Phytolacca americana 美洲商陸

POISONOUS PARTS

Wholeplant, especially the roots and fruits.²

TOXICITY

• Toxic Constituents

  Phytolaccatoxins such as esculentoside and phytolaccoside.^4,5

• Mechanism

  Phytolaccatoxins are cytotoxic. They are irritants to mucosal surface and have haemolytic effect. They may cause convulsion, especially at high dose. Esculentoside has analgesic, anxiolytic and muscle relaxing effect. It is also a stimulant to parasympathetic nervous system.⁶

• Poisoning Features

  Weakness, nausea, vomiting, diarrhoea and abdominal pain. Respiratory depression , convulsion, heart block and even death in severe cases.^7,8

• Poisoning Events

  In Asia, the root is also called "false ginseng". Hence, cases of poisoning due to misidentification or substitution as ginseng occur sporadically. In western countries, consumption of salad made from the leaves or herbal tea have been reported to cause poisoning. A fatal paediatric case has been reported following consumption of juice made from its fruits.^7–9

CLINICAL MANAGEMENT

Supportive treatment. Correction of fluid and electrolyte disturbances in patients with severe gastrointestinal symptoms.

IDENTIFICATION FEATURES

Perennial herbs, 1–1.5 m tall, with thick, conical root. Stems erect, sometimes reddish purple. Leaves simple, alternate; leaf blades 10–30 × 5–16 cm, apex mucronate. Racemes 10–15 cm long; flowers about 6 mm in diameter. Perianth-segments 5, white, slightly red. Stamens, carpels and styles 10; carpels connate. Infructescence pendulous. Berries purple-black when ripe.¹⁰

MEDICINAL USES

Uses in TCM—roots: induce diuresis and disperse swelling, relieve constipation, dissipate bind, remove toxin; flowers: resolve phlegm; leaves: clear heat; seeds: promote urination to alleviate oedema. Recommended dose: roots 3–9 g, flowers 1–3 g, leaves 3–6 g.^2,11,12

CASES IN TRL

In 2014, a 40-year-old woman developed repeated vomiting 2 hours after drinking herbal tea made with the fresh roots of self-grown “ginseng” (photo A). The patient recovered uneventfully. The plant was subsequently identified as P. americana, and esculentoside A was detected in the plant specimen.¹³

LABORATORY ANALYSIS

Esculentoside and phytolaccoside can be detected by LC-MS/MS.¹⁴