Dioscorea cayenensis

Sautour M, Mitaine-Offer A-C, Miyamoto T, Dongmo A, Lacaille-Dubois MA (2004) Antifungal Steroid Saponins from Dioscorea cayenensis. Planta Med 70 90... 

Yam tubers of Dioscorea alata (Umudike cultivar), D. rotundata (asukwu and obiaturugo cultivars)" and D. cayenensis (water yam and Nkokpu cultivars) were obtained from the National Root Crops Research Institute, Umudike, Nigeria. Some tubers were stored 6 or 12 months at room temperature (25-27 °C), some in vacuum dessicators over a suitable dessicant, and some in paper bags placed in a dark cabinet (absence of circulating air). Fresh tubers were peeled by carefully scraping away the cork layer to minimize loss of outer tissue since much of the protein is concentrated here ( ). They were then cut into 2 cu. cm. pieces, quickly frozen with solid CO2 in 50 9 portions in plastic bags, and stored in a freezer until needed. 

About 600 species of Dioscorea (Dioscoreaceae) are known, and a number of these are cultivated for their large starchy tubers, commonly called yams, which are an important food crop in many parts of the world. Important edible species are Dioscorea alata and D. esculenta (S E Asia), D. rotundata and D. cayenensis (W Africa) and D. trifida (America). A number of species accumulate quite high levels of saponins in their tubers, which make them bitter and inedible, but these provide suitable sources of steroidal material for drug manufacture. 

Yamogenin and yamogenin isomer diosgenin, (25J )-spirost-5-en-3P-ol (10-64) are the aglycones of saponins in yams Dioscorea spp., Dioscoraceae) whose starchy tubers are eaten in Africa, Southeast Asia and the Pacific region (D. alata and D. escuknta in Southeast Asia, D. trifida in South America, D. rotundata and D. cayenensis in West Africa). Yams typically contain 4-8% saponins, which are also a source of steroids for the pharmaceutical industry. 

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