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Family Dioscoreaceae
Nami
Dioscorea hispida Dennst.
INTOXICATING YAM
Bai shu liang

Scientific names  Common names 
Dioscorea daemona Roxburgh Bagay (Mbo.) 
Dioscorea hirsuta Blume Gagos (Bis.) 
Dioscorea hispida Dennst. Kalut (Tag., Pamp., Sbl.) 
Dioscorea lunata Roth Karot (Ilk.) 
Dioscorea mollissima Blume Karoti (Sul.) 
Helmia daemona (Roxb.) Kunth Kayos (Tag.) 
Helmia hirsuta (Blume) Kunth Kalot (Bis.) 
  Korot (S.L. Bis.) 
  Kulot (Sbl.) 
  Kurot (Mind.)
  Mamo (Bik.) 
  Nami (Tag.) 
  Orkot (Bis.) 
  Asiatic bitter yam (Engl.) 
  Intoxicating yam (Engl.) 
  Starch tuber (Engl.) 
Dioscorea hispida Dennst. is an accepted name The Plant List

Other vernacular names
ASSAMESE: Hati-muria alu.
BURMESE: Kywey, Kywe.
CHINESE: Bai shu liang, Bai, Da.
FRENCH: Igname épineuse Amère, Morsure De Cobra.
GERMAN: Bittere yamswurzel, Giftige yams.
JAPANESE: Mitsuba dokoro.
LAOS: Houo Koi
MALAY: Gadog, Gadong Mabuk, Gadung (Java), Taring Pelanduk, Ubi Akas, Ubi Arak, Ubi gadung.
MALAYALAM: Podava Kelengu.
LAOS: Houo Koi
MARATHI: Baichandi, Bhul Kand, Dukar Kand.
PORTUGUESE: Inhame.
SANSKRIT: Hastyaluka.
SUNDANESE: Gadung.
TAMIL: Kavalakodi, Pei Perendai, Periperendai.
TELUGU: Chanda gadda, Puli dumpa, Tellaagini geddalu, Thella chanda gadda, Thella gadda.
THAI: Khil, Kloi hua niao, Kloi khao khao, Kiok nok, Koi, Man kloi.

Botany
Nami is a twining vine, arising from tuberous roots, and reaching a length of several meters. Stems covered with few or many short, sharp spines. Leaves are 3-foliolate, the leaflets 12 to 20 centimeters long, somewhat hairy, the lateral ones oblique, oblong-ovate, the terminal one equilateral, oblong to oblong-obovate. Panicle is axillary, slender, hairy, 12 to 20 centimeters long. Flowers are small; unisexual male flowers with 6 stamens; female flowers similar to males, 3-winged, 3-celled, ovules 2 in each cell. Fruit is a capsule, oblong and about 5 centimeters long. Flesh and sap of tubers are yellowish.

Distribution
- Growing wild, chiefly in thickets and forests at low and medium altitudes throughout the Philippines.
- Rarely cultivated.
- Occurs in India to China and Taiwan and through Malaya to New Guinea.

Constituents
- Tubers yield alkaloid dioscorine a and 4-epidioscorine and a neuromuscular blocking agent.

- Study yielded a saponin glycoside, diosgenin. The primary active ingredient in Dioscorea species, diosgenin is D. hispida is reported at 57µg/g dw.
- Study of mineral content reports the tubers are a good source of phosphorus, calcium and iron.
- A mature gadung tuber weighs up to 15 kg, each 100 g of tuber (wet basis) yields 20 g of carbohydrates, 78 g water, 1.81 g protein, 0.16 g fat, 0.93 g fiber and 0.69 ash.
- Extracts of tubers yielded hydroxybenzoic acid, hydroxycinnamic acid, and their derivatives. Peel yielded caffeic acid, chlorogenic acid, p-hydroxybenzaldehyde and methylester of protocatechuic acid. Phenolic acid content of both peel and flesh were very low. (11)

Properties
- Resistant starch is slowly digested in the lower parts of the GIT, with slow release and absorption of glucose. Starch is also gluten free.
- Sweet tart-tasting, cooling.
- Yellow flesh tubers reported to have a better taste than white flesh tubers.
- Flesh and sap of the tubers are yellowish.
- Anti-infectious, antiphlogistic, anticontusion, hemostatic.
- Juice of underground stems reported to possess narcotic properties.
- Studies suggest anthelmintic, antioxidant, anti-inflammatory, analgesic, and anti-tumor activities.

Toxin removal
- There regional variations to the removal of toxin from the intoxicating tubers. Pulau Redang has several detoxification techniques. One requires thin slicing of yam, the soaking it in salted water for three days, then placing it in a sac to re-soak in a river or flowing water for another three days, finally testing edibility to see if fish would feed on them.
- In Papua New Guinea, the tubers are sliced and boiled for two days before cooking the yam.
- In Thailand, the Sakai remove the toxin by boiling with wood ashes.

