Immunomodulatory activity of dioscorin, the storage protein of yam (Dioscorea alata cv. Tainong No. 1) tuber.
The purified dioscorin from yam (Dioscorea alata L. cv. Tainong 1) tuber was previously reported (Hsu et al., 2002. J. Agric. Food Chem., 50, 6109-6113). In this report, we evaluated its immunomodulatory ability in vitro in the presence of polymyxin B (50 microg/ml) to eliminate lipopolysaccharide (LPS) contamination. Dioscorin (5-100 microg/ml) was able to stimulate nitric oxide production (expressed as nitrite concentrations) in RAW264.7 cells. The stimulation index on the phagocytosis of RAW264.7 cells against E. coli and the oxidative burst (determined by the intensity of rhodamine fluorescence) of RAW264.7 cells were both enhanced by different concentrations of dioscorin (5-100 microg/ml). The cytokine production, including IL-6, TNF-alpha, and IL-1beta in dioscorin-treated RAW264.7 cells or human monocytes, was measured in the cultured medium. Dioscorin (5-100 microg/ml) was found able to induce IL-6, TNF-alpha, and IL-1beta production in RAW264.7 cells and human monocytes. To evaluate the effects of dioscorin on the proliferation of spleen cells from BALB/c mice, phytohemagglutinin (PHA, 2 microg/ml) alone or PHA mixed with different concentrations of dioscorin (10, 25, and 50 microg/ml) was used to treat spleen cells for 24h. The stimulated proliferation index of splenic cells ranged from 1.38- to 1.48-fold of PHA alone for PHA mixed with different concentrations of dioscorin (10, 25, and 50 microg/ml). We suggest that the tuber storage protein of yam dioscorin functions as an immunomodulatory substance.
Liu
Yen-Wenn
YW
Graduate Institute of Pharmacy, College of Pharmacy, Taipei Medical University, Taipei 110, Taiwan.
Shang
Huey-Fang
HF
Wang
Chung-Kwe
CK
Hsu
Feng-Lin
FL
Hou
Wen-Chi
WC
D000818:Animals; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism; D027742:Dioscorea / Q000737:chemistry*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007155:Immunologic Factors / Q000737:chemistry / Q000494:pharmacology*; D008070:Lipopolysaccharides; D008264:Macrophages / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D009000:Monocytes / Q000187:drug effects; D009569:Nitric Oxide / Q000378:metabolism; D010940:Plant Proteins / Q000737:chemistry / Q000494:pharmacology*; D035281:Plant Tubers / Q000737:chemistry; D011112:Polymyxin B; D016897:Respiratory Burst; D013154:Spleen / Q000166:cytology
D016207:Cytokines; D007155:Immunologic Factors; D008070:Lipopolysaccharides; D010940:Plant Proteins; C095057:dioscorin protein, Dioscorea; D009569:Nitric Oxide; D011112:Polymyxin B