Antifungal Activity of New Diterpenoid Alkaloids Isolated by Different Chromatographic Methods from Delphinium peregrinum L. var. eriocarpum Boiss.

This paper aimed to investigate the potential antifungal influences of new alkaloids from Delphinium peregrinum L. var. eriocarpum Boiss. New Diterpenoid alkaloids Delcarpum (1), Hydrodavisine (4) and known alkaloids Peregrine (2), Delphitisine (3) were isolated by different chromatographic methods from the aerial parts of D. Peregrinum eriocarpum Boiss, which grows in Syria. The structures of alkaloids were proposed based on 1D NMR spectroscopy 1H-NMR, 13C-NMR, DEPT-135, DEPT-90, 2D NMR spectroscopy DQF-COSY, HMQC, EI-Ms mass spectrum, and IR spectroscopic measurements. The antifungal activity of the isolated alkaloids was evaluated against different dermatophyte fungal isolates compared with fluconazole. In the case of Peregrine (2) the minimum inhibitory concentrations(MICs) recorded 128-256, 32-64, and 32 for Epidermophyton floccosum, Microsporum canis, and Trichophyton rubrum, respectively, compared to 32-64, 16, and 32 µg/mL in the case of fluconazole, respectively. The MICs recorded on application of the four alkaloids mixture were 64, 32, and 16 in the case of E. floccosum, M. canis, and T. rubrum, respectively, which were significantly lower than that measured for each of the individual alkaloid and were compatible for fluconazole. In conclusion, MICs of the tested alkaloids showed a variable potential effect on the investigated fungal isolates. Peregrine (2) was the most effective alkaloid, however, the application of the mixture of alkaloids induced significant synergistic activity that was more pronounced than the application of individual ones.

Antifungal activity of lichen compounds against dermatophytes: a review.

The growth rate inhibition of dermatophytes by compounds extracted by acetone, ethanol, methanol and water derived from representatives of several lichen genera (e.g. Caloplaca, Everniastrum, Heterodermia, Hypotrachyna, Platismatia and Ramalina) were compared on the basis of a worldwide review of published research. The examined dermatophytes included Epidermophyton floccosum, Microsporum audouinii, M. canis, M. gypseum, M. nanum, Trichophyton longifusus, T. mentagrophytes, T. rubrum, T. tonsurans and T. violaceum. The influence of selected secondary lichen compounds, for example, usnic acid, on the growth rates of these dermatophytes was also reviewed. The measurement of inhibition by lichen compounds was performed by several methods, but mostly those employing disc diffusion, broth dilution and agar dilution. The fungicidal activity of water-extracted compounds from Heterodermia leucomela and Hypotrachyna cirrhata and of methanol-extracted compounds from Evernia divaricata and Ramalina pollinaria, as well as protolichesterinic and 2-hydroxy-4-methoxy-3,6-dimethylbenzoic acids, are distinguished.

Fingerprinting, Antimicrobial, Antioxidant, Anticancer, Cyclooxygenase and Metabolic Enzymes Inhibitory Characteristic Evaluations of Stachys viticina Boiss. Essential Oil.

The present study aimed to identify the chemical constituents and to assess the in-vitro, antimicrobial, anticancer, antioxidant, metabolic enzymes and cyclooxygenase (COX) inhibitory properties of essential oil (EO) of Stachys viticina Boiss. leaves. The S. viticina EO was isolated and identified using microwave-ultrasonic and GC-MS techniques, respectively. Fifty-two compounds were identified, of which endo-borneol was the major component, followed by eucalyptol and epizonarene. The EO was evaluated against a panel of in-vitro bioassays. The EO displayed antimicrobial activity against methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli and Epidermophyton floccosum, with MIC values of 0.039, 0.078 and 0.78 mg/mL, respectively. The EO exhibited cytotoxicity against HeLa (cervical adenocarcinoma) and Colo-205 (colon) cancer cell lines with percentages of inhibition of 95% and 90%, for EO concentrations of 1.25 and 0.5 mg/mL, respectively. Furthermore, it showed metabolic enzyme (α-amylase, α-glucosidase, and lipase) inhibitory (IC50 = 45.22 ± 1.1, 63.09 ± 0.26, 501.18 ± 0.38 µg/mL, respectively) and antioxidant activity, with an IC50 value of 19.95 ± 2.08 µg/mL. Moreover, the S. viticina EO showed high cyclooxygenase inhibitory activity against COX-1 and COX-2 with IC50 values of 0.25 and 0.5 µg/mL, respectively, similar to those of the positive control (the NSAID etodolac). Outcomes amassed from this investigation illustrate that S. viticina EO represents a rich source of pharmacologically active molecules which can be further validated and explored clinically for its therapeutic potential and for the development and design of new natural therapeutic preparations.

