Alocasia cucullata 尖尾芋

Araceae 天南星科

Chinese Taro1

假海芋、老虎耳、獨腳蓮、觀音蓮、姑婆芋2

POISONOUS PARTS

Whole plant.3–5

TOXICITY

  • Toxic Constituents
    Calcium oxalate raphides, sapotoxins and other unidentified toxins.2
  • Toxic Dose
    Small amount of sap can cause local symptoms. Ingestion of less than half a fruit can be fatal.2–5
  • Mechanism
    The toxic mechanism of the poisonous plants in the Araceae family is not fully understood. Calcium oxalate raphides stored in specialized cells known as idioblasts are released when subjected to mechanical pressure such as ingestion and contact, causing tissue irritation and inflammation. Other toxic ingredients that are commonly found in the family, such as sapotoxins and cyanogenic glycosides, may also play a role.4,6
  • Poisoning Features
    Skin contact with sap: itchiness. Eye contact with sap: may cause blindness. Ingestion of stems or leaves: burning sensation of the tongue, oral cavity and stomach, salivation, nausea, vomiting, diarrhoea, dysphagia, dysphonia; convulsion, airway obstruction and death in severe cases. Ingestion of fruits: metabolic acidosis, liver impairment, arrhythmias and even death.2–5
  • Poisoning Events
    In Sri Lanka, 2 siblings had fatal poisoning after sharing a fruit of the plant. The 4-year-old sister, who took a larger portion, died 20 hours after consumption. The 7-year-old brother, despite intensive hospital care, died 5 days later.5

CLINICAL MANAGEMENT

Supportive treatment. Maintenance of airway by intubation or tracheostomy may be required for severe cases with airway compromise.7,8

IDENTIFICATION FEATURES

Evergreen herbs, caulescent stock branched, 3–6 cm thick, stoloniferous. Leaves peltate; petioles 25–80 cm long; leaf blades 10–16(–40) × 7–18(–28) cm, base shallowly cordate, lateral veins 4–8 pairs. Inflorescence usually solitary, peduncles 20–30 cm long; spathes 4–8 cm long, limb 5–15 cm long, spadix with terminal appendage. Berries 6–8 mm in diameter, red when ripe.9

MEDICINAL USES

Rhizomes used in TCM: clear heat and remove toxin, disperse swelling, dissipate binds and relieve pain. Recommended dose: 3–9 g.2,10,11

LABORATORY ANALYSIS

Calcium oxalate raphides can be detected by polarizing microscopy.12