In vitro antiproliferative and cytotoxic activities of novel kojic acid derivatives: 5-benzyloxy-2-selenocyanatomethyl- and 5-methoxy-2-selenocyanatomethyl-4-pyranone

Comparative Neuroprotective Potential of Nanoformulated and Free Resveratrol Against Cuprizone-Induced Demyelination in Rats

Demyelination is a frequent yet crippling neurological disease associated with multiple sclerosis (MS). The cuprizone (CZ) model, which causes demyelination through oxidative stress and neuroinflammation, is a popular tool used by researchers to examine this process. The polyphenol resveratrol (RESV) has become a promising neuroprotective agent in seeking for efficient therapies. In a rat model given CZ, we created and examined iron oxide nanoparticles (IONPs) loaded with RESV (IONP-RESV) to see how effective they were as a therapeutic agent against free RESV. According to molecular mechanisms, exposure to CZ resulted in a marked downregulation of myelin proteolipid protein (PLP) expression and an overexpression of the inflammatory markers tumor necrosis factor-α (TNF-α) and S100β, which are indicators of demyelination and neuroinflammation. It is remarkable that these CZ-induced alterations could be reversed by therapy with either RESV or IONP-RESV. Interestingly, IONP-RESV showed even stronger anti-inflammatory activity, as shown by a more noticeable downregulation of TNF-α and S100β expression. These results were confirmed by histopathological examination of the cerebral cortices. Our findings support the better neuroprotective benefits of RESV-loaded IONPs over free RESV in reducing demyelination and neuroinflammation brought on by CZ. Owing to their pro-remyelinating, anti-inflammatory, and antioxidant properties, RESV-loaded IONPs show promise as a neurotherapeutic intervention in the future for neurological diseases such as multiple sclerosis.

Production of kojic acid by Aspergillus flavus OL314748 using box-Behnken statistical design and its antibacterial and anticancer applications using molecular docking technique

Kojic acid is a wonderful fungal secondary metabolite that has several applications in the food, medical, and agriculture sectors. Many human diseases become resistant to normal antibiotics and normal treatments. We need to search for alternative treatment sources and understand their mode of action. Aspergillus flavus ASU45 (OL314748) was isolated from the caraway rhizosphere as a non-aflatoxin producer and identified genetically using 18S rRNA gene sequencing. After applying the Box-Behnken statistical design to maximize KA production, the production raised from 39.96 to 81.59 g/l utilizing (g/l) glucose 150, yeast extract 5, KH2PO4 1, MgSO4.7H2O 2, and medium pH 3 with a coefficient (R2) of 98.45%. Extracted KA was characterized using FTIR, XRD, and a scanning electron microscope. Crystalized KA was an effective antibacterial agent against six human pathogenic bacteria (Bacillus cereus, Staphylococcus aureus, Escherichia coli, Klebsiella pneumonia, Serratia marcescens, and Serratia plymuthica). KA achieves high inhibition activity against Bacillus cereus, K. pneumonia, and S. plymuthica at 100 μg/ml concentration by 2.75, 2.85, and 2.85 compared with chloramphenicol which gives inhibition zones 1, 1.1, and 1.6, respectively. Crystalized KA had anticancer activity versus three types of cancer cell lines (Mcf-7, HepG2, and Huh7) and demonstrated high cytotoxic capabilities on HepG-2 cells that propose strong antitumor potent of KA versus hepatocellular carcinoma. The antibacterial and anticancer modes of action were illustrated using the molecular docking technique. Crystalized kojic acid from a biological source represented a promising microbial metabolite that could be utilized as an alternative antibacterial and anticancer agent effectively.

Neurotherapeutic efficacy of loaded sulforaphane on iron oxide nanoparticles against cuprizone-induced neurotoxicity: role of MMP-9 and S100β

Cuprizone (CUP) induces neurotoxicity and demyelination in animal models by provoking the activation of glial cells and the generation of reactive oxygen species (ROS). Sulforaphane (SF) is a phytochemical that exhibits a neuroprotective potential. In this study, we investigated the neurotherapeutic and pro-remyelinating activities of SF and SF-loaded within iron oxide nanoparticles (IONP-SF) in CUP-exposed rats. Magnetite iron oxide nanoparticles (IONPs) were prepared using the hydrothermal method that was further loaded with SF (IONP-SF). The loading of SF within the magnetite nanoparticles was assessed using FTIR, TEM, DLS, Zetasizer, and XPS. For the in vivo investigations, adult male Wistar rats (n = 40) were administrated either on a regular diet or a diet with CUP (0.2%) for 5 weeks. The rats were divided into four groups: negative control, CUP-induced, CUP + SF, and CUP + IONP-SF. CUP-exposed brains exhibited a marked elevation in lipid peroxidation, along with a significant decrease in the activities of glutathione peroxidase (GPx), and catalase (CAT). In addition, CUP intoxication downregulated the expression of myelin basic protein (MBP) and myelin proteolipid protein (PLP), upregulated the expression of Matrix metallopeptidase-9 (MMP-9) and S100β, and increased caspase-3 immunoexpression, these results were supported histopathologically in the cerebral cortexes. Treatment of CUP-rats with either SF or IONP-SF demonstrated remyelinating and neurotherapeutic activities. We could conclude that IONP-SF was more effective than free SF in mitigating the CUP-induced downregulation of MBP, upregulation of S100β, and caspase-3 immunoexpression.