Nitric Oxide-Releasing Macromolecule Exhibits Broad-Spectrum Antifungal Activity and Utility as a Topical Treatment for Superficial Fungal Infections.

Cutaneous and superficial fungal infections affecting the skin, nails, and hair of humans are caused primarily by dermatophytes of the genera Trichophyton and Epidermophyton or by yeasts of the genera Candida and Malassezia. Onychomycosis is a common fungal infection of the nail that frequently coexists with tinea pedis, the most prevalent mycotic skin infection. Efficacy rates for current topical onychomycosis therapies are hampered by low drug penetration across the nail plate, which is theoretically obviated with nitric oxide (NO)-based topical therapies. The Nitricil technology platform is comprised of polysiloxane-based macromolecules that stably release therapeutic levels of NO. In the reported studies, NVN1000, the lead candidate of the platform, was assessed for its spectrum of in vitro activity against a broad range of filamentous fungi and yeast species commonly associated with cutaneous fungal infections. Time-kill assays demonstrated that NVN1000 exhibited fungicidal activity as early as 4 h. Additionally, the penetration of several unique NVN1000 NO-releasing drug product formulations (gel, cream, and lacquer) was evaluated following a single topical application in an in vitro infected human nail assay, with all formulations showing similar inhibition of fungal growth. Repeated topical application in this model demonstrated that a lower-strength dose of NO could achieve the same efficacy as a higher-strength dose after 7 days. Together, these in vitro results demonstrate that NO-releasing treatments rapidly penetrate the nail plate and eradicate the fungal infection, representing promising novel topical therapies for the treatment of onychomycosis and other cutaneous fungal infections.

Lichen Xanthones as Models for New Antifungal Agents.

Due to the emergence of multidrug-resistant pathogenic microorganisms, the search for new antimicrobial compounds plays an important role in current medicinal chemistry research. Inspired by lichen antimicrobial xanthones, a series of novel chlorinated xanthones was prepared using five chlorination methods (Methods A⁻E) to obtain different patterns of substitution in the xanthone scaffold. All the synthesized compounds were evaluated for their antimicrobial activity. Among them, 3-chloro-4,6-dimethoxy-1-methyl-9H-xanthen-9-one 15 showed promising antibacterial activity against E. faecalis (ATCC 29212 and 29213) and S. aureus ATCC 29213. 2,7-Dichloro-3,4,6-trimethoxy-1-methyl-9H-xanthen-9-one 18 revealed a potent fungistatic and fungicidal activity against dermatophytes clinical strains (T. rubrum, M. canis, and E. floccosum (MIC = 4⁻8 µg/mL)). Moreover, when evaluated for its synergistic effect for T. rubrum, compound 18 exhibited synergy with fluconazole (ΣFIC = 0.289). These results disclosed new hit xanthones for both antibacterial and antifungal activity.

Inhibition of dermatophytes by photodynamic treatment with curcumin.

Treatment of dermatophytoses with currently available antimycotic agents is often tedious and sometimes unsatisfactory. A search for better therapeutic methods-ideally with an immediate fungicidal effect-has, among others, lead to photodynamic procedures as a promising alternative, and recently curcumin was found to be a suitable agent for this application. In this study the effect of photodynamic treatment with curcumin on dermatophytes was tested in vitro. Wells of microtiter plates were filled with conidia of Trichophyton rubrum, Trichophyton interdigitale, Trichophyton terrestre, Microsporum canis, Microsporum gypseum and Epidermophyton floccosum in buffer. Then curcumin was added to the conidia and after 20 min the assays were irradiated one time only with visible light (peak wave length 367 nm, 5 J/cm2). Thereafter the wells were filled up with Sabouraud's glucose broth and in the following fungal growth was measured photometrically. The results showed that all dermatophytes were markedly inhibited depending on the concentration of curcumin. With 5.4 mg/l curcumin plus irradiation fungal growth was significantly suppressed over a period of 96 h (P < .001). Even after 96 h inhibition of T. rubrum was still complete and marked for all other species as well. M. gypseum was least susceptible. Our results are very encouraging to pursue the development of a photodynamic therapy of tinea with curcumin. The outstanding tolerance of curcumin and the innocuousness of the required light are favorable preconditions for this task.