Parts utilized
- Underground tubers.

Uses
Edibility / Nutrition
- Tuber crop is an important source of carbohydrates; has been used a staple foods during WWI.
- Roots used as food by the Ayta communities from Porac, Pampanga.
- Rootcrop, kurot or nami, used as supplementary food by the Hanunuo Mangyans of Mindoro. (20)
- Despite known toxicity, in Thailand, where it is referred to as Kloi, tubers are used to make a dessert called Kao Nuew Kloi.
- In India used as famine food. Poison removed by boiling or keeping the tubers overnight in water.
- In Kerala, India, tuberous herb cooked with salt, chili, tamarind and tumeric powder and used as curry.
- Caution: See toxin removal.
Folkloric
- Tuber, raw or cooked used as anodyne and maturative for tumors and buboes.
- Also used arthritic and rheumatic pains. sprains and contusions.
- Used by the Ayta communities of Porac, Pampanga for wounds and clotting. (16)
- Use poultice of freshly pounded material or decoction as external wash.
- In Bangladesh, tubers used to kill worms in wounds. Various plant parts used in whitlow, sores, boils, and bites of rabbit, jackal or dog.
- In India, tubers used for birth control. Also used for ulcer treatment.
- Tuber paste is applied to peeling skin of feet.
- In Malaysia, pounded leaves applied to sores of yaw.
- In Johore, decoction of tuber used as alterative and diuretic in chronic rheumatism.
- In Malaysia, the Temuan tribe uses pounded leaves from intoxicating yam for healing sores of yaw. Infusion of corms of detoxicated tubers used to decrease blood glucose. Tendril of yam have been used as deworming medicine.
- In Thailand, used to treat constipation.
Others
Bleaching: Yellow juice from the flesh and sap of tubers is used for bleaching clothes and abaca fibers.
Poison: Juice of tubers used in criminal poisoning.
Also, used as an ingredient together with Antiaris toxicaria in the preparation of arrow poisons.
Intoxicant: Jeypore people of India reportedly use the intoxicating effect of D. hispida to forget their sorrows, as they get an effect similar to drinking beer.
Insecticidal: Residue after extraction of poison used as insecticidal.
Livestock: Tubers used as cure for myiasis of the scrotum in carabaos.

Studies
Phytochemicals / Phenolic Content: Study showed phenolic acids were present in only small amounts in Kloi tuber, compared to relatively high phenolic content for other yam Dioscorea species. The anomaly was attributed to the sample preparation, hydrolysis time and/or pH. Preliminary findings and documented nutritive value suggest the tuber as a potential source of phytochemicals for cosmetic, pharmaceutical or dietary antioxidant use. (2)
Anti-Inflammatory / Analgesic: Study of extract of D. hispida in animal models showed potent analgesic and anti-inflammatory effects and therapeutic efficacy, comparable to standard drugs Pentazocine and indomethacin respectively. (3)

Toxicity Study: Study of ethanolic extract showed no toxicity or death at given test dose levels. LD50 was >2000 mg/kbw for the extract.
Hypoglycemic Effect: Study in alloxan-induced hyperglycemic rats evaluated the hypoglycemic effect of a water soluble polysaccharide extracted from yam tuber (D. hispida). All the WSP extracts exhibited an ability to decrease blood glucose in hyperglycemic condition as well as inhibit glucose absorption and short chain fatty acid (SCFA) formation. (4)
Gadung Starch / Modification with Raw and Ginger Oil: Use of starch is limited by its high content of toxic substances, i.e. alkaloids and hydrogen cyanide in free and bound forms, high moisture content and a disposition to post harvest deterioration. Previous efforts have been successful in reducing the bitter and toxic compounds to a safe level. Study showed processing and modification resulted properties comparable to American wheat flour. One drawback was the presence of remaining ginger aroma. (7)
Pharmacologic Effects of Extracts: Purified extracts studied in animals showed: (1) Properties resembling nicotine (2) Injection caused hyperpnea, tachycardia, increase in blood pressure, contraction of nictitating membrane. (3) Rise in BP and contraction of nictitating membrane and of smooth muscle were inhibited by pretreatment with hexamethonium. (4) Striated muscle contraction was inhibited by pretreatment with d-turbocurarine. (9)
Antitumor / Antioxidant: Study evaluated D. hispida against an animal model of Ehrlich Ascites Carcinoma. An ethanolic extract showed significant anticancer activity at varying doses, increasing survival, and decreasing tumor burden. Reduced elevated levels of lipid peroxidation was attributed to a high content of phenolic compounds. (10)
Mosquito Repellent Additive: Study showed nami (Discorea hispida) tuber crude extract added to the citronella, neem, and eucalyptus mosquito repellent product is very acceptable based on skin tolerance and overall repellency, while providing a non-irritating alternative to synthetic compounds. (12)
Dioscorine / Neurotoxic / Dried Tubers: Dioscorea hispida contains the neurotoxic dioscorine, an isoquinuclidine alkaloid that causes nervous system paralysis. Study evaluated the dioscorine content of D. hispida dried tubers in Thailand. TLC-densitometry and TLC image analysis yielded a dioscorine content of 0.72 ± 0.07 % w/w and 0.66 ± 0.07 % w/w, respectively. (14)
Starch-Based Hydrogels / Disinfectants: Novel Dioscorea hispida starch-based hydrogels inhibited Escherichia coli, Staphylococcus aureus, Saccharomyces cerevisiae, and Salmonella typhimurium growth. it showed an acceptable level of toxicity. Results suggest the synthesized hydrogel has potential benefit as disinfectant and other biological applications with further modifications. (15)
• Hypnotic Effect / Leaves: A previous study has shown the aqueous crude extract of nami leaf to have sedative effect. This study evaluated and compared an aqueous leaf extract with 70% v/v methanol leaf extract in BALB/c mice. Results showed the crude aqueous leaf extract to possess potent hypnotic activities, supporting its therapeutic effect for insomnia. However, on semi-purification, no significant hypnotic effect was observed. (17)

