Health risk assessment of arsenic in Realgar and NiuHuangJieDu Tablets based on pharmacokinetic study

The alleviation effect and its mechanism of Niuhuang Jiedu prescription on realgar-induced genotoxicity in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Realgar (As2S2 or As4S4) is a traditional Chinese medicine (TCM) containing arsenic. Existing studies have shown that it has genotoxicity under long-term use with large doses. Niuhuang Jiedu (NHJD) is a Chinese medicine prescription containing realgar and seven other TCMs. Whether the multiple TCMs combination in NHJD can reduce the genotoxicity induced by realgar in equivalent doses is still unknown.

AIM OF THE STUDY

To research the effect of NHJD on realgar's genotoxicity and the possible mechanism involved based on the arsenic methylation metabolic pathway.

MATERIAL AND METHODS

Six groups (control, realgar (0.8 g/kg), NHJD (12.48 g/kg), as well as Glycyrrhiza uralensis Fisch (GU), Scutellaria baicalensis Georg (SB), Rheum palmatum L (RP) plus equivalent doses of realgar, respectively) were set up. ICR mice were intragastric administered for 12 weeks. First, genotoxicology tests were conducted to evaluate the effect of NHJD, GU, SB, and RP on reducing realgar's genotoxicity. The inorganic arsenic (iAs), dimethyl arsenic acid (DMA), and monomethyl arsenic acid (MMA) were determined by HPLC-AFS, and the iAs%, MMA%, DMA%, primary methylation index (PMI), etc. Were calculated. Meanwhile, the S-adenosyl methionine (SAM) and arsenate reductase (ARR) levels, the arsenic (+3)methyltransferase (As3MT), purine-nucleoside phosphorylase (PNP), glutathione S-transfer omega1 (GSTO1) gene expression were detected, aimed to explore the possible alleviation mechanisms of NHJD.

RESULTS

The combination of multiple TCMs in NHJD decreased the levels of MN‰, SPA%, and DNA damage caused by realgar, with similar effects observed when SB, RP, and GU were used separately with realgar. Notably, the iAs% significantly decreased, while DMA% and PMI notably increased in the NHJD and realgar + SB (or RP) groups compared to the realgar-only group (P < 0.05). Increases in SAM and ARR levels were observed across various groups, but only the ARR increase in the NHJD group was statistically significant. Moreover, significant increases in As3MT mRNA and GSTO1 mRNA were noted in the NHJD group, and PNP mRNA levels significantly rose in the realgar + SB group.

CONCLUSIONS

This study revealed that NHJD could attenuate the genotoxic effects of realgar. The botanicals SB, RP, and GU within NHJD may be key contributors to this effect. Enhancements in arsenic methylation capabilities through increased levels of SAM and ARR and elevated gene expressions of As3MT, PNP, and GSTO1 suggest potential mechanisms behind these findings.

Associations of Urinary Total Arsenic and Arsenic Species and Periodontitis

AIMS

Arsenic exposure is a significant global public health concern and has been implicated in endocrine disruption and increased oxidative stress, both of which are crucial pathogenic mechanisms of periodontitis. This study aimed to investigate the association of urinary total arsenic and arsenic species with periodontitis and to further explore the potential mediating roles of sex hormones and oxidative stress indicators.

METHODS

Data used in this study were derived from the 2013-2014 National Health and Nutrition Examination Survey (NHANES) in the US population. In all, 1063 participants with complete data were included in this study. Weighted logistic regression analyses were used to evaluate the relationship between urinary arsenic and periodontitis. Mediation analyses were used to explore the effects of potential mediators on these associations.

RESULTS

High concentrations of urinary dimethylarsinic acid (DMA), monomethylarsonic acid (MMA), 2 types of toxic urinary arsenic (TUA2), and 4 types of toxic urinary arsenic (TUA4) were positively related to periodontitis (P < .05). After adjusting for potential confounders, the positive association remained significant (odds ratio, 1.32; 95% confidence interval, 1.01-1.71). Testosterone may partially mediate the relationship between MMA and periodontitis, with mediating effects of 21.78% and 39.73% of the total effect. No significant mediation effect of oxidative stress indicators was found for this relationship.

