Comparative analysis of immunological changes following realgar and arsenic trioxide treatments in a murine model of myelodysplastic syndrome.

BACKGROUND: Myelodysplastic syndrome (MDS) is a prevalent hematological neoplastic disorder in clinics and its immunopathogenesis has garnered growing interest. Oral and intravenous arsenic agents have long been used to treat hematological malignancies. The main component of oral arsenic is realgar (arsenic disulfide), while arsenic trioxide is the main component of intravenous arsenic. METHODS: This study aimed to assess the effects of ATO and Realgar on the enhancement of peripheral blood, drug safety, and T cell immune status in the NUP98-HOXD13 (NHD13) mice model of MDS, specifically in the peripheral blood, spleen, and liver. RESULTS: The study findings indicate that realgar and arsenic trioxide (ATO) can improve peripheral hemogram in mice, whereas realgar promotes higher peripheral blood cell production than ATO. Furthermore, the clinical administration method and dose did not cause significant toxicity or side effects and thus can be considered safe. Coexistence and interconversion of hyperimmune function and immunosuppression in mice were also observed in this study. In addition, there were interactions between immune cells in the peripheral blood, spleen, and liver to regulate the immune balance of the body and activate immunity via T-cell activation. CONCLUSION: In summary, oral and intravenous arsenic agents are beneficial in improving peripheral hemogram and immunity in mice.

[Research hotspots and frontiers of Realgar based on CiteSpace knowledge graph analysis].

This study employed knowledge graph technology to analyze the research status and hot spots of Realgar and provide guidance for clinical application and further research of this drug. The research articles both in English and Chinese involving Realgar were retrieved from five databases including CNKI, Wanfang, VIP, SinoMed, and Web of Science. And NoteExpress, a literature management software was used to screen literature. CiteSpace was utilized for visualized analysis and presentations of the authors, institutions, and keywords. 2 879 articles in Chinese and 194 articles in English were included. China Journal of Chinese Materia Medica and Journal of Ethnopharmacology were the top Chinese and English journals in terms of publication volume. Realgar is widely used in the treatment of skin diseases, blood diseases, and cancer. JIANG Hong was the author who have published more articles in Chinese and English working with teams. School of Public Health of China Medical University and China Academy of Chinese Medical Sciences published the most articles in Chinese and English. The research on Realgar mainly focuses on clinical application, mechanism of action, reduction of toxicity, and enhancement of efficacy. The authors and institutions of Realgar research are mainly concentrated in China. The study on the mechanism of treating hematological diseases and cancer with Realgar, as well as the research on its effects of reducing toxicity and enhancing efficacy, are the current research hotspots. The mechanism of "same treatment for different diseases" in Realgar needs to be further explored. It is urgent to carry out interdisciplinary research on Realgar. This study can provide a refe-rence for the clinical application of Realgar and provide ideas for further research on Realgar.

Acid ground nano-realgar processed product inhibits breast cancer by inducing mitophagy via the p53/BNIP3/NIX pathway.

Breast cancer is a highly prevalent malignancy with the first morbidity and the primary reason for female cancer-related deaths worldwide. Acid ground nano-realgar processed product (NRPP) could inhibit breast cancer cell proliferation and induce autophagy in our previous research; however, the underlying mechanisms are still unclear. Therefore, this research aimed to verify whether NRPP induces breast cancer mitophagy and explore the mitophagy-mediated mechanism. Primarily, rhodamine-123 assay and transmission electron microscopy were applied to detect mitochondrial membrane potential (MMP) and ultrastructural changes in the MDA-MB-435S cells, respectively. Mito-Tracker Green/Lyso-Tracker Red staining, western blot, immunofluorescence and RT-PCR were used to explore molecular mechanisms of NRPP-induced mitophagy in vitro. MDA-MB-435S breast cancer xenograft models were established to assess the activity and mechanisms of NRPP in vivo. Our results showed that NRPP decreased MMP and increased autophagosome numbers in MDA-MB-435S cells and activated mitophagy. Furthermore, mitophagy was consolidated because mitochondria and lysosomes colocalized phenomenology were observed, and the expression of LC3II/I and COXIV was upregulated. Additionally, we found the p53/BNIP3/NIX pathway was activated. Finally, NRPP inhibited tumour growth and downregulated the levels of TNF-α, IL-1ß and IL-6. Necrosis, damaged mitochondria and autophagosomes were observed in xenograft tumour cells, and proteins and mRNA levels of LC3, p53, BNIP3 and NIX were increased. Overall, NRPP inhibited MDA-MB-435S cell proliferation and tumour growth by inducing mitophagy via the p53/BNIP3/NIX pathway. Thus, NRPP is a promising candidate for breast cancer treatment.

Field and laboratory investigations on factors affecting the diel variation of arsenic in Huangshui Creek from Shimen Realgar Mine, China: implications for arsenic transport in an alkali stream.

