Epigenetic Manipulation Induced Production of Immunosuppressive Chromones and Cytochalasins from the Mangrove Endophytic Fungus Phomopsis asparagi DHS-48

Abstract

A mangrove endophytic fungus Phomopsis asparagi DHS-48 was found to be particularly productive with regard to the accumulation of substantial new compounds in our previous study. In order to explore its potential to produce more unobserved secondary metabolites, epigenetic manipulation was used on this fungus to activate cryptic or silent genes by using the histone deacetylase (HDAC) inhibitor sodium butyrate and the DNA methyltransferase (DNMT) inhibitor 5-azacytidine (5-Aza). Based on colony growth, dry biomass, HPLC, and 1H NMR analyses, the fungal chemical diversity profile was significantly changed compared with the control. Two new compounds, named phaseolorin J (1) and phomoparagin D (5), along with three known chromones (2–4) and six known cytochalasins (6–11), were isolated from the culture treated with sodium butyrate. Their structures, including their absolute configurations, were elucidated using a combination of detailed HRESIMS, NMR, and ECD and 13C NMR calculations. The immunosuppressive and cytotoxic activities of all isolated compounds were evaluated. Compounds 1 and 8 moderately inhibited the proliferation of ConA (concanavalin A)-induced T and LPS (lipopolysaccharide)-induced B murine spleen lymphocytes. Compound 5 exhibited significant in vitro cytotoxicity against the tested human cancer cell lines Hela and HepG2, which was comparative to the positive control adriamycin and fluorouracil. Our finding demonstrated that epigenetic manipulation should be an efficient strategy for the induction of new metabolites from mangrove endophytic fungi.

Metabolomics-Guided Discovery of New Dimeric Xanthones from Co-Cultures of Mangrove Endophytic Fungi Phomopsis asparagi DHS-48 and Phomopsis sp. DHS-11

“…All the isolated metabolites were evaluated for their cytotoxic and immunosuppressive activities according to the previously described methods [ 46 , 47 , 48 ]. Compounds 1 – 9 showed broad cytotoxic activity ( Table 2 ).…”

“…The cells were cultivated using RPMI-1640 culture medium. To assess cytotoxicity against HepG2 and HeLa cells, the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method, sourced from Sigma-Aldrich in St. Louis, Missouri, USA, was employed as described previously [ 47 ]. Furthermore, adriamycin (from Shanghai Macklin Biochemical Co., Ltd., with a purity of 99.8%) (Shanghai, China) and 5-fluorouracil (5-FU) (from Beijing Solarbio Science and Technology Co., Ltd., with a purity of 99.8%) (Beijing, China), both served as positive controls.…”

“…In continuing the search for structurally novel and biologically active natural products from mangrove endophytic fungi [ 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 ], a strain of Phomopsis asparagi DHS-48 isolated from the fresh root of Rhizophora mangle was found to be particularly productive with regard to the accumulation of a series of immunosuppressive chromones and cytochalasins [ 46 , 47 , 48 ]. With the goal of tapping the metabolic potential of this titled fungal strain, we initiated the co-culture fermentation process of well-characterized DHS-48 with other fungal strains.…”

“…Mar. Drugs 2024, 22, x FOR PEER REVIEW 3 of 20 cytochalasins [46][47][48]. With the goal of tapping the metabolic potential of this titled fungal strain, we initiated the co-culture fermentation process of well-characterized DHS-48 with other fungal strains.…”

Recent Advances in Search of Bioactive Secondary Metabolites from Fungi Triggered by Chemical Epigenetic Modifiers

“…Both phaseolorin J ( 386 ) and cytochalasin J2 ( 393 ) moderately inhibited the proliferation of concanavalin A-induced T and lipopolysaccharide-induced B murine spleen lymphocytes. Phomoparagin D ( 387 ) exhibited significant in vitro cytotoxicity against the tested human cancer cell lines HeLa and HepG2, which was comparative to the positive controls adriamycin and fluorouracil [ 131 ].…”