[Synthesis and antifungal activities of N-1,3,4-thiadiazol-2-yl-4-oxo-thiochroman-2-yl-formamide derivatives].

Thiochromanones and 1,3,4-thiadiazoles as heterocyclic compounds have broad biological activities. In order to find novel compounds with antifungal bioactivity, substituted thiophenol and maleic anhydride were used to synthesize the intermediate 4-oxothiochromane-2-carboxylic acid. It was reacted with 2-amino-1,3,4-thiadiazole to get fourteen target compounds containing 1,3,4-thiadiazole moiety. The structures of the obtained compounds were confirmed by 1H NMR, 13C NMR and HR-MS. All compounds were investigated for antifungal activity via microdilution broth method. The results showed that the target compounds 3a and 3c to Epidermophyton floccosum and Mucor racemosus exhibited better antifungal activity than the positive control fluconazole, in which the minimum inhibition concentration can reach 8 µg·mL−1 and 16 µg·mL−1. Compound 3e showed significant inhibitory activity to Helminthosporium maydis, Sclerotinia sclerotiorum and Botrytis cinerea compared with that of the positive control carbendazim. Compound 3b exhibited inhibitory activity to Helminthosporium maydis better than the positive control carbendazim.

In vitro susceptibility patterns of clinically important Trichophyton and Epidermophyton species against nine antifungal drugs.

Despite the common, worldwide, occurrence of dermatophytes, little information is available regarding susceptibility profiles against currently available and novel antifungal agents. A collection of sixty-eight clinical Trichophyton species and Epidermophyton floccosum were previously identified and verified to the species level by sequencing the internal transcribed spacer (ITS) regions of rDNA. MICs of amphotericin B, fluconazole, itraconazole, voriconazole, posaconazole, isavuconazole, terbinafine and MECs of caspofungin and anidulafungin were performed based on CLSI M38-A2. The resulting MIC90 s of all strains were, in increasing order, as follows: terbinafine (0.063 mg l(-1) ); posaconazole (1 mg l(-1) ); isavuconazole and anidulafungin (2 mg l(-1) ); itraconazole, voriconazole, amphotericin B, and caspofungin (4 mg l(-1) ) and fluconazole (>64 mg l(-1) ). These results confirm that terbinafine is an excellent agent for treatment of dermatophytosis due to T. rubrum, T. mentagrophytes, T. verrucosum, T. schoenleinii and E. floccosum. In addition, the new azoles POS and ISA are potentially useful antifungals to treat dermatophytosis. However, the clinical effectiveness of these novel antifungals remains to be determined.

Sporicidal effect of amorolfine and other antimycotics used in the therapy of fungal nail infections.

Although topical antifungal therapies for treating onychomycosis are available, the cure rate is unsatisfactorily low with a simultaneously high risk of recurrence. One reason might be the formation of dormant fungal cells by the pathogen, known as spores, which can survive in the affected nail keratin, thereby evading the effect of antifungal drugs. In this in vitro study, the ability of amorolfine and four other antimycotics (ciclopirox, bifonazole, terbinafine and fluconazole) to kill microconidia of the dermatophyte Trichophyton rubrum, chlamydospores of the dermatophyte Epidermophyton floccosum and blastospores of the yeast Candida albicans was extensively studied as these fungi occur predominantly in onychomycosis. The effectiveness of all five antimycotics depended on the drug concentration and the incubation time: a concentration of 10-1000 times the minimum inhibitory concentration against growing hyphae cells is needed to exert a sporicidal action. Amorolfine and ciclopirox showed the same sporicidal efficacy and kinetics for all three varieties of spores. Both were more effective than fluconazole and bifonazole against microconidia and chlamydospores as well as slightly more potent against chlamydospores and blastospores than terbinafine after 4 days of incubation and at concentrations of ≥10 µg ml(-1). Finally, sporicidal activity on the tested strains was demonstrated for all five different antimycotics used for onychomycosis treatment.

