Estrogenic effects of fusarielins in human breast cancer cell lines

New Zosteropenillines and Pallidopenillines from the Seagrass-Derived Fungus Penicillium yezoense KMM 4679

Ten new decalin polyketides, zosteropenilline M (1), 11-epi-8-hydroxyzosteropenilline M (2), zosteropenilline N (3), 8-hydroxyzosteropenilline G (4), zosteropenilline O (5), zosteropenilline P (6), zosteropenilline Q (7), 13-dehydroxypallidopenilline A (8), zosteropenilline R (9) and zosteropenilline S (10), together with known zosteropenillines G (11) and J (12), pallidopenilline A (13) and 1-acetylpallidopenilline A (14), were isolated from the ethyl acetate extract of the fungus Penicillium yezoense KMM 4679 associated with the seagrass Zostera marina. The structures of isolated compounds were established based on spectroscopic methods. The absolute configurations of zosteropenilline Q (7) and zosteropenilline S (10) were determined using a combination of the modified Mosher's method and ROESY data. The absolute configurations of zosteropenilline M (1) and zosteropenilline N (3) were determined using time-dependent density functional theory (TD-DFT) calculations of the ECD spectra. A biogenetic pathway for compounds 1-14 is proposed. The antimicrobial, cytotoxic and cytoprotective activities of the isolated compounds were also studied. The significant cytoprotective effects of the new zosteropenilline M and zosteropenillines O and R were found in a cobalt chloride (II) mimic in in vitro hypoxia in HEK-293 cells. 1-Acetylpallidopenilline A (14) exhibited high inhibition of human breast cancer MCF-7 cell colony formation with IC50 of 0.66 µM and its anticancer effect was reduced when MCF-7 cells were pretreated with 4-hydroxitamoxifen. Thus, we propose 1-acetylpallidopenilline A as a new xenoestrogen with significant activity against breast cancer.

Two New Cytotoxic Decalin Derivatives from Marine-Derived Fungus Talaromyces sp

Two new decalin derivatives named fusarielins O (1) and P (2), together with seven known compounds (3-9) were isolated from the crude extract of the marine-derived fungus Talaromyces sp. The planar structures of the new compounds were elucidated by comprehensive spectroscopic analyses of NMR and HR-ESI-MS. The absolute configuration of 1 was assigned by Snatzke's method and comparison of experimental and calculated electronic circular dichroism (ECD) spectra. Compounds 1-9 were evaluated for their cytotoxic activities against three tumor cell lines and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities.

Production and Selectivity of Key Fusarubins from Fusarium solani due to Media Composition

Natural products display a large structural variation and different uses within a broad spectrum of industries. In this study, we investigate the influence of carbohydrates and nitrogen sources on the production and selectivity of production of four different polyketides produced by Fusarium solani, fusarubin, javanicin, bostrycoidin and anhydrofusarubin. We introduce four different carbohydrates and two types of nitrogen sources. Hereafter, a full factorial design was applied using combinations of three levels of sucrose and three levels of the two types of nitrogen. Each combination displayed different selectivity and production yields for all the compounds of interest. Response surface design was utilized to investigate possible maximum yields for the surrounding combinations of media. It was also shown that the maximum yields were not always the ones illustrating high selectivity, which is an important factor for making purification steps easier. We visualized the production over time for one of the media types, illustrating high yields and selectivity.

Characterization of Eight Novel Spiroleptosphols from Fusarium avenaceum

Chemical analyses of Fusarium avenaceum grown on banana medium resulted in eight novel spiroleptosphols, T1, T2 and U-Z (1-8). The structures were elucidated by a combination of high-resolution mass spectrometric data and 1- and 2-D NMR experiments. The relative stereochemistry was assigned by ¹H coupling and NOESY/ROESY experiments. Absolute stereochemistry established for 7 by vibrational circular dichroism was found analogous to that of the putative polyketide spiroleptosphol from Leptosphaeria doliolum.

