Transcript Elephant Ear - University of New Mexico

Toxicity in Humans by Ingestion of
Colocasia esculenta
(Elephant Ear)
Audrey Medina
Barry Sandall
Loucia Jose
Biology 445
May 04, 2007
What is Colocasia esculenta?
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Herbaceous, flowering plant of the family Araceae.
Commonly referred to as ‘Elephant Ear’
because of its large leaves
resembling elephant ears.
Grown in tropical areas as a staple food resource
(taro) by many indo-asian countries
Description
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Perinnial monocot
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Large, arrowhead-shaped leaves
can grow to be 3’ X 2’
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Long stalk
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Flowers are arranged in a spadix
with green or yellow spathe
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Taro corms present in the root
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similar in appearance to a yam or
potato
Distribution
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Native to tropical Polynesia and southeastern Asia
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Grows naturally in tropical and subtropical areas but will
grown in temperate climates as well
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Introduced to United States, considered an invasive
species in some areas
Uses:
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Grown primarily as a vegetable food for its
edible corm
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Taro corms are used most
famously in the Hawaiian
dish known as poi.
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Also grown as a leaf vegetable for food.
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Popular in the United States for its foliage and used
mainly for aesthetic purposes.
Toxic Parts of Plant
The entire plant is toxic!
Leaf, stem, and root.
SO WATCH OUT!!!
Signs and Symptoms
If Ingested Raw:
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Intense burning and irritation of lips, mouth, tongue,
and throat.
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Vomiting
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Diarrhea (Uncommon)
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Base of tongue swells and can be fatal if swelling is
large enough to block the air passage of the throat.
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Death by asphyxiation!
Toxic Agent
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Elephant ear contains calcium oxalate crystals
which are needle-shaped and arranged in
compact bundles.
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When chewed the crystals are ejected from
specialized explosive ejector cells.
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Needles get lodged in the lining of the mouth,
tongue, and throat leading to local
inflammatory reactions.
Toxic Principle
Calcium oxalate crystals-Raphides
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Oxalate is an unstable salt of oxalic acid
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Oxalic acid is soluble in water, alcohol, and
ether.
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Composed of:
2 carboxyl groups
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Creates dangerous
free-radicals in body.
Mechanism
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Needle fibers induce inflammatory response and
edema in oral cavities and mucous membranes.
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Can lead to aphyixiation
Calcium oxalate dissolves in the stomach to form
oxalic acid.
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more readily absorbed into the
blood and circulation system.
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Very dangerous if ingested in large amounts
Toxicity
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Oxalic acid can binds with calcium in the body
resulting in hypocalcemia.
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Can lead to muscle cramps, hypotension, bradycardia, and
cardiac arrhythmia.
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Binding of oxalic acid with calcium in the body can
induce crystallization of calcium oxalate.
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Calcium oxalate can build up in the body.
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Major cause of kidney stones.
Can lead to liver and kidney failure and cause permanent
damage.
Treatment and Other Precautions
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Calcium chloride and calcium gluconate should be
administered for large ingestion of plant…why?
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Calcium chloride and gluconate act by replenishing the
calcium in the circulation, thus reducing the toxic effects.
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Providing extra calcium reduces the toxic danger of the
free oxalic radicals.
As a precaution, Elephant Ear
should be eaten with milk or
other foods rich in calcium.
Summary of Toxicity
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Oxalate crystals on plant cause extreme inflammatory immune
response which may lead to death.
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Minor gastrointestinal distresses to serious heart conditions
can be caused by low calcium levels due to oxalic acid
ingested from Colocasia esculenta.
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Kidney stones, major organ failure,
and tissue damage can also result
from deposits of calcium oxalate,
formed by oxalic acid binding
calcium in the body.
Conclusions
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Colocasia esculenta (Elephant Ear, taro) can cause many toxic
effects in humans with potential for serious damge or death.
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Colocasia esculenta should NEVER be eaten raw.
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Proper cooking methods and precautions should be followed
closely.
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Calcium should be taken appropriately when ingesting.
Conclusions cont…
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Taro must be the most delicious dish in the
world.
Because, really, why the hell is anyone eating
this thing?
Yummy!
References
Beaulieu, David. 2007. Elephant Ear Plants. About: Landscaping.
<http://landscaping.about.com/od/unusualplants1/p/elephant_ears.htm>
Kuhlken, R. 2002. Intensive Agricultural Landscapes of Oceania. Journal of
Cultural Geography. 19: 161-195.
Plant Profile: Colocasia esculenta . USDA Natural Resources Conservation
Services. 2007. <http://plants.usda.gov/java/profile?symbol=COES>
Tagwireyi, D. and Ball D.E. 2001. The management of Elephant’s Ear
poisoning. Human & Experimental Toxicology. 20: 189-192.
Wagner, W. L., D. R. Herbst, and S. H. Sohmer. 1999. Manual of the
Flowering Plants of Hawai‘i. Revised edition. Vol. 2. University of Hawaii
Press/Bishop Museum Press. p. 1357.