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Family Discororeaceae

Tugi
Dioscorea esculenta Lour.
LESSER YAM
Gan shu

Scientific names Common names
Dioscorea esculenta (Lour.) Burkill Aneg (Ibn.)
Dioscorea fasciculata Roxb. Boga (Ilk.)
Discorea papillaris Blanco Dukai (Iv.)
Dioscorea papuana Warb. Kamiging (Bik.)
Discorea tiliifolia Kunth Luttu (Ibn.)
Discorea tugui Blanco Toñgo (Tag.)
Onchorhiza esculentus (Lour.) Pers. Tugi (Tag., Ilk.)
Oncus esculentus Lour. Tuñgo (Tag.)
  Asiatic yam (Engl.)
  Chinese yam (Engl.)
  Lesser yam (Engl.)
Dioscorea esculenta (Lour.) Burkill is an accepted name The Plant List

Other vernacular names
ASSAMESE: Moa alu, Ruipheng silu.
CHINESE: Ci shu yu, You ci gan shu, Tian shu.
FRENCH: Igname De Chine épineuse, Igname Des Blancs.
GERMAN: Chinesischer yam.
PORTUGUESE: Inhame, Inhame-De-São.
SPANISH: Batata de China.
TAMIL: Siruvalli kilangu.
TELUGU: Tippa Tiga.

Botany
Tugi is a slender, slightly hairy, spiny vine, reaching a height of several meters. Tubers are 15 to 20 centimeters long, except in the case of some cultivated forms. Leaves are simple, suborbicular to reniform, 6 to 12 centimeters long, apiculate, the base 11- to 15-nerved, prominently heart-shaped, with rounded lobes. Spikes are slender, axillary, pubescent, up to 50 centimeters long. Flowers are green, about 4 millimeters in diameter.

Distribution
- In thickets and secondary forests at low altitudes in Bataan Islands, in Cagayan, Benguet, La Union, Pangasinan in Luzon, and in Semirara.
- Also cultivated, but not as extensively as ubi (Dioscorea alata).
- Also occurs in China, India to Malaya and Polynesia.

Constituents
- Contains 83% starch, 12% protein.
- Tubers are a good source of vitamin B.
- Phytochemical screening yielded saponins, diosgenin, ß-sitosterol, stigmasterol, cardiac glycosides, fat and starch.
- Edible yams have yield polyphenolic substances such as catechins, epicatechins, chlorogenic acids, leucoanthocyanidins and anthocyanins.
- Study of chemical composition of flours and starches (% dry weight basis) yielded total starch 74.66±0.66, protein 9.02±0.65, crude fat 1.5±0.2, crude fiber 2.33±0.15, ash 2.1±0.2. Phytochemical composition yielded
saponins 20.01±0.26, flavonoids 12.4±0.46, alkaloids 1.89±0.02. Mineral content analysis yielded calcium 8.29±0.06, iron 6.12±0.03, magnesium 33.6±1.19, potassium 190.91±0.78, zinc 1.19±0.08. (11)

Properties
- Traditionally uses suggest anti-inflammatory, anti-stress, anti-spasmodic properties.
- Studies have suggest antioxidant, antifertility, antibacterial, anti-inflammatory properties.

Part utilized
Root.

Uses
Edibility / Nutritional
- Tubers are boiled and eaten; cooked like potatoes.
- Rich in carbohydrates, a good source of vitamin B, with a nutritional value similar to ubi.
Folkloric
- The raw tubers are applied to swellings.
- In Indo-China, decoction of the tubers used for rheumatism and as diuretic.
- In China, used for beriberi.

- Tuber paste applied to ulcers, boils, abscesses.
- Used in the treatment of menopausal symptoms and other genital organ disorders.

