Griseofulvin and ketoconazole in the treatment of dermatophyte infections

In Silico Exploration of Microtubule Agent Griseofulvin and Its Derivatives Interactions with Different Human β-Tubulin Isotypes

Tubulin isotypes are known to regulate microtubule stability and dynamics, as well as to play a role in the development of resistance to microtubule-targeted cancer drugs. Griseofulvin is known to disrupt cell microtubule dynamics and cause cell death in cancer cells through binding to tubulin protein at the taxol site. However, the detailed binding mode involved molecular interactions, and binding affinities with different human β-tubulin isotypes are not well understood. Here, the binding affinities of human β-tubulin isotypes with griseofulvin and its derivatives were investigated using molecular docking, molecular dynamics simulation, and binding energy calculations. Multiple sequence analysis shows that the amino acid sequences are different in the griseofulvin binding pocket of βI isotypes. However, no differences were observed at the griseofulvin binding pocket of other β-tubulin isotypes. Our molecular docking results show the favorable interaction and significant affinity of griseofulvin and its derivatives toward human β-tubulin isotypes. Further, molecular dynamics simulation results show the structural stability of most β-tubulin isotypes upon binding to the G1 derivative. Taxol is an effective drug in breast cancer, but resistance to it is known. Modern anticancer treatments use a combination of multiple drugs to alleviate the problem of cancer cells resistance to chemotherapy. Our study provides a significant understanding of the involved molecular interactions of griseofulvin and its derivatives with β-tubulin isotypes, which may help to design potent griseofulvin analogues for specific tubulin isotypes in multidrug-resistance cancer cells in future.

Griseofulvin: An Updated Overview of Old and Current Knowledge

Griseofulvin is an antifungal polyketide metabolite produced mainly by ascomycetes. Since it was commercially introduced in 1959, griseofulvin has been used in treating dermatophyte infections. This fungistatic has gained increasing interest for multifunctional applications in the last decades due to its potential to disrupt mitosis and cell division in human cancer cells and arrest hepatitis C virus replication. In addition to these inhibitory effects, we and others found griseofulvin may enhance ACE2 function, contribute to vascular vasodilation, and improve capillary blood flow. Furthermore, molecular docking analysis revealed that griseofulvin and its derivatives have good binding potential with SARS-CoV-2 main protease, RNA-dependent RNA polymerase (RdRp), and spike protein receptor-binding domain (RBD), suggesting its inhibitory effects on SARS-CoV-2 entry and viral replication. These findings imply the repurposing potentials of the FDA-approved drug griseofulvin in designing and developing novel therapeutic interventions. In this review, we have summarized the available information from its discovery to recent progress in this growing field. Additionally, explored is the possible mechanism leading to rare hepatitis induced by griseofulvin. We found that griseofulvin and its metabolites, including 6-desmethylgriseofulvin (6-DMG) and 4- desmethylgriseofulvin (4-DMG), have favorable interactions with cytokeratin intermediate filament proteins (K8 and K18), ranging from -3.34 to -5.61 kcal mol-1. Therefore, they could be responsible for liver injury and Mallory body (MB) formation in hepatocytes of human, mouse, and rat treated with griseofulvin. Moreover, the stronger binding of griseofulvin to K18 in rodents than in human may explain the observed difference in the severity of hepatitis between rodents and human.

In Silico Molecular Dynamics of Griseofulvin and Its Derivatives Revealed Potential Therapeutic Applications for COVID-19

Treatment options for Coronavirus Disease 2019 (COVID-19) remain limited, and the option of repurposing approved drugs with promising medicinal properties is of increasing interest in therapeutic approaches to COVID-19. Using computational approaches, we examined griseofulvin and its derivatives against four key anti-SARS-CoV-2 targets: main protease, RdRp, spike protein receptor-binding domain (RBD), and human host angiotensin-converting enzyme 2 (ACE2). Molecular docking analysis revealed that griseofulvin (CID 441140) has the highest docking score (–6.8 kcal/mol) with main protease of SARS-CoV-2. Moreover, griseofulvin derivative M9 (CID 144564153) proved the most potent inhibitor with −9.49 kcal/mol, followed by A3 (CID 46844082) with −8.44 kcal/mol against M protease and ACE2, respectively. Additionally, H bond analysis revealed that compound A3 formed the highest number of hydrogen bonds, indicating the strongest inhibitory efficacy against ACE2. Further, molecular dynamics (MD) simulation analysis revealed that griseofulvin and these derivatives are structurally stable. These findings suggest that griseofulvin and its derivatives may be considered when designing future therapeutic options for SARS-CoV-2 infection.

