Impaired vitamin A-mediated mucosal IgA response in IL-5 receptor-knockout mice.

To clarify actions of vitamin A on mucosal immunity associated with interleukin-5 (IL-5), we examined effects of vitamin A on mucosal IgA level in IL-5 receptor alpha-chain-knockout (IL-5Ralpha(-/-)) mice. Daily supplementation of retinyl acetate (1 mg/mouse) increased Th2 cytokine levels and a number of their positive cells in the small intestinal mucosa of IL-5Ralpha(-/-) mice, as observed in wild-type or IL-5Ralpha(+/-) mice. Wild-type and heterozygous mice increased the IgA level and a number of IgA-containing cells in the mucosa in response to the vitamin A treatment, but not in IL-5Ralpha(-/-) mice. Retinyl acetate increased anti-cholera toxin (CT) IgA level in the mucosa of wild-type mice, improving their survival rate after an exposure to 0.4 mg of CT. However, retinyl acetate failed to induce resistance to CT toxicity in IL-5Ralpha(-/-) mice. Our results suggest that IL-5 may play an important role in an action of vitamin A on mucosal IgA system.

Inhibitory effects of dehydrocorydaline isolated from Corydalis Tuber against type I-IV allergic models.

An alkaloidal component, dehydrocorydaline (DHC) isolated from Corydalis Tuber (tuber of Corydalis turtschaninovii forma yanhusuo), has been screened for activity against types I-IV allergic reactions. In a type I allergic models, DHC at a dose of 0.5 mmol/kg, p.o. inhibited 48 h homologous passive cutaneous anaphylaxis (PCA) in rats, which is related to IgE. DHC also exhibited an inhibitory effect on antigen-induced histamine release from peritoneal mast cells. In a type II allergic model, DHC did not inhibit reversed cutaneous anaphylaxis (RCA) in rats. In a type III allergic model, DHC showed weak inhibition on direct passive arthus reaction (DPAR) in rats. Furthermore, in a type IV allergic model, DHC had inhibitory effects on the induction phase and effector phase in picryl chloride-induced contact dermatitis (PC-CD). These results indicated that DHC not only inhibits antibody-mediated allergic reactions but also influences cell-mediated allergia reactions, and the inhibitory effect of Corydalis Tuber on allergic reactions may be partially attributed to DHC.

Inhibitory effects of methanolic extract from corydalis tuber against types I-IV allergic models.

Methanolic extract (CM-ext) from tubers of Corydalis turtschaninovii forma yanhusuo has been screened for activity in experimental models of types I-IV allergy. In type I allergic models, CM-ext at doses of 200, 500 mg/kg, p.o. inhibited 48-h homologous passive cutaneous anaphylaxis (PCA) in rats which is related to IgE, and 4-h heterologous PCA in guinea pigs which is related to IgG. The inhibition of CM-ext on 48-h PCA was also recognized in adrenalectomized rats. CM-ext exhibited the inhibitory effect on formation of IgE antibody in BALB/c mice. In type II allergic model, it was found that CM-ext inhibits reversed cutaneous anaphylaxis (RCA). In type III allergic model, CM-ext showed the inhibitory effect on direct passive arthus reaction (DPAR) in rats. Furthermore, in type IV allergic model, CM-ext had the inhibitory effects on induction phase and effector phase in picryl chloride-induced contact dermatitis (PC-CD). It also showed therapeutic action on PC-CD. These results indicated that CM-ext not only inhibits antibody-mediated allergic reactions but also influences cell-mediated allergic reactions and should be recognized as a potent material for allergic reactions, although the mechanisms and active principles of CM-ext have not yet been completely determined.

Studies of anti-cataract drugs from natural sources. I. Effects of a methanolic extract and the alkaloidal components from Corydalis tuber on in vitro aldose reductase activity.

The inhibitory of Corydalis tuber (Corydalis turtschaninovii Besser forma yanhusuo Y. H. Chou et C. C. Hsu) was tested on crude rat lens aldose reductase, an enzyme involved in the complications of diabetes. The methanolic extract (CM-ext) inhibited aldose reductase, while the aqueous extract (CA-ext) was ineffective. Only dehydrocorydaline, of the seven alkaloidal components isolated from CM-ext, inhibited aldose reductase. It is suggested that the inhibitory effect of CM-ext on aldose reductase may be partially attributed to dehydrocorydaline.

Anti-inflammatory activities of methanolic extract and alkaloidal components from Corydalis tuber.

A methanolic extract (CM-ext) from Corydalis tuber (Corydalis turtschaninovii Besser forma yanhusuo Y. H. Chou et C. C. Hsu) has been screened for activity in experimental models of inflammation. CM-ext (200 or 500 mg/kg, p.o.) inhibited an increase in vascular permeability in mice induced by acetic acid, and reduced acute paw edema in rats induced by compound 48/80 or carrageenin. CM-ext suppressed the development of adjuvant-induced edema in arthritic rats. CM-ext and its alkaloidal components, dehydrocorydaline, d-glaucine and l-tetrahydrocoptisine inhibited compound 48/80-induced histamine release from peritoneal mast cells of rats. Since these substances from C. tuber were found to be effective in both the acute and chronic phases of inflammation, the crude drug C. tuber can be considered to exert anti-inflammatory activity.