Ginsenoside Rh1 Possesses Antiallergic and Anti-Inflammatory Activities

<i>Background:</i> Ginseng (the root of <i>Panax ginseng</i> C.A. Meyer, Araliaceae) has been reported to possess various biological activities, including anti-inflammatory and antitumor actions. In this study, we investigated the antiallergic activity of ginsenosides isolated from ginseng. <i>Method:</i> We isolated ginsenosides by silica gel column chromatograghy and examined their in vitro and in vivo antiallergic effect on rat peritoneal mast cells and on IgE-induced passive cutaneous anaphylaxis (PCA) in mice. The in vitro<i></i>anti-inflammatory activity of ginsenoside Rh1 (Rh1) in RAW264.7 cells was investigated. <i>Results:</i> Rh1 potently inhibited histamine release from rat peritoneal mast cells and the IgE-mediated PCA reaction in mice. The inhibitory activity of Rh1 (87% inhibition at 25 mg/kg) on the PCA reaction was found to be more potent than that of disodium cromoglycate (31% inhibition at 25 mg/kg); Rh1 was also found to have a membrane-stabilizing action as revealed by differential scanning calorimetry. It also inhibited inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) protein expression in RAW 264.7 cells, and the activation of the transcription factor, NF-ĸB, in nuclear fractions. <i>Conclusion:</i> The antiallergic action of Rh1 may originate from its cell membrane-stabilizing and anti-inflammatory activities, and can improve the inflammation caused by allergies.