Ginsenoside Rh1 possesses antiallergic and anti-inflammatory activities.

Ginseng (the root of Panax ginseng 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. We isolated ginsenosides by silica gel column chromatography 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 anti-inflammatory activity of ginsenoside Rh1 (Rh1) in RAW264.7 cells was investigated. 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-kappaB, in nuclear fractions. The antiallergic action of Rh1 may originate from its cell membrane-stabilizing and anti-inflammatory activities, and can improve the inflammation caused by allergies.