CONCLUSIONS

This study reports a positive association between urinary MMA and periodontitis, and testosterone may mediate this relationship. Our findings serve as a call for action to avoid the deployment of arsenic-containing therapeutic agents as treatment modalities for oral afflictions.

Target RNA expression omics approach to reveal the liver detoxification effect induced by Chinese medicine prescription Niu Huang Jie Du against realgar overexposure to mice

ETHNOPHARMACOLOGICAL RELEVANCE

Niu Huang Jie Du prescription (NHJD) is a traditional Chinese medicine (TCM) widely used in patients suffering from excessive inner fire toxin (Huo Du Nei Sheng) syndrome, such as sore throat, gingival swelling, and pain, mouth and tongue sores, etc. This formula contains realgar (As₄S₄) which is one of the 28 toxic medicinal materials promulgated by the Chinese Ministry of Health. Many studies reported its toxicity on the liver and kidney, and the detoxification effect of NHJD. However, its detoxification mechanism is still unclear.

AIM OF THE STUDY

To clarify the detoxification mechanism of NHJD to realgar, this study evaluated the detoxification effect of NHJD on realgar exposure in mice, and analyzed differences in mRNA expression profiles in liver tissues and associated functional predictions.

MATERIAL AND METHODS

ICR mice were administered with NHJD, realgar, and CMC-Na as blank control for 12 weeks, respectively. Liver injury was evaluated by histopathologic examination and liver mRNA gene were sequenced by Illumina. Differentially expressed gene, functionally enrichment and protein association network analysis were conducted.

RESULTS

43 genes were screened out, among which 15 genes in the realgar group were decreased, but the extent of the decline has been restored in the NHJD group. The remaining 28 genes have exactly the opposite trends. Functional module analysis revealed that those detoxification function-related genes were primarily for positive regulation of glutathione metabolism, P450 on the metabolism of exogenous compounds, oxidative stress and immune-related, etc. CONCLUSIONS: The results indicated that realgar mainly causes liver damage by changing the common enzymes of drug metabolism, especially the expression of genes related to CYPs, GSTs family, oxidative stress, and complement immunity, while the TCM prescription NHJD has a regulatory effect on the abnormal expression of corresponding genes. Our results will provide some clues for the detoxification mechanism of arsenic-containing TCM prescriptions.

Comparative pharmacokinetics and urinary excretion of arsenic and mercury after oral administration of realgar, cinnabar and AnGongNiuHuang Pill to rats

Realgar- and cinnabar-containing AnGongNiuHuang Pill (AGNHP) is widely used for treating encephalopathy syndrome. However, it raises great safety concerns due to the adverse effects reported by arsenic or mercury poisoning. Although AGNHP has been generally recognized, little is known about the metabolism of arsenic and mercury and their resulting potential health risk in vivo. Thus, comparative pharmacokinetics and urinary excretion of arsenic and mercury were conducted in rats after oral administration of realgar, cinnabar and AGNHP, respectively. The contents of arsenic and mercury in rat blood and urine were determined by hydride-generation atomic fluorescence spectrometry (HG-AFS) after wet digestion. AGNHP significantly reduced the absorption of arsenic in blood and promoted urinary arsenic excretion. Whereas, it increased the blood mercury absorption and reduced urinary mercury excretion. No significant toxicity was observed in the clinical dose range of AGNHP. However, excessive exposure to arsenic and mercury may still pose risks especially by long-term or excessive medication. The results are helpful for the rational clinical applications of realgar- and cinnabar-containing TCMs.

Compatibility of Niuhuang Jiedu Tablets Results in Attenuated Arsenic Bioaccumulation and Consequent Protection against Realgar-Induced Toxicity in Mice

