Evaluation of the antidermatophytic activity of potassium salts of N-acylhydrazinecarbodithioates and their aminotriazole-thione derivatives

Nowadays, dermatophyte infections are relatively easy to cure, especially since the introduction of orally administered antifungals such as terbinafine and itraconazole. However, these drugs may cause side effects due to liver damage or their interactions with other therapeutics. Hence, the search for new effective chemotherapeutics showing antidermatophyte activity seems to be the urge of the moment. Potassium salts of N-acylhydrazinecarbodithioates are used commonly as precursors for the synthesis of biologically active compounds. Keeping that in mind, the activity of a series of five potassium N-acylhydrazinecarbodithioates (1a-e) and their aminotriazole-thione derivatives (2a-e) was evaluated against a set of pathogenic, keratinolytic fungi, such as Trichophyton ssp., Microsporum ssp. and Chrysosporium keratinophilum, but also against some Gram-positive and Gram-negative bacteria. All tested compounds were found non-toxic for L-929 and HeLa cells, with the IC30 and IC50 values assessed in the MTT assay above 128 mg/L. The compound 5-amino-3-(naphtalene-1-yl)-4,5-dihydro-1H-1,2,4-triazole-5-thione (2d) was found active against all fungal strains tested. Scanning Electron Microscopy (SEM) revealed inhibition of mycelium development of Trichophyton rubrum cultivated on nail fragments and treated with 2d 24 h after infection with fungal spores. Transmission Electron Microscopy (TEM) observation of mycelium treated with 2d showed ultrastructural changes in the morphology of germinated spores. Finally, the RNA-seq analysis indicated that a broad spectrum of genes responded to stress induced by the 2d compound. In conclusion, the results confirm the potential of N-acylhydrazinecarbodithioate derivatives for future use as promising leads for new antidermatophyte agents development.

Antidermatophytic quinolizidine alkaloids from Calpurnia aurea subsp. aurea (Aiton) Benth

From the leaves and stem bark of the Kenyan medicinal plant Calpurnia aurea subsp. aurea, four previously undescribed quinolizidine alkaloids namely, 2β-methoxy-13α-O-(2'-pyrrolylcarbonyl) virgiline, 2α-methoxy-13β-O-(2'-pyrrolylcarbonyl) virgiline, 3α-O-angelate-2β-hydroxy-13α-O-(2'-pyrrolylcarbonyl) virgiline, 2,3-dehydro-virgiline were isolated together with four known ones. Structural elucidation of the compounds was based on 1D and 2D NMR spectroscopy and mass spectrometry. Their relative configurations were determined by NOESY correlations and literature. The quinolizidine alkaloids were tested against Trichophyton rubrum, Trichophyton interdigitale, Trichophyton benhamiae, Microsporum canis and Nannizzia gypsea, common causative agents of most of the tinea infections in human. All the isolated quinolizidine alkaloids exhibited antidermatophytic activity with MIC ranging from 37.5 μg/ml to 300 μg/ml.

Antidermatophytic lead compounds from Streptomycetes albidoflavus STV1572a against Tinea infections by Tricophyton mentagrophytes

Dermatophytic infection is a psychological burden due to its inefficacy in prolonged effectiveness during its course of treatment. The present study reports a novel antidermatophytic property from actinomycetes of wetlands soil. Total of 37 Streptomyces isolates were screened for antidermatophytic activity against Trichophyton mentagrophytes. The best isolate with 100% novel activity, was characterized and designated as Streptomyces albidoflavus STV1572a. Antidermatophytic compounds extracted from the mentioned strain were partially purified by chromatographic techniques. Further, it was characterized using UV-Vis spectroscopy, FTIR spectroscopy, and GC-MS analysis. Compound identified were, Phenol 2, 4-bis (1, 1-dimethylethyl), 9-octadecene (E), E-14- Hexadecenal, e-15- Heptadecenal, 1- Heneicosanol, Hypophosphonousdichloride bis (1, 1-dimethylethyl) and Heptadecyl trifluoroacetate. To sum up, this study illustrates an antidermatophytic lead compounds that pave its way for further purification and characterization of these compounds for their optimum utilization for antimycotic purposes.

Antidermatophytic Activity of Pogostemon parviflorus Benth

In the developing countries of tropical regions, mycotic infections are common cause of skin diseases.The use of medicinal plants in the treatment of skin diseases including mycotic infections is an age-old practice in many parts of the world. The drugs used against dermatophytosis have several side effects, but limited efficacy. There is therefore a distinct need for discovery of new, safer and more effective antifungal agents. Medicinal plants used in traditional folk medicine may help us to overcome the growing problem of resistance to antifungal drugs and also their relative toxicity. In this study, in vitro antifungal activity of Pogostemon parviflorus leaf extracts were evaluated against three different genera of dermatophytes including Microsporum, Trichophyton and Epidermophyton, using the agar dilution method. Pogostemon parviflorus Benth. belongs to Labiatae family. The ethanolic extract of Pogostemon parviflorus leaf inhibited the growth of tested dermatophytes at different concentrations. The ethanolic extract of Pogostemon parviflorus leaf completely prevented the growth of tested dermatophytic species, with minimum inhibitory concentration (MIC) values between 2.5-10 mg/mL. The minimum fungicidal concentration (MFC) values of this plant were also in the range of 2.5-10 mg/mL. Results of phytochemical screening tests indicated that the leaf of Pogostemon parviflorus contained saponins, reducing sugars, tannins, phenols and proteins, but it did not have any glycosides, anthraquinones, alkaloids or flavonoids. Results of High Performance Thin Layer Chromatography (HPTLC) studies indicated that the ethyl acetate extract of Pogostemon parviflorus leaves included triterpenes, as 10 and 14 peaks of ultra violet (UV) absorption were observed in 254 nm and 366 nm, respectively. Hence, triterpenes may be responsible for antidermatophytic activity of this plant.