Cadmium, mercury and lead in medicinal herbs in Brazil

Samples of herbal medicine used in Brazil were analyzed, after nitric digestion, for the content of cadmium, mercury and lead, by atomic absorption spectrophotometry. Fifteen samples of ginkgo biloba (Ginkgo biloba), 13 of celastraceae (Maytenus ilicifolia), 14 of cascara buckthorn (Rhamnus purshiana), 13 of eggplant (Solanum melongena), 15 of horse chestnut (Aesculus hippocastanum), 13 of Brazilian ginseng (Pffafia glomerata), 17 of centella asiatic (Hydrocotyle asiatica), 13 of guarana (Paullinia cupana), 12 of artichoke (Cynara scolymus) and five samples of chlorella (Chlorella pyrenoidosa) were analyzed. Cadmium, mercury and lead were not detected (limit of quantifications of 0.20, 0.01 and 2.0 mg/kg, respectively) in any sample of artichoke, eggplant and guarana. Cadmium was found in samples of the other medicinal herbs at levels up to 0.74 μg/g and mercury up to 0.087 μg/g. Three samples of horse chestnut contained 153, 156 and 1480 μg Pb/g, while the highest concentration found in the other samples analyzed was 22 μg Pb/g. The estimated lead intake through the consumption of horse chestnut reached 440% of Provisional Tolerable Weekly Intake (PTWI), and might be of concern to consumers if the medicine was taken on a long-term basis. Cadmium and mercury exposure through the herbal medicines does not appear to be of health concern.