Dioscorea japonica Thunb. - Dioscoreaceae \\
Japanese yam, mountain yam 山芋 (jap.), **Japanische Yamswurzel**

Native to Japan, Korea, China; tubers vertical, long cylindric, to 3 cm in diam. \\
[[http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=200028115]]

D.japonica tubers are used as food and medicinal source known as “San Yak” in Korea. They contain cytotoxic withanolides. \\
[Withanolides from the Rhizomes of Dioscorea japonica and Their Cytotoxicity.  Kim, K. H., Choi, S. U., Choi, S. Z., Son, M. W., Lee, K. R., Journal of agricultural and food chemistry, Vol.59(13), 2011, 6980-6984]

(+)-β-eudesmol and notably 2-hydroxy-4-methoxyacetophenone (paeonol) from a methanol extract of D.japonica showed antimutagenic activity. \\
[ Antimutagenic activity of (+)-β-eudesmol and paeonol from Dioscorea japonica.  Miyazawa, M., Shimamura, H., Nakamura, S. I., Kameoka, H., Journal of agricultural and food chemistry, Vol.44(7), 1996, 1647-1650]