Studies of the Immunity Regulation Mechanism of Auraptene in Citrus Peel

Research Project

Project/Area Number	14560108
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Single-year Grants
Section	一般
Research Field	食品科学・栄養科学
Research Institution	Prefectural University of Kumamoto
Principal Investigator	SUGANO Michihiro Prefectural University of Kumamoto, Faculty of environmental and symbiotic sciences, Professor(President), 環境共生学部, 教授(学長) (70038181)
Co-Investigator(Kenkyū-buntansha)	AKAHOSHI Asuka Prefectural University of Kumamoto, Faculty of environmental and symbiotic science, Assistant, 環境共生学部, 助手 (10316193)
Project Period (FY)	2002 – 2003
Project Status	Completed (Fiscal Year 2003)
Budget Amount *help	¥3,300,000 (Direct Cost: ¥3,300,000) Fiscal Year 2003: ¥600,000 (Direct Cost: ¥600,000) Fiscal Year 2002: ¥2,700,000 (Direct Cost: ¥2,700,000)
Keywords	Auraptene / Citrus speel / Rats / TNF-α / IL-4 / INF-γ / IgA / 血清トリグリセリド / インスリン / 腫瘍壊死因子 / レプチン / 体脂肪
Research Abstract	Auraptene (Aur) is a kind of coumarin compounds, occurring in the peel of specific citrus, exerts beneficial physiological functions such as anti-carcinogenic and suppression of active oxygen production. In the present study, to gain further information on physiological functions of Aur, the effects on various parameters were confirmed in rat feeding studies or lymphocyte culture system. First, using dried powders from different citrus peels either Amanatsu containing 0.01 % Aur, Ponkan essentially free from Aur or control containing cellulose were fed to rats for 4 weeks. The liver weight and the concentration of serum glucose were significantly lowered in the Amanatsu and Ponkan groups, while kidney weight and the concentration of serum TNF-α were obviously increased in rats fed Amanatsu. Then, the Aur concentrate was prepared from Amanatsu orange peel, and fed to rats 0.04 % level for 3 weeks. Aur did not affect weight gain and food efficiency, although feec intake tended to be high … More er. In the Aur group, kidney weight trended to be higher, while weight of white adipose tissue was reduced. The concentration of serum triglyceride significantly decreased in the rats fed Aur. The concentration of serum insulin trended to lower in the Aur group, however, that of serum glucose remained unchanged. There was a decreasing trend of the concentration of serum TNF-a when rats were fed Aur. When rat spleen lymphocytes were incubated with high-purity Aur prepared from Amanatsu peel, the production of IgA decreased with an increasing concentration of Aur, irrespective of the incubation time. The IgA production tended to decrease irrespective of the concentration of Aur added to the medium. The trace Aur significantly increased the production of IL-4 during 24 hours of incubation, but this effect disappeared after 72 hours. There was no obvious effect on the concentration of TNF-a, however it increased with incubation time, and the difference became significant when Aur was added in the medium. Although no clear-cut effect of Aur on the production of IFN-γ was observed, it tended to increase with incubation time. Overall, in animal experiments, it was confirmed that Aur increase the concentration of serum TNF-α. There is also a possibility that Aur affects body fat metabolism, however the effect on immune functions was not unequivocal. While in the lymphocyte experiment, the results suggested that Aur may have unique functions in the production of immunoglobulins and some cytokines. Although it is difficult to draw a distinct conclusion from the present study, Aur appears to have a potential to promote and regulate immune functions. Less