Bioaccessibility of mercury in selected Ayurvedic medicines.

Five Ayurvedic medicines with mercury concentrations of 85mg/kg and higher were characterized with respect to their speciation and their bioaccessibility. X-ray absorption spectroscopy revealed that the mercury in the Ayurvedic medicines was inorganic and best matched to cinnabar, even in samples that had been hypothesized to contain mercury through plant sources only. The bioaccessibility (bioaccessible concentrations and percent bioaccessibility) was measured using two methods: a two-phase physiologically based extraction test (PBET gastric, G and gastric+intestinal phase, GI); and the fed organic estimation human simulation test (FOREhST). The percent bioaccessibility of mercury in all Ayurvedic samples was very low (<5%), corresponding to the low solubility of cinnabar, but it increased with increasing dissolved organic carbon content of the bioaccessibility solutions (PBET-G

Bioaccessibility of lead and arsenic in traditional Indian medicines.

Arsenic and lead have been found in a number of traditional Ayurvedic medicines, and the practice of Rasa Shastra (combining herbs with metals, minerals and gems), or plant ingredients that contain these elements, may be possible sources. To obtain an estimate of arsenic and lead solubility in the human gastrointestinal tract, bioaccessibility of the two elements was measured in 42 medicines, using a physiologically-based extraction test. The test consisted of a gastric phase at pH 1.8 containing organic acids, pepsin and salt, followed by an intestinal phase, at pH 7 and containing bile and pancreatin. Arsenic speciation was measured in a subset of samples that had sufficiently high arsenic concentrations for the X-ray absorption near edge structure analysis used. Bioaccessible lead was found in 76% of samples, with a large range of bioaccessibility results, but only 29% of samples had bioaccessible arsenic. Lead bioaccessibility was high (close to 100%) in a medicine (Mahayograj Guggulu) that had been compounded with bhasmas (calcined minerals), including naga (lead) bhasma. For the samples in which arsenic speciation was measured, bioaccessible arsenic was correlated with the sum of As(V)-O and As(III)-O and negatively correlated with As-S. These results suggest that the bioaccessible species in the samples had been oxidized from assumed As-S raw medicinal ingredients (realgar, As(4)S(4), added to naga (lead) bhasma and As(III)-S species in plants). Consumption at recommended doses of all medicines with bioaccessibile lead or arsenic would lead to the exceedance of at least one standard for acceptable daily intake of toxic elements.

Bioaccessibility and excretion of arsenic in Niu Huang Jie Du Pian pills.

Traditional Chinese medicines (TCMs) often contain significant levels of potentially toxic elements, including arsenic. Niu Huang Jie Du Pian pills were analyzed to determine the concentration, bioaccessibility (arsenic fraction soluble in the human gastrointestinal system) and chemical form (speciation) of arsenic. Arsenic excretion in urine (including speciation) and facial hair were studied after a one-time ingestion. The pills contained arsenic in the form of realgar, and although the total arsenic that was present in a single pill was high (28 mg), the low bioaccessibility of this form of arsenic predicted that only 4% of it was available for absorption into the bloodstream (1 mg of arsenic per pill). The species of arsenic that were solubilized were inorganic arsenate (As(V)) and arsenite (As(III)) but DMAA and MMAA were detected in urine. Two urinary arsenic excretion peaks were observed: an initial peak several (4-8) hours after ingestion corresponding to the excretion of predominantly As(III), and a larger peak at 14 h corresponding predominantly to DMAA and MMAA. No methylated As(III) species were observed. Facial hair analysis revealed that arsenic concentrations did not increase significantly as a result of the ingestion. Arsenic is incompletely soluble under human gastrointestinal conditions, and is metabolized from the inorganic to organic forms found in urine. Bioaccessible arsenic is comparable to the quantity excreted. Facial hair as a bio-indicator should be further tested.