Niuhuang Jiedu Tablets (NJT) is a popular over-the-counter traditional Chinese medicine (TCM) preparation. It is composed of realgar (As₂S₂) and seven other TCMs. The safety of NJT is of growing concern because arsenic (As) is carcinogenic to humans. The toxicity of realgar in vivo can mainly be attributed to the absorbed and accumulated As. This study investigated the correlation between the detoxification effects of the other TCMs in NJT on realgar and their influences on arsenic accumulation of realgar in mice. Histopathological examination, clinical biochemical test, and metabolic profiling analysis were used to evaluate the toxicity of realgar. The concentration of arsenic in mice whole blood as the hazard indicator was determined by inductively coupled plasma mass spectrometry (ICP-MS). The compatibility of NJT could decrease arsenic bioaccumulation of realgar in mice whole blood and consequently reduce the toxicity of realgar, which could be considered as one detoxification mechanism to realgar in NJT. The combination of Rhei Radix et Rhizoma, Scutellariae Radix, Platycodonis Radix, and Glycyrrhizae Radix et Rhizoma exhibited almost the same effects as NJT in regulating the serum biochemical parameters and metabolic profiles disturbed by realgar and in reducing arsenic accumulation of realgar in mice whole blood.

Realgar facilitates the Nrf2-Keap1-p62 positive feedback signaling axis via MAPKs and AKT to interfere with autophagy-induced apoptosis and oxidative stress in the hippocampus

Realgar, as a commonly used traditional Chinese medicine, exerts both pharmacological and biological effects. However, the mechanism by which it causes nervous system injury remains unclear. This study aimed to elucidate the specific mechanism underlying the hippocampal neurotoxicity caused by realgar. Nrf2 is an important receptor of exogenous toxic substances and oxidative stress. We utilized a p38-specific inhibitor (SB20358), ERK1/2-specific inhibitor (PD98059), JNK-specific inhibitor (SP600125) and AKT-specific inhibitor (LY249002) to establish the corresponding animal models and explore how realgar activates Nrf2. We established an Nrf2-shRNA gene silencing model in rats and an autophagy-specific inhibitor treatment model to further explore realgar-induced neurotoxicity and the role of Nrf2 in realgar-induced damage to the hippocampus. The results showed that realgar passed through the blood-brain barrier and accumulated in brain tissue to induce central nervous system toxicity. The specific mechanism was that realgar activated MAPKs and AKT signaling molecules to activate the Nrf2-Keap1-p62 positive feedback signaling axis, induced abnormal autophagy initiation and degradation, and promoted oxidative damage and apoptosis in neurons. Effective measures should be taken to prevent and control the arsenic poisoning caused by realgar in the early stage, and this study provides a theoretical and practical basis for the rational use of drugs in the clinic.

Arsenic-Related Health Risk Assessment of Realgar-Containing NiuHuangJieDu Tablets in Healthy Volunteers Po Administration

Realgar, an arsenic-containing traditional Chinese medicine of As₂S₂, has significant therapeutic effects for hundreds of years. NiuHuangJieDu tablets (NHJDT) is one of the most commonly prescribed realgar-containing preparations for the treatment of sore throat, swelling, and aching of gums. However, realgar-containing TCMs raise great safety concerns due to the adverse effects reported by arsenic poisoning. In this study, the arsenic-related health risk assessment of NHJDT was conducted in healthy volunteers after single and multiple doses oral administration. Blood, plasma, and urine samples were collected after dosing at predetermined time points or periods. Simple, rapid, and sensitive methods were established for the quantification of total arsenic and arsenic speciation in biological samples. The total arsenic and arsenic speciation were determined by hydride generation-atomic fluorescence spectrometry (HG-AFS) and high-performance liquid chromatography–hydride generation–atomic fluorescence spectrometry (HPLC-HG-AFS), respectively. No significant fluctuation of total arsenic was observed in human blood, and no traces of arsenic speciation were found in human plasma. Dimethylarsenic acid was detected as the predominated arsenic species in human urine after dosing. Therapeutic dose administration of NHJDT was relatively safe in single dose for the limited blood arsenic exposure, but long-term medication may still pose health risks due to the accumulation of arsenics in blood and its extremely slow excretion rate. Therefore, arsenic exposure should be carefully monitored during realgar-containing TCM medication, especially for long-term regimen. The results obtained in this study will provide scientific references for the clinical application of realgar and its-containing TCMs.

