Potential Cancer Chemopreventive in Vitro Activities of Monomeric Xanthone Derivatives from the Marine Algicolous Fungus Monodictys putredinis

Abstract

Investigation of the fungal strain Monodictys putredinis isolated from the inner tissue of a marine green alga led to the isolation of four new monomeric xanthones and a benzophenone. All structures were elucidated by extensive spectroscopic measurements. The relative configuration of compound 1 was determined by X-ray crystal structure analysis, while for 2 and 3 configurations were confirmed by NOE experiments. Absolute configurations for compounds 1-3 were deduced by comparing experimental circular dichroism spectroscopic data with those calculated employing quantum-chemical time-dependent density functional theory (TDDFT). The compounds were examined for their cancer chemopreventive potential. Xanthone 2 was shown to inhibit cytochrome P450 1A activity with an IC50 value of 3.0 microM. Compounds 2 and 3 displayed moderate activity as inducers of NAD(P)H:quinone reductase (QR) in cultured mouse Hepa 1c1c7 cells, with CD values (concentration required to double the specific activity of QR) of 12.0 and 12.8 microM, respectively. Compound 3 showed weak inhibition of aromatase activity.

Oxepinochromenones, Furochromenone, and their Putative Precursors from the Endolichenic Fungus Coniochaeta sp.

“…A NOESY correlation of H-7 with H 3 -13 suggested a cis relationship for the 7,8-diol moiety, implying that its absolute configuration could be assigned using the in situ dimolybdenum CD method developed by Frelek. 24,25 Upon addition of dimolybdenum tetraacteate [Mo 2 (OAc) 4 ] to a solution of 3 in DMSO, a metal complex was generated as an auxiliary chromophore. Since the contribution from the inherent CD resulting from the C-9 and C-12 carbonyls was subtracted to give the induced CD of the complex, the observed sign of the Cotton effect in the induced spectrum originates solely from the chirality of the Vic-diol moiety expressed by the sign of the O-C-C-O torsion angle.…”

“…The absolute configuration of C-8 was assigned via the CD data of the [Rh 2 (OCOCF 3 ) 4 ] complex, 26 with the inherent contribution subtracted. Upon addition of [Rh 2 (OCOCF 3 ) 4 ] to a solution of 5 in CH 2 Cl 2 , a metal complex was generated as an auxiliary chromophore. It has been demonstrated that the sign of the E band (at ca.…”

“…HPLC grade DMSO was dried with 4 Å molecular sieves. According to a published procedure, 30 a mixture of 1:1.3 diol-Mo 2 (OAc) 4 for 3 was subjected to CD measurements at a concentration of 1.0 mg/mL. The first CD spectrum was recorded immediately after mixing, and its time evolution was monitored until stationary (about 10 min after mixing).…”

Endophytic fungi associated withTaxus fuana(West Himalayan Yew) of Pakistan: potential bio-resources for cancer chemopreventive agents

“…Fungal metabolites with azol rings act as inhibitors of different P450 enzymes including aromatase (Zhang et al 2002). Various other fungal metabolites, such as monomeric xanthones, benzophenone, depsidones and diaryl ethers, also inhibit P450 enzymes (Krick et al 2007;Chomcheon et al 2009;Sureram et al 2012). In this work, isolates NFW3 and NFW9 showed aromatase inhibition of 73.3 and 76.4% with IC 50 values of 12.2 and 10.5 lg/mL, respectively.…”

“…Some compounds suppressing superoxide generation and showing antioxidant activity are associated with cancer chemoprevention (Krick et al 2007). To determine the free radical scavenging potential of our samples, the DPPH assay was performed.…”