• 1937 Toxicological Study: This 1937 study reports on the toxicological evaluation of Dioscorea hispida. It makes mention of nami as a cause of accidental food poisoning and use with criminal intent. An alkaloid was present, more or less uniformly distributed, in both cortical and medullary parts. The toxicity was tested on mosquito fish, mice, and monkey; by analogy, the fatal dose for a 50 kg ma would be 2.5-3 gm. (18)
• Anthelmintic / Leaves: Study investigated alcoholic extracts of leaves of D. hispida for anthelmintic activity against Pheretima posthuma. Results showed significant anthelmintic activity comparable to standard Albendazole. (19)
• Potential as Rodenticide: Study evaluated a formulation of yam-tuber as rodenticide for rat pest control using three treatment doses i.e., 300 g, 600 g, and 900 g of yam tuber. Rats that fed on baits showed slow motion movement, quiet stay, shaking, paralysis before death and the higher the dose the more significant the effects. (21)

Caution !
- Tubers contain the poisonous alkaloid dioscorine, resembling picrotoxin.
- It is a nervous system paralyzant, not a protoplasmic poison.
- Neurotoxicity manifestations range from dizziness, altered consciousness, muscle paralysis and seizures.
- It has been reportedly used in criminal poisoning.

Availability
Wild-crafted.


Updated July 2018 / October 2016

IMAGE SOURCE: Dioscorea hispida Dennst. [as pódava keléngú] [syn. Dioscorea hirsuta Blume] . / Rheede tot Drakestein, Hendrik van, Hortus Indicus Malabaricus, vol. 7: t. 51 (1686)/ Illustration contributed by the Library of the Missouri Botanical Garden, U.S.A./ http://plantillustrations.org/illustration.php?id_illustration=123074 / Plant Illustration
OTHER IMAGE SOURCE: Dioscorea hispida, leaves & stem. Banyumas, Central Java. / Berkas:Diosc hispi 090103-5117 rwg.JPG / 3 January 2009 / Karya sendiri / Wibowo Djatmiko/ isensi Dokumentasi Bebas GNU / click on photo to go to source image / Wikipedia
OTHER IMAGE SOURCE: Photograph / Tuber / Berkas:Umbi-gadung.jpg / Dari Wikipedia bahasa Indonesia, ensiklopedia bebas / Gambar ini mungkin dilindungi hak cipta dan tidak memiliki izin dari pemilik hak ciptanya. Penggunaan gambar dengan resolusi rendah ini diyakini / click on photo to go to source image / Wikipedia

