Immunomodulatory action of citrus auraptene on macrophage functions and cytokine production of lymphocytes in female BALB/c mice.

The modifying effects of auraptene isolated from the peel of citrus fruit (Citrus natsudaidai Hayata) on macrophage and lymphocyte functions were investigated in mice. Female BALB/c mice were gavaged with auraptene at a dose of 100, 200 or 400 mg/kg once a day for 10 consecutive days. Glucose consumption of peritoneal macrophages was significantly higher than that in the control group (P < 0.05-0.001) in auraptene-treated mice at all doses at 24, 48 and 72 h incubation except for mice given 200 mg/kg auraptene at 24 h incubation. Activity of acid phosphatase in peritoneal macrophages was significantly increased in mice treated with auraptene at a dose level of 100 mg/kg (P < 0.001). Activity of beta-glucuronidase in peritoneal macrophages in the auraptene-treated mice at all doses was significantly higher than that in the control group (P < 0.001), but there was no significant difference in lactate dehydrogenase activity of peritoneal macrophages at any dose. Interleukin (IL)-1beta production of peritoneal macrophages in the auraptene-treated mice at all doses was significantly higher than that in the control group (P < 0.05-0.001). Tumor necrosis factor alpha production of peritoneal macrophages in mice gavaged with auraptene at a dose of 200 mg/kg was significantly higher than that in the control group (P < 0.05). Auraptene did not affect proliferation of spontaneous splenic lymphocytes in mice at any dose. Stimulation indices in mice given auraptene at a dose of 200 mg/kg were significantly higher than that in the control group (P < 0.05). When spleenic lymphocytes were cultured without concanavalin A (Con A), IL-2 and interferon (IFN) gamma productions were not detectable in the supernatant. However, IL-2 and IFN production stimulated by Con A were significantly increased in mice gavaged with auraptene at dose levels of 100 and 200 mg/kg (P 0.05-0.001). Auraptene did not enhance spontaneous IL-4 production by splenocytes. There was no significant difference in IL-4 production of splenic lymphocytes stimulated by Con A in all groups. These findings might suggest that oral administration of citrus auraptene effectively enhanced macrophage and lymphocyte functions in mice.