Raw data: Mercury leaching ratio (μg/g) from Tibetan medicine Zuotai,β-HgS and α-HgS in pure water and artificial gastrointestinal juices containing Cys(or GSH) or not.
Zuotai, a known Tibetan medicinal mixture containing insoluble cubic mercuric sulfide (β-HgS), has been used to treat diseases with long history. The mercury leaching ratio from Zuotai in gastrointestinal environment is one determinant factor for its bioavailability and biological effect. However, the information is still scarce now. Therefore, the study was designed to investigate the effect of sulfhydryl biomolecules [L-cysteine (Cys) and glutathione (GSH)] on mercury leaching from Zuotai, β-HgS, and α-HgS in artificial gastrointestinal juices or pure water.
The artificial gastric juice and artificial intestinal juice were prepared according to the methods described in Chinese Pharmacopoeia (2010 version). The following solutions were prepared: Cys in pure water (5.21 g/L), GSH in pure water (13.21 g/L), Cys in artificial gastric juice (5.21 g/L), GSH in artificial gastric juice (13.21 g/L), Cys in artificial intestinal juice (5.21 g/L), and GSH in artificial intestinal juice (13.21 g/L). The moles of Cys and GSH in this study were 0.215 mmol—the same as that of β-HgS and α-HgS. A solid-liquid ratio of 1:100 was adopted in all leaching experiments. Digestion, peristalsis and emptying of drug in the gastrointestinal tract were simulated in vitro. We detected the mercury released in solutions using Automatic Direct Mercury Analyzer. Leaching Ratio of Mercury (μg/g)=[Total Weight of Mercury Released (μg)]/[Total Weight of Substance Tested (g)]
The results showed the following trend for the mercury leaching ratio of Zuotai: artificial gastric juice > artificial intestinal juice > pure water, whereas the trend for β-HgS and α-HgS was as follows: artificial intestinal fluid > artificial gastric fluid > pure water. The mercury leaching ratios of Zuotai, β-HgS, and α-HgS significantly increased in artificial intestinal juice containing L-Cys or GSH compared to that without sulfhydryl biomolecules in the juice. However, in pure water and artificial gastric juice with Cys or GSH, the mercury leaching ratio of Zuotai reduced remarkably, in contrast to the results observed for β-HgS and α-HgS.