Enhancing the Production of the Fungal Pigment Aurofusarin in Fusarium graminearum

There is an increasing demand for products from natural sources, which includes a growing market for naturally-produced colorants. Filamentous fungi produce a vast number of chemically diverse pigments and are therefore explored as an easily accessible source. In this study we examine the positive regulatory effect of the transcription factor AurR1 on the aurofusarin gene cluster in Fusarium graminearum. Proteomic analyses showed that overexpression of AurR1 resulted in a significant increase of five of the eleven proteins belonging to the aurofusarin biosynthetic pathway. Further, the production of aurofusarin was increased more than threefold in the overexpression mutant compared to the wild type, reaching levels of 270 mg/L. In addition to biosynthesis of aurofusarin, several yet undescribed putative naphthoquinone/anthraquinone analogue compounds were observed in the overexpression mutant. Our results suggest that it is possible to enhance the aurofusarin production through genetic engineering.

Structure elucidation of new fusarielins from Fusarium sp. and their antimicrobial activity

Three new fusarielins, 3-epi-fusarielin H (1), 3-O-methyl-fusarielin H (2), and 3-O-methyl-epi-fusarielin H (3), were isolated from the fungus Fusarium sp. together with the known analogues, fusarielins F (4) and G (5). The structures of these compounds were elucidated by analysis of their ESI-HRTOFMS, 1D and 2D NMR spectroscopic data. The new compounds exhibited weak antibacterial effect against Staphylococcus aureus.

Estrogen receptor agonists/antagonists in breast cancer therapy: A critical review

Estrogens display intriguing tissue selective action that is of great biomedical importance in the development of optimal therapeutics for the prevention and treatment of breast cancer. There are also strong evidences to show that both endogenous and exogenous estrogens are involved in the pathogenesis of breast cancer. Tamoxifen has been the only drug of choice for more than 30years to treat patients with estrogen related (ER) positive breast tumors. There is a need therefore, for identifying newer, potential and novel candidates for breast cancer. Keeping this in view, the present review focuses on selective estrogen receptor modulators and estrogen antagonists such as sulfatase and aromatase inhibitors involved in breast cancer therapy. A succinct and critical overview of the structure of estrogen receptors, their signaling and involvement in breast carcinogenesis are herein described.

Subglutinol A, an immunosuppressive α-pyrone diterpenoid from Fusarium subglutinans, acts as an estrogen receptor antagonist

Subglutinol A is an immunosuppressive α-pyrone diterpenoid isolated from Fusarium subglutinans that exhibits osteogenic activity. Several non-steroid mycotoxins isolated from various strains of Fusarium fungi exhibit female steroid hormone activities. In this study, we characterized the estrogenic activity of subglutinol A (1). Subglutinol A blocked the 17β-estradiol-induced activation of reporter plasmids and endogenous estrogen-responsive target genes in a dose-dependent manner and efficiently destabilized ER proteins as shown using the estrogen receptor antagonist ICI 182,780. Subglutinol A also displaced the specific binding of [(3)H]17β-estradiol from ER in MCF-7 whole-cell ligand binding assays. These data demonstrate the potential of subglutinol A as an ER antagonist though its competition with 17β-estradiol for direct ER association.

Deficient glutathione in the pathophysiology of mycotoxin-related illness

Evidence for the role of oxidative stress in the pathophysiology of mycotoxin-related illness is increasing. The glutathione antioxidant and detoxification systems play a major role in the antioxidant function of cells. Exposure to mycotoxins in humans requires the production of glutathione on an “as needed” basis. Research suggests that mycotoxins can decrease the formation of glutathione due to decreased gene expression of the enzymes needed to form glutathione. Mycotoxin-related compromise of glutathione production can result in an excess of oxidative stress that leads to tissue damage and systemic illness. The review discusses the mechanisms by which mycotoxin-related deficiency of glutathione may lead to both acute and chronic illnesses.