Worldwide Occurrence and Investigations of Contamination of Herbal Medicines by Tropane Alkaloids

Thomas Chan

doi:10.3390/toxins9090284

Abstract

Tropane alkaloids occur mainly in Solanaceae plants. In the present review, the main objective is to describe the worldwide occurrence and investigations of anticholinergic poisoning due to the contamination of herbal teas and herbs by tropane alkaloids. Tropane alkaloid poisoning can occur after consumption of any medicinal plant if Solanaceae plants or plant parts are present as contaminants. Globally, almost all reports in 1978–2014 involve herbal teas and one of the prescribed herbs in composite formulae. Contamination most likely occurs during harvest or processing. As for prescribed herbs, on-site inspection is necessary to exclude cross-contamination and accidental mix-up at the retail level. The diagnosis is confirmed by screening for the presence of Solanaceae species and tropane alkaloids. Herbal teas and herbs contaminated by tropane alkaloids can pose a serious health hazard because these relatively heat-stable alkaloids may exist in large quantities. The WHO repeatedly emphasises the importance of good agricultural and collection practices for medicinal plants. DNA barcoding is increasingly used to exclude the presence of contaminants (particularly toxic species) and product substitution. All suspected cases should be reported to health authorities so that investigations along the supply chain and early intervention measures to protect the public can be initiated.

Highlights

Tropane alkaloids occur mainly in the plants of the Solanaceae genus, in species that have long been known for their medicinal, toxic, and hallucinogenic properties [1,2,3]
The toxicity of Solanaceae plants can be attributed to their tropane alkaloids content and profile, which can differ greatly between species, geographical regions, and harvesting stages [3]
Anticholinergic poisoning caused by the contamination of medicinal plants should be a high priority for early detection and containment, since potent alkaloids capable of causing severe toxicity and even death are involved [2,5]

Summary

Introduction

Tropane alkaloids (e.g., atropine, hyoscyamine, and scopolamine, Figure 1) occur mainly in the plants of the Solanaceae genus, in species that have long been known for their medicinal, toxic, and hallucinogenic properties [1,2,3]. These plants include: Datura metel, D. innoxia, D. ferox, D. stramonium (Jimson weed or thorn apple), Hyoscyamus niger (henbane), Atropa mandragora (mandrake), and A. belladonna (deadly nightshade). The toxicity (anticholinergic effects) of Solanaceae plants can be attributed to their tropane alkaloids content and profile (i.e., the relative amount of atropine, hyoscyamine, and scopolamine), which can differ greatly between species, geographical regions, and harvesting stages [3].

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Discussion

Conclusion