Search Results (56)

COVID-19 has claimed around 7 million lives (from December 2019–November 2023) worldwide and continues to impact global health. SARS-CoV-2, the virus causing COVID-19 disease, is characterized by a high rate of mutations, which contributes to its rapid spread, virulence, and vaccine escape. While several vaccines have been produced to minimize the severity of the coronavirus, and diverse treatment regimens have been approved by the US FDA under Emergency Use Authorization (EUA), SARS-CoV-2 viral mutations continue to derail the efforts of scientists as the emerging variants evade the recommended therapies. Nonetheless, diverse computational models exist that offer an opportunity for the swift development of new drugs or the repurposing of old drugs. In this review, we focus on the use of various virtual screening techniques like homology modeling, molecular docking, molecular dynamics simulations, QSAR, pharmacophore modeling, etc., in repurposing SARS-CoV-2 therapeutics against major variants of SARS-CoV-2 (Alpha, Beta, Gamma, Delta, and Omicron). The results have been promising from the computer-aided drug design (CADD) studies in suggesting potential compounds for the treatment of COVID-19 variants. Hence, in silico therapeutic studies represent a transformative approach that holds great promise in advancing our fight against the ever-evolving landscape of SARS-CoV-2 and its variants. Full article

The natural product Desmosdumotin D (hereafter referred to as Des-D), isolated from the plant Desmos dumosus, showed potent anti-HIV activity. However, the subsequent pharmacological activity and clinical studies are limited due to the low content of Des-D in the plant. Therefore, the total synthesis path of Des-D was optimized in this paper, and the total yield was increased from 4.4% to 11.9%. Additionally, twelve analogues were obtained following the synthesis route of Des-D. The anti-HIV activity evaluation results in vitro showed that Des-D had the highest activity, with an IC₅₀ value of 13.6 μM, and compounds 17 and 11 had the lowest anti-HIV activity, with IC₅₀ values of 101.3 μM and 161.0 μM, respectively. Through the molecular docking of compounds Des-D and 17 with HIV-IN, the results show that phenolic hydroxyl groups and two benzene rings interact with HIV-IN and are possible pharmacodynamic groups. Full article

The development of antimicrobial resistance has increased the prevalence of infectious diseases, causing a global health problem that accounts for over 4.95 million deaths worldwide annually. The side effects associated with current antibiotics prompt a crucial need to search for effective and safe antimicrobial agents. In this study, silver nanoparticles (AgNPs) were prepared by chemical reduction method using silver nitrates as a metallic precursor and Croton macrostachyus bark aqueous extract as a reducing and capping agent. The nanoparticles were further functionalized using C. macrostachyus-based activated carbon (CAC) to generate nanocomposites (CAC-AgNPs). The nanomaterials were characterized by ultraviolet-visible (UV–vis) absorption spectra and Fourier transform infrared (FTIR) spectra. The antibacterial activity of the as-prepared nanomaterials was evaluated against an array of bacterial strains by microdilution method, whereas their cytotoxicity profile was evaluated using Vero cells (human mammalian cells). Antibacterial mechanistic studies of active nanomaterials were carried out through bacterial growth kinetics, nucleic acid leakage tests, and catalase inhibition assays. As a result, the as-prepared nanomaterials exhibited antibacterial activity against an array of bacterial strains (minimum inhibitory concentration (MIC) range: 62.5 to 500 µg/mL), the most susceptible being Escherichia coli and Staphylococcus aureus. Cytotoxicity studies of the nanomaterials on Vero cells revealed that the nanocomposite (median cytotoxic concentration (CC₅₀): 213.6 µg/mL) was less toxic than its nanoparticle (CC₅₀ value: 164.75 µg/mL) counterpart. Antibacterial mechanistic studies revealed that the nanomaterials induced (i) bacteriostatic activity vis à vis E. coli and S. aureus and (ii) inhibition of catalase in these bacteria. This novel contribution regarding the antibacterial mechanisms of action of silver nanocomposites from C. macrostachyus-based activated carbon may contribute to our understanding of the antibacterial action of these biomaterials. Nevertheless, more chemistry and in vivo experiments as well as in depth antibacterial mechanistic studies are warranted for the successful utilization of these antibacterial biomaterials. Full article

