Nitrophenylpiperazine derivatives as novel tyrosinase inhibitors: design, synthesis, and in silico evaluations

A novel series of 4-nitrophenylpiperazine derivatives (4a-m) was designed and synthesized as potential tyrosinase inhibitors. Comprehensive characterization using 1H-NMR, 13C-NMR, CNH, and IR techniques was performed for all target compounds. Subsequently, the derivatives were evaluated for their inhibitory activity against tyrosinase. Among them, compound 4l, featuring an indole moiety at the N-1 position of the piperazine ring, exhibited a significant tyrosinase inhibitory effect with an IC50 value of 72.55 μM. Enzyme kinetics analysis revealed that 4l displayed mixed inhibition of the tyrosinase enzymatic reaction. Molecular docking was carried out in the enzyme's active site to further investigate the enzyme-inhibitor interactions. Based on the findings, compound 4l shows promise as a lead structure for the design of potent tyrosinase inhibitors. This study paves the way for the development of more effective tyrosinase inhibitors for potential applications in various fields.

Preparation, Optimization and In Vitro Characterization of Fluticasoneloaded Mixed Micelles Based on Stearic Acid-g-chitosan as a Pulmonary Delivery System

PURPOSE

The primary objective of this study was to optimize formulation variables and investigate the in vitro characteristics of fluticasone propionate (FP)-loaded mixed polymeric micelles, which were composed of depolymerized chitosan-stearic acid copolymer (DC-SA) in combination with either tocopheryl polyethylene glycol succinate or dipalmitoylphosphatidylcholine for pulmonary drug delivery.

METHODS

A D-optimal design was employed for the optimization procedure, considering lipid/ polymer ratio, polymer concentration, drug/ polymer ratio, and lipid type as independent variables. Dependent variables included particle size, polydispersion index, zeta potential, drug encapsulation efficiency, and loading efficiency of the polymeric micelles. Additionally, the nebulization efficacy and cell viability of the optimal FP-loaded DC-SA micellar formulations were evaluated.

RESULTS

The mixed polymeric micelles were successfully prepared with properties falling within the desired ranges, resulting in four optimized formulations. The release of FP from the optimal systems exhibited a sustained release profile over 72 hours, with 70% of the drug still retained within the core of the micelles. The nebulization efficiency of these optimal formulations reached up to 63%, and the fine particle fraction (FPF) ranged from 41% to 48%. Cellular viability assays demonstrated that FP-loaded DC-SA polymeric micelles exhibited lower cytotoxicity than the free drug but were slightly more cytotoxic than empty mixed micelles.

CONCLUSION

In conclusion, this study suggests that DC-SA/ lipid mixed micelles have the potential to serve as effective carriers for nebulizing poorly soluble FP.

Thioquinoline derivatives conjugated to thiosemicarbazide as potent tyrosinase inhibitors with anti-melanogenesis properties

In the present study, a series of aryl-substituted thioqunoline conjugated to thiosemicarbazide were rationally designed and synthesized. The formation of target compounds was confirmed by spectral characterization techniques such as IR, ¹H-NMR, ¹³C-NMR, ESI-MS, and elemental analysis. Among the synthesized derivatives, compound 10g bearing para-chlorophenyl moiety was proved to be the most potent tyrosinase inhibitor with an IC₅₀ value of 25.75 ± 0.19 µM. Compound 10g as the most potent derivative exhibited a noncompetitive inhibition pattern against tyrosinase in the kinetic study. Furthermore, the in silico cavity detection, as well as the molecular docking assessments, were performed to follow the behavior of 10g within the proposed binding site. Besides, the toxicity of 10g and its potency to reduce the melanin content on A375 cell lines were also measured. Consequently, aryl-substituted thioqunolines conjugated to thiosemicarbazide might be a promising candidate in the cosmetics, medicine, and food industry as tyrosinase inhibitors.

Ugi Bis-Amide Derivatives as Tyrosinase Inhibitor; Synthesis, Biology Assessment, and in Silico Analysis

Herein, a straightforward synthetic strategy mediated by Ugi reaction was developed to synthesize novel series of compounds as tyrosinase inhibitors. The structures of all compounds were confirmed by FT-IR, ¹ H-NMR, ¹³ C-NMR, and CHNOS techniques. The tyrosinase inhibitory activities of all synthesized derivatives 5a-m were determined against mushroom tyrosinase and it was found that derivative 5c possesses the best inhibition with an IC₅₀  value of 69.53±0.042 μM compared to the rest of the synthesized derivatives. Structure-activity relationships (SARs) showed that the presence of 4-MeO or 4-NO₂ at the R² position plays a key role in tyrosinase inhibitory activities. The enzyme kinetics studies showed that compound 5c is an noncompetitive inhibitor. For in silico study, the allosteric site detection was first applied to find the appropriate binding site and then molecular docking and molecular dynamic studies were performed to reveal the position and interactions of 5c as the most potent inhibitor within the tyrosinase active site. The results showed that 5c bind well with the proposed binding site and formed a stable complex with the target protein.

In vitro cell-based models of drug-induced hepatotoxicity screening: progress and limitation

Drug-induced liver injury (DILI) is one of the major causes of post-approval withdrawal of therapeutics. As a result, there is an increasing need for accurate predictive in vitro assays that reliably detect hepatotoxic drug candidates while reducing drug discovery time, costs, and the number of animal experiments. In vitro hepatocyte-based research has led to an improved comprehension of the underlying mechanisms of chemical toxicity and can assist the prioritization of therapeutic choices with low hepatotoxicity risk. Therefore, several in vitro systems have been generated over the last few decades. This review aims to comprehensively present the development and validation of 2D (two-dimensional) and 3D (three-dimensional) culture approaches on hepatotoxicity screening of compounds and highlight the main factors affecting predictive power of experiments. To this end, we first summarize some of the recognized hepatotoxicity mechanisms and related assays used to appraise DILI mechanisms and then discuss the challenges and limitations of in vitro models.