The release of arsenic and related species from mining activities has been investigated widely at both seasonal and diel scales, contributing to the understanding of arsenic cycles, its ultimate fate, and enabling accurate estimates of arsenic flux in specific areas. To enrich the research in this area, a case study was undertaken in Huangshui Creek, Hunan province, China. Here, arsenic is present in the sediment at the Creek entrance to a reservoir and in the widely developed alkali realgar(α-As4S4)-calcite(CaCO3)-dolomite[CaMg(CO3)2] strata (pH 7-11). Water from different levels in the Huangshui Creek, the Creek/reservoir entrance, and the downstream reservoir together with corresponding sediments were collected and analyzed. The local algae were separated and cultured. A diel variation of arsenic (688 ug/L in AM 3:50-1152 ug/L in PM 19:50) was observed in the Creek. The largest difference in arsenic concentration between the upper and lower water body was at the mixed creek/reservoir site (364 ug/L). Laboratory experiments showed that arsenic release from Creek sediment and pristine realgar was 1.3-2.7 times and 2.0-2.3 times at 25 and 37 °C, respectively, than low-temperature samples (8 °C) over 24 h. However, temperature variation is not the only factor controlling arsenic release from Huangshui Creek. Batch experiments show that both sediment and pristine realgar can release arsenic(III). In addition, the presence of bicarbonate promotes arsenic(V) release by 15.2-24.3 times for the sediment and by 1.7-3.4 times for pristine realgar compared to the control, though it restrains arsenic(III) release. High levels of algae have a complex effect on arsenic release; it increases arsenic(V) release by accelerating dissolution of realgar but decreases arsenic(III) release through adsorption. The field observations-variation of bicarbonate (67 mg/L in day and 201 mg/L in night) and chlorophyll-a (0.06-0.87)-support that both dissolved bicarbonate and algae affect arsenic concentration. These factors establish a circadian rhythm in the Creek, which coupled with arsenic release, ultimately affect the fate of arsenic.

Safe, accurate, and precise sulfur isotope analyses of arsenides, sulfarsenides, and arsenic and mercury sulfides by conversion to barium sulfate before EA/IRMS.

The stable isotope ratios of sulfur (δ34S relative to Vienna Cañon Diablo Troilite) in sulfates and sulfides determined by elemental analysis and isotope ratio mass spectrometry (EA/IRMS) have been proven to be a remarkable tool for studies of the (bio)geochemical sulfur cycles in modern and ancient environments. However, the use of EA/IRMS to measure δ34S in arsenides and sulfarsenides may not be straightforward. This difficulty can lead to potential health and environmental hazards in the workplace and analytical problems such as instrument contamination, memory effects, and a non-matrix-matched standardization of δ34S measurements with suitable reference materials. To overcome these practical and analytical challenges, we developed a procedure for sulfur isotope analysis of arsenides, which can also be safely used for EA/IRMS analysis of arsenic sulfides (i.e., realgar, orpiment, arsenopyrite, and arsenian pyrite), and mercury sulfides (cinnabar). The sulfur dioxide produced from off-line EA combustion was trapped in an aqueous barium chloride solution in a leak-free system and precipitated as barium sulfate after quantitative oxidation of hydrogen sulfite by hydrogen peroxide. The derived barium sulfate was analyzed by conventional EA/IRMS, which bracketed the δ34S values of the samples with three international sulfate reference materials. The protocol (BaSO4-EA/IRMS) was validated by analyses of reference materials and laboratory standards of sulfate and sulfides and achieved accuracy and precision comparable with those of direct EA/IRMS. The δ34S values determined by BaSO4-EA/IRMS in sulfides (arsenopyrite, arsenic, and mercury sulfides) samples from different origins were comparable to those obtained by EA/IRMS, and no sulfur isotope fractionations were introduced during sample preparation. We report the first sulfur isotope data of arsenides obtained by BaSO4-EA/IRMS.

Realgar-induced nephrotoxicity via ferroptosis in mice.

Ferroptosis is a novel form of iron-dependent cell death that is involved in arsenic-induced toxicity. Realgar is an arsenic-containing Chinese medicine, which can result in nephrotoxicity because of long-term exposure. However, it remains scientifically unknown whether Realgar is an inducer of ferroptosis in the kidney. This study investigated the role of ferroptosis in Realgar-induced kidney toxicity in mice. ICR mice were exposed to Realgar for 28 days, and HK2 cells were exposed to Realgar in the presence or absence of treatment with ferrostatin-1, a ferroptosis inhibitor. The ferroptosis-related indicators were further evaluated. Realgar can cause nephrotoxicity in mice by continuous gavage for 28 days, accompanied by an increase in iron accumulation and reactive oxygen species (ROS). The reduced expression of Slc7A11 and Gpx4 further confirmed the ferroptosis mediated by Realgar. Meanwhile, Realgar disrupted the antioxidant system as evidenced by the formation of ROS leading to the inactivation of antioxidant enzymes. Realgar caused ferroptosis in a dose-dependent manner, which was significantly reduced by ferrostatin-1 in HK2 cells. This study revealed that Realgar-induced ferroptosis triggered nephrotoxicity in mice and provided new clues to elucidate the mechanism of Realgar-induced nephrotoxicity.

