title: Isolation of five types of flavonol from seabuckthorn (Hippophae rhamnoides) and induction of apoptosis by some of the flavonols in human promyelotic leukemia HL-60 cells.
abstract: Five types of flavonol were isolated from seabuckthorn (Hippophae rhamnoides) and identified by mass, 1H- and 13C-NMR. The proliferations of human promyelotic leukemia HL-60 cells were inhibited as the concentrations of these flavonols were increased. The order of the extent of growth inhibition by the flavonols at a concentration of 20 microM is as follows: pentamethylquercetin > syringetin > isorhamnetin > quercetin > kaempherol > myricetin. Apoptotic morphological changes of the nucleus, including chromatin condensation were induced in the HL-60 cells treated with quercetin, kaempherol and myricetin, respectively, but not in the cells treated with the other flavonols. The fragmentations of DNA by quercetin, kaempherol and myricetin, respectively, to oligonucleosomal-sized fragments, a characteristic of apoptosis, were observed to be dose-dependent in the HL-60 cells. These findings suggest that growth inhibition by quercetin, kaempherol and myricetin, respectively, results from the induction of apoptosis by these flavonols. The other flavonols (pentamethylquercetin, syringetin and isorhamnetin) having methoxy (-OCH3) group inhibited more strongly than the above 3 flavonols without induction of apoptosis in the HL-60 cells. These findings suggest that mechanisms of growth inhibition by pentamethylquercetin, syringetin and isorhamnetin are different from the apoptosis caused by quercetin, kaempherol and myricetin.
authors.affiliation: Faculty of Medicine, Mie University, Tsu-city, Mie 514-0001, Japan.
authors.forename: Hiroshige
authors.initials: H
authors.lastname: Hibasami
authors.forename: Akihiro
authors.initials: A
authors.lastname: Mitani
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Katsuzaki
authors.forename: Kunio
authors.initials: K
authors.lastname: Imai
authors.forename: Kazumi
authors.initials: K
authors.lastname: Yoshioka
authors.forename: Takashi
authors.initials: T
authors.lastname: Komiya
mesh_terms: D000970:Antineoplastic Agents / Q000302:isolation & purification / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D053938:DNA Fragmentation / Q000187:drug effects; D044948:Flavonols / Q000302:isolation & purification / Q000494:pharmacology*; D018922:HL-60 Cells; D031281:Hippophae / Q000737:chemistry*; D006801:Humans
chemical_list: D000970:Antineoplastic Agents; D044948:Flavonols