Studies
Anti-inflammatory / Phytochemicals: Methanol extract study of D esculenta exhibited significant dose-dependent inhibition of carrageenan-induced edema and supports its folkloric use in inflammation. Phytochemical screening yielded saponins, diosgenin, ß-sitosterol, stigmasterol, cardiac glycosides, fat and starch. (1)
Antioxidant:
Study screening the phenolic content of different varieties of root crops in the Philippines, including D esculenta, found the roots crops a rich source of phenolic compounds with antioxidant activity.
Storage Effect:
Study of 1 to 7 weeks of storage revealed the moisture content, dray weight and starch levels decreased gradually with a concomitant increase in sugar content under different stages of dormancy. (
3)
Antioxidant / Phenolic Content:
Study of a methanolic extract showed a total phenolic content of 0.7 g/110g. Results confirmed potential in vitro antioxidant activity, which was attributed to phenols and flavonoids. (
6)
Inulin:
Study showed the production of inulin powder from lesser yam through the foam mat drying method using maltodextrin and egg white as filler and foaming agent. Inulin is a natural nondigestible fructooligosaccharide that occurs as reserve carbohydrate in several plants. Higher amounts of inulin could be extracted from D. esculenta compared to other tubers. (
7)
Antifertility Activity:
Study investigated the antifertility effect of an ethanol extract in male albino rats. Results showed antifertility effects by inhibition of sperm concentration, motility, and testosterone. (8)
Antibacterial / Mucilage:
Study investigated the in vitro antimicrobial activity of tuber mucilage extracted from D. esculenta against five human pathogenic bacterial strains. The extracts showed antibacterial activity against E. coli, P. aeruginosa, and S. aureus, with no activity against K pneumonia and S. pyogenes. (10)
Starch and Sugar Conversion During Storage:
Study showed moisture content, dry weight, and starch levels decreased gradually with a concomitant increase in sugar content under different stages of dormancy. (12)
Inulin Extract from Gembili Tubers as Prebiotic:
Prebiotic is added to food to support the growth of probiotics. Inulin is a carbohydrate that serves as an effective prebiotic that cannot be digested by digestive enzymes. Study tested gembili tubers as a source of prebiotic in probiotic bacteria L. casei. Best treatment results were obtained with isolates of L. casei obtained in fermentation medium with the addition of inulin from gembili tubers. (13)


Availability
Wild-crafted. 

Godofredo U. Stuart Jr., M.D.

Last Update December 2015

Photo © Godofredo Stuart / StuartXchange
IMAGE SOURCE: Dioscorea esculenta / File:Dioscorea esculenta 002.JPG / H. Zell / 27 September 2009 / GNU Free Documentaion License / Wikimedia Commons

Additional Sources and Suggested Readings
(1)
Anti-inflammatory studies of yam (Dioscorea esculenta) extract on wistar rats/ J O Olayemi and E O Ajaiyeoba / African Journal of Biotechnology Vol. 6 (16), pp. 1913-1915, 20 August 2007
(2)
Local Root Crops as Antioxidants / Innovations Report

(3)
Starch and sugar conversion in Dioscorea esculenta tubers and Curcuma longa rhizomes during storage / R Panneerselvam and C Abdul Jaleel / Caspian J. Env. Sci. 2008, Vol. 6 No. 2 pp. 151~160
(4)
Dioscorea esculenta (Lour.) Burkill (accepted name) / Chinese names / Catalogue of Life, China
(5)
Dioscorea esculenta (Chinese Yam) / Common names / Zipcodezoo
(6)
In vitro antioxidant studies of Dioscorea esculenta (Lour). Burkill
/ Manickam Murugan, Veerabahu Ramasamy Mohan* / Asian Pacific Journal of Tropical Biomedicine (2012)S1620-S1624
(7)
Preparation of Inulin Powder from Dioscorea Esculenta Tuber with Foam Mat Drying Method / Eni Harmayani, Sri Winarti, Rudi Nurismanto / 121th Asean Food Conference 2011.
(8)
Antifertility acitivity of ethanol extract of Dioscorea esculenta (L.) Schott on male albino rats. / P.S. Shajeela, V.R.Mohan*, L. Louis Jesudas and P.Tresina Soris / International Journal of PharmTech Research, Vol. 3, No.2, pp 946-954, April-June 2011
(9)
Dioscorea esculenta / Synonyms / The Plant List
(10)
Evaluation of Antibacterial Activity of the Mucilage of Dioscorea esculenta (Lour.) Burkill
/ A. Thajunnisha Begum, S. Anbazhakan * / International Journal of Modern Biology and Medicine, 2013, 4(3): 140-146
(11)
PROXIMATE ANALYSIS AND PHYTOCHEMICAL AND MINERAL CONSTITUENTS IN FOUR CULTIVARS OF YAMS AND TUBER CROPS IN SRI LANKA / Senanayake SA*, Ranaweera KKDS, Bamunuarachchi A and Gunaratne A / Tropical Agricultural Research & Extension 15(1): 2012
(12)
Starch and sugar conversion in Dioscorea esculenta tubers and Curcuma longa rhizomes during storage
/ R. Panneerselvam*, C. Abdul Jaleel / Caspian J. Env. Sci. 2008, Vol. 6 No. 2 pp. 151~160
(13)
Comparative Study of Inulin Extracts from Dahlia, Yam, and Gembili Tubers as Prebiotic
/ Elok Zubaidah, Wilda Akhadiana / Food and Nutrition Sciences, 2013, 4, 8-12 Published Online November 2013 / http://dx.doi.org/10.4236/fns.2013.411A002

It is not uncommon for links on studies/sources to change. Copying and pasting the information on the search window or using the DOI (if available) will often redirect to the new link page.

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