Additional Sources and Suggested Readings
(1)
The Wild Yam – a review / Anthony Dweck
(2)
Analysis and identification of phenolic compounds in Dioscorea hispida Dennst / Sudawadee Theerasin and A T Baker / As. J. Food Ag-Ind. 2009, 2(04), 547- 560
(3)
Evaluation of Ethanolic Extract of Dioscorea hispida Dennst. for Anti-Inflammatory and Analgesic Activities / Panduranga Murthy et al / Int. J. Pharm & Ind. Res, Vol 1, No 2, Apr-June 2011
(4)
Hypoglycemic Activity of Water Soluble Polysaccharides of Yam (Dioscorea hispida Dents) Prepared by Aqueous, Papain, and Tempeh Inoculum Assisted Extractions
/ Teti Estiasih, Harijono, Weny Bekti Sunarharum, Atina Rahmawati / World Academy of Science, Engineering and Technology 70 2012
(5)
DIOSCOREA HISPIDA Dennstedt / Medicinal Plants of Bangladesh
(6)
Dioscorea hispida / Common names / Zipcodezoo
(7)
Water Solubility, Swelling and Gelatinization Properties of Raw and Ginger Oil Modified Gadung (Dioscorea hispida Dennst) Flour / Andri Cahyo Kumoro, Diah Susetyo Retnowati, Catarina Sri Budiyati, Thamrin Manurung and Siswanto / Research Journal of Applied Sciences, Engineering and Technology 4(17): 2854-2860, 2012
(8)
Ethnobotany and Distribution of Wild Edible Tubers in Pulau Redang and Nearby Islands of Terengganu, Malaysia / M. Nashriyah, M. Y. Nur Athiqah, H. Syahril Amin, N. Norhayati, A. W. Mohamad Azhar, M. Khairil / World Academy of Science, Engineering and Technology 60 2011
(9)
Pharmacological effects of the extract of dioscorea hispida / Natural Sciences Repository
(10)
Evaluation of antitumour activity and antioxidant status in Discorea hispida Dennst. leaves on Ehrlich Ascites Carcinoma in Swiss Albino Mice / Punith Kumar, Pandurang Murthy, G Suresh et al / Int. J. Drug Dev. & Res., Apr -Jun 2011, 3(20: 203-210.
(11)
Analysis and identification of phenolic compounds in Dioscorea hispida Dennst / Sudawadee Theerasin* and A.T. Baker / As. J. Food Ag-Ind. 2009, 2(04), 547- 560
(12)
Utilization of Nami Roots (Dioscorea hispida) as an Additive in Citronella, Neem and Eucalyptus Oil-Based Mosquito Repellent
(13)
Dioscorea hispida / Synonyms / The Plant List
(14)
Dioscorine content in Dioscorea hispida dried tubers in Thailand by TLC-densitometry and TLC image analysis / Nonglapat Sasiwatpaisit, Worathat Thitikornpong, Chanida Palanuvej / Journal of Chemical and Pharmaceutical Research, 2014; 6(4): pp 803-806
(15)
Novel Dioscorea hispida starch-based hydrogels and their beneficial use as disinfectants
/ Imran Azman,
Sahilah A Mutalib, Siti Fairus M Yusoff, Shazrul Fazry, Akram Noordin, Malina Kumaran, Azwan Mat Lazim / Journal of Bioactive and Compatible Polymers: Biomedical Applications, January 2016 Vol 31 No 1 / doi: 10.1177/0883911515597704
(16)
Useful Plants of Selected Ayta Communities from Porac, Pampanga, Twenty Years after the Eruption of Mt. Pinatubo / Elena M. Ragragio*, Cynthia Neri Zayas** and Jasper John A. Obico* / Philippine Journal of Science, 142: 169-181, Special Issue
(17)
Bioassay-guided fractionation of hypnotic component from Nami (Dioscorea hispida Dennst.) leaf extract using balb/C mice. / Ana Joy P. Padua / Thesis/Dissertation 2014: University of the Philippines / Herdin Record #: PCHRD14061816344943 
(18)
Toxicological Studies of Nami, Dioscorea hispida, Dennst. / Leyva, Jose F; Gutierrez, Eusebio / Journal of the Philippine Islands Medical Association, 1937; Vol 17, No 6: pp 349-356
(19)
In Vitro Anthelmintic Activity of Dioscorea hispida (Dennst.) Leaves / Suresh A, Panduranga Murthy G, Punith Kumar T G,, Karthika T S, Sanjay Prajapati, Atif Abdelgalil Hasab / International Journal of Xenobiotics and Pharma Technology, 2011; 1(2): pp 41-43
(20)
The Kurot or Nami (Dioscorea hispida Dennst.) and its uses as a supplementary food supply among the Hanunuo Mangyans of Mindoro, Philippines / Postma, Antoon / Manuscript / Mangyan Heritage Center: Safeguarding the indigenous culture of Mindoro, Philippines
(21)
TROPICAL YAM-TUBER (DIOSCOREA HISPIDA DENNST.): FORMULATION AND A FUTURE NATURAL RODENTICIDE TO CONTROL RAT PEST IN RICE FARMING / Ahdin Gassa / International Journal of Chemical and Pharmaceutical Analysis, 2017; Vol 4, No 3.


 

 


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