| 15336266 |
Matsuda H, Tewtrakul S, Morikawa T, Yoshikawa M: Anti-allergic activity of stilbenes from Korean rhubarb (Rheum undulatum L.): structure requirements for inhibition of antigen-induced degranulation and their effects on the release of TNF-alpha and IL-4 in RBL-2H3 cells. Bioorg Med Chem. 2004 Sep 15;12(18):4871-6.
Stilbenes isolated from the rhizomes of Rheum undulatum (Korean rhubarb) and the related compounds were investigated on their anti-allergic activities. The results revealed that 3,5,4'-trimethylpiceatannol exhibited the most potent inhibition against beta-hexosaminidase release as a marker of degranulation in RBL-2H3 cells with IC (50) of 2.1 microM, followed by trimethylresveratrol (IC (50)=5.1 microM). Structural requirements of stilbenes for the activity are as follows: (1) The oxygen functions (-OCH (3), -OH), especially methoxyl groups, are essential and their positions on aromatic rings are important for the activity; (2) the alpha-beta double bond increased the activity; (3) the glycoside moiety dramatically decreased the activity; and (4) the substitution group at the 3'-position in trimethylresveratrol (3,5,4'-trimethoxystilbene) was preferably OH> H> OCH (3) for the activity. Several active stilbenes (piceatannol, 3,5,4'-trimethylpiceatannol, resveratrol, trimethylresveratrol) also inhibited ionomycin-induced beta-hexosaminidase release, suggesting that inhibition of Ca (2+) influx or degranulation mechanisms after Ca (2+) influx is important for their activities. Piceatannol, 3,5,4'-trimethylpiceatannol, resveratrol, and trimethylresveratrol also significantly inhibited antigen-induced release of TNF-alpha and IL-4 in RBL-2H3 cells. |
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