An Experimental Study Reveals the Protective Effect of Autophagy against Realgar-Induced Liver Injury via Suppressing ROS-Mediated NLRP3 Inflammasome Pathway.

Realgar, a poisonous traditional Chinese medicine, has been shown to cause liver injury when used for long periods or overdoses. However, the underlying molecular mechanisms and therapeutic targets have not been fully elucidated. The aim of this study is to explore the role of autophagy in sub-chronic realgar exposure-induced liver injury. Here, the liver injury model was established by continuously administrating mice with 1.35 g/kg realgar for 8 weeks. 3-methyladenine (3-MA) and rapamycin (RAPA) were used to regulate autophagy. The results showed that realgar induced abnormal changes in liver function, pathological morphology, expression of inflammatory cytokines, and upregulated NLRP3 inflammasome pathway in mouse livers. RAPA treatment (an inducer of autophagy) significantly improved realgar-induced liver injury and NLRP3 inflammasome activation, while 3-MA (an inhibitor of autophagy) aggravated the realgar-induced liver injury and NLRP3 inflammasome activation. Furthermore, we found that realgar-induced NLRP3 inflammasome activation in mouse livers is mediated by ROS. RAPA eliminates excessive ROS, inhibits NF-κB nuclear translocation and down-regulates the TXNIP/NLRP3 axis, consequently suppressing ROS-mediated NLRP3 inflammasome activation, which may be the underlying mechanism of the protective effect of autophagy on realgar-induced liver injury. In conclusion, the results of this study suggest that autophagy alleviates realgar-induced liver injury by inhibiting ROS-mediated NLRP3 inflammasome activation. Autophagy may represent a therapeutic target in modulating realgar-induced liver injury.

Unique diversity and functions of the arsenic-methylating microorganisms from the tailings of Shimen Realgar Mine.

Microbial arsenic (As) methylation plays important roles in the As biogeochemical cycle. However, little is known about the diversity and functions of As-methylating microorganisms from the tailings of a Realgar Mine, which is characterized as containing extremely high concentrations of As. To address this issue, we collected five samples (T1-T5) from the tailings of Shimen Realgar Mine. Microcosm assays without addition of exogenous As and carbon indicated that all the five samples possess significant As-methylating activities, producing 0.8-5.7 µg/L DMAsV, and 1.1-10.7 µg/L MMAsV with an exception of T3, from which MMAsV was not detectable after 14.0 days of incubation. In comparison, addition of 20.0 mM lactate to the microcosms significantly enhanced the activities of these samples; the produced DMAsV and MMAsV are 8.0-39.7 µg/L and 5.8-38.3 µg/L, respectively. The biogenic DMAsV shows significant positive correlations with the Fe concentrations and negative correlations with the total nitrogen concentrations in the environment. A total of 63 different arsM genes were identified from the five samples, which code for new or new-type ArsM proteins, suggesting that a unique diversity of As-methylating microbes are present in the environment. The microbial community structures of the samples were significantly shaped by the environmental total organic carbon, total As contents and NO3- contents. These data help to better understand the microorganisms-catalyzed As methylation occurred in the environment with extremely high contents of As.

[Preliminary study of Realgar and arsenic trioxide on gut microbiota of mice].

The aim of this paper was to observe the effect of Realgar and arsenic trioxide on gut microbiota. The mice were divided into low-dose Realgar group(RL), medium-dose Realgar group(RM), high-dose Realgar group(RH), and arsenic trioxide group(ATO), in which ATO and RL groups had the same trivalent arsenic content. Realgar and arsenic trioxide toxicity models were established after intragastric administration for 1 week, and mice feces were collected 1 h after intragastric administration on day 8. The effects of Realgar on gut microbiota of mice were observed through bacterial 16 S rRNA gene sequences. The results showed that Lactobacillus was decreased in all groups, while Ruminococcus and Adlercreutzia were increased. The RL group and ATO group were consistent in the genera of Prevotella, Ruminococcus, and Adlercreutzia but different in the genera of Lactobacillus and Bacteroides. Therefore, the effects of Realgar and arsenic trioxide with the same amount of trivalent arsenic on gut microbiota were similar, but differences were still present. Protective bacteria such as Lactobacillus were reduced after Realgar administration, causing inflammation. At low doses, the number of anti-inflammatory bacteria, such as Ruminococcus, Adlercreutzia and Parabacteroides increased, which can offset the slight inflammation caused by the imbalance of bacterial flora. At high doses, the flora was disturbed and the number of Proteobacteria was increased, with aggravated intestinal inflammation, causing edema and other inflammatory reactions. Based on this, authors believe that the gastrointestinal reactions after clinical use of Realgar may be related to flora disorder. Realgar should be used at a small dose in combination with other drugs to reduce intestinal inflammation.

Realgar and cinnabar are essential components contributing to neuroprotection of Angong Niuhuang Wan with no hepatorenal toxicity in transient ischemic brain injury.

Realgar and cinnabar are commonly used mineral medicine containing arsenic and mercury in Traditional Chinese Medