A review of cinnabar (HgS) and/or realgar (As4S4)-containing traditional medicines.

ETHNOPHARMOCOLOGICAL RELEVANCE: Herbo-metallic preparations have a long history in the treatment of diseases, and are still used today for refractory diseases, as adjuncts to standard therapy, or for economic reasons in developing countries. AIM OF THE REVIEW: This review uses cinnabar (HgS) and realgar (As4S4) as mineral examples to discuss their occurrence, therapeutic use, pharmacology, toxicity in traditional medicine mixtures, and research perspectives. MATERIALS AND METHODS: A literature search on cinnabar and realgar from PubMed, Chinese pharmacopeia, Google and other sources was carried out. Traditional medicines containing both cinnabar and realgar (An-Gong-Niu-Huang Wan, Hua-Feng-Dan); mainly cinnabar (Zhu-Sha-An-Shen Wan; Zuotai and Dangzuo), and mainly realgar (Huang-Dai Pian; Liu-Shen Wan; Niu-Huang-Jie-Du) are discussed. RESULTS: Both cinnabar and realgar used in traditional medicines are subjected to special preparation procedures to remove impurities. Metals in these traditional medicines are in the sulfide forms which are different from environmental mercurials (HgCl2, MeHg) or arsenicals (NaAsO2, NaH2AsO4). Cinnabar and/or realgar are seldom used alone, but rather as mixtures with herbs and/or animal products in traditional medicines. Advanced technologies are now used to characterize these preparations. The bioaccessibility, absorption, distribution, metabolism and elimination of these herbo-metallic preparations are different from environmental metals. The rationale of including metals in traditional remedies and their interactions with drugs need to be justified. At higher therapeutic doses, balance of the benefits and risks is critical. Surveillance of patients using these herbo-metallic preparations is desired. CONCLUSION: Chemical forms of mercury and arsenic are a major determinant of their disposition, efficacy and toxicity, and the use of total Hg and As alone for risk assessment of metals in traditional medicines is insufficient.

Zuotai and HgS differ from HgCl2 and methyl mercury in Hg accumulation and toxicity in weanling and aged rats.

Mercury sulfides are used in Ayurvedic medicines, Tibetan medicines, and Chinese medicines for thousands of years and are still used today. Cinnabar (α-HgS) and metacinnabar (ß-HgS) are different from mercury chloride (HgCl2) and methylmercury (MeHg) in their disposition and toxicity. Whether such scenario applies to weanling and aged animals is not known. To address this question, weanling (21d) and aged (450d) rats were orally given Zuotai (54% ß-HgS, 30mg/kg), HgS (α-HgS, 30mg/kg), HgCl2 (34.6mg/kg), or MeHg (MeHgCl, 3.2mg/kg) for 7days. Accumulation of Hg in kidney and liver, and the toxicity-sensitive gene expressions were examined. Animal body weight gain was decreased by HgCl2 and to a lesser extent by MeHg, but unaltered after Zuotai and HgS. HgCl2 and MeHg produced dramatic tissue Hg accumulation, increased kidney (kim-1 and Ngal) and liver (Ho-1) injury-sensitive gene expressions, but such changes are absent or mild after Zuotai and HgS. Aged rats were more susceptible than weanling rats to Hg toxicity. To examine roles of transporters in Hg accumulation, transporter gene expressions were examined. The expression of renal uptake transporters Oat1, Oct2, and Oatp4c1 and hepatic Oatp2 was decreased, while the expression of renal efflux transporter Mrp2, Mrp4 and Mdr1b was increased following HgCl2 and MeHg, but unaffected by Zuotai and HgS. Thus, Zuotai and HgS differ from HgCl2 and MeHg in producing tissue Hg accumulation and toxicity, and aged rats are more susceptible than weanling rats. Transporter expression could be adaptive means to reduce tissue Hg burden.

[Effect of Zhusha Anshen pill, cinnabar, HgS, HgCl2 and MeHg on gene expression of renal transporters in mice].

OBJECTIVE: To study the effect of Zhusha Anshen pill, cinnabar, HgS, HgCl2 and MeHg on the gene expression of renal transporters in mice. METHOD: Healthy male mice were given equivalent physiological saline, Zhusha Anshen pill (1.8 g · kg(-1), containing 0.17 g · kg(-1) of mercury), cinnabar (0.2 g · kg(-1), containing 1.7 g · kg(-1) of mercury), high dose cinnabar (2 g · kg(-1), containing 1.7 g · kg(-1) of mercury), HgS (0.2 g · kg(-1), containing 0.17 g · kg(-1) of mercury), HgCl2 (0.032 g · kg(-1), containing 0. 024 g · kg(-1) of mercury), MeHg (0.026 g · kg(-1), containing 0.024 g · kg(-1) of mercury), once daily, for 30 d, measuring body mass gain. 30 days later, the mice were sacrificed. The mercury accumulation in kidneys was detected with atomic fluorescence spectrometer. Expressions of Oat1, Oat2, Oat3, Mrp2, Mrp4, Urat1 were detected with RT-PCR. RESULT: Compared with the normal control group, a significant accumulation of Hg in kidney in HgCl2 and MeHg groups was observed (P <0.05), but these changes were not found in other groups. Compared with normal control group, mRNA expressions of Oat1 and Oat2 were evidently lower in HgCl2 and MeHg groups, but mRNA expressions of Mrp2 were apparently higher in HgCl2 group (P <0.05), mRNA expression of Mrp4 was significant higher in HgCl2 and MeHg groups, and mRNA expression of Urat1 was apparently lower in MeHg group. CONCLUSION: HgCl2 and MeHg groups show significant difference from the normal group in mercury accumulation in kidneys and gene expression of kidney transporters, but with no difference between other groups and the normal group. Compared with HgCl2 and MeHg, cinnabar and its compounds could cause lower renal toxicity to mice.

[Distinct effect of Wansheng Huafeng Dan containing ardisia crenata on renal transporters, mercury accumulation and Kim-1 expression from mercuric chloride].

To study the effect of Wansheng Huafeng Dan (WSHFD) and mercuric chloride on renal mercury (Hg) extraction transporters (Oat1, Oct2), renal mercury excretion transporters (Mrp4, Mate2K), renal mercury accumulation and kidney injury molecule-1 (Kim-1). The ancient prescription of WSHFD containing 10-fold Hg caused much lower renal mercury accumulation and renal toxicity than HgCl2 in rats, with less effect on renal transporters than HgCl2. The above indicators had no significant difference in WSHFDO, WSHFD2 and WSHFD3 groups, indicating no effect of WSHFD with reduced or no cinnabar.

Synthesis and the hepatoprotective activity of dibenzocyclooctadiene lignan derivatives.

The halogenated and oxidized derivatives (1a-1e, 1a'-1c', 2a-2d, 2a'-2b', 3a-3e, 3' and 3a'-3b') of schizandrin (1), schizandrin B (2) and schisanhenol (3) were synthesized. The hepatoprotective effects of these dibenzocyclooctadiene lignan analogues against CCl4-induced injury were preliminarily evaluated. Most of the analogues exhibited higher protective effects than the positive control biphenyldicarboxylate (DDB). Among these active analogues, dichloroschisanhenol (3a) exhibited the strongest protective activity (cell survival rate exceeding 98.0%).

Realgar, cinnabar and An-Gong-Niu-Huang Wan are much less chronically nephrotoxic than common arsenicals and mercurials.

Realgar (As(4)S(4)) and cinnabar (HgS) are frequently included in traditional Chinese medicines and Indian Ayurvedic medicines. Both As and Hg are well known for toxic effects, and their safety is of concern. The aim of this study was to compare chronic nephrotoxicity of An-Gong-Niu-Huang Wan (AGNH), realgar and cinnabar with common arsenicals and mercurials. Mice were orally administrated with AGNH (3 g/kg, 6-fold of clinical dose), cinnabar (0.3 g/kg, amount in AGNH) and realgar (0.3 g/kg, amount in AGNH), HgCl(2) (0.118 mmol/kg, 1/10 of cinnabar), MeHg (0.012 mmol/kg, 1/100 of cinnabar), NaAsO(2) (As(3+) 0.028 mmol/kg, 1/100 of realgar) or Na(2)HAsO(4) (As(5+) 0.056 mmol/kg, 1/50 of realgar), daily for six weeks, and nephrotoxicity was examined. Animal body weights were decreased by MeHg and HgCl(2). Blood urea nitrogen and creatinine levels were elevated by MeHg. Renal pathology was severe in the MeHg and HgCl(2) groups, moderate in the arsenite, arsenate and realgar groups and mild in the cinnabar and AGNH groups. Renal Hg accumulation in the MeHg and HgCl(2) groups was 50-200 folds higher than the cinnabar group. Expressions of metallothionein-1 and heme oxygenase-1, biomarkers for metal toxicity, were increased 2-5 folds by arsenite, arsenate, MeHg and HgCl(2), but not by realgar, cinnabar and AGNH. The chemokine and glutathione-S transferase-α4, markers for inflammation, were also increased by MeHg and HgCl(2). Expressions of cell adhesion gene S100a9 and E-cadherin were altered by HgCl(2), arsenite and realgar. Taken together, chemical forms of mercury and arsenic are major determinants in their disposition and toxicity.

Chemical form of metals in traditional medicines underlines potential toxicity in cell cultures.

ETHNOPHARMACOLOGICAL RELEVANCE: Mercury (Hg) and arsenic (As) are frequently found in traditional medicines as sulfides, such as cinnabar (HgS) and realgar (As(4)S(4)). There is a general perception that any medicinal use of such metal-containing remedies is unacceptable. An opposing opinion is that different chemical forms of arsenic and mercury have different toxic potentials. AIM OF THE STUDY: To clarify this question, cinnabar, realgar, and cinnabar- and realgar-containing traditional medicine An-Gong-Niu-HuangWan (AGNH), were compared to well-known mercurials (HgS, HgCl(2) and MeHg) and arsenicals (As(2)S(2), As(2)O(3), NaAsO(2), and Na(2)HAsO(4)) for their cytotoxicity in human and rodent cell lines. MATERIALS AND METHOD: Cultured cells derived from target organs such as brain (HAPI) and liver (Hep3B, HepG2 and TRL1215) were treated with chemicals for 48 h and cytotoxicity was determined by the MTS assay. RESULTS: MeHg was most toxic with LC(50) of 4-20µM, followed by NaAsO(2) (LC(50), 25-250 µM) and HgCl(2) (LC(50,) 50-100 µM), Na(2)HAsO(4)(LC(50), 60-400µM), As(2)O(3)(LC(50), 30-900 µM), and As(2)S(2) (LC(50), 100-500 µM). In comparison, the LC(50) of realgar ranged from 250 to1500 µM; whereas cinnabar or HgS were approximately 20,000 µM and the toxicity of AGNH was in the range of 1500-8000 µM. Approximately 5000-fold differences exist between MeHg and HgS, and over 10-fold differences exist between NaAsO(2) and As(4)S(4). CONCLUSIONS: Chemical forms of metals are important factor in determining their toxicity in traditional medicines, both cinnabar and realgar are much less toxic than well-known mercurial and arsenicals.

Nephrotoxicity of mercuric chloride, methylmercury and cinnabar-containing Zhu-Sha-An-Shen-Wan in rats.

Cinnabar (HgS) is used in traditional medicines, and total Hg content is used for risk assessment of cinnabar-containing traditional medicines such as Zhu-Sha-An-Shen-Wan (ZSASW). Is ZSASW or cinnabar toxicologically similar to common mercurials? Adult Sprague-Dawley rats were gavaged with ZSASW (1.4 g/kg), cinnabar (0.2g/kg), HgCl(2) (0.02 g/kg), MeHg (0.001 g/kg), or saline daily for 60 days, and toxicity was determined. Animal body-weight gain was decreased by HgCl(2) and MeHg. Blood urea nitrogen (BUN) was increased by MeHg. Histology showed severe kidney injury following MeHg and HgCl(2) treatments, but mild after ZSASW and cinnabar. Renal Hg contents were markedly increased in the HgCl(2) and MeHg groups but were not elevated in the ZSASW and cinnabar groups. The expression of kidney injury molecule-1 was increased 50-fold by MeHg, 4-fold by HgCl(2), but was unaltered by ZSASW and cinnabar; the expression of matrilysin was increased 3-fold by MeHg. In contrast, the expression of N-cadherin was decreased by HgCl(2). Thus, ZSASW and cinnabar are much less nephrotoxic than HgCl(2) and MeHg, indicating that chemical forms of mercury underlie their disposition and toxicity.

Realgar- and cinnabar-containing an-gong-niu-huang wan (AGNH) is much less acutely toxic than sodium arsenite and mercuric chloride.

An-gong-niu-huang wan (AGNH) is a famous traditional Chinese medicine used for brain trauma, hemorrhage, and coma. AGNH contains 10% realgar (As4S4) and 10% cinnabar (HgS). Both As and Hg are well-known for their toxic effects, and the safety of AGNH is of concern. To address this question, the acute toxicity of AGNH, realgar and cinnabar were compared to sodium arsenite (NaAsO2) and mercuric chloride (HgCl2). Mice were administrated orally AGNH at 1, 3 and 6g/kg. AGNH at 3g/kg contains 2.8mmol As/kg as realgar and 1.18mmol Hg/kg as cinnabar. Realgar, cinnabar, arsenite (0.28 mmol/kg, 10% of realgar) and HgCl2 (0.256 mmol/kg, 20% of cinnabar) were orally given to mice for comparison. Blood and tissues were collected 8h later for toxicity evaluation. Serum alanine aminotransferase was increased by arsenite and blood urea nitrogen was increased by HgCl2. Total As accumulation after arsenite in liver (100-fold) and kidney (13-fold) was much higher than that after realgar. The accumulation of Hg after HgCl2 in liver was 400-fold higher and kidney 30-fold higher than after cinnabar. Histopathology showed moderate liver and kidney injuries after arsenite and HgCl2, but injuries were mild or absent after AGNH, realgar, and cinnabar. The expression of metallothionein-1, a biomarker of metal exposure, was increased 4-10-fold by arsenite and HgCl2, but was unchanged by AGNH, realgar and cinnabar. Thus, AGNH, realgar and cinnabar are much less toxic acutely than arsenite and HgCl2. The chemical forms of As and Hg are extremely important factors in determining their disposition and toxicity.