Penicillium italicum: An Underexplored Postharvest Pathogen

In the agricultural sector, citrus is one of the most important fruit genus in the world. In this scenario, Brazil is the largest producer of oranges; 34% of the global production, and exporter of concentrated orange juice; 76% of the juice consumed in the planet, summing up US$ 6.5 billion to Brazilian GDP. However, the orange production has been considerable decreasing due to unfavorable weather conditions in recent years and the increasing number of pathogen infections. One of the main citrus post-harvest phytopathogen is Penicillium italicum, responsible for the blue mold disease, which is currently controlled by pesticides, such as Imazalil, Pyrimethanil, Fludioxonil, and Tiabendazole, which are toxic chemicals harmful to the environment and also to human health. In addition, P. italicum has developed considerable resistance to these chemicals as a result of widespread applications. To address this growing problem, the search for new control methods of citrus post-harvest phytopathogens is being extensively explored, resulting in promising new approaches such as biocontrol methods as “killer” yeasts, application of essential oils, and antimicrobial volatile substances. The alternative methodologies to control P. italicum are reviewed here, as well as the fungal virulence factors and infection strategies. Therefore, this review will focus on a general overview of recent research carried out regarding the phytopathological interaction of P. italicum and its citrus host.

A new mixed inhibitor of adenosine deaminase produced by endophytic Cochliobolus sp. from medicinal plant seeds

Medicinal plants have been studied for potential endophytic interactions and numerous studies have provided evidence that seeds harbor diverse microbial communities, not only on their surfaces but also within the embryo. Adenosine deaminase (ADA) is known as a potential therapeutic target for the treatment of lymphoproliferative disorders and cancer. Therefore, in this study, 20 types of medicinal plant seeds were used to screen endophytic fungi with tissue homogenate and streak. In addition, 128 morphologically distinct endophyte strains were isolated and their ADA inhibitory activity determined by a spectrophotometric assay. The strain with the highest inhibitory activity was identified as Cochliobolus sp. Seven compounds were isolated from the strain using a chromatography method. Compound 3 showed the highest ADA inhibitory activity and was identified as 5-hydroxy-2-hydroxymethyl-4H-pyran-4-one, based on the results of 1H and 13C NMR spectroscopy. The results of molecular docking suggested that compound 3 binds to the active site and the nonspecific binding site of the ADA. Furthermore, we found that compound 3 is a mixed ADA inhibitor. These results indicate that endophytic strains are a promising source of ADA inhibitors and that compound 3 may be a superior source for use in the preparation of biologically active ADA inhibitor compounds used to treat cancer.

Adamantyl pyran-4-one derivatives and their in vitro antiproliferative activity

Pyran-4-one (maltol, kojic acid and chlorokojic acid 1) esters of adamantan-1-ylacetic acid were prepared through efficient synthetic routes in good yields and evaluated for their in vitro antiproliferative activity on four cancer cell lines: K562 (chronic myelogenous leukemia), HeLa (cervical cancer), Caco-2 (colorectal adenocarcinoma) and NCI-H358 (bronchioalveolar carcinoma). The results indicate that the presence and the position of the adamantyl acyl group or chlorine atom are the necessary requirement for antitumor activity of pyranone systems. Derivatives of kojic acid with either free (compounds 1 and 8) or acylated 5-OH group (compounds 2 and 9) have shown good-to-moderate activity (IC₅₀ values ranging from 13.1 to 43.0 μM) on all cell lines. Adamantyl kojic acid derivative 5 with a free OH group on the position 2 showed activity only on the K562 cell line. It seems that removal of halogen or adamantyl unit from position 2 elicits antileukemic activity, as observed in compound 5. The positive influence of the adamantyl unit was also observed on a 3-OH acylated derivative of maltol I which was also selectively active on the same cell line. 5-O-benzylated adamantyl compounds 6 and 7 and unmodified starting pyranones were found to be inactive. Antibacterial activity of compounds was also evaluated on S. aureus ATCC 13709, M. catarrhalis ATCC 23246, E. faecalis ATCC29212 and E. coli TolC-Tn10, but no activity was observed (MIC values 128-256 µg/mL).