The high frequency of infectious diseases has spurred research into effective tactics to combat microorganisms that are resistant to several drugs. The overproduction of the transmembrane efflux pump protein NorA, which may export hydrophilic fluoroquinolones, is a common mechanism of resistance in S. aureus strains. This work evaluated the antimicrobial activity of the ethanolic extract from the leaves of Croton heliotropiifolius (EECH) against different bacterial and fungal strains, as well as investigating its modulating effect on the resistance to norfloxacin in a Staphylococcus aureus SA1199B overproducing the NorA efflux pump. Microdilution assays were used to assess the EECH’s antibacterial efficacy. The MIC of norfloxacin or ethidium bromide (EtBr) against the SA1199B strain was determined in the presence or absence of the EECH in order to assess the modifying influence on drug resistance. The EECH showed no activity against the Gram-positive and Gram-negative bacterial strains tested. The EECH also showed no antifungal activity against Candida albicans ATCC 10231. On the other hand, the extract reduced the MIC values for norfloxacin against SA1199B at subinhibitory concentrations. In addition, the EECH also reduced the MIC values of EtBr at subinhibitory concentrations, suggesting the occurrence of phytochemicals that inhibit efflux pumps. Molecular docking showed that retusin, a flavonoid found in the extract, could compete with norfloxacin at the orthosteric site of the NorA, indicating that it could be a potential efflux pump inhibitor. However, isolated retusin did not enhance the activity of norfloxacin or EtBr and it did not inhibit the EtBr efflux, showing that it is not a NorA inhibitor. Even though C. heliotropiifolius is a source of phytochemicals that function as adjuvants for norfloxacin, isolated retusin cannot be used in conjunction with norfloxacin to treat infections brought on by S. aureus that overproduces NorA. Full article

The dietary reference levels for vitamin D were established with an emphasis on its role in bone health; however, with the identification of vitamin D receptors in all body tissues novel associations with other metabolic disorders, such as diabetes, are being researched. Aside from its standard function as the main regulator of calcium absorption, vitamin D also controls the calcium pool, mediates the activity of beta cell calcium-dependent endopeptidases, encourages the conversion of proinsulin to insulin, increases insulin output, and raises insulin activity in peripheral insulin target tissues. Both immune cells and pancreatic beta cells include vitamin D receptors. A deficiency of vitamin D causes glucose intolerance and affects insulin secretion. Different pathogenic characteristics of the disease are linked to a number of vitamin D-related genes. It has been proven that vitamin D supplementation lowers the risk of type 1 and type 2 diabetes and its associated problems. In this article, we discussed a few prospective clinical trials on vitamin D that are necessary to clearly demonstrate the role of vitamin D in the prevention and management of diabetes. Full article

This review article emphasizes the current enlargements in the formation and properties of the various nanostructured aggregates resulting from the self-assembly of a variety of block copolymers (BCPs) in an aqueous solution. The development of the different polymerization techniques which produce polymers with a desired predetermined molecular weight and low polydispersity is investigated with regard to their technological and biomedical applications; in particular, their applications as vehicles for drug delivery systems are considered. The solution behavior of amphiphilic BCPs and double-hydrophilic block copolymers (DHBCs), with one or both blocks being responsive to any stimulus, is discussed. Polyion complex micelles (PICMs)/polymersomes obtained from the electrostatic interaction of a polyelectrolyte-neutral BCP with oppositely charged species are also detailed. Lastly, polymerization-induced self-assembly (PISA), which forms nanoscale micellar aggregates with controlled size/shape/surface functionality, and the crystallization-driven self-assembly of semicrystalline BCPs facilitated when one block of the BCP is crystallizable, are also revealed. The scalability of the copolymeric micelles in the drug delivery systems and pharmaceutical formations that are currently being used in clinical trials, research, or preclinical testing is emphasized as these micelles could be used in the future to create novel nanomedicines. The updated literature and the future perspectives of BCP self-assembly are considered. Full article

Multiple sclerosis (MS) afflicts millions of people worldwide. While multiple therapeutics have recently been developed and approved as treatment agents, they are not 100% effective. Recent developments investigating the endogenous opioid system involvement in MS has revealed that agonists of the kappa opioid receptor (KOR) have beneficial effects in both animal models of MS (and demyelinating disorders more generally) as well as in vitro models of remyelination. Several groups have contributed to this development. We summarize here the findings of these published studies, with comparisons of the effects and discussion of similarities and differences. The effects of KOR agonists involve both neuroimmunomodulation as well as remyelination, in different populations of cells. The compelling findings in MS model systems using KOR agonists strongly indicate that further investigations at both mechanistic and translational therapeutic levels are warranted. Full article

For decades, oxybutynin hydrochloride has been prescribed to improve bladder control in cases of incontinence and excessive urination frequency. This review summarizes synthetic methods enabling the preparation of the racemic drug and, in a detailed manner, preparation of (S)-2-cyclohexyl-2-hydroxy-2-phenylacetic acid, a key intermediate in the synthesis of (S)-oxybutynin. The mode of action and metabolism are briefly addressed in order to explain the main adverse effects associated with its use and to justify the evolution observed in the diverse commercial formulations. Repositioning opportunities are discussed in terms of clinical trials for the management of hyperhidrosis, hot flashes, and obstructive sleep apnea. Full article

Plants belonging to the genus Irvingia are widespread across the African and Southeast Asian regions of the world. Irvingia gabonensis, Irvingia malayana, and Irvingia grandifolia are among the commonly used species in ethnomedicine, especially in Africa. Fever, scabies, toothache, inflammation, and liver and gastrointestinal disorders are among the pathological conditions that are reverted by Irvingia plants upon traditional preparations. Modern pharmacological investigations have substantiated the ethnomedicinal uses of Irvingia spp. Reports on the phytochemical analysis of Irvingia plants have revealed the presence of a number of secondary metabolites such as flavonoids, phenolic compounds, tannins, saponins, and alkaloids. Based on the foregoing, the present study provides a comprehensive evaluation of reports on the ethnomedicinal use, phytochemistry, pharmacology, and toxicity of plants from the genus Irvingia. Relevant information on Irvingia plants was mostly obtained from major scientific databases from their inception until July 2023. As a result, more than forty compounds have been identified in Irvingia spp., proving the abundance of secondary metabolites in these plants. Reports have pointed out modern pharmacological activities such as antiprotozoal, antimicrobial, antioxidant, antidiabetic, anti-inflammatory, and hepatoprotective activities. The present study provides more insights for the successful utilization of Irvingia plants and may guide further research on their therapeutic potential in the treatment of various diseases. Full article

Treatment of hyperpigmented skin disorders by novel drug candidates without side effects remains an ongoing area of research. Chemically modified tetracyclines (CMTs) are a group of nonantimicrobial tetracycline drugs that have been shown to possess multiple pharmacological activities. We have previously documented the anti-melanogenic effects of CMT-3 and its 9-amino derivative, CMT-308. Herein, we have extended our analysis to evaluate other CMT analogs, namely CMT-1, CMT-4, CMT-5, CMT-6, and CMT-8, for their impact on melanogenesis using primary human epidermal melanocytes (HEMn-DP cells). CMT analogs were screened using a tetrazolium-based assay to identify nontoxic concentration ranges that were further used to analyze the effects of CMTs on cellular melanin content and morphology (via quantitation of dendricity). Cellular tyrosinase (TYR) activity and levels of melanogenesis proteins, TYR, and microphthalmia transcription factor (MITF) were also evaluated to elucidate the mechanisms underlying their effects on melanogenesis. The findings demonstrated that exposure to CMT-8 resulted in notable cytotoxic effects at concentrations >10 µM; hence, all five analogs were further evaluated and compared at 10 µM. None of the five CMT analogs exhibited any impact on intracellular melanin in HEMn-DP cells at the concentration of 10 µM. However, CMT-1, CMT-4, and CMT-8 robustly suppressed dendricity parameters in HEMn-DP cells, while CMT-5 and CMT-6 showed no effect, suggesting that only a subset of CMT analogs can attenuate melanocyte dendricity. Moreover, the analog CMT-5, which has β-diketone blocked, was ineffective, thus confirming the role of this moiety in suppressing dendrite formation. CMT-1 and CMT-8 did not affect cellular tyrosinase activity, while CMT-4 suppressed TYR activity at 10 µM. The capacity of CMT-4 and CMT-8 to suppress dendricity was partly associated with their ability to downregulate MITF protein levels, while CMT-1 had no effect on MITF but suppressed TYR protein levels. The results of this study indicate that CMT-1, CMT-4, and CMT-8 merit further investigation using in vivo studies as potential drug candidates for the treatment of hyperpigmentation disorders. Full article

