Datura metel 洋金花

POISONOUS PARTS

Whole plant, especially the flowers and seeds.³

TOXICITY

• Toxic Constituents

  Solanaceous tropane alkaloids such as atropine, hyoscine (scopolamine) and hyoscyamine.^4,5

• Toxic Dose

  2 seeds, ¼ of a fruit or 1 g dried flowers can be toxic.⁶

• Mechanism

  Solanaceous tropane alkaloids cause anticholinergic toxidrome by competitive blockade of cholinergic muscarinic receptors.^7,8

• Poisoning Features

  Anticholinergic toxidrome, including dry mouth, dry skin, flushing, hyperthermia, tachycardia, hypertension, urinary retention, decreased bowel sounds, mydriasis and confusion. Convulsion, coma and even death in severe cases.⁹

• Poisoning Events

  As TCM, the flowers of D. metel and the flowers of non-toxic Campsis grandiflora are not uncommonly mixed up, therefore accidental poisoning have been periodically reported in Hong Kong. Fatal case can occur in severe poisoning.^9–12

CLINICAL MANAGEMENT

Supportive treatment. Activated charcoal therapy has been used for gastrointestinal decontamination and physostigmine has been used as an antidote for Datura poisoning.¹⁰

IDENTIFICATION FEATURES

Annual stout herbs, 50–150 cm tall. Leaves alternate; leaf blades 5–20 × 4–15 cm, base asymmetrical, margin irregular in shape. Flowers solitary, calyx 4–9 cm long. Corolla white, yellowish, or pale purple, 14–20 cm long, funnelform; limb 6–10 cm in diameter; lobes mucronate at apex. Stamens 5; styles 11–16 cm long. Capsules about 3 cm in diameter, with short prickles. Seeds about 3 mm wide, pale brown.¹³

MEDICINAL USES

Highly toxic; use with caution. Flowers used in TCM: reduce wheezing and suppress cough, dispel wind, stop convulsions and relieve pain. Recommended dose: 0.3–0.6 g.^2,14–16

CASES IN TRL

In 2004, a 60-year-old woman was admitted with confusion, tachycardia and agitation after taking a herbal broth prepared with "Ju Lung Fa" collected in Sheung Shui. The plant was subsequently identified as D. metel. In 2010, a 57-year-old woman was admitted with similar clinical features after taking a herbal broth prepared with C. grandiflora flowers as one of the ingredients. The source was traced to the mixing up of the herb with flowers of D. metel. In both cases, solanaceous tropane alkaloids were detected in the concerned specimens; and they recovered uneventfully.⁹

LABORATORY ANALYSIS

Solanaceous tropane alkaloids can be detected by GC-MS and LC-MS/MS.¹⁷