Adulteration of Selected Unprocessed Botanicals in the U.S. Retail Herbal Trade

Adulteration of Selected Unprocessed Botanicals in the U.S. Retail Herbal Trade. Adulteration of botanical dietary supplements through the accidental or deliberate use of a plant species other than the one claimed to be present is a well-publicized concern. Recent surveys of these products have found that some historically reported adulterations still occur despite strict quality control regulations. For a few botanicals, the accidental inclusion of toxic lookalike species has caused consumer illnesses. Since most of the Western market, as measured by monetary value, consists of processed dietary supplements, relatively little attention has been paid to the question of whether unprocessed bulk herbs sold to herbalists and in herb stores are equally subject to adulteration. We hypothesized that adulterations similar to those seen in materials sold for use in dietary supplements would occur. Nine botanicals were selected that had been previously reported to be adulterated, or were suspected to be at risk of adulteration, and that could be distinguished from known or likely adulterants by the morphology of parts in commerce. Samples were purchased from eleven vendors and authenticated by morphological examination. Most were correctly identified, and no toxic adulterants were found. Samples of Juniperus and Tilia commonly contained species other than those specified, and most samples of alleged Arnica montana were entirely composed of Heterotheca inuloides (“false arnica”). We conclude that the likelihood of adulteration of crude botanicals in retail commerce is taxon-specific; while most species are consistently correctly identified, a few are often confused. One implication is that botanicals purchased for use in research should always be independently authenticated in some fashion.