Anti-dermatophyte efficacy and environmental safety of some essential oils commercial and in vitro extracted pure and combined against four keratinophilic pathogenic fungi.

AIM: Establish new biocontrol practices with low persistence in the environment against dermatophyte causing mycosis. METHODS: Antimycotic activity of twenty-six plant-derived commercial essential oils (EOs) was evaluated against four dermatophyte keratinophilic fungi (Microsporum canis, Epidermophyton floccosum, Trichophyton rubrum and Trichophyton mentagrophytes). Commercial EOs which showed the strongest mycelial growth inhibitions were selected and re-extracted in vitro from fresh plant samples. Minimal inhibition concentration (MIC) and antifungal index (AI) of pure and combined extracted oils and were evaluated. All samples were collected and examined during the year of 2014. RESULTS: The results revealed that commercial EOs of Prunus armeniaca, Prunus dulcis var. amara, Olea europaea and Mentha piperita were the most potent antidermatophyte. The mixture of the extracted four oils was the strongest fungicides followed by the alternative two-oil combined extractions then pure extracted oils. MIC was at 50, 25 and 12.5 µg/disc for pure oils, two-oil combinations and four-oil mixture, respectively. Achieved values of AI were found variable. CONCLUSION: Using of natural products like plant-derived EOs instead of chemotherapy on pathogens can be regarded as an environmental safety mode of diseases control.

In vitro antifungal activity of naftifine hydrochloride against dermatophytes.

The incidence of superficial dermatophytoses is high in developed countries, and there remains a need for effective topical antifungals. In this study, we evaluated the in vitro antifungal activity of naftifine hydrochloride, the active ingredient in naftifine hydrochloride cream and gel 1% and 2%, against dermatophytes. The MICs and minimum fungicidal concentrations (MFCs) of naftifine hydrochloride against 350 clinical strains, including Trichophyton rubrum, T. mentagrophytes, T. tonsurans, Epidermophyton floccosum, and Microsporum canis, were determined using the CLSI methodology. Subsets from this test panel were subsequently tested in a time-kill assay at 0.125×, 0.25×, 0.5×, and 1× the MFC for each isolate. CFU counts were performed over a period of 48 h of incubation. Additionally, in order to determine the potential for resistance development, six strains were subjected to 15 serial passages in concentrations higher than the MIC for each strain. MICs were determined following each passage. The MIC range against the dermatophyte isolates tested was 0.015 to 1.0 µg/ml, with naftifine hydrochloride being fungicidal against 85% of the Trichophyton species. The time-kill assay showed dose-dependent activity, with the greatest reduction in the numbers of CFU corresponding to the highest drug concentration. There was no increase in MIC for any strains following repeated exposure to naftifine hydrochloride. Naftifine hydrochloride demonstrated potent activity against all dermatophytes tested, and none of the isolates within this test panel demonstrated the potential for the development of resistance. Thus, future clinical studies of naftifine hydrochloride against dermatophytes may be warranted for the treatment of superficial dermatophytoses.

In vitro antifungal activity of micafungin and caspofungin against dermatophytes isolated from China.

AIMS: The aims of this study are to investigate the in vitro activities of micafungin and caspofungin that are two new echinocandin antifungal drugs against clinically isolated dermatophytes in China and to define MEC (minimal effective concentration) as the reading endpoints of this study in accordance with (Clinical and laboratory Standards Institute) CLSI M38-A2 reference. METHODS: Minimal effective concentrations (MECs) of micafungin and caspofungin for 82 dermatophyte strains were determined according to CLSI (formerly NCCLS) M38-A2 broth microdilution methods. RESULTS: (1) The MEC(90s) of micafungin for Trichophyton violaceum and Trichophyton tonsurans were 0.25 µg/mL, and for Microsporum canis and Trichophyton verrucosum were 0.06 µg/mL. The MEC(90s) for Trichophyton rubrum, Trichophyton mentagrophytes, Microsporum gypseum and Epidermophyton floccosum were 0.03 µg/mL. (2) The MEC(90s) of caspofungin for T. rubrum, T. violaceum and T. tonsurans were 1 µg/mL, and for T. mentagrophytes, M. canis, M. gypseum, E. floccosum and T. verrucosum were 0.5 µg/mL. (3) Compared with caspofungin, micafungin demonstrated lower MEC value to dermatophytes (P < 0.05). CONCLUSIONS: Micafungin has stronger in vitro antifungal activity than caspofungin.

