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Botany
Biga is a coarse and erect plant with a stout
trunk, growing up to 2 meters high. Leaves are very large, broadly
ovate, the larger ones up to 1.5 meters long, with slightly undulate margins, a pointed apex
and a deeply cordate base, not at all peltate. Petiloes are long and stout. Spathes are
peduncled with the tube 4 to 5 cm long, the blade yellowish to yellowish-green
up to 23 cm long and 9 cm wide when spread, slightly mottled with purple inside. Spadix pistillate
is 3 to 4 cm long, 1.5 cm thick, contracted above. Fertile part of the male inflorescence is about 6 cm long, the appendage about 15 cm long.
Berries are globose or ovoid, fleshy, and red when mature.
Distribution
Wild in clearings and secondary forests
at low and medium altitudes.
Commonly cultivated as an ornamental.
Occurs in India to Malaya.
Constituents
Rhizomes contain phytosterols,
alkaloids, glucose and fructose.
Root tuber contains neurotoxin, sapotoxin.
Study has yielded alocasin, an antifungal and trypsin inhibitor.
Study isolated a new ceramide, alomacrorrhiza A, from an ethanolic extract.
Stems, corms, leaves and petioles contains numerous, needlelike, stinging crystals of calcium oxalte (raphides).
Parts used
Stems, leave, rhizomes.
Uses
Nutritional
Stems and corms are edible; used as food during
scarce times.
Folkloric
• Leaves and
corms used for furuncles, impetigo and snake bites
• Ground petioles in near-decayed state are placed in cloth and
heated in coals, used for toothaches.
• Decoction of rhizomes used for abdominal pains and vomiting.
• Acrid juice used for stings of giant nettles (Laportea).
• In Java, chopped
roots and leaves applied to painful joints.
• In India, rhizomes
are rubefacient; employed as external stimulant and for fevers.
• In Vietnam used to treat inflammation, eczema and abscesses.
Studies
• Antifungal / Anti-HIV1 Reverse Transcriptase:
Alocasin, an anti-fungal protein was isolated from the rhizome of Alocasia
macrorrhiza. and showed antifungal activity against Botrytis
cineria. Alocasin also reduced the activity of HIV1 reverse transcriptase.
• Neurotoxicity / Sapotoxin:
A case report of poisoning due to the raw root tuber of Chinese medicinal
plant, A macrorrhiza, presenting with severe pain and numbness periorally,
with nausea, vomiting and abdominal pain. Root tuber is known to contain
the neurotoxin, sapotoxin.
• Anti-Tumor:
In a study of the antitumor effect of water extract of Alocasia macrorrhiza, the inhibitory rate was 29.38% against S180 in mice and 51.72% against transplantable human gastroadenitis in nude mice.
• Hepatorenal Effects / Concerns:
Plant extract was studied for effects on hepatorenal functions in mice. After treatment, RBC, Hb, protein, albumin and globulin were significantly decreased while AST, ALT, GGT, LDH,creatinine, total lipid and cholesterol were significantly increased after treatment and recovery period of 10 days. Histopath changes noted after treatment disappeared after a recovery period of 20 days. However, vascular congestion persisted. The high LD50 of the reversible action of the plant require more studies before recommendations are made regarding its safety as a medicinal plant.
• Calcium Oxalate:
Plant extract
Caution
/ Toxicity
• Stinging Raphides: Stems, corms,
leaves and petioles contain stinging raphides (calcium oxalate crystals)
that are destroyed by boiling and roasting.
• Neurotoxicity:
Case report possiblty caused by tuber root neurotoxin, sapotoxin.
• Retrospective study: Retrospective study on A. macrorrhiza poisonings of 27 cases (25 leaf or tuber consumption, 1 eye contact, 1 skin contact) suggests sapotoxin and calcium oxalte as the toxic components. Primary symptom was sore throat redness with numbness of the oral cavity. Other complaints were salivation, dysphonia, abdominal pain, mouth cavity ulcers, dysphagia, thoracodynia. chest tightness and swollen lips.
Availability
Wildcrafted.
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