Comparative study of stirred and fluidized tank reactor for hydroxyl-kojic acid derivatives synthesis and their biological activities

Background:

Study on the synthesis of kojic acid derivatives (KADs) in solvent-free system using scalable reactors and their biological activities is still lacking.

Methods:

In this study, two types of KADs, were synthesized using saturated-fatty acid [lauric acid (LA)] and unsaturated-fatty acid [oleic acid (OA)] in stirred tank reactor (STR) and fluidized tank reactor (FTR). The yield and biological activities of the synthesized KADs were evaluated and compared.

Results:

The highest yield of KADs (42.95%) was obtained in the synthesis using OA, with molar ratio of 1:1, enzyme loading of 5% (w/v), temperature of 70°C, using immobilized lipase N435 in STR. However, FTR may provide biocatalyst protection and reusability with reduced loss of KADs yield up to three cycles. In antioxidant assay, the hydroxyl-unsaturated-fatty acid of kojic acid (HUFA-KA) showed better activity as compared to hydroxyl-saturated-fatty acid of kojic acid (HSFA-KA) at concentrations ranging from 125 to 2000 μg/mL. In contrast, HSFA-KA showed better cytotoxicity effect against G361 melanoma cell as compared to HUFA-KA.

Conclusion:

The yield of KADs obtained in STR was higher than that obtained in FTR. HUFA-KA could be used as potential lipophilic antioxidant while HSFA-KA has the potential to be used to treat melanoma skin disorder.

Novel functionalized monomers based on kojic acid: snythesis, characterization, polymerization and evalution of antimicrobial activity

Two novel acrylate monomers, [5-(benzyloxy)-4-oxo-4H-pyran-2-yl]methyl acrylate and {1-[(5-(benzyloxy)-4-oxo-4H-pyran-2-yl)methyl]-1,2,3-triazol-4-yl}methyl acrylate were synthesized by the reaction of 5-benzyloxy-2-(hydroxymethyl)-4H-pyran-4-one and 5-(benzyloxy)-2-{[4-(hydroxymethyl)-1,2,3-triazol-1-yl]methyl}-4H-pyran-4-one with acryloyl chloride in the presence of triethylamine, respectively. These monomers were polymerized using 2,2^′-azobisisobutyronitrile (AIBN) as the initiator in N,N-dimethylformamide:14-dioxane (10:1) solution. The thermal behavior of the polymers was investigated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The synthesized compounds were evaluated for their antibacterial and antifungal activites aganist bacteria and fungi using the disk diffusion method. The results indicated that some of these compounds demonstrated moderate to good antibacterial and antifungal activities.

Ciprofloxacin containing Mannich base and its copper complex induce antitumor activity via different mechanism of action

The Mannich base containing ciprofloxacin and kojic acid structural units was prepared and evaluated in antitumor activity. The enhancement in antitumor activity was observed both from the Mannich base (IC(50): 103.3±5.0 µM for HepG2, 87.9±8.0 µM for HCT-116 cell) and its copper complex (IC(50): 11.5±1.8 µM for HepG2, 44.4±2.5 µM for HCT-116 cell) compared to the ciprofloxacin and kojic acid. The mechanistic studies via RT-PCR, cell cycle analysis, mitochondrial membrane potential measurement, inhibition of topoisomerase and molecular docking indicated that there is a different molecular mechanism between the Mannich base and its copper complex. The cytotoxicity of the Mannich base was involved in apoptosis, cell cycle arrest, depolarization of mitochondrial membrane and weaker topoisomerase II inhibition, but the copper complex exerted its cytotoxicity mainly through dual topoisomerase inhibition, especially stabilizing the intermediate of cleavage DNA-topoisomerase complex.