Inhibition of dermatophytes by the antimicrobial peptides human ß-defensin-2, ribonuclease 7 and psoriasin.

Previous studies have described some antibacterial effects of antimicrobial peptides (AMPs) expressed in human skin, but little is known about their possible activity against dermatophytes. Therefore we have tested the effects of human ß-defensin 2 (hBD-2), ribonuclease 7 (RNase 7) and psoriasin on the in vitro growth of four dermatophyte species. Germinating conidia of Trichophyton rubrum, T. mentagrophytes, Microsporum canis and Epidermophyton floccosum were exposed in vitro to hBD-2, RNase 7, psoriasin and fluconazole. Subsequent fungal growth was measured photometrically over 168 hours. All AMPs significantly inhibited fungal growth, with the degree of inhibition dependent on the dermatophyte species and the specific AMP. E. floccosum was found to be the most susceptible species in that it was markedly suppressed by all AMPs, whereas M. canis was inhibited only by psoriasin. Overall, psoriasin was the most effective AMP and had even stronger inhibitory effects on some dermatophytes than fluconazole. Our findings show that AMPs expressed in human skin can, in principal, inhibit the growth of dermatophytes in vitro. Therefore the question whether AMPs are relevant for human protection against tineas is justified and should be addressed by investigating their role in vivo.

[Study on antifungal susceptibility of different extract of Dryopteris fragrans].

OBJECTIVE: To examine the antifungal effect of different extract of Dryopteris fragrans (L.) Schott. in vitro, and screen the effective fraction from those extracts. METHODS: Separated the Dryopteris fragrans extract and got four parts by refluxing extraction,and determined the contents of total phloroglucinol. Disc agar diffusion method and solid agar dilution method were used to determine inhibitory effect. Minimum inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) of different parts of Dryopteris fragrans extract against four strains of common clinical dermatophytes were investigated. RESULTS: The data showed that the contents sequence of total phloroglucinol was in the following order: 95% -ethanol extract > water extract > diethyl ether extract > petroleum ether extract, and the antimicrobial activities against the four dermatophytes were as following order: 95% -ethanol extract > water extract > di-ethyl ether extract > petroleum ether extract. CONCLUSION: The contents of total phloroglucinol in 95% -ethanol extract of Dryopteris fragrans is the highest, and the antifungal activity against dermatophytes in vitro is the strongest. The effective fraction of Dryopteris fragrans is the 95%-ethanol extract.

Efficacy of antifungal agents against fungal spores: An in vitro study using microplate laser nephelometry and an artificially infected 3D skin model.

Dermal fungal infections seem to have increased over recent years. There is further a shift from anthropophilic dermatophytes to a growing prevalence of zoophilic species and the emergence of resistant strains. New antifungals are needed to combat these fungi and their resting spores. This study aimed to investigate the sporicidal effects of sertaconazole nitrate using microplate laser nephelometry against the microconidia of Trichophyton, chlamydospores of Epidermophyton, blastospores of Candida, and conidia of the mold Scopulariopsis brevicaulis. The results obtained were compared with those from ciclopirox olamine and terbinafine. The sporicidal activity was further determined using infected three-dimensional full skin models to determine the antifungal effects in the presence of human cells. Sertaconazole nitrate inhibited the growth of dermatophytes, molds, and yeasts. Ciclopirox olamine also had good antifungal activity, although higher concentrations were needed compared to sertaconazole nitrate. Terbinafine was highly effective against most dermatophytes, but higher concentrations were required to kill the resistant strain Trichophyton indotineae. Sertaconazole nitrate, ciclopirox olamine, and terbinafine had no negative effects on full skin models. Sertaconazole nitrate reduced the growth of fungal and yeast spores over 72 h. Ciclopirox olamine and terbinafine also inhibited the growth of dermatophytes and molds but had significantly lower effects on the yeast. Sertaconazole nitrate might have advantages over the commonly used antifungals ciclopirox olamine and terbinafine in combating resting spores, which persist in the tissues, and thus in the therapy of recurring dermatomycoses.

