scholarly journals Antifungal Activity of Gentamicin B1 against Systemic Plant Mycoses

Molecules ◽  
2020 ◽  
Vol 25 (10) ◽  
pp. 2401
Author(s):  
Gaspar Banfalvi

Background: Gentamicin is a broad-spectrum aminoglycoside antibiotic produced by Micromonospora purpurea bacteria, effective against Gram-negative bacterial infections. Major fractions of the gentamicin complex (C1, C1a, C2, C2a) possess weak antifungal activity and one of the minor components (A, A1–A4, B, B1, X), gentamicin B1 was found to be a strong antifungal agent. Methods: This work uses in vitro and in vivo dilution methods to compare the antifusarial, antiaspergillic and anticryptococcal effects of gentamicin derivatives and structurally-related congeners. Results: The in vitro antifusarial activity of gentamicin B1 (minimum inhibitory concentration (MIC) 0.4 μg/mL) and structurally-related compounds (MIC 0.8–12.5 μg/mL) suggests that the purpuroseamine ring substituents are responsible for the specific antimycotic effect. The functional groups of the garoseamine and 2-deoxystreptamine rings of gentamicin derivatives are identical in gentamicin compounds and are unlikely to exert a significant antifungal effect. Among soil dermatophytes, Microsporum gypseum was more susceptible to gentamicin B1 (MIC 3.1 µg/mL) than Trichophyton gypseum (MIC 25 µg/mL). The in vitro antifungal effect of gentamicin B1 against plant pathogenic fungi was comparable to primary antifungal agents. Conclusion: Gentamicin is already in medical use. In vitro and preclinical in vivo synergisms of gentamicin B1 with amphotericin B suggest immediate clinical trials starting with subtoxic doses.

2018 ◽  
Vol 5 (suppl_1) ◽  
pp. S411-S412
Author(s):  
Edward P Garvey ◽  
Andrew Sharp ◽  
Peter Warn ◽  
Christopher M Yates ◽  
Robert J Schotzinger

Abstract Background VT-1598 is a novel fungal CYP51 inhibitor with potent in vitro activity against yeast, mold, and endemic pathogenic fungi (Wiederhold, JAC, 2017). Its tetrazole-based rational drug design imparts much greater selectivity vs. human CYPs (Yates, BMCL, 2017), which could reduce human CYP-related side effects and DDIs. We report here VT-1598’s in vivo activity in an invasive aspergillosis (IA) model. Methods MIC was determined as outlined in CLSI M38-A2. Plasma PK was measured after 4 days of oral doses in neutropenic ICR mice without fungal inoculation. In vivo antifungal activity was determined in a tail-vein IA model in neutropenic mice inoculated with A. fumigatus (AF) ATCC 204305 (N = 10 per dose). Two separate studies were conducted, with oral VT-1598 treatment starting either 48 hours prior (prophylaxis) or 5 hours postinoculation (delayed), with 4 days of postinoculation dosing, and kidney fungal burden measured 1 day post last dose by both CFU and qPCR. Drug control was 10 mg/kg AmBisome i.v. Results The MIC for VT-1598 against AF 204305 was 0.25 μg/mL. The plasma PK of VT-1598 was linearly proportional between the 5 and 40 mg/kg once-daily doses, with AUCs of 155 and 1,033 μg h/mL for the two doses, respectively. VT-1598 was similarly effective in reducing fungal burden when given in delayed treatment compared with prophylaxis, and both studies demonstrated a full dose–response (i.e., no to full reduction of fungal burden). When comparing fungal burdens of each dose group to the fungal burden at the start of treatment, the dose of VT-1598 to achieve fungal stasis ranged from 20.5 to 25.9 mg/kg and to achieve a 1-log10 fungal kill ranged from 30.9 to 50.5 mg/kg. Using the previously measured mouse plasma binding (>99.9%), the free AUC /MIC values for stasis and 1-log10 kill ranged from 2.1–2.7 and 3.2–5.2, respectively. These values are within the range of 1–11 that have been reported for posaconazole and isavuconazole (Lepak, AAC, 2013). Conclusion VT-1598 had potent antifungal activity in a murine model of IA. The PK/PD relationship was the same as clinically used mold-active CYP51 agents, suggesting that it could have similar clinical efficacy. If correct, the tetrazole-based greater selectivity may significantly differentiate VT-1598 from current IA therapies. Disclosures E. P. Garvey, Viamet Pharmaceuticals, Inc.: Employee, Salary. A. Sharp, Evotec (UK) Ltd.: Employee, Salary. P. Warn, Evotec (UK) Ltd.: Employee, Salary. C. M. Yates, Viamet Pharmaceuticals, Inc.: Employee, Salary. R. J. Schotzinger, Viamet Pharmaceuticals, Inc.: Board Member and Employee, Salary.


