Family • Dioscoreaceae - Dioscorea alata - YAM
|Ubi (Tag., Bis., Ilk.)|
A slender creeping vine reaching a length of several meters. The leaf-stalk slightly purple at both points of attachment. Root is tumorous, often with small axillary tubers.
Throughout the Philippines in thickets at low and medium altitudes.
Parts utilized and preparation
Tuber, 16″ long.
Additional Sources and Suggested Readings
(1) Anti-Fenton reaction activity of three taxa of water yam (Dioscorea alata L.) / Tsu-Shing Wang et al /International journal of food science & technology ISSN 0950-5423 / 2007, vol. 42, no9, pp. 1107-1113
(4) Effect of Yam (Dioscorea alata Compared to Dioscorea japonica) on Gastrointestinal Function and Antioxidant Activity in Mice / Journal of Food Science Vol 71 Issue 7, Pages S513 – S516 / 10.1111/j.1750-3841.2006.00113.x
(5) Both dioscorin, the tuber storage protein of yam (Dioscorea alata cv. Tainong No. 1), and its peptic hydrolysates exhibited angiotensin converting enzyme inhibitory activities / Feng-Lin Hsu et al /Agric Food Chem. 2002 Oct 9;50(21):6109-13.
(6) Cytokine-Mimetic Properties of Some Philippine Food and Medicinal Plants / Journal of Medicinal Food / June 2007, 10(2): 290-299. doi:10.1089/jmf.2006.067.
(7) Dioscorin isolated from Dioscorea alata activates TLR4-signaling pathways and induces cytokine expression in macrophages / Shu-Ling Fu et al / Biochemical and Biophysical Research Communications
Volume 339, Issue 1, 6 January 2006, Pages 137-144 • doi:10.1016/j.bbrc.2005.11.005
(8) The bone-protective effect of a Taiwanese yam (Dioscorea alata L. cv. Tainung No. 2) in ovariectomised female BALB/C mice / J Sci Food Agric 2009; 89: 517–522 / DOI 10.1002/jsfa.3489
(9) Chinese Yam (Dioscorea alata cv. Tainung No. 2) Feeding Exhibited Antioxidative Effects in Hyperhomocysteinemia Rats / Sue-Joan Chang et al / J. Agric. Food Chem., 2004, 52 (6), pp 1720–1725
(10) Effects of “Chinese yam” on hepato-nephrotoxicity of acetaminophen rats / Shih-Chang Lee et al / Acta Pharmacol Sin . Jun 2002; 23 (6)
• Antioxidant Activity (1) Local Root Crops as Antioxidant: A 2006 study of commonly consumed roots crops in the Philippines (Kamote, Ipomoea batata; ubi, purple yam, Dioscorea alata; cassava, Manihot esculenta; taro or gabi, Colocasia esculenta; carrot, Daucus carota; yacon (Smallanthus sonchifolius) showed them to be rich sources of phenolic compounds with antioxidant acitivity, highest in sweet potato, followed by taro, potato, purple yam and lowest in the carrot. (2) Study showed hyperhomocysteinemia induced by methionine could be reversed by D alata feeding. D alata feeding showed antioxidative effects.
• Anti-Fenton Reaction Activity / Copper-chelating and absorbing capability: Study of three taxa of D alata showed significant anti-Fenton reaction activity, similar to EDTA. Study showed copper-chelating and absorbing capability of yam tuber pulp.
• Bowel function benefits: Study showed 25% to 59% yam diet increased fecal mass and SCFA (short-chain fatty acid) output, modulated fecal microflora and thickened caecal mucosal lining in mice.
• GI function / Antioxidant: Rhizome extract of DA has been shown to possess radical scavenging activity. Study showed both Chinese yam and Japanese yam were beneficial for intestinal health and oxidation prevention.
• Estrogenic activity: Extract study isolated new and known compounds and showed activation of estrogen receptors alpha and beta. Results suggest beneficial effect of yam for menopausal women.
• Dioscorin / Angiotensin converting enzyme inhibition / Antihypertensive: Dioscorin, the tuber storage protein of yam and its hydrolysates presents potential use for hypertension control.
• Cholesterol lowering: Study showed reducing leffects of 50% yam diet on plasma and hepatic cholesterol levels probably through inflated fecal fat and steroid excretion.
• Cytokine-Mimetic property: Study that from extracts of yam roots and leaves( D alata), taro roots (Colocasia esculenta), buyo leaf (Piper betle) showed strongly stimulated proliferation of both bone marrow cells and splenocytes, significantly increasing cell concentrations.
• Disocorin / Cytokine Expression / TLR4-Signaling Pathway: TLR4 is a promising target for immunomodulating drugs and TLR4 agonists have therapeutic potential for treating immune diseases and cancer. Study shows dioscorin is a novel TLR4 activator and iinduces macrophage activation via TLR4-signaliing pathways.
• Estrogenic effect in menopausal women : In a study of menopausal women with rice staple diet replaced by yam (D alata) for 30 days showed improvement in status of sex hormones (estrone, sex hormone binding globulin, estradiol), blood lipids and antioxidants suggesting possible benefits in reducing breast cancer and cardiovascular disease in postmenopausal women.
• Bone-Protective Effect: Yam prevented loss of BMD (bone mineral density) and improved calcium status without stimulating uteriine hypertrophy in ovariectomized mice. TNG yam may be beneficial for postmenopausal women for preventing bone loss.
• Hypo-Triglyceridemic Effect: Yam may inhibit the acute induction of hypertriglyceridemia and liver enlargement in rats fed a high cholesterol diet.
• Renal Protective / Hepatoprotective: Pharmacologic and biochemical studies showed yam have both renal protective and hepatic fortification effects in acetaminophen rats. Results provide basis for the use of yam in traditional Chinese medicine for deficiencies of liver-yin and kidney-yin.