Immunomodulating effects of the hydrolysis products of formosanin C and beta-ecdysone from Paris formosana Hayata.

Formosanin C (PF-3, I), a diosgenin glycoside with four sugars isolated from Paris formosana Hayata as main constituent, significantly showed immunomodulating effects on the proliferative response of mouse lymphocytes to concanavalin A (Con A). The partialy hydrolysis products of formosanin C, dioscin (II) and prosapogenin A of dioscin (III), also increased 3H-thymidine incorporation of Con A-stimulated lymphocytes maximally at 0.01 micrograms/ml, whereas formosanin C did so at 0.0001 micrograms/ml. However, trillin (IV) and diosgenin (V) obtained from the partial hydrolysis of formosanin C had no effects on these immune responses. Evidently, the immunomodulating activities increased in the order of increasing polarity. Probably the solubility in water was a factor. This demonstrated that the sugar moiety in the structure of formosanin C (I) displays a very important pattern for the effect on the proliferative response of mouse lymphocytes to Con A. On the other hand, these hydrolysis products at higher concentrations of 1 and 10 micrograms/ml reduced the cytotoxic effects on spleen cells as compared with formosanin C. The other constituent, beta-ecdysone (VI) isolated from the stems of Paris formosana Hayata also increased 3H-thymidine incorporation of Con A-stimulated splenocytes. At the concentration of 0.001 micrograms/ml, the stimulation index of beta-ecdysone (2) is higher than that of formosanin C (1.65), and at the concentration of 100 micrograms/ml, beta-ecdysone had no cytotoxicity for normal spleen cells whereas formosanin C at the lower concentration of 10 micrograms/ml showed cytotoxicity. Based on this study, beta-ecdysone (VI) is therefore a better immunomodulator than formosanin C.