Thevetia peruviana 黃花夾竹桃

POISONOUS PARTS

Whole plant, especially the seed kernels.^4,5

TOXICITY

• Toxic Constituents

  Cardiac glycosides such as thevetin A, thevetin B and neriifolin.⁶

• Toxic Dose

  Reported lethal dose: 1 seed.⁷

• Mechanism

  Cardiac glycosides inhibit Na⁺/K⁺-ATPase of the myocardium, increase its excitability and may lead to arrhythmias.^8–10

• Poisoning Features

  Digitalis-like toxicity such as nausea, vomiting, abdominal pain, dizziness, headache, hypotension, arrhythmias, hyperkalaemia, agitation, confusion, convulsion, coma and even death.¹¹

• Poisoning Events

  Poisoning cases due to oleander occurred in all parts of the world. In Sri Lanka, thousands of patients self-poisoned by ingesting the seeds every year; the mortality rate was more than 10%.⁷

CLINICAL MANAGEMENT

Supportive treatment. Multiple-dose activated charcoal therapy has been used for gastrointestinal decontamination in cardiac glycoside poisoning, and digoxin-specific antibody has been used as antidote.^12,13

IDENTIFICATION FEATURES

Small evergreen trees, up to 6 m tall, with milky sap; bark lenticellate. Branches slender and pendulous, leaves crowding near the end of branchlets. Leaves subleathery; leaf blades 10–15 × 0.5–1.2 cm, lateral veins obscure. Flowers yellow, corolla 6–7 × 4.5–5.5 cm. Drupes 2.5–4 cm in diameter. Seeds about 2 × 3.5 cm, light grey.¹⁴

MEDICINAL USES

Highly toxic; use with caution. Uses in TCM—leaves (for external use only): remove toxin and disperse swelling; kernel extract: induce diuresis and disperse swelling, strengthen heart. Fresh kernels should not be taken internally.^2,15

LABORATORY ANALYSIS

Thevetin A, thevetin B and neriifolin can be detected by LC-MS/MS.^16,17