Therapeutic applications of biosimilar monoclonal antibodies: Systematic review of the efficacy, safety, and immunogenicity in autoimmune disorders

PURPOSE

Biosimilars are biological products that could be used instead of reference biological drugs to provide a less costly option for treating patients with autoimmune disorders. With the introduction of biosimilar monoclonal antibodies into the drug market, the main concern is confirming the similarity in terms of efficacy, safety, and immunogenicity of these biosimilars with their reference products. The presence of valuable comparative clinical trials to demonstrate these similarities with analytical methods is challenging. This review discusses the similarity between biosimilar mAbs and reference products as candidates for autoimmune diseases.

METHODS

Data on efficacy endpoints, adverse events, production of anti-drug antibodies (ADAs), and neutralizing antibodies (nAbs) were collected from trials.

FINDINGS

Overall, these data suggest the similarity between biosimilar mAbs and reference products in terms of safety and efficacy.

IMPLICATIONS

Biosimilars are used in a wider range of diseases, and by examining their similarities in all those diseases with reference drugs, more comprehensive results can be obtained.

HPLC methods for quantifying anticancer drugs in human samples: A systematic review

Pharmacokinetic (PK) study of anticancer drugs in cancer patients is highly crucial for dose selection and dosing intervals in clinical applications. Once an anticancer drug is administered, it undergoes various metabolic pathways; to determine these pathways, it is necessary to follow the administered drug in biological samples via different analytical methods. In addition, multi-drug quantification methods in patients undergoing multi-drug regimens of cancer therapy can have several benefits, such as reduced sampling time and analysis costs. In order to collect and categorize these studies, we conducted a systematic review of HPLC methods reported for the analysis of anticancer drugs in biological samples. A systematic search was performed on PubMed Medline, Scopus, and Web of Science databases, and 116 studies were included. In summary of included studies, when the objective of a method was to quantify a single drug, MS, or UV detectors were utilized equivalently. On the other hand, in methods with the aim of quantifying drug and metabolite(s) in a single run, MS detectors were the most utilized. This review can provide a comprehensive insight for researchers prior to developing a quantification method and selecting a detector.

Medicinal Plants Used in Iranian Traditional Medicine (ITM) as Contraceptive Agents

BACKGROUND

In recent years, rapid population growth and unsafe abortions have emerged as controversial health issues in some countries. Hence, safe and effective contraceptive methods or agents have attracted a great deal of attention and the corresponding market has been widely expanded.

OBJECTIVE

In this study, we present a review profiting from Iranian Traditional Medicine (ITM) to introduce expedient plants as efficient contraceptive agents.

METHODS

Medicinal plants suggested as contraceptive agents were obtained from ITM text books and they were also investigated using search engines to confirm their in vitro and in vivo efficacy.

RESULTS

According to credible Iranian medical literature a wide spectrum of plants possesses contraceptive activity and among them, Ruta graveolens, Ricinus communis, Piper nigrum, and Physalis alkekengi were found to be more efficient.

CONCLUSION

Complementary and Alternative Medicine (CAM), particularly herbal remedies have received a lot of attention because of their truly healing properties. Focusing on ITM knowledge, there are various comments based on medicinal plants to reduce unsafe abortions leading to better public health in the society.

Treatment of Helicobacter pylori infection: Current and future insights

Helicobacter pylori (H. pylori) is an important major cause of peptic ulcer disease and gastric malignancies such as mucosa-associated lymphoid tissue lymphoma and gastric adenocarcinoma worldwide. H. pylori treatment still remains a challenge, since many determinants for successful therapy are involved such as individual primary or secondary antibiotics resistance, mucosal drug concentration, patient compliance, side-effect profile and cost. While no new drug has been developed, current therapy still relies on different mixture of known antibiotics and anti-secretory agents. A standard triple therapy consisting of two antibiotics and a proton-pump inhibitor proposed as the first-line regimen. Bismuth-containing quadruple treatment, sequential treatment or a non-bismuth quadruple treatment (concomitant) are also an alternative therapy. Levofloxacin containing triple treatment are recommended as rescue treatment for infection of H. pylori after defeat of first-line therapy. The rapid acquisition of antibiotic resistance reduces the effectiveness of any regimens involving these remedies. Therefore, adding probiotic to the medications, developing anti-H. pylori photodynamic or phytomedicine therapy, and achieving a successful H. pylori vaccine may have the promising to present synergistic or additive consequence against H. pylori, because each of them exert different effects.

Evaluation of the 10th External Quality Assessment Scheme results in clinical microbiology laboratories in Tehran and districts

We evaluated the performance of microbiology laboratories in the 10th run of the external quality assessment scheme (EQAS) in Tehran and districts. Each laboratory was sent 2 species of bacteria for identification. Of the 487 laboratories that participated, 437 returned their findings. While 77.0% and 69.9% correctly identified Staphylococcus saprophyticus and Citrobacter freundii respectively, only 29.8% correctly identified Acinetobacter baumanii, 25.3% identified Enterococcus faecalis and 35.6% identified Enterobacter agglomerans. However 78.7% and 79.5% of the laboratories reported correct -results for susceptibility testing for S. saprophyticus and C. freundii respectively.