Dioscorea yams

Protein-Nitrogen Conservation in Fresh Stored Dioscorea Yams... 

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. 

Although all the main classes of steroids have now been attained by total synthesis, most drugs are in fact, as noted above, prepared by partial synthesis from natural products that contain the steroid nucleus. The bulk of the world s supply of steroid starting material is derived by differing chemical routes from only two species of plants the Mexican yam, a species of Dioscorea, and the humble soybean. The advantage of using plants rather than valuable domestic animals as raw material is fairly obvious. 

Dimethothiazine, 374 Dimethoxanate, 390 Dimethylpyrindene, 145 Dimethylthiambutene, 106 Dimetridazole, 240 Dinoprost, 27, 33, 34 Dinoprostone, 27, 30, 33, 35 Dioscorea, see Mexican yam Diosgenin, 156, 182 Dioxyline, 349 Diphenhydramine, 41 Diphenidol, 45 Diphenoxylate, 302 Diphenylhydantoin, 246 Di phepanol, 46 Dipipanone, 80 Dipiproverin, 94 Dipyridamole, 428 Displacement, bromine by nitro, 247... 

Wild yam (Dioscorea) Menopause symptoms does not supply progesterone... 

Yoshida, K. et al., Structures of alatanin A, B and C isolated from edible purple yam Dioscorea alata, Tetrahedron Lett., 32, 5575, 1991. 

Dioscorea batatus Decaisue Shu Yu (Yam) (root) Allantoin, arginine, d-abscisin, mannan, phytic acid, diosgenin, protein, glycosides, triterpene glucosides.48-461-462 Antitumor, sore throat, swelling, food poisoning, goiter, hernia, purulent inflammations. 

Dioscorea bulbifera L. Huang Yao Zi (Potato yam) (rhizome) Saponins, dioscorecin, iodine, dioscoretoxin, saponins, diosgenin, diosbulbin, tannins, campesterol, beta-sotpsterols, stigmasterol, diosbulbines 3348 Treat cancer, goiter. 

Dioscorea cirrhosa L. D. hispida Dennst. D. japonica Thunb. Shu Liang (Dyeing yam) (tuber) Tannins, mucus 33 Hemostatic, increases platelet aggregation, increases uterine contraction. 

Dioscorea nipponica Makino Chuan Shan Long (Japanese yam) (root) Dioscin, diosgenin, trillin, 25 -D- spire sta-3,5 -diene33 -53 Anti-inflammatory, antitussive, expectorant, antiasthmatic. 

Dioscorea opposita Thunb. Shan Yao (Chinese yam) (leaf, tuber, root) Allantoin, arginine, choline, glutamine, leucine, tyrosine, diosgenin, sinodiosgenin.50 Leaf juice for snakebite, root for asthma, cachexia, cough, debility, diarrhea, neurasthenia, polyuria, tuber is anthelmintic. 

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. 

Powdered Dioscorea (wild yam) root or extract is also marketed to treat the symptoms of menopause as an alternative to hormone replacement therapy (see page 279). Although there is a belief that this increases levels of progesterone, which is then used as a biosynthetic precursor of other hormones, there is no evidence that diosgenin is metabolized in the human body to progesterone, and any beneficial effects may arise from diosgenin itself. 

Dormancy in yam bulbs (Dioscorea batatas) was found to be induced by three inhibitors, batatasins I, II, and III (72, 73). The structures for batatasins I and III were assigned recently. Batatasin I is 6-hydroxy-2,4,7-trimethoxyphenanthrene and batatasin III is 3,3-dihydroxy-5-methoxy-bibenzyl. Biogeneti-cally, hydrangenol, lunalaric acid and batatasin III appear to... 

Ex precursor Protogracillin in Dioscorea spp. (Mexican yam) (Dioscoreaceae) [anti-rheumatic, anti-arthritic plant], Costus speciosus (Zingiberaceae)... 

They are also an insect pheromone (grandisol) and defence substance (polyzonimlne), stephanine is an aporphine alkaloid, scytalone a fungal metabolite, and diosgenin is a rare vegetable saponin from Dioscorea, the Mexican yam. It is useful as animal steroids can be made from it (p. 999). 

People around the world enjoy Africa s culinary contributions. These include the peanut Arachis hypogaea, Fabaceae), yam (Dioscorea spp., Dioscoreaceae), watermelon Citrullus lanatus, Cucurbitaceae), okra Abelmoschus esculentus, Malvaceae) and many other foods and flavors. In North America and in many other parts of the world there is little recognition of the many contributions that Africa has made to modem culture, i.e., perhaps beyond the domain of etlmobotanists and pharmacognosists. 

Dioscorea dregeana (Knnth) T. Durand Schinz [ndiyaza, wild yam] (Dioscoreaceae) bnlb decoction is used for psychosis (11). 

Extracts of Mexican wild yam (Dioscorea) can also be used, or other estrogen precursors or dehydroepiandros-terone (DHEA). 

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