Conservation of griseofulvin genes in the gsf gene cluster among fungal genomes

The polyketide griseofulvin is a natural antifungal compound and research in griseofulvin has been key in establishing our current understanding of polyketide biosynthesis. Nevertheless, the griseofulvin gsf biosynthetic gene cluster (BGC) remains poorly understood in most fungal species, including Penicillium griseofulvum where griseofulvin was first isolated. To elucidate essential genes involved in griseofulvin biosynthesis, we performed third-generation sequencing to obtain the genome of P. griseofulvum strain D-756. Furthermore, we gathered publicly available genome of 11 other fungal species in which gsf gene cluster was identified. In a comparative genome analysis, we annotated and compared the gsf BGC of all 12 fungal genomes. Our findings show no gene rearrangements at the gsf BGC. Furthermore, seven gsf genes are conserved by most genomes surveyed whereas the remaining six were poorly conserved. This study provides new insights into differences between gsf BGC and suggests that seven gsf genes are essential in griseofulvin production.

Multipurpose Drugs Active Against Both Plasmodium spp. and Microorganisms: Potential Application for New Drug Development

Malaria, a disease caused by the protozoan parasites Plasmodium spp., is still causing serious problems in endemic regions in the world. Although the WHO recommends artemisinin combination therapies for the treatment of malaria patients, the emergence of artemisinin-resistant parasites has become a serious issue and underscores the need for the development of new antimalarial drugs. On the other hand, new and re-emergences of infectious diseases, such as the influenza pandemic, Ebola virus disease, and COVID-19, are urging the world to develop effective chemotherapeutic agents against the causative viruses, which are not achieved to the desired level yet. In this review article, we describe existing drugs which are active against both Plasmodium spp. and microorganisms including viruses, bacteria, and fungi. We also focus on the current knowledge about the mechanism of actions of these drugs. Our major aims of this article are to describe examples of drugs that kill both Plasmodium parasites and other microbes and to provide valuable information to help find new ideas for developing novel drugs, rather than merely augmenting already existing drug repurposing efforts.

A systematic review of synthetic tyrosinase inhibitors and their structure-activity relationship

Tyrosinase is a copper-containing oxidation enzyme, which is responsible for the production of melanin. This enzyme is widely distributed in microorganisms, animals and plants, and plays an essential role in undesirable browning of fruits and vegetables, antibiotic resistance, skin pigment formation, sclerotization of cuticle, neurodegeneration, etc. Hence, it has been recognized as a therapeutic target for the development of antibrowning agents, antibacterial agents, skin-whitening agents, insecticides, and other therapeutic agents. With great potential application in food, agricultural, cosmetic and pharmaceutical industries, a large number of synthetic tyrosinase inhibitors have been widely reported in recent years. In this review, we systematically summarized the advances of synthetic tyrosinase inhibitors in the literatures, including their inhibitory activity, cytotoxicity, structure-activity relationship (SAR), inhibition kinetics, and interaction mechanisms with the enzyme. The collected information is expected to provide a rational guidance and effective strategy to develop novel, potent and safe tyrosinase inhibitors for better practical applications in the future.

A metabolomic perspective of griseofulvin-induced liver injury in mice

Griseofulvin (GSF) causes hepatic porphyria in mice, which mimics the liver injury associated with erythropoietic protoporphyria (EPP) in humans. The current study investigated the biochemical basis of GSF-induced liver injury in mice using a metabolimic approach. GSF treatment in mice resulted in significant accumulations of protoporphyrin IX (PPIX), N-methyl PPIX, bile acids, and glutathione (GSH) in the liver. Metabolomic analysis also revealed bioactivation pathways of GSF that contributed to the formation of GSF-PPIX, GSF-GSH and GSF-proline adducts. GSF-PPIX is the precursor of N-methyl PPIX. A six-fold increase of N-methyl PPIX was observed in the liver of mice after GSF treatment. N-methyl PPIX strongly inhibits ferrochelatase, the enzyme that converts PPIX to heme, and leads to PPIX accumulation. Excessive PPIX in the liver results in bile duct blockage and disturbs bile acid homeostasis. The accumulation of GSH in the liver was likely due to Nrf2-mediated upregulation of GSH synthesis. In summary, this study provides the biochemical basis of GSF-induced liver injury that can be used to understand the pathophysiology of EPP-associated liver injury in humans.

Fungal skin infections in children. New developments and treatments

Recognizing the common manifestations of pediatric fungal infections is a key part of any primary care practice. Of paramount importance is the clinical acumen of the physician. In this article, Drs Berg and Erickson discuss several types of fungal infections in children, identify tools for diagnosis, and outline the most effective options for treatment. Newer "off-label" therapies are also examined.

