title: Silychristin: Skeletal Alterations and Biological Activities.
abstract: Silychristin is the second most abundant flavonolignan (after silybin) present in the fruits of Silybum marianum. A group of compounds containing silychristin (3) and its derivatives such as 2,3-dehydrosilychristin (4), 2,3-dehydroanhydrosilychristin (5), anhydrosilychristin (6), silyhermin (7), and isosilychristin (8) were studied. Physicochemical data of these compounds acquired at high resolution were compared. The absolute configuration of silyhermin (7) was proposed to be identical to silychristin A (3a) in ring D (10R,11S). The preparation of 2,3-dehydrosilychristin (4) was optimized. The Folin-Ciocalteau reduction and DPPH and ABTS radical scavenging assays revealed silychristin and its analogues to be powerful antioxidants, which were found to be more potent than silybin and 2,3-dehydrosilybin. Compounds 4-6 exhibited inhibition of microsomal lipoperoxidation (IC504-6 μM). Moreover, compounds 4-8 were found to be almost noncytotoxic for 10 human cell lines of different histogenetic origins. On the basis of these results, compounds 3-6 are likely responsible for most of the antioxidant properties of silymarin attributed traditionally to silybin (silibinin).
authors.affiliation: Institute of Microbiology, Laboratory of Biotransformation, Czech Academy of Sciences , Vídeňská 1083, CZ 142 20 Prague, Czech Republic.
authors.forename: David
authors.identifier: http://orcid.org/0000-0001-6726-9301
authors.initials: D
authors.lastname: Biedermann
authors.affiliation: Stolařská 601/4 , CZ 747 14 Ludgeřovice, Czech Republic.
authors.forename: Martin
authors.initials: M
authors.lastname: Buchta
authors.affiliation: Institute of Microbiology, Laboratory of Biotransformation, Czech Academy of Sciences , Vídeňská 1083, CZ 142 20 Prague, Czech Republic.
authors.forename: Veronika
authors.initials: V
authors.lastname: Holečková
authors.affiliation: CZ-OPENSCREEN: National Infrastructure for Chemical Biology, Institute of Molecular Genetics, Czech Academy of Sciences , Vídeňská 1083, CZ 142 20 Praha 4, Czech Republic.
authors.forename: David
authors.initials: D
authors.lastname: Sedlák
authors.affiliation: Institute of Microbiology, Laboratory of Biotransformation, Czech Academy of Sciences , Vídeňská 1083, CZ 142 20 Prague, Czech Republic.
authors.forename: Kateřina
authors.identifier: http://orcid.org/0000-0002-7714-5350
authors.initials: K
authors.lastname: Valentová
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences , Flemingovo náměstí 2, CZ 166 10 Prague, Czech Republic.
authors.forename: Josef
authors.identifier: http://orcid.org/0000-0002-3590-9009
authors.initials: J
authors.lastname: Cvačka
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences , Flemingovo náměstí 2, CZ 166 10 Prague, Czech Republic.
authors.forename: Lucie
authors.initials: L
authors.lastname: Bednárová
authors.affiliation: Institute of Microbiology, Laboratory of Biotransformation, Czech Academy of Sciences , Vídeňská 1083, CZ 142 20 Prague, Czech Republic.
authors.forename: Alena
authors.initials: A
authors.lastname: Křenková
authors.affiliation: Institute of Microbiology, Laboratory of Biotransformation, Czech Academy of Sciences , Vídeňská 1083, CZ 142 20 Prague, Czech Republic.
authors.forename: Marek
authors.initials: M
authors.lastname: Kuzma
authors.affiliation: CZ-OPENSCREEN: National Infrastructure for Chemical Biology, Institute of Molecular Genetics, Czech Academy of Sciences , Vídeňská 1083, CZ 142 20 Praha 4, Czech Republic.
authors.forename: Ctibor
authors.initials: C
authors.lastname: Škuta
authors.affiliation: CZ-OPENSCREEN: National Infrastructure for Chemical Biology, Institute of Molecular Genetics, Czech Academy of Sciences , Vídeňská 1083, CZ 142 20 Praha 4, Czech Republic.
authors.forename: Žaneta
authors.initials: Ž
authors.lastname: Peikerová
authors.affiliation: CZ-OPENSCREEN: National Infrastructure for Chemical Biology, Institute of Molecular Genetics, Czech Academy of Sciences , Vídeňská 1083, CZ 142 20 Praha 4, Czech Republic.
authors.forename: Petr
authors.initials: P
authors.lastname: Bartůněk
authors.affiliation: Institute of Microbiology, Laboratory of Biotransformation, Czech Academy of Sciences , Vídeňská 1083, CZ 142 20 Prague, Czech Republic.
authors.forename: Vladimír
authors.initials: V
authors.lastname: Křen
mesh_terms: D000975:Antioxidants / Q000737:chemistry* / Q000494:pharmacology; D005638:Fruit / Q000737:chemistry*; D006801:Humans; D020944:Silybum marianum / Q000737:chemistry*; D015394:Molecular Structure; D010936:Plant Extracts / Q000032:analysis; D018517:Plant Roots / Q000737:chemistry; D000077385:Silybin; D012838:Silymarin / Q000737:chemistry* / Q000494:pharmacology
chemical_list: D000975:Antioxidants; D010936:Plant Extracts; D012838:Silymarin; C515097:dehydrosilybin; D000077385:Silybin; C011471:folin; C015504:silychristin