Research progress on analysis of mercury in cinnabar and its preparations
Cinnabar is a commonly used mineral medicinal material in my country. It is obtained by mining and processing cinnabar ore of the sulfide mineral cinnabar family. According to traditional Chinese medicine theory, it is sweet, slightly cold, toxic, and belongs to the heart meridian. It has the effects of clearing the heart and calming the nerves, calming the mind, improving eyesight, and detoxifying. It is used to treat palpitations, insomnia, epilepsy, infantile convulsions, blurred vision, mouth ulcers, throat paralysis, sores, swelling and infection [1]. Cinnabar is widely used in traditional Chinese medicine and Mongolian and Tibetan prescriptions due to its unique therapeutic effect. However, since it contains 86% mercury, the safety of this medicinal material and its preparations has been controversial.
The main chemical component of cinnabar is natural mercuric sulfide (HgS), which is a stable covalently bonded compound with very low solubility. It is insoluble in water, organic solvents, hot hydrochloric acid and nitric acid. Modern research believes that mercuric sulfide is difficult to be absorbed by the human body. Other mercury compounds that can dissolve or solubilize in the gastrointestinal tract are the active ingredients of cinnabar that produce pharmacological and toxicological effects. On the other hand, the toxicity of mercury depends largely on its form of existence. Mercury forms include elemental mercury (mercury vapor and liquid mercury), inorganic mercury (such as mercuric chloride, mercuric acetate) and organic mercury (such as methylmercury, ethylmercury, phenylmercury). Among organic mercury, alkylmercury is more toxic than both arylmercury and inorganic mercury, and among alkylmercury, methylmercury is the most toxic [2]. Therefore, the study of the toxicity and pharmacological mechanism of cinnabar must take into account the state of mercury in the drug, its dissolution and absorption in the gastrointestinal tract, and its transformation, accumulation and excretion of morphological and valence states in the body. These processes cannot be simply expressed by the total amount of mercury, but need to rely on detection methods of different forms and valence states.
With the development of analytical technology, research on the chemical composition of cinnabar and its preparations has made great progress, but a comprehensive and systematic discussion has not yet been reported. Therefore, it is necessary to summarize the progress of analytical research on mercury in cinnabar and its preparations to provide a reference for the quality control of related drugs and rational clinical use of drugs.
