Isothiocyanates as potential antifungal agents: a mini-review.

Cruciferous vegetables and mustard oil are rich in the glucosinolate group of molecules. Isothiocyanates are an important group of glucosinolate derivatives. These derivatives have various bioactive properties, including antioxidant, antibacterial, anticarcinogenic, antifungal, antiparasitic, herbicidal and antimutagenic activity. Previous studies indicate that regular intake of such vegetables may considerably reduce the incidence of various types of cancer. These studies have inspired studies where the bioactive agents of these plants have been isolated and explored for their therapeutic applications. The use of these bioactive compounds as antifungals could be a new therapeutic approach against human pathogenic fungi. Isothiocyanates have been studied for their antifungal activity and have the potential to be used for antifungal therapy.

Vegetables like cabbage, cauliflower and broccoli have a distinct flavor because of chemicals called glucosinolates. Whenever we cut and eat these vegetables, glucosinolates are broken down into isothiocyanates. Glucosinolates and isothiocyanates have health benefits because they stop the growth of bacteria, parasites and fungi that cause disease, such as Candida albicans. They may also prevent cancer, as regularly eating these vegetables has been shown to reduce the development of some types of cancer in humans. Investigation is needed to explore how glucosinolates and isothiocyanates could be used to treat fungal infections.

Anti-Candida properties of asaronaldehyde of Acorus gramineus rhizome and three structural isomers.

BACKGROUND: Asaronaldehyde (2, 4, 5-trimethoxybeznaldehyde) is an active component of Acorus gramineus rhizome. This study aims to evaluate the anti-Candida efficacy of asaronaldehyde and its three structural isomers, namely, 2, 3, 4-trimethoxybenzaldehyde, 3, 4, 5-trimethoxybenzaldehyde, and 2, 4, 6- trimethoxybenzaldehyde. METHODS: Susceptibility testing of test compounds was carried out using standard methodology (M27-A2) as per clinical and laboratory standards institute guidelines. Minimum fungicidal concentration (MFC) was determined as the lowest concentration of drug killing 99.9% of Candida cells. The effect on sterol profile was evaluated using the ergosterol quantitation method. Effects on morphogenesis, adhesion and biofilm formation in C. albicans were studied using germ-tube, adherence and biofilm formation assays respectively. Cytotoxicity of test compounds to human RBCs was determined by hemolysis assay. RESULTS: 2, 4, 6-Trimethoxybenzaldehyde exhibited significant anti-Candida activity (P = 0.0412). Minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) were established as 0.25 and 0.5 mg/mL, respectively. All of the test compounds showed significant inhibition of hyphal form transition in yeast at MIC/2 and MIC/4 values. 3, 4, 5-Trimethoxybenzaldehyde and 2, 4, 6-trimethoxybenzaldehyde inhibited adhesion and biofilms. A hemolytic assay of these compounds revealed that they were non-toxic at MIC values. Asaronaldehyde reduced sterol content. CONCLUSION: Asaronaldehyde and 2, 4, 6-trimethoxybenzaldehyde showed anti-Candida efficacy.

Sensitization of Candida albicans biofilms to various antifungal drugs by cyclosporine A.

BACKGROUND: Biofilms formed by Candida albicans are resistant towards most of the available antifungal drugs. Therefore, infections associated with Candida biofilms are considered as a threat to immunocompromised patients. Combinatorial drug therapy may be a good strategy to combat C. albicans biofilms. METHODS: Combinations of five antifungal drugs- fluconazole (FLC), voriconazole (VOR), caspofungin (CSP), amphotericin B (AmB) and nystatin (NYT) with cyclosporine A (CSA) were tested in vitro against planktonic and biofilm growth of C. albicans. Standard broth micro dilution method was used to study planktonic growth, while biofilms were studied in an in vitro biofilm model. A chequerboard format was used to determine fractional inhibitory concentration indices (FICI) of combination effects. Biofilm growth was analyzed using XTT-metabolic assay. RESULTS: MICs of various antifungal drugs for planktonic growth of C. albicans were lowered in combination with CSA by 2 to 16 fold. Activity against biofilm development with FIC indices of 0.26, 0.28, 0.31 and 0.25 indicated synergistic interactions between FLC-CSA, VOR-CSA, CSP-CSA and AmB-CSA, respectively. Increase in efficacy of the drugs FLC, VOR and CSP against mature biofilms after addition of 62.5 µg/ml of CSA was evident with FIC indices 0.06, 0.14 and 0.37, respectively. CONCLUSIONS: The combinations with CSA resulted in increased susceptibility of biofilms to antifungal drugs. Combination of antifungal drugs with CSA would be an effective prophylactic and therapeutic strategy against biofilm associated C. albicans infections.

Estrogen receptor-alpha binds p53 tumor suppressor protein directly and represses its function.

Estrogen receptor-alpha (ERalpha) promotes proliferation of breast cancer cells, whereas tumor suppressor protein p53 impedes proliferation of cells with genomic damage. Whether there is a direct link between these two antagonistic pathways has remained unclear. Here we report that ERalpha binds directly to p53 and represses its function. The activation function-2 (AF-2) domain of ERalpha and the C-terminal regulatory domain of p53 are necessary for the interaction. Knocking down p53 and ERalpha by small interfering RNA elicits opposite effects on p53-target gene expression and cell cycle progression. Remarkably, ionizing radiation that causes genomic damage disrupts the interaction between ERalpha and p53. Ionizing radiation together with ERalpha knock down results in additive effect on transcription of endogenous p53-target gene p21 (CDKN1) in human breast cancer cells. Our findings reveal a novel mechanism for regulating p53 and suggest that suppressing p53 function is an important component in the pro-proliferative role of ERalpha.