Evaluation of antifungal activity of natural compounds on growth and aflatoxin B1 production of Aspergillus parasiticus and Aspergillus flavus.

BACKGROUND: Aspergillus species cause broad spectrum infections especially invasive lethal infections in immunocompromised patients. This study aimed to assess the antifungal activity of plants and compounds including Aloe vera, Thyme, carvacrol, and nano-encapsulation of carvacrol on the growth and production of aflatoxin B1 production by Aspergillus parasiticus and Aspergillus flavus. METHODS AND RESULTS: Minimum inhibitory concentrations of extracts Aloe vera, Thyme, carvacrol, and nanocarvacrol, and fluconazole as a control were determined according to Clinical and Laboratory Standards Institute by serial microdilution protocol. Then, the effect of inhibitory concentrations of these compounds on the aflatoxin B1 production level was evaluated by real-time PCR and high-performance liquid chromatography. Our results indicate that the Aspergillus parasiticus and Aspergillus flavusare sensitive to selected plants and compounds. CONCLUSION: Our findings showed that the compounds are appropriate alternative candidates against growth and production of aflatoxin of Aspergillus spp.

Antifungal effects of indolicidin-conjugated gold nanoparticles against fluconazole-resistant strains of Candida albicans isolated from patients with burn infection.

Background: Candida albicans as an opportunistic fungus is one of the most important causes of late-onset morbidity and mortality in patients with major burns and severely impaired immune system. In recent years, the emergence of resistance to opportunistic fungi and toxicity of antimicrobial drugs make it necessary to develop new drugs. Methods: In the present study, we investigated anticandidal effects of indolicidin, as a representative of host defense peptide, conjugated with gold nanoparticles in fluconazole-resistant clinical isolates of C. albicans. After characterizing the conjugation of indolicidin using biophysical methodologies, the cytotoxicity and hemolytic activity of the nanocomplex were examined. In addition, the expression level of ERG11, responsible for antifungal resistance, and the immunomodulatory effect of peptide-nanomaterial conjugates were assessed. Results: Our data indicated that the nanocomplex was nontoxic for the fibroblast cells and erythrocytes. Treatment with the nanocomplex significantly reduced the expression levels of the ERG11 gene in fluconazole-resistant C. albicans isolates and the iNOS gene in macrophages. Conclusion: The study data provides a chance to develop innovative therapies for the treatment of C. albicans burn infections. However, further investigation is required to examine the efficiency of the nanocomplex.

Design and synthesis of mucoadhesive nanogel containing farnesol: investigation of the effect on HWP1, SAP6 and Rim101 genes expression of Candida albicans in vitro.

The evolution of drug resistance of Candida species to conventional antifungal agents has been a major medical challenge worldwide; attempt to use the potential antifungal agents with appropriate therapy efficacy and minimum effects is considerably growing. This study was conducted to evaluate the use of nanogel as a nanocarrier for pharmaceutical application of farnesol. The nanogels were synthetized using alginate (AL) and chitosan (CS) polymers containing 300 µM of farnesol in the nano-range 42-70 nm size. In vitro release studies indicated that release of farnesol from CS and AL nanogels was as 58% and 37%, respectively. Chitosan nanogel showed more in inhibitory zone as compared to AL nanogel (9 mm). Also, cytotoxicity assay showed no significant difference between control and treatment groups (p>.05). Finally, the effect of nanogels on genes expression of HWP1, SAP6 and Rim101 in Candida albicans ATCC10231 was assessed using real-time polymerase chain reaction (PCR). Expression of HWP1 and SAP6 genes in C. albicans treated with CS nanogel was significantly decreased (p<.01). In general, the obtained finding showed that, CS nanogel contains farnesol with proper antifungal activity and as a new approach used in pharmaceutical applications against C. albicans; however, more studies in vitro and in vivo are needed in the future.

ALS1 and ALS3 gene expression and biofilm formation in Candida albicans isolated from vulvovaginal candidiasis.

BACKGROUND: A cluster of genes are involved in the pathogenesis and adhesion of Candida albicans to mucosa and epithelial cells in the vagina, the important of which is agglutinin-like sequence (ALS) genes. As well as vaginitis is a significant health problem among women, the antifungal resistance of Candida species is continually increasing. This cross-sectional study investigates the expression of ALS1 and ALS3 genes and biofilm formation in C. albicans isolate isolated from vaginitis. MATERIALS AND METHODS: Fifty-three recognized isolates of C. albicans were collected from women with recurrent vulvovaginal candidiasis in Iran, cultured on sabouraud dextrose agar, and then examined for gene expression. Total messenger RNA (mRNA) extracted from C. albicans isolates and complementary DNA synthesized using reverse transcriptase enzyme. Reverse transcription-polymerase chain reaction (RT-PCR) using specific primer was used to evaluate the expression of ALS1 and ALS3 through housekeeping (ACT1) genes. 3-(4,5-dimethyl-2-thiazyl)-2,5-diphenyl-2H-tetrazolium bromide assay was performed to assess adherence capacity and biofilm formation in the isolated. RESULTS: Forty isolates (75.8%) expressed ALS1 and 41 isolates (77.7%) expressed ALS3 gene. Moreover, 39 isolates (74%) were positive for both ALS1 and ALS3 mRNA by the RT-PCR. Adherence capability in isolates with ALS1 or ALS3 genes expression was greater than the control group (with any gene expression), besides, it was significantly for the most in the isolates that expressed both ALS1 and ALS3 genes simultaneously. CONCLUSION: The results attained indicated that there is an association between the expression of ALS1 and ALS3 genes and fluconazole resistance in C. albicans. A considerable percent of the isolates expressing the ALS1 and ALS3 genes may have contributed to their adherence to vagina and biofilm formation.

Fumonisin B1 contamination of cereals and risk of esophageal cancer in a high risk area in northeastern Iran.

INTRODUCTION: Fumonisin B1 (FB1) is a toxic and carcinogenic mycotoxin produced in cereals due to fungal infection. This study was conducted to determine FB1 contamination of rice and corn samples and its relationship with the rate of esophageal cancer (EC) in a high risk area in northeastern Iran. METHODS: In total, 66 rice and 66 corn samples were collected from 22 geographical subdivisions of Golestan province of Iran. The levels of FB1 were measured for each subdivision by thin layer and high pressure liquid chromatographies. The mean level of FB1 and the proportions of FB1 contaminated samples were compared between low and high EC-risk areas of the province. RESULTS: The mean of FB1 levels in corn and rice samples were 223.6 and 21.6 µg/g, respectively. FB1 contamination was found in 50% and 40.9% of corn and rice samples, respectively. FB1 level was significantly higher in rice samples obtained from high EC-risk area (43.8 µg/g) than those obtained from low risk area (8.93 µg/g) (p-value=0.01). The proportion of FB1 contaminated rice samples was also significantly greater in high (75%) than low (21.4%) EC-risk areas (p-value=0.02). CONCLUSION: We found high levels of FB1 contamination in corn and rice samples from Golestan province of Iran, with a significant positive relationship between FB1 contamination in rice and the risk of EC. Therefore, fumonisin contamination in commonly used staple foods, especially rice, may be considered as a potential risk factor for EC in this high risk region.