2019 ◽  
Vol 14 (18) ◽  
pp. 1545-1557 ◽  
Author(s):  
Ying Gong ◽  
Siwen Li ◽  
Weixin Wang ◽  
Yiman Li ◽  
Wenli Ma ◽  
...  

Aim: To evaluate whether chelerythrine (CHT) exhibited antifungal activity against Candida albicans in vitro and in vivo and to explore the underlying mechanisms. Materials & methods: Broth microdilution assay and Galleria mellonella model were used to evaluate the antifungal effect in vitro and in vivo, respectively. Mechanism studies were investigated by morphogenesis observation, Fluo-3/AM, DCFH-DA and rhodamine6G assay, respectively. Results: CHT exhibited antifungal activity against C. albicans and preformed biofilms with minimum inhibitory concentrations ranged from 2 to 16 μg/ml. Besides, CHT protected G. mellonella larvae infected by C. albicans. Mechanisms studies revealed that CHT inhibited hyphal growth, increased intracellular calcium concentration, induced accumulation of reactive oxygen species and inhibited drug transporter activity. Conclusion: CHT exhibited antifungal activity against C. albicans.


Dose-Response ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 155932582090485 ◽  
Author(s):  
Syed Ali Raza Naqvi ◽  
Syed Muhammad Ali Shah ◽  
Laiba Kanwal ◽  
Muhammad Saeed ◽  
Atta-ul-Haq ◽  
...  

Multidrug resistance has increased globally in the communities. Bacterial infections associated with health care have weakened the existing antimicrobial therapy and demand the search for alternative therapies. In the present investigation, the medicinal plant Pulicaria gnaphalodes from Quetta, Pakistan, has been screened for antimicrobial potential. In vitro antimicrobial efficacy of P gnaphalodes extracts (methanol and ethanol) was quantitatively evaluated on the basis of zone of inhibition against different bacteria and minimum inhibitory concentration (MIC). In vivo, antihypercholesterolemic activity is determined in different rat groups. The results of the study indicated that the ethanol extract of P gnaphalodes showed maximum zone of inhibition for Bacillus subtilis of 12.1 ± 1.1 mm from all others. The methanol extract showed maximum zone of inhibition for Staphylococcus aureus of 11.9 ± 1.0 mm and rifampicin showed maximum zone of inhibition of 23.1 ± 0.9 mm. The results of ethanol and methanol extract of P gnaphalodes against different bacteria revealed that this plant has greater antimicrobial activity. However, the plant extract shows nonsignificant antihypercholesterolemic activity. The extract of this plant can be utilized as medicine to inhibit several infections caused by some bacterial pathogens found in human body.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Daisy Savarirajan ◽  
V. M. Ramesh ◽  
Arunachalam Muthaiyan

AbstractFungal infections are among the most difficult diseases to manage in humans. Eukaryotic fungal pathogens share many similarities with their host cells, which impairs the development of antifungal compounds. Therefore, it is desirable to harness the pharmaceutical potential of medicinal plants for antifungal drug discovery. In this study, the antifungal activity of sixteen plant extracts was investigated against selected dermatophytic fungi. Of the sixteen plants, the cladode (leaf) of Asparagus racemosus, and seed extract of Cassia occidentalis showed antifungal activity against Microsporum gypseum, Microsporum nanum, Trichophyton mentagrophytes and Trichophyton terrestre. The plant antifungal compounds were located by direct bioassay against Cladosporium herbarum. IR and NMR spectrometry analyses of these compounds identified the presence of saponin (in A. racemosus) and hydroxy anthraquinone (in C. occidentalis) in these antifungal compounds. The antidermatophytic activity of plant anthraquinone and saponins with reports of little or no hemolytic activity, makes these compounds ideal for alternative antifungal therapy and warrants further in-depth investigation in vivo.


1993 ◽  
Vol 16 (11) ◽  
pp. 765-770 ◽  
Author(s):  
J.W. Costerton ◽  
A.E. Khoury ◽  
K.H. Ward ◽  
H. Anwar

Direct examination of medical devices that have been foci of chronic device-related bacterial infections has shown that the causative organisms grow predominantly in slime-enclosed biofilms. These adherent biofilms are inherently resistant to host defences (antibodies, phagocytes) and to conventional antibiotic therapy. Device-related infections can be prevented by careful cleaning and sterilization of the device, and by the avoidance of any manipulations that would allow the formation of even the most rudimentary biofilm prior to implantation. Once a device-related infection has become established, both the Minimum Inhibitory Concentration (MIC) and the Biofilm Eliminating Concentration (BEC) of the causative organism must be determined and therapeutic strategy must aim at the use of the MIC to control the acute phase caused by planktonic bacteria and of the BEC to eliminate the biofilm nidus of infection. The removal of the colonized device should be considered early in the course of treatment if the BEC cannot be delivered to the colonized device. We describe a new bioelectric technology presently in the in vitro stage of development which, if it can be reproduced in vivo, will be very effective in the prevention and control of device-related bacterial infections.