Hypoxia enhances the cytotoxic effect of As4S4 on rat ventricular H9c2 cells through activation of ubiquitin-proteasome system

BACKGROUND

As₄S₄ is widely used in Chinese traditional medicine compound. However, based on some recent studies, we found that the cardiotoxicity risk of using As₄S₄ in ischemic heart disease patients may be increased. To study this potential risk, we compared the effects of As₄S₄ on rat ventricular H9c2 cell line with or without hypoxic pretreatment, and to elucidate mechanisms of c-Cbl mediated ubiquitination/degradation of integrin β1.

METHODS

The present study was conducted on rat ventricular H9c2 cell line in the absence or presence of hypoxic pretreatment for 6 h followed by As₄S₄ treatment for 24 h. Following As₄S₄ treatment, cell viability assay, flow cytometric quantification of apoptotic cells, caspase-3 activity assay and DAPI staining were conducted. Western blotting was carried out to detect expressions of ubiquitination related proteins. In addition, the ubiquitination/degradation of integrin β1 and the role of c-Cbl in it was evaluated by immunoprecipitation and immunoblot assay.

RESULTS

The viability of cells with hypoxic pretreatment followed by As₄S₄ treatment was decreased significantly, apoptosis rate and the activity of caspase-3 were increased than As₄S₄ treatment alone. The ubiquitin-proteasome degradation pathway induced by As₄S₄ was further enhanced by hypoxic pretreatment. The results of IP and immunoblot assay showed hypoxic enhanced down-regulation effect of As₄S₄ on integrin β1 probably through c-Cbl activation.

CONCLUSIONS

This study demonstrated that the hypoxia enhanced cytotoxicity of As₄S₄ on H9c2 cells may through increasing the ubiquitin-proteasome degradation of integrin β1 mediated by the E3 ligase c-Cbl. The results provide an important clue that, in patients with ischemic heart disease, use of As₄S₄ may be associated with increased cardiotoxicity. We believe that the results worth to be further illuminated by in vivo and clinical research.

Ursodeoxycholic Acid Protects Against Arsenic Induced Hepatotoxicity by the Nrf2 Signaling Pathway

Arsenic is ubiquitous toxic metalloid responsible for many human diseases all over the world. Contrastingly, Ursodeoxycholic acid (UDCA) has been suggested as efficient antioxidant in various liver diseases. However, there are no reports of the effects of UDCA on arsenious acid [As(III)]-induced hepatotoxicity. The objective of this study is to elucidate the protective actions of UDCA on As(III)-induced hepatotoxicity and explore its controlling role in biomolecular mechanisms in vivo and in vitro. The remarkable liver damage induced by As(III) was ameliorated by treatment with UDCA, as reflected by reduced histopathological changes of liver and elevation of serum AST, ALT levels. UDCA play a critical role in stabilization of cellular membrane potential, inhibition of apoptosis and LDH leakage in LO2 cells. Meanwhile, the activities of SOD, CAT and GSH-Px and the level of TSH, GSH were enhanced with UDCA administration, while the accumulations of intracellular ROS, MDA and rate of GSSG/GSH were decreased in vivo and in vitro. Further study disclosed that UDCA significantly inhibited As(III)-induced apoptosis through increasing the expression of Bcl-2 and decreasing the expression of Bax, p53, Cyt C, Cleaved caspase-3 and 9. Moreover, UDCA promoted the expression of nuclear Nrf2, HO-1, and NQO1, although arsenic regulated nuclear translocation of Nrf2 positively. When Nrf2 was silenced, the protective effect of UDCA was abolished. Collectively, the results of this study showed that UDCA protects hepatocytes antagonize As(III)-induced cytotoxicity, and its mechanism may be related to activation of Nrf2 signaling.

Arsenic Accumulation of Realgar Altered by Disruption of Gut Microbiota in Mice

Objective

To investigate the influence of gut microbiota on arsenic accumulation of realgar in mice.

Methods

Mice were treated with antibiotics to form a mouse model of gut microbial disruption. Antibiotic-treated and normally raised mice were given 15 mg/kg, 150 mg/kg, and 750 mg/kg realgar by gavage and 0.2 mg/kg and 1 mg/kg arsenic solution by subcutaneous injection for 7 days. The concentration of arsenic in mice whole blood was determined by inductively coupled plasma mass spectrometry (ICP-MS). Arsenic accumulation in antibiotic-treated mice and normally raised mice was compared.

Results

After exposure to low dose (15 mg/kg) and middle dose (150 mg/kg) of realgar, significantly, more arsenic was accumulated in the whole blood of antibiotic-treated mice compared to normally raised counterparts, which indicated that the disruption of gut microbiota could lead to higher arsenic load of realgar in mice. The homeostasis of gut microbiota was supposed to be disrupted by high dose (750 mg/kg) of realgar because after exposure to high dose of realgar, there was no significant difference in arsenic accumulation between antibiotic-treated and normally raised mice. Furthermore, arsenic solution was administered by subcutaneous injection to mice to investigate the influence of gut microbial differences on arsenic accumulation in addition to the absorption process, and there was no significant difference in arsenic accumulation between mice with these two different statuses of gut microbiota.

Conclusions

Gut microbiota disruption could increase arsenic accumulation of realgar in mice.

Identification of neurotoxicity markers induced by realgar exposure in the mouse cerebral cortex using lipidomics

Realgar is a traditional Chinese medicine containing arsenic and has neurotoxicity. This study used realgar exposure mice model, neurobehavioral tests, analytical chemistry, molecular biology and nontargeted lipidomics to explore the mechanism of realgar damages the nervous system. The arsenic contained in realgar passed through the BBB and accumulated in the brain. Neurons, synapses and myelin showed abnormal changes in the cerebral cortex. The number of autophagosomes were incresed as well as levels of MDA, Lp-PLA2, and cPLA2 but the CAT level was significant reduced. Finally, the cognition and memory of mice were decreased. Nontargeted lipidomics detected 34 lipid subclasses including 1603 lipid molecules. The levels of the LPC and LPE were significantly increased. Under the condition of variable importance for the projection (VIP)>1 and P < 0.05, only 28 lipid molecules satisfied the criteria. The lipid molecular markers SM (d36:2), PE (18:2/22:6) and PE (36:3) which were filtered by receiver operating characteristic (ROC) curve (AUC>0.8 or AUC<0.2) were used to identify the neurotoxicity induced by realgar. Therefore, realgar induces neurotoxicity through exacerbating oxidative damage and lipid dysfunction. Providing research basis for the clinical diagnosis and treatment of realgar-induced neurotoxicity.

Comparative health risk assessment of realgar and NiuHuangJieDu tablets based on tissue arsenic levels after multiple oral administration to rats

ETHNOPHARMACOLOGICAL RELEVANCE

Realgar (As₂S₂), a mineral traditional Chinese medicine (TCM), is proved to have great therapeutic effects in clinic and has been widely used in China for hundreds of years. As one of the most popular realgar-containing TCMs, NiuHuangJieDu Tablets (NHJDT) is used as OTC (over-the-counter) drug in daily life for fever relieving, detoxicating, as well as cure of sore throat and gingival swelling. However, the safety of realgar and its-containing TCMs still remains unclear.

AIM OF THE STUDY

This study was to investigate the accumulation of arsenic in rat body and evaluate the safety of realgar-containing TCMs in vivo.

MATERIALS AND METHODS

The health risk of arsenic was evaluated in rats by tissue distribution and histopathology, as well as arsenic speciation in plasma after multiple oral gavage of low and high doses of realgar and NiuHuangJieDu Tablets (NHJDT), respectively. Total arsenic and arsenic speciation were determined by hydride generation-atomic fluorescence spectrometry (HG-AFS) and high performance liquid chromatography-hydride generation-atomic fluorescence spectrometry (HPLC-HG-AFS), respectively.

RESULTS

Arsenic accumulated in rat tissues especially in heart, liver, spleen, lung, kidney, uterus and ovary. Dimethylarsenic acid (DMA) was detected as the predominant species in rat plasma after dosing. In comparison of realgar, NHJDT with co-existing components significantly alleviated tissues injury, and reduced arsenic concentration in rat tissues and plasma.

CONCLUSIONS

NHJDT with co-existing components combination was relatively safer than realgar, but the accumulation of arsenic was still significant after long-term medication. Therefore, great attentions should be paid to realgar-containing TCMs to avoid toxicity from arsenic accumulation. Moreover, the dose regimen of realgar-containing TCMs should be designed rationally for clinical application. These results may provide useful references for the application of realgar-containing TCMs and might be helpful for the understanding of TCM compound compatibility.

