Affiliations: Department of Biotechnological Science, Faculty of
Biology-Oriented Science and Technology, Kinki University, Iwade-Uchita,
Wakayama 649-6493, Japan | Division of Applied Life Sciences, Graduate School of
Agriculture, Kyoto University, Kyoto 606-8502, Japan | Department of Citriculture, Fruit Tree Research
Station, Okitsu, Shimizu, Shizuoka 424-0292, Japan | Department of Biochemistry, Kyoto Prefecture
University of Medicine, Kawaramachi-Hirokoji, Kamigyoku, Kyoto 602-0841,
Japan
Note: [] Division of Applied Life Sciences, Graduate School of
Agriculture, Kyoto University, Kyoto 606-8502, Japan. Fax: +81 75 753 6284;
E-mail: [email protected]
Abstract: Citrus fruit intake is known to be associated with a reduction of
cancer incidence. Free radicals, including superoxide (O_2\!
^-) and nitric oxide (NO), are involved in some epithelial
carcinogenesis processes. In the present study, we screened thirty-one citrus
fruits for their suppressive activities toward three lines of free radical
generating systems: 1) O_2\! ^- generation by the xanthine
(XA)-xanthine oxidase (XOD) system; 2) O_2\! ^- generation
induced by 12-O-tetradecanoylphorbol-13-acetate (TPA) in differentiated human
promyelocytic HL-60 cells; and 3) NO generation in murine macrophage RAW264.7
cells stimulated with lipopolysaccharide (LPS) and interferon
(IFN)-\gamma. As a result, the inhibitory activities of peel
parts were largely found to be higher than those of the corresponding juice sac
parts. In particular, the peel portion of Dancy tangerine ({\it Citrus
tangerina}) showed marked anti-oxidative activities in these systems. In
addition, nobiletin, a polymethoxyflavonoid isolated from {\it C. nobilis},
showed a higher anti-inflammatory activity than indomethacin in a TPA-induced
edema formation test in mouse ears. These results indicate that citrus fruits
could be notable sources of anti-oxidative, anti-inflammatory, and cancer
preventive compounds.
Journal: BioFactors, vol. 12, no. 1-4, pp. 187-192, 2000
