ascorbic-acid and xanthohumol

Xanthohumol (1) and xanthohumol D (2) were isolated from spent hops. Isoxanthohumol (3) was obtained from xanthohumol by isomerisation in alkaline solution. Six metabolites were obtained as a result of transformation of xanthohumol (1) by selected fungal cultures. Their structures were established on the basis of their spectral data. One of them: 2″-(2'''-hydroxyisopropyl)-dihydrofurano-[4″,5″:3',4']-4',2-dihydroxy-6'-methoxy-α,β-dihydrochalcone (6) has not been previously reported in the literature. The antioxidant properties of hops flavonoids and xanthohumol derivatives were investigated using the 2,2'-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging method. The effects of these compounds on proliferation of MCF-7, PC-3 and HT-29 human cancer cell lines were determined by the SRB assay. With the exception of one metabolite, all tested compounds showed antiproliferative activity against the tested human cancer lines. α,β-Dihydroxanthohumol (4), obtained through the biotransformation of xanthohumol, showed higher antiproliferative activity against MCF-7 human breast carcinoma cell line than cisplatin, a widely used anticancer therapeutic agent, and a comparably high activity against PC-3 human prostate cancer cell line.

Topics: Antineoplastic Agents; Antioxidants; Biotransformation; Cell Line, Tumor; Cell Proliferation; Flavonoids; Fungi; Humans; Humulus; Neoplasms; Propiophenones

The biotransformation of xanthohumol (1), a prenylated chalcone isolated from hops by selected fungi, was investigated. Microbial regioselective glycosylation at the C-4' position led to xanthohumol 4'-O-β-d-glucopyranoside (2) and xanthohumol 4'-O-β-d-(4'''-O-methyl)-glucopyranoside (3). The subsequent cyclization of 2 resulted in isoxanthohumol 7-O-β-glucopyranoside (4). The structures of the products were identified based on spectroscopic methods. The biological activity of isolated metabolites has been evaluated. Compared to xanthohumol (1), metabolite 2 is a better 2,2'-diphenyl-1-picrylhydrazyl (DPPH) radical scavenger, while 2 and 3 have stronger antiproliferative activity against the human HT-29 colon cancer cell line.

Topics: Antineoplastic Agents; Antioxidants; Biotransformation; Cell Proliferation; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Flavonoids; Glycosides; Glycosylation; HT29 Cells; Humans; Molecular Structure; Propiophenones; Structure-Activity Relationship