference drug kojic acid for determination of depigmentation and melanin quantification. In vitro assays were also performed to examine the impact of PP60 on mushroom tyrosinase activity. To determine cytotoxicity, MTT was used against melanoma cell line A375. Results. PP60 showed good tyrosinase inhibitory activity with an IC50 value of 0.697 ± 0.021 µg/mL as compared to kojic acid a reference drug with an IC50 value of 2.486 ± 0.085 µg/mL. Kinetic analysis revealed its mixed type of inhibition against mushroom tyrosinase. In addition, western blot analysis showed that at 60 µg/mL dose of PP60 significantly reduced L-DOPA-induced tyrosinase expression in melanoma cells. PP60 significantly inhibits the cellular tyrosinase (p < 0.05) and reduces the melanin (p < 0.05) contents of melanoma cells. Furthermore, PP60 was found to be very potent in significantly reducing the zebrafish embryos' pigmentation (p < 0.05) and melanin (p < 0.05) content at the dose of 60 µg/mL. Conclusions. Our results demonstrate that PP60 has a strong potency to reduce pigmentation. It may be useful for the cosmetic industries to develop skin whitening agents with minimal toxic effects.

Subversive molecular role of Krüppel-like factor 5 in extracellular matrix degradation and chondrocyte dedifferentiation.

Osteoarthritis (OA) is the most common joint disorder worldwide and a leading cause of pain and disability. However, the pathogenesis of osteoarthritis has not been elucidated. Krüppel-like factor (KLF)-5 is involved in several biological processes, including inflammation and cell differentiation, but its role in OA has not been evaluated. In this study, we investigated the role of KLF-5 in chondrocyte differentiation. KLF-5 overexpression in chondrocytes induced a loss of type II collagen expression and sulfated proteoglycan synthesis at the transcriptional and translational levels. Based on immunofluorescence staining, the ectopic expression of KLF-5 reduced type II collagen expression. In contrast, with KLF-5-transfected cells, KLF-5 siRNA transfection-induced type II expression also blocked dedifferentiation caused by the overexpression of KLF-5. In zebra fish, KLF-5 reduced the sulfated proteoglycan synthesis of ceratobranchial cartilage. Our results suggest that KLF-5 plays a pivotal role in the dedifferentiation of rabbit articular cartilage and zebra fish, providing a basis for therapeutic strategy for osteoarthritis aimed at controlling cartilage destruction.

Inhibitors of EYA3 Protein in Ewing Sarcoma.

OBJECTIVE: Among sarcomas, Ewing sarcoma (EWS) is characterized as a highly malignant type of bone tumor caused by the fusion of EWS RNA Binding Protein-1 (EWSR1)/ Friend leukemia integration 1 (FLI1) genes. The product of fusion gene gives rise to EWSR1/FLI1 which activates the activity of Eyes absent homolog 3 (EYA3) which causes tumor growth and angiogenesis. EYA3 is now considered as a therapeutic drug target for EWS . The study was designed to gather potential inhibitors for the EYA3 target using medicinal compounds. METHODS: In this study, we have obtained a list of medicinal compounds from the NuBBE database and downloaded their structural information. Then insilico screening analysis of >2,000 medicinal compounds was performed with PyRX virtual drug screening software to discover potential inhibitors for the treatment of EWS. RESULTS: Our investigation revealed that Sorbifolin and 1,7-Dihydroxy-3-methylanthracene-9.10-dione show interactive affinity for EYA3 active residues. Moreover, these compounds have adequate toxicity, can induce cytotoxicity in EWS cells, and are capable of regulating the expression of genes activated by EWSR1/FLI1. CONCLUSION: Our study concluded that Sorbifolin and 1,7-Dihydroxy-3-methylanthracene-9.10-dione are promising drug candidates for the treatment of EWS and should be further subjected to invitro testing.