This studies were conducted to develop cultivation methods on three Asclepiadaceae fami-lies(Cynanchum wilfordii Hemsley, C. auriculatum Royle ex Wight and Metaplexis japonica Makino) ofwhich products are conventionally used as medicinal materials by analyzing plant growth. The variationof leaf weight of Asclepiadaceae families showed culmination point at August 15, and the stem showedhighest growth on August 30. The root weight increased linearly during the growth. The days for sprout-ing was most shortened in the Cynanchum wilfordii as 18 days, and C. auriculatum, Metaplexis japonicafollowed after. The seed harvesting dates was Oct. 8 in the Cynanchum wilfordii, Oct. 23 in the Metaplexisjaponica, and Nov. 1 in the C. auriculatum, respectively.

The purpose of this study was to evaluate the antioxidant activity of Metaplexis japonica by using hot-water and ethanol extracts of its leaf and stem. Yields of hot-water and ethanol extracts of M. japonica leaf were high at 6.89 and 6.23%, respectively. The polyphenol and flavonoid contents in ethanol extracts of M. japonica leaf (ALEE) were high (86.96 and 60.73 mg/g, respectively). The electron-donating ability of all M. japonica extracts increased with an increase in extract concentration, with the highest electron-donating ability of 36.20~68.19% shown by hot-water extracts of M. japonica leaf (ALWE). The superoxide dismutase (SOD)-like activities of ALWE and ALEE increased with an increase in extract concentration. The nitrite-scavenging ability of the extracts was the highest at pH 1.2 and that of ALWE was higher than that of ALEE. The reducing power of 62.5 μg/mL ALEE was 0.09 and that of 1,000 μg/mL ALWE was 0.44. The inhibitory effect of an ethanol extract of M. japonica stem (ASEE) on tyrosinase was 13.81% at a concentration of 62.5 μg/mL and that of 1,000 μg/mL ALEE was 57.04%.

These studies were conducted to discriminate Cynanchum wilfordii, C. auriculatum, Metaplexis japonica, andPolygonum multiflorum by morphological characters. Cynanchum wilfordii, C. auriculatum, and Metaplexis japonica(Ascle-piadaceae) were easily distinguished from Polygonum multiflorum by twining stem to the left, producing opposite leaves,having laticiferous stems and leaves at cutting cross-sectionally, and lacking lignification of the stem. Four species had differ-ent morphological characters of flower. Comparing four species to fruit type, three species of Asclepiadaceae had follicle,while Polygonum multiflorum had achene with three wings. Follicle shape was lanceolate, narrowly lanceolate, and widelylanceolate in C. wilfordii, C. auriculatum, and Metaplexis japonica, respectively. Whereas seed color of four species was darkbrown similarly, seed shape and 1,000 seed weight were useful characters to discrimate between three species ofAsclepiadaceae and Polygonum multiflorum. Shape and color of root were thickened and yellowish brown in C. wilfordii andC. auriculatum. They were thin and long and white in Metaplexis japonica, and fusiform and reddish brown in Polygonummultiflorum. They would be useful characters to distinguish Cynanchum spp., Metaplexis japonica, and Polygonummultiflorum, however, impossible characters to discriminate between C. wilfordii and C. auriculatum.