Dioscorea japonica (PROSEA)

Plant Resources of South-East Asia Introduction

List of species

Dioscorea japonica Thunb.

Protologue: Nova Acta Soc. Sci. upsal. 4: 39 (1783).

Vernacular names

• Japanese yam (En).
• Igname du Japon (Fr)
• Vietnam: từ nhật lản.

Distribution

From China, Japan, Korea, to Taiwan, Vietnam and Thailand; cultivated in Japan, China and Uzbekistan.

Uses

In Korea, China, Japan and Indo-China, the juice of the tuber is used to treat indigestion, intestinal troubles including dysentery and diarrhoea, and night disturbances of the urogenital system as well as spermatorrhoea. The mucilage from the freshly crushed tuber is applied to treat intestinal pain caused by stoppage or inflammation. The tuber is eaten in China and Japan.

Observations

• A twining vine with slender stems, loosely branched, bulbils present, tuber cylindrical, large, fleshy.
• Leaves opposite, rarely alternate, triangular or ovate-triangular, 5-10 cm × 2-5 cm, apex acuminate, glabrous, 5-9-veined, petiole 2-3 cm long.
• Spike with crowded flowers, male spikes 3-5 together, erect, peduncle short, rudimentary pistil present, female spikes solitary, pendulous, staminodes present.
• Capsule broadly ovoid, 1.4-2 cm long, 1.5 cm in diameter.

D. japonica occurs in hilly bushland and along streams, and flowers in August in Japan.

Selected sources

• [135] Burkill, I.H., 1966. A dictionary of the economic products of the Malay Peninsula. Revised reprint. 2 volumes. Ministry of Agriculture and Co-operatives, Kuala Lumpur, Malaysia. Vol. 1 (A—H) pp. 1—1240, Vol. 2 (I—Z) pp. 1241—2444.
• [311] Flora of Thailand (various editors), 1970—. The Forest Herbarium, Royal Forest Department, Bangkok, Thailand.
• [605] Li, H.-L. et al. (Editors), 1975—1979. Flora of Taiwan. Angiospermae. 6 volumes. Epoch Publishing Co., Taipei, Taiwan, Republic of China.
• [679] Miyazawa, M., Shimamura, H., Nakamura, S.I. & Kameoka, H., 1996. Antimutagenic activity of (+)—eudesmol and paeonol from Dioscorea japonica. Journal of Agricultural and Food Chemistry 44(7): 1647—1650.
• [750] Ohwi, J., 1965. Flora of Japan. Smithsonian Institution, Washington D.C., United States. 1067 pp.
• [753] Okagami, N. & Tanno, N., 1993. Gibberellic acid-induced prolongation of the dormancy in tubers or rhizomes of several species of East Asian Dioscorea. Plant Growth Regulation 12(1—2): 119—123.

Main genus page

• Dioscorea (Medicinal plants)

Authors

• R.C.K. Chung