title: Isolation and identification of novel tocotrienols from rice bran with hypocholesterolemic, antioxidant, and antitumor properties.
abstract: Two novel tocotrienols were isolated from stabilized and heated rice bran, apart from the known alpha-, beta-, gamma-, and delta-tocopherols and tocotrienols. These new tocotrienols were separated by HPLC, using a normal phase silica column. Their structures were determined by ultraviolet, infrared, nuclear magnetic resonance, circular dichroism, and high-resolution mass spectroscopies and established as desmethyl tocotrienol [3, 4-dihydro-2-methyl-2-(4,8,12-trimethyltrideca-3'(E),7'(E), 11'-trienyl)-2H-1-benzopyran-6-ol] and didesmethy tocotrienol [3, 4-dihydro-2-(4,8,12-trimethyltrideca-3'(E),7'(E), 11'-trienyl)-2H-1-benzopyran-6-ol]. These tocotrienols significantly lowered serum total and LDL cholesterol levels and inhibited HMG-CoA reductase activity in chickens. They had much greater in vitro antioxidant activities and greater suppression of B16 melanoma cell proliferation than alpha-tocopherol and known tocotrienols. Results indicated that the number and position of methyl substituents in tocotrienols affect their hypocholesterolemic, antioxidant, and antitumor properties.
authors.affiliation: Advanced Medical Research, Madison, Wisconsin 53719, USA.
authors.forename: A A
authors.initials: AA
authors.lastname: Qureshi
authors.forename: H
authors.initials: H
authors.lastname: Mo
authors.forename: L
authors.initials: L
authors.lastname: Packer
authors.forename: D M
authors.initials: DM
authors.lastname: Peterson
mesh_terms: D000818:Animals; D000924:Anticholesteremic Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D000975:Antioxidants / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D002645:Chickens; D002851:Chromatography, High Pressure Liquid; D008297:Male; D012275:Oryza / Q000737:chemistry*; D013057:Spectrum Analysis; D014407:Tumor Cells, Cultured; D014810:Vitamin E / Q000031:analogs & derivatives* / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology
chemical_list: D000924:Anticholesteremic Agents; D000970:Antineoplastic Agents; D000975:Antioxidants; D014810:Vitamin E