Mercury in traditional medicines: is cinnabar toxicologically similar to common mercurials?
Mercury is a major toxic metal ranked top in the Toxic Substances List. Cinnabar, which contains mercury sulfide, has been used in Chinese traditional medicines for thousands of years as an ingredient in various remedies, and 40 cinnabar-containing traditional medicines are still used today. Little is known about toxicology profiles or toxicokinetics of cinnabar and cinnabar-containing traditional medicines, and the high mercury content in these Chinese medicines raises justifiably escalations of public concern. This minireview, by searching the available database of cinnabar and by comparing cinnabar with common mercurials, discusses differences in their bioavailability, disposition, and toxicity. The analysis showed that cinnabar is insoluble and poorly absorbed from the gastrointestinal tract. Absorbed mercury from cinnabar is mainly accumulated in the kidneys, resembling the disposition pattern of inorganic mercury. Heating cinnabar results in release of mercury vapor, which in turn can produce toxicity similar to inhalation of these vapors. The doses of cinnabar required to produce neurotoxicity are 1000 times higher than methyl mercury. Following long-term use of cinnabar, renal dysfunction may occur. Dimercaprol and succimer are effective chelation therapies for general mercury intoxication including cinnabar. Pharmacological studies of cinnabar suggest sedative and hypnotic effects, but the therapeutic basis of cinnabar is still not clear. In summary, cinnabar is chemically inert with a relatively low toxic potential when taken orally. In risk assessment, cinnabar is less toxic than many other forms of mercury, but the rationale for its inclusion in traditional Chinese medicines remains to be fully justified.
Liu
Jie
J
Inorganic Carcinogenesis Section, NCI at NIEHS, Mail Drop F0-09, Research Triangle Park, NC 27709, USA. Liu6@niehs.nih.gov
Shi
Jing-Zheng
JZ
Yu
Li-Mei
LM
Goyer
Robert A
RA
Waalkes
Michael P
MP
D004305:Dose-Response Relationship, Drug; D006801:Humans; D008516:Medicine, Chinese Traditional; D008627:Mercuric Chloride / Q000627:therapeutic use / Q000633:toxicity; D008628:Mercury / Q000627:therapeutic use* / Q000633:toxicity; D017669:Mercury Compounds / Q000627:therapeutic use / Q000633:toxicity*; D008767:Methylmercury Compounds / Q000627:therapeutic use / Q000633:toxicity
D017669:Mercury Compounds; D008767:Methylmercury Compounds; D008627:Mercuric Chloride; D008628:Mercury; C034211:cinnabar