title: Speciation and bioavailability of lead in complementary medicines.
abstract: Complementary medicines have associated risks which include toxic heavy metal(loid) and pesticide contamination. The objective of this study was to examine the speciation and bioavailability of lead (Pb) in selected complementary medicines. Six herbal and six ayurvedic medicines were analysed for: (i) total heavy metal(loid) contents including arsenic (As), cadmium (Cd), Pb and mercury (Hg); (ii) speciation of Pb using sequential fractionation and extended x-ray absorption fine structure (EXAFS) techniques; and (iii) bioavailability of Pb using a physiologically-based in vitro extraction test (PBET). The daily intake of Pb through the uptake of these medicines was compared with the safety guidelines for Pb. The results indicated that generally ayurvedic medicines contained higher levels of heavy metal(loid)s than herbal medicines with the amount of Pb much higher than the other metal(loid)s. Sequential fractionation indicated that while organic-bound Pb species dominated the herbal medicines, inorganic-bound Pb species dominated the ayurvedic medicines. EXAFS data indicated the presence of various Pb species in ayurvedic medicines. This implies that Pb is derived from plant uptake and inorganic mineral input in herbal and ayurvedic medicines, respectively. Bioavailability of Pb was higher in ayurvedic than herbal medicines, indicating that Pb added as a mineral therapeutic input is more bioavailable than that derived from plant uptake. There was a positive relationship between soluble Pb fraction and bioavailability indicating that solubility is an important factor controlling bioavailability. The daily intake values for Pb as estimated by total and bioavailable metal(loid) contents are likely to exceed the safe threshold level in certain ayurvedic medicines. This research demonstrated that Pb toxicity is likely to result from the regular intake of these medicines which requires further investigation.
authors.affiliation: School of Natural and Built Environments, University of South Australia, SA 5095, Australia; Global Centre for Environmental Remediation (GCER), University of Newcastle, NSW 2308, Australia. Electronic address: Shiv.Bolan@UON.edu.au.
authors.forename: S
authors.initials: S
authors.lastname: Bolan
authors.affiliation: Global Centre for Environmental Remediation (GCER), University of Newcastle, NSW 2308, Australia; Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), University of South Australia, SA 5095, Australia.
authors.forename: R
authors.initials: R
authors.lastname: Naidu
authors.affiliation: Chemical Safety Division, Department of Agro-Food Safety, National Academy of Agricultural Science, Wanju-gun, Jeollabuk-do, 565-851, Republic of Korea.
authors.forename: A
authors.initials: A
authors.lastname: Kunhikrishnan
authors.affiliation: Global Centre for Environmental Remediation (GCER), University of Newcastle, NSW 2308, Australia.
authors.forename: B
authors.initials: B
authors.lastname: Seshadri
authors.affiliation: Korea Biochar Research Center & Department of Biological Environment, Kangwon National University, Chuncheon 200-701, Republic of Korea.
authors.forename: Y S
authors.initials: YS
authors.lastname: Ok
authors.affiliation: Global Centre for Environmental Remediation (GCER), University of Newcastle, NSW 2308, Australia.
authors.forename: T
authors.initials: T
authors.lastname: Palanisami
authors.affiliation: Global Centre for Environmental Remediation (GCER), University of Newcastle, NSW 2308, Australia.
authors.forename: M
authors.initials: M
authors.lastname: Dong
authors.affiliation: School of Natural and Built Environments, University of South Australia, SA 5095, Australia.
authors.forename: I
authors.initials: I
authors.lastname: Clark
mesh_terms: D001151:Arsenic / Q000032:analysis; D001682:Biological Availability; D002104:Cadmium / Q000032:analysis; D007854:Lead / Q000032:analysis*; D008515:Medicine, Ayurvedic; D008628:Mercury / Q000032:analysis; D028321:Plant Preparations / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis*
chemical_list: D028321:Plant Preparations; D012989:Soil Pollutants; D002104:Cadmium; D007854:Lead; D008628:Mercury; D001151:Arsenic
keywords: Ayurvedic medicines; Chinese medicines; Complementary medicines; Heavy metal(loid)s; Toxicity