Oral tissue samples were studied using mid-IR fiber-optic attenuated total reflectance spectroscopy and other spectral techniques. The 1745 cm(-1) band, which is assigned to the ester group (C==O) vibration of triglycerides, is a reliable marker that is present in normal tissues but absent or a weak band in malignant oral tissues. Other bands such as C--H stretching bands and the amide bands are also helpful in distinguishing malignant tissues from normal tissues. Subtraction spectra confirmed the above conclusion. In addition, Raman spectroscopic measurements were in agreement with the results observed from FTIR spectra.

Chemical examination of a sponge (Cinachyrella sp.)-associated Emericella variecolor fungus resulted in the isolation of seven new polyketide derivatives, namely, varioxiranols A-G (1-7), and a new hybrid PKS-isoprenoid metabolite, 19-O-methyl-22-methoxypre-shamixanthone (8), together with nine known analogues. Their structures were elucidated on the basis of extensive spectroscopic analyses, including ECD effects, Mosher's method, X-ray diffraction, and chemical conversion for the determination of absolute configurations. Varioxiranols F and G were found for the first time to link a xanthone moiety with a benzyl alcohol via an ether bond, while the dioxolanone group of 5 is unusual in nature. A cell-based lipid-lowering assay revealed that pre-shamixanthone (12) exerted significant inhibition against lipid accumulation in HepG2 cells without cytotoxic effects, accompanying the potent reduction of total cholesterol and triglycerides. Real-time quantitative PCR indicated that pre-shamixanthone (12) mediated the reduction of lipid accumulation related to the down-regulation of the expression of the key lipogenic transcriptional factor SREBP-1c and its downstream genes encoding FAS and ACC.

Three novel asteltoxin-bearing dimers namely diasteltoxins A-C (1-3) along with asteltoxin were isolated from a mutated strain of a sponge-derived fungus Emericella variecolor XSA-07-2. Their structures were determined by extensive spectroscopic analyses including the computed electronic circular dichroism (ECD) data for the configurational assignment. The biogenetic formation of the dimers through [2 + 2] cycloaddition of asteltoxin was postulated. Diasteltoxins 1-3 exerted inhibitory effects against the tumor cell lines H1299 and MCF7 and exhibited significant inhibition against thioredoxin reductase (TrxR).

No abstract

Chemical examination of the sponge-associated fungus Emericella variecolor resulted in the isolation of four new lactones namely varioxiranols I-L(1-4)with different scaffolds, together with asteltoxin (5) and asteltoxin B (6). The structure elucidation of new compounds was accomplished by spectroscopic analysis, while the absolute configurations were determined by computed circular dichroism (ECD) and induced CD effects. Antitumor activities of these compounds were evaluated against different tumor cell lines, while the result indicated that the new compounds showed moderate cytotoxic activity against a panel of tumor cell lines.