2022 ◽  
Vol 22 (1) ◽  
Author(s):  
Fang Yang ◽  
Yi Sun ◽  
Qiaoyun Lu

Abstract Background This study was aimed to determine the potency of Minocycline (MIN) and azoles, including itraconazole (ITR), voriconazole (VOR) and posaconazole (POS) against Scedosporium and Lomentospora species. Results This study revealed that MIN exhibited no significant antifungal activity against any of the tested strains, whereas in vitro combination of MIN with ITR, VOR or POS showed satisfactory synergistic effects against 8 (80%), 1 (10%), and 9 (90%) strains, respectively. Moreover, combined use of MIN with azoles decreased the minimum inhibitory concentration (MIC) range from 5.33–16 μg/ml to 1–16 μg/ml for ITR, from 0.42–16 μg/ml to 0.21–16 μg/ml for VOR, and from 1.33–16 μg/ml to 0.33–16 μg/ml for POS. Meanwhile, no antagonistic interactions were observed between the above combinations. The G. mellonella infection model demonstrated the in vivo synergistic antifungal effect of MIN and azoles. Conclusions The present study demonstrated that combinations between MIN and azoles lead to synergistic antimicrobial effects on Scedosporium and Lomentospora species, while showing a potential for overcoming and preventing azole resistance.


2018 ◽  
Vol 15 (1) ◽  
pp. 105-112 ◽  
Author(s):  
Phạm Đình Dũng ◽  
Nguyễn Tiến Thắng ◽  
Dương Hoa Xô ◽  
Lê Quang Luân

Chitosan was degraded by gamma rays irradiation method using 5% chitosan solution in 0.5% acetic acid with and without addition of 1% H2O2 for preparation of oligochitosan. The oligochitosan product with molecular weight (Mw) ~ 14.84 kDa prepared by radiation in combination with H2O2 treatment was used to fractionate into 5 different Mw fractions (F1: Mw < 1kDa, F2: Mw ~ 1-3 kDa, F3: Mw ~ 3-10 kDa, F4: Mw ~ 10-30 kDa và F5: Mw > 30 kDa) for testing its biological effects on red pepper plant (Capsicum frutescens L.). The obtained results showed that all separated fractions had the growth promotion effects on the increase of fresh biomass (9.9 - 56.3%) and chlorophyll content (20 - 92%) compared to those of the control one. In addition, the in vitro test of antifungal effect of separated fraction against C. capsici causing anthracnose on capsicum indicated that the fractions F3, F4 and F5 with Mw ≥ 3 kDa inhibited the growth of C. capsici colonies in a Potato Dextrose Agar (PDA) media at the concentration of 0.5%. While the the results from in vivo tests pointed out that the fractions F2, and F3 with the Mw in range of 1-10 kDa not only strongly stimulated the defense respose of tested plants to this pathogenic fungi causing anthracnose desease, but also the increased significantly gains of fruit biomass in 39 - 47%. Thus the oligochitosan fractions with Mw ~ 1-10 kDa are quite good products for both growth promotion efect as well as antifungal purpose for C. capsici causing anthracnose desease on capsicum.


Author(s):  
Abdelbagi Alfadil ◽  
Hamoud A. Alsamhan ◽  
Ahmed S. Ali ◽  
Huda M. Alkreathy ◽  
Mohammad W. Alrabia ◽  
...  

Aims: To explore the antifungal activity of 2,3-dimethylquinoxaline. Study Design: A preclinical study of a compound against 10 fungal species. Backgrounds: Severe fungal infections cause significant clinical problem and need more effort to search for new antifungals. Methodology: We evaluated the susceptibility of 2,3-dimethylquinoxaline in vitro against a wide range of pathogenic fungi, including six Candida species, two Aspergillus species, one Cryptococcus species, and one Trichophyton species. Also, we evaluated the susceptibility of 2,3-dimethylquinoxaline in vivo against oral candidiasis using a mice model. Results: The highest score of the minimum inhibitory concentration was 9 µg/ml against Cryptococcus neoformans. While, the lowest score was 1125 µg/ml against Candida tropicalis. The oral candidiasis in a mouse model was resolved using 2,3-dimethylquinoxaline 1% gel. Conclusion: The 2,3-Dimethyquinoxaline has interesting antifungal activity. Quinoxalines in general need to be further developed as a promising antifungal candidate.


ChemInform ◽  
2006 ◽  
Vol 37 (38) ◽  
Author(s):  
Ryuichi Kanasaki ◽  
Fumie Abe ◽  
Shigetada Furukawa ◽  
Koji Yoshikawa ◽  
Akihiko Fujie ◽  
...  

2021 ◽  
Vol 57 (1) ◽  
pp. 38-43
Author(s):  
Xiao-Long Zhao ◽  
Chun-Qing Li ◽  
Xiao-Mei Song ◽  
Shuang-Mei Yan ◽  
Du-Qiang Luo

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