title: Suppressive effects of Okinawan food items on free radical generation from stimulated leukocytes and identification of some active constituents: implications for the prevention of inflammation-associated carcinogenesis.
abstract: Okinawa prefecture in Japan is a distinct area characterized by unique traditional food habits and longevity. Prolonged exposure to activated leukocytes, playing pivotal roles in chronic inflammation-associated carcinogenesis, is known to lead to oxidative and nitrosative damage to macromolecules in the body since they are primary sources of free radicals, such as superoxide anion (O(2)(-)) and nitric oxide (NO). In this study, we estimated anti-oxidative and anti-nitrosative activities of Okinawan food items by employing two cellular experimental systems: (1) phorbol ester-induced O(2)(-) generation from differentiated HL-60 human promyelocytic leukemia cells; and (2) lipopolysaccharide (LPS)-induced NO generation in RAW264.7 murine macrophages. A total of 138 food items, consisting of 42 samples unique to Okinawa and 96 common in the Japanese main island, were purchased at local markets in Okinawa and extracted with chloroform. When tested at a concentration of 100 microg/ml, 38% (16/42) of the former showed 70% or more inhibition of O(2)(-) generation while 21% (20/96) of the latter did so. In parallel, 64% (27/42) of the former showed significant NO generation suppression in contrast to 48% (46/96) of the latter . Twenty-one active species were further tested at a concentration of 20 mug/ml, and eleven species, including sugar cane, wild turmeric, and zedoary, were indicated to be most promising items with anti-oxidative and anti-nitrosative properties. In addition, some of the active constituents (chebulagic acid, a resveratrol derivative, and sesquiterpenoids) were identified. Our results suggest that food items typical in the Okinawa area have higher cancer preventive potential than those common in Japan.
authors.affiliation: Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan. cancer@kais.kyoto-u.ac.jp
authors.forename: Akira
authors.initials: A
authors.lastname: Murakami
authors.forename: Hisashi
authors.initials: H
authors.lastname: Ishida
authors.forename: Kimie
authors.initials: K
authors.lastname: Kobo
authors.forename: Ikuyo
authors.initials: I
authors.lastname: Furukawa
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Ikeda
authors.forename: Megumi
authors.initials: M
authors.lastname: Yonaha
authors.forename: Yohko
authors.initials: Y
authors.lastname: Aniya
authors.forename: Hajime
authors.initials: H
authors.lastname: Ohigashi
mesh_terms: D000818:Animals; D018929:Cell Culture Techniques; D042381:Granulocyte Precursor Cells / Q000187:drug effects* / Q000378:metabolism; D018922:HL-60 Cells; D006801:Humans; D007564:Japan; D008264:Macrophages / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D009569:Nitric Oxide / Q000378:metabolism*; D010936:Plant Extracts / Q000494:pharmacology; D018514:Plant Structures; D010945:Plants, Edible; D012717:Sesquiterpenes / Q000494:pharmacology; D013267:Stilbenes / Q000494:pharmacology; D013481:Superoxides / Q000378:metabolism*
chemical_list: D010936:Plant Extracts; D012717:Sesquiterpenes; D013267:Stilbenes; D013481:Superoxides; D009569:Nitric Oxide