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Studies on Palauan medicinal herbs. IV. Immunopotentiatory activities of Ongael, leaves of Phaleria cumingii (Meisn.) F. Vill. in diabetic mice
Abstract
Diabetes is often identified as a risk factor for infections. We were interested in investigating the effect of “Ongael” on immunosuppressive diabetic mice. Ongael [leaves of Phaleria cumingii (Meisn.) F. Vill.] is used as a panacea for traditional treatment of many kinds of diseases in Palau. On the production of cytokine in the spleen from BKS. Cg-+Leprdb/+Leprdb mice, an animal model of non-insulin-dependent diabetes mellitus, oral administration of the 50% ethanolic extract (ONG-ext, 500 mg/kg) of Ongael significantly increased the production of interferon (IFN)-γ compared to that of vehicle control group. Mangiferin (100 mg/kg, p.o.), a major constituent of ONG-ext, significantly enhanced secretion of IFN-γ, tumor necrosis factor (TNF)-α and interleukin (IL)-2 compared to that of vehicle control group. These results suggest that Ongael acts as an immunopotentiator to immunoincompentence in diabetes mellitus. © 2006, Medical and Pharmaceutical Society for WAKAN-YAKU. All rights reserved.
Diabetes mellitus is one of the major health problems in the world, the incidence and associated mortality are increasing. Inadequate regulation of the blood sugar imposes serious consequences for health. Conventional antidiabetic drugs are effective, however, also with unavoidable side effects. On the other hand, medicinal plants may act as an alternative source of antidiabetic agents. Examples of medicinal plants with antidiabetic potential are described, with focuses on preclinical and clinical studies. The beneficial potential of each plant matrix is given by the combined and concerted action of their profile of biologically active compounds.
The 50% ethanolic extract (ONG-ext) of “Ongael” [leaves of Phaleria cumingii (MEISN.) F. VILL.] inhibited proliferation of mice mammary carcinoma cells (MM46) and human leukemia cells (HL60) at a concentration of 50 to 200 μg/ml. Mangiferin (1), a major constituent of ONG-ext, showed antiproliferative activities on MM46 and HL60 cells at a concentration of 100 μg/ml. Oral administration of ONG-ext (50 and 500 mg/kg) and 1 (10, 50 and 100 mg/kg) to MM46 cells transplanted C3H/HeN mice showed significant antitumor effects. In HL60 cells transplanted C.B-17/Icr SCID mice, ONG-ext (50 and 500 mg/kg, p.o.) showed no significant antitumor effect. On cytokines production in the spleen isolated from MM46 carcinoma bearing mice, ONG-ext (500 mg/kg, p.o.) and 1 (100 mg/kg, p.o.) significantly inhibited the reduction of tumor necrosis factor (TNF)-α and interleukin (IL)-2 levels, and ONG-ext (500 mg/kg, p.o.) increased interferon (IFN)-γ level compared to that of vehicle control group. As to in vitro mitogen response of mice spleen T cells in the presence of sample-treated macrophage, ONG-ext (25, 50 μg/ml) and acylglucosylsterol (2) (10 μg/ml) significantly increased both TNF-α and IFN-γ levels. It has been indicated that the in vivo antitumor effect of ONG-ext partly depends on immunostimulatory activity, and active constituents are 1 and 2. © 2005, Medical and Pharmaceutical Society for WAKAN-YAKU. All rights reserved.