Pathogenesis and treatment of hyperkeratotic tinea pedis in Japan

In this paper, we describe the major characteristics of hyperkeratotic tinea pedis and review therapeutic results obtained in the Department of Dermatology of Kitasato University Hospital and those reported in the literature in Japan and abroad.

The dermatophytes

The etiologic agents of the dermatophytoses (ringworm) are classified in three anamorphic (asexual or imperfect) genera, Epidermophyton, Microsporum, and Trichophyton. Species capable of reproducing sexually belong in the teleomorphic genus, Arthroderma, of the Ascomycota. On the basis of primary habitat association, they may be grouped as geophilic (soil associated), zoophilic, and anthropophilic. Adaptation to growth on humans by most geophilic species resulted in diminished loss of sporulation, sexuality, and other soil-associated characteristics. The dermatophytes have the ability to invade keratinized tissue (skin, hair, and nails) but are usually restricted to the nonliving cornified layer of the epidermis because of their inability to penetrate viable tissue of an immunocompetent host. However, invasion does elicit a host response ranging from mild to severe. Acid proteinases, elastase, keratinases, and other proteinases reportedly act as virulence factors. The development of cell-mediated immunity correlated with delayed hypersensitivity and an inflammatory response is associated with clinical cure, whereas the lack of or a defective cell-mediated immunity predisposes the host to chronic or recurrent dermatophyte infection. Chronic dermatophytosis is mostly caused by Trichophyton rubrum, and there is some evidence that mannan produced by this fungus suppresses or diminishes the inflammatory response. Since dermatophytes cause a communicable disease, modes of transmission and control are discussed as well as a survey of recent trends in therapy. Collection of specimens, culture media, and tests for identification are also presented. Genetic studies have led to an understanding of incompatibility mechanisms, pleomorphism and variation, resistance to griseofulvin, and virulence. Molecular biology has contributed to our knowledge of the taxonomy and phylogenetic relationships of dermatophytes.

Tinea capitis: new perspectives on an old disease

Tinea capitis caused by Trichophyton tonsurans is a common infection in children, and has become a significant public health problem in the United States. Epidemics of tinea capitis occur both in families and in institutions such as schools and day care centers. Infection is often difficult to eradicate. Fomites and asymptomatic carriers likely contribute to the spread of the disease and to re-infection of treated patients. The morphology of tinea capitis is diverse, from seborrhea-like scaling to tender, inflammed nodules on the scalp. Because a lengthy course of systemic griseofulvin is required to treat this infection, management of tinea capitis can be challenging. As newer antifungal agents are developed, more effective and convenient therapy for tinea capitis may become available.

Topical antifungal drugs in the treatment of tinea pedis, tinea cruris, and tinea corporis

Topical treatment of fungal infections took a step forward in the 1960s with the introduction of biologically active agents with specific antifungal mechanisms of action. Most modern broad-spectrum antifungal agents act by blocking specific steps in the synthesis of fungal cell membrane components. The broad-spectrum topical antifungal drugs now in use include the imidazoles (e.g. clotrimazole and miconazole), a pyridone-ethanolamine salt, dimethylmorpholines, and the newest class, the allylamines (e.g., naftifine and terbinafine). The topical allylamines have been shown in comparative studies to produce higher cure rates and more rapid responses in dermatophyte infections than many of the older agents.

Outbreak of tinea capitis by Trichophyton tonsurans and Microsporum canis in Niterói, RJ, Brazil

18 girls from an orphanage (Orfanato Santo Antônio) in Niterói presented tinea capitis due to Trichophyton tonsurans (15 cases-83.3%) and Microsporum canis (3 cases-26.7%). Comments are made about clinical, mycological and therapeutic aspects of this microepidemic.

Successful 2-week treatment with terbinafine (Lamisil) for moccasin tinea pedis and tinea manuum

A new orally active antifungal agent, terbinafine, was used in the treatment of tinea pedis ('dry type' or moccasin type) and tinea manuum. Fifty-three adults over the age of 16 years with fungal infections of the feet and/or hands were treated with either oral terbinafine, 250 mg, or placebo, once daily for 2 weeks. The diagnosis of fungal infection was confirmed by examination of skin scrapings by microscopy and culture. Of these, 28 patients were evaluable for efficacy. At 8 weeks, 12 out of 14 (86%) patients who received terbinafine were mycologically negative (microscopy and culture) compared to one out of 14 (7%) patients on placebo (P less than 0.001, Fishers exact test, one-sided). At the end of the study 71% of patients in the terbinafine group were judged to have received effective therapy compared to 0% in the placebo group (P less than 0.001). Terbinafine was well tolerated, and more side-effects were seen in the placebo group.