Sources, distribution, bioavailability, toxicity, and risk assessment of heavy metal(loid)s in complementary medicines

Shiv Bolan, Anitha Kunhikrishnan, Balaji Seshadri, Girish Choppala, Ravi Naidu, Nanthi S. Bolan, Yong Sik Ok, Ming Zhang, Chun Guang Li, Feng Li, Barry Noller, Mary Beth Kirkham

Research output: Contribution to journalReview articlepeer-review

84 Citations (Scopus)

Abstract

The last few decades have seen the rise of alternative medical approaches including the use of herbal supplements, natural products, and traditional medicines, which are collectively known as ‘Complementary medicines’. However, there are increasing concerns on the safety and health benefits of these medicines. One of the main hazards with the use of complementary medicines is the presence of heavy metal(loid)s such as arsenic (As), cadmium (Cd), lead (Pb), and mercury (Hg). This review deals with the characteristics of complementary medicines in terms of heavy metal(loid)s sources, distribution, bioavailability, toxicity, and human risk assessment. The heavy metal(loid)s in these medicines are derived from uptake by medicinal plants, cross-contamination during processing, and therapeutic input of metal(loid)s. This paper discusses the distribution of heavy metal(loid)s in these medicines, in terms of their nature, concentration, and speciation. The importance of determining bioavailability towards human health risk assessment was emphasized by the need to estimate daily intake of heavy metal(loid)s in complementary medicines. The review ends with selected case studies of heavy metal(loid) toxicity from complementary medicines with specific reference to As, Cd, Pb, and Hg. The future research opportunities mentioned in the conclusion of review will help researchers to explore new avenues, methodologies, and approaches to the issue of heavy metal(loid)s in complementary medicines, thereby generating new regulations and proposing fresh approach towards safe use of these medicines.

Original languageEnglish
Pages (from-to)103-118
Number of pages16
JournalEnvironment international
Volume108
DOIs
Publication statusPublished - 2017

Bibliographical note

Publisher Copyright:
© 2017 Elsevier Ltd

Keywords

  • Bioavailability
  • Complementary medicines
  • Heavy metal(loid)s
  • Risk assessment
  • Toxicity

ASJC Scopus subject areas

  • General Environmental Science

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