Sertaconazole nitrate shows fungicidal and fungistatic activities against Trichophyton rubrum, Trichophyton mentagrophytes, and Epidermophyton floccosum, causative agents of tinea pedis.

The fungistatic and fungicidal activities of sertaconazole against dermatophytes were evaluated by testing 150 clinical isolates of causative agents of tinea pedis, Trichophyton rubrum, Trichophyton mentagrophytes, and Epidermophyton floccosum. The overall geometric means for fungistatic and fungicidal activities of sertaconazole against these isolates were 0.26 and 2.26 µg/ml, respectively, although values were higher for T. mentagrophytes than for the others. This is the first comprehensive demonstration of the fungicidal activity of sertaconazole against dermatophytes.

Activity of TDT 067 (terbinafine in Transfersome) against agents of onychomycosis, as determined by minimum inhibitory and fungicidal concentrations.

TDT 067 is a novel carrier-based dosage form (liquid spray) of 15 mg/ml of terbinafine in Transfersome that has been developed to deliver terbinafine to the nail bed to treat onychomycosis. In this study, we report the in vitro activities of TDT 067 against dermatophytes, compared with those of the Transfersome vehicle, naked terbinafine, and commercially available terbinafine (1%) spray. The MICs of TDT 067 and comparators against 25 clinical strains each of Trichophyton rubrum, T. mentagrophytes, and Epidermophyton floccosum were determined according to the CLSI M38-A2 susceptibility method (2008). Minimum fungicidal concentrations (MFCs) were determined by subculturing visibly clear wells from the MIC microtiter plates. TDT 067 demonstrated potent activity against the dermatophyte strains tested, with an MIC range of 0.00003 to 0.015 µg/ml. Overall, TDT 067 MIC(50) values (defined as the lowest concentrations to inhibit 50% of the strains tested) were 8-fold and 60-fold lower than those of naked terbinafine and terbinafine spray, respectively. The Transfersome vehicle showed minimal inhibitory activity. TDT 067 demonstrated lower MFC values for T. rubrum and E. floccosum than naked terbinafine and terbinafine spray. TDT 067 has more potent antifungal activity against dermatophytes that cause nail infection than conventional terbinafine preparations. The Transfersome vehicle appears to potentiate the antifungal activity of terbinafine. Clinical investigation of TDT 067 for the topical treatment of onychomycosis is warranted.

Toxic effect of heavy metals on dermatophytes.

For determining the toxic effect of heavy metals on dermatophytes, eight heavy metals were tested using colony diameter method. Cadmium showed high toxicity effects on isolated fungi at minimal inhibitory concentration of 27 µg ml(-1) for Trichophyton mentagrophytes and of 20 µg ml(-1) for Epidermophyton floccosum, while iron enhanced dermatophytic growth. Other heavy metals revealed variable effect on isolated fungi. Susceptibility of E. floccosum to the activity of tested metals was greater than those of T. mentagrophytes. In conclusion, cadmium and silver are regarded to be the effective metals to prevent the development of two isolated species of dermatophytes. Growth of fungi in the presence of iron was greater than control.

Comparison of the in vitro activity of terbinafine and lanoconazole against dermatophytes.

The objective of this study was to compare the antifungal activity of terbinafine (TERB) with that of lanoconazole (LAN). Test isolates, which were clinical isolates of Japanese origin, included 10 strains each of Trichophyton rubrum, T. mentagrophytes and Epidermophyton floccosum. The minimum inhibitory concentration (MIC) of TERB and LAN against each dermatophyte isolate was determined according to the Clinical and Laboratory Standards Institute microbroth methodology, M38-A2. Minimum fungicidal concentrations were determined by subculturing the contents of each visibly clear well from the MIC assay for colony count. All LAN MICs were