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An Anaerobic Biosensor Assay for the Detection of Mercury and Cadmium
Published on: December 17, 2018
Cinnabar is not converted into methylmercury by human intestinal bacteria
Xinrui Zhou1, Liming Wang, Xinming Sun
1State Key Laboratories of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100191, PR China.
Journal of Ethnopharmacology
|March 9, 2011
Summary
Cinnabar (HgS) does not transform into toxic methylmercury in the human gut. Instead, human intestinal bacteria convert cinnabar into nontoxic mercuric polysulfides, supporting its traditional medicinal use.
Area of Science:
- Pharmacology
- Toxicology
- Microbiology
Background:
- Cinnabar (mercuric sulfide, HgS) is a mineral historically used in traditional Chinese medicine.
- A key concern is its potential transformation into toxic methylmercury by gut bacteria.
- Previous assumptions lacked human evidence regarding this biotransformation.
Purpose of the Study:
- To investigate the biotransformation of cinnabar (HgS) by human intestinal bacteria.
- To determine if cinnabar is converted to methylmercury in the human gut.
- To identify potential transformation products using advanced analytical techniques.
Main Methods:
- Incubation of cinnabar with human intestinal bacteria.
- Detection of methylmercury using gas chromatography with electron capture detection (GC-ECD) and mass spectrometry (GC-MS).
- Quantification of soluble mercury via cold vapor-atomic absorption spectrometry (CV-AAS).
- Analysis of mercury and sulfur species using X-ray absorption near-edge structure spectroscopy (XANES).
Main Results:
- Methylmercury was not detected by GC-ECD or GC-MS, indicating no methylation occurred.
- A small amount of soluble mercury was released into the bacterial medium.
- XANES analysis identified polysulfides, and simulated reactions showed mercuric polysulfides as products.
Conclusions:
- Cinnabar transforms into nontoxic mercuric polysulfides, not methylmercury, under human gut flora conditions.
- This study provides evidence for a safe biotransformation pathway of cinnabar in the human intestine.
- Findings support the historical use of cinnabar in traditional medicine by clarifying its metabolic fate.
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