Arsenic Bioaccessibility of Realgar Influenced by the Other Traditional Chinese Medicines in Niuhuang Jiedu Tablet and the Roles of Gut Microbiota

Niuhuang Jiedu tablet (NJT), a realgar (As2S2) containing Traditional Chinese Medicine (TCM), is a well-known formula. The safety of NJT is of growing concern since arsenic (As) is considered as one of the most toxic elements. NJT was demonstrated to be safer than realgar by our previous experiments and some other studies. The toxicity of realgar has been shown to be related to the amount of soluble or bioaccessible arsenic. In this study, the influences of the other TCMs in NJT on the bioaccessibility of arsenic from realgar, and the roles of gut microbiota during this process were investigated in vitro. Results showed that Dahuang (Rhei Radix et Rhizoma), Huangqin (Scutellariae Radix), Jiegeng (Platycodonis Radix), and Gancao (Glycyrrhizae Radix et Rhizoma) could significantly reduce the bioaccessibility of arsenic from realgar in artificial gastrointestinal fluids. Gut microbiota played an important role in decreasing the bioaccessibility of realgar because it was demonstrated to be able to absorb the soluble arsenic from realgar in the incubation medium. Dahuang, Huangqin, and Jiegeng could modulate the gut microbiota to enhance its arsenic absorption activity.

Fatal acute arsenic poisoning by external use of realgar: Case report and 30 years literature retrospective study in China

Realgar (arsenic sulfide) is widely used in combination with other herbs as Chinese patent medicine to treat a variety of diseases in China. As a mineral arsenic, its mild toxicity was also well known. Longtime over-dose usage or wrongly oral intake of realgar can cause chronic arsenic poisoning and/or death, but acute fatal arsenic poisoning resulted from short-term dermal use of realgar-containing medicine was very rare. Here, we present the case of a 35-year-old Chinese man, who was diagnosed with severe psoriasis and died of fatal acute arsenic poisoning after he applied a local folk prescription ointment containing mainly the realgar to the affected skin for about 4 days. The autopsy showed multiple punctate hemorrhages over the limbs, pleural effusion, edematous lungs with consolidation, mild myocardial hypertrophy and normal-looking kidneys. The histopathological examination of renal tissue showed severe degeneration, necrosis and desquamation of renal tubular epithelial cells, presence of protein cast and a widened edematous interstitium with interstitial fibrosis. The presence of arsenic in large amount in the ointment (about 6%), in blood (1.76 μg/mL), and in skin (4.71 μg/g), were confirmed analytically. We also provide the clinical records of the deceased and briefly reviewed 7 similar cases in literature (6 in Chinese and 1 in English) in the past 30 years in China.

Assessment of quality consistency in traditional Chinese medicine using multi-wavelength fusion profiling by integrated quantitative fingerprint method: Niuhuang Jiedu pill as an example

Under the wave of the revival of traditional Chinese medicine, there is a quite imperative duty to study an integrated and comprehensive method of fingerprint data processing and analysis on the quality consistency of traditional Chinese medicine. So, we proposed six parameters from two aspects (qualitative and quantitative), three levels (biased to strong peaks, biased to weak peaks, no obvious bias), to comprehensively evaluate the similarity of the two fingerprints. On this basis, another five parameters were proposed to evaluate the integrated effects (consistency, volatility, and similarity). This method was applied to 22 batches of Niuhuang Jiedu pill samples. Next, a practical and convenient multi-wavelength fusion method was designed to provide more information, and the generated fusion profilings were used for subsequent evaluation. The characteristics of the parameters were confirmed by correlation analysis. The results of both hierarchical clustering analysis and principal component analysis for raw data and standardized data were consistent with integrated quantitative fingerprint method results. At the same time, this method gave a reasonable explanation for abnormal and dissimilar samples. This work illustrated that the proposed method was particularly suitable for similarity analysis of fingerprints and capable of ensuring the quality consistency in traditional Chinese medicine.