Novel kojic acid-polymer-based magnetic nanocomposites for medical applications

Iron oxide magnetic nanoparticles (MNPs) were synthesized by the coprecipitation of iron salts in sodium hydroxide followed by coating separately with chitosan (CS) and polyethylene glycol (PEG) to form CS-MNPs and PEG-MNPs nanoparticles, respectively. They were then loaded with kojic acid (KA), a pharmacologically bioactive natural compound, to form KA-CS-MNPs and KA-PEG-MNPs nanocomposites, respectively. The MNPs and their nanocomposites were characterized using powder X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, vibrating sample magnetometry, and scanning electron microscopy. The powder X-ray diffraction data suggest that all formulations consisted of highly crystalline, pure magnetite Fe₃O₄. The Fourier transform infrared spectroscopy and thermogravimetric analysis confirmed the presence of both polymers and KA in the nanocomposites. Magnetization curves showed that both nanocomposites (KA-CS-MNPs and KA-PEG-MNPs) were superparamagnetic with saturation magnetizations of 8.1 emu/g and 26.4 emu/g, respectively. The KA drug loading was estimated using ultraviolet–visible spectroscopy, which gave a loading of 12.2% and 8.3% for the KA-CS-MNPs and KA-PEG-MNPs nanocomposites, respectively. The release profile of the KA from the nanocomposites followed a pseudo second-order kinetic model. The agar diffusion test was performed to evaluate the antimicrobial activity for both KA-CS-MNPs and KA-PEG-MNPs nanocomposites against a number of microorganisms using two Gram-positive (methicillin-resistant Staphylococcus aureus and Bacillus subtilis) and one Gram-negative (Salmonella enterica) species, and showed some antibacterial activity, which could be enhanced in future studies by optimizing drug loading. This study provided evidence for the promise for the further investigation of the possible beneficial biological activities of KA and both KA-CS-MNPs and KA-PEG-MNPs nanocomposites in nanopharmaceutical applications.

Asymmetric Michael/hemiketalization of 5-hydroxy-2-methyl-4H-pyran-4-one to β,γ-unsaturated α-ketoesters catalyzed by a bifunctional rosin–indane amine thiourea catalyst

A highly efficient enantioselective Michael-hemiketalization cascade process is reported using a chiral bifunctional rosin–indane amine thiourea catalyst.

Synthesis and antiproliferative activity of novel selenoester derivatives

A series of 31 new selenoesters were synthesized and their cytotoxic activity was evaluated against a prostate cancer cell line (PC-3). The most active compounds were also tested against three tumoural cell lines (MCF-7, A-549 and HT-29) and one non-tumour prostate cell line (RWPE-1). Thirteen compounds showed significant activity towards all tumour cells investigated, and some of them were even more potent than etoposide and cisplatin, which were used as reference drugs. Because of their pronounced potency and/or selectivity, four analogues (5, 21, 28 and 30), were selected in order to assess their redox properties related to a possible redox modulating activity. The glutathione peroxidase (GPx) assay showed slight activity for compound 30 and the 2,2-diphenyl-1-picrylhydrazyl-(DPPH) assay showed a weak activity for compounds 5 and 28. The present results revealed that analogues 5, 21, 28 and 30 might serve as a useful starting point for the design of improved anti-tumour agents.

CeCl3⋅7H2O/SiO2as an Efficient and Recyclable Catalyst for the Synthesis of Dihydropyrano[3,2-b]chromenediones

Dihydropyrano[3,2-b]chromenedione derivatives were synthesized in moderate-to-high yields in one-pot three-component reaction from the corresponding aromatic aldehydes, kojic acid, and dimedone, in the presence of catalytic amount ofCeCl3⋅7H2O/SiO2as a nontoxic, reusable, inexpensive, and easily available reagent, under solvent-free conditions.

FeCl3–SiO2 as heterogeneous catalysts for the preparation of dihydropyrano[3,2-b]chromenediones

FeCl3–SiO2 is environment-friendly heterogeneous catalyst for the condensation of kojic acid and aldehydes with dimedone to afford dihydropyrano[3,2-b]chromenediones. The solid acid catalyst is stable and can be easily recovered and reused without appreciable change in its efficiency.

Kojic acid, a secondary metabolite from Aspergillus sp., acts as an inducer of macrophage activation

KA (kojic acid) is a secondary metabolite isolated from Aspergillus fungi that has demonstrated skin whitening, antioxidant and antitumour properties among others. However, limited information is available regarding its effects on macrophages, the major cell involved in cell defence. The aim of the present study was to analyse whether KA affects functional properties related to macrophage activation, such as phagocytosis and spreading ability over a substrate. Treatment of resident macrophages with 50 μg/ml KA for 1 h induced both morphological and physiological alterations in cells. Immunofluorescence microscopy revealed enhanced cell spreading and an increase in cell surface exposure, associated with a rearrangement of microtubules, actin filaments and intermediate filaments. KA also potentiated phagocytosis by macrophages, as demonstrated by the increase in phagocytic activity towards yeast, when compared to untreated cells. KA increased the production of ROS (reactive oxygen species), but not NO (nitric oxide) production. Three tests were used to assess cell viability; MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide], NR (neutral red) uptake and PI (propidium iodide) exclusion test, which showed that macrophages maintain their viability following KA treatment. Results indicate that KA can modulate macrophage activation through cytoskeleton rearrangement, increase cell surface exposure, enhance the phagocytic process and ROS production. The study demonstrates a new role for KA as a macrophage activator.