A non-absorbable therapeutic candidate for the treatment of hyperammonemia has been identified and characterized. Conventional approaches to reducing ammonia concentration in the blood and colon include acidifying the colon, inhibiting the bacterial production of ammonia, and activation of the urea cycle. Addressing gaps in the literature around therapeutic ammonia adsorption, this study established assays for ammonia uptake from both NH₄OH and NH₄Cl solutions as well as interference and selectivity for potassium absorption. Performance was characterized for a large number and variety of materials, spanning zeolites, ion-exchange resins, metallopolymers, metal–organic frameworks (MOFs), and polymeric carboxylic acids. The latter class showed low potassium capacity (poly(acrylic acid): 10 mg/g, poly(maleic-co-acrylic acid): 4 mg/g) and a therapeutically relevant depression of pH in buffered simulated intestinal fluid (SIF) (poly(acrylic acid): −2.01 and poly(maleic-co-acrylic acid): −3.23) compared to lactulose (−3.46), an approved therapeutic for hyperammonemia that works by acidifying the colon. In the polymeric organic acids evaluated, pH depression correlated well with pKa and acid site density. Additionally, this class of candidates should avoid the undesirable side effects of lactulose, such as the potential for hyperglycemia in diabetic patients and incompatible use with galactosemic patients. Full article

SARS-CoV-2 (severe acute respiratory distress syndrome coronavirus 2) is the causative agent for the novel coronavirus disease 2019 (COVID-19). It raises serious biosecurity questions due to its high contagious potential, thereby triggering rapid and efficient responses by the scientific community to take necessary actions against viral infections. Cumulative scientific evidence suggests that natural products remain one of the main sources for pharmaceutical consumption. It is due to their wide chemical diversity that they are able to fight against almost all kinds of diseases and disorders in humans and other animals. Knowing the overall facts, this study was carried out to investigate the chemical interactions between the active constituents of a promising medicinal plant, Myracrodruon urundeuva, and some specific proteins of SARS-CoV-2. For this, we used molecular docking to predict the most appropriate orientation by binding a molecule (a ligand) to its receptor (a protein). The best results were evaluated by screening their pharmacokinetic properties using the online tool pkCSM. Findings suggest that among 44 chemical compounds of M. urundeuva, agathisflavone, which is abundantly present in its leaf, exhibited excellent molecular affinity (−9.3 to −9.7 kcal.mol⁻¹) with three functional proteins, namely, Spike, M^Pro, and RBD of SARS-CoV-2. In conclusion, M. urundeuva might be a good source of antiviral agents. Further studies are required to elucidate the exact mechanism of action of the bioactive compounds of M. urundeuva acting against SARS-CoV-2. Full article

Based on the demonstrated and reported trypanocidal, leishmanicidal, and antiplasmodial activities of two menthol prodrugs, it was decided to proceed with preformulation studies, which are of key relevance in the drug discovery process. The aim of this study is to examine the stability and permeability of two new menthol prodrugs with antiparasitic activity. To determine the stability of menthol and its prodrugs, the corresponding studies were carried out in buffered solutions at pH values of 1.2, 5.8, and 7.4 at 37 °C. In silico permeability studies were performed using the free PerMM software and then in vitro permeability studies were performed using a biomimetic artificial membrane (BAM). Permeability studies conducted in silico predicted that both menthol and its prodrugs would pass through biological membranes via flip-flop movement. This prediction was subsequently confirmed by in vitro BAM permeability studies, where it was observed that the menthol prodrugs (1c and 1g) exhibited the highest P_app (apparent permeability) value compared to the parent compound. The study reveals that menthol prodrugs exhibit stability at a pH of 5.8 and possess sufficient in vitro permeability values as preformulation parameters. Full article

The Warburg effect (or aerobic glycolysis), which was first described in 1926 by Otto Heinrich Warburg, consists of the change in glucose metabolism in cancer cells. In normal cells, glucose metabolism finalizes in the mitochondria through oxidative phosphorylation (OXPHOS) in the presence of oxygen. However, the Warburg effect describes a change in the glucose metabolism in cancer cells, consuming excess glucose and converting it into lactate independently of the presence of oxygen. During this process, a wide variety of enzymes can modify their expression and activity to contribute to the mechanism of deregulated cancer metabolism. Therefore, the modulation of enzymes regulating aerobic glycolysis is a strategy for cancer treatment. Although numerous enzymes play a role in regulating aerobic glycolysis, hexokinase 2 (HK2), pyruvate dehydrogenase kinase (PDK), pyruvate kinase (PK), and lactate dehydrogenase (LDH) are worth mentioning. Numerous modulators of these enzymes have been described in recent years. This review aims to present and group, according to their chemical structure, the most recent emerging molecules targeting the above-mentioned enzymes involved in the Warburg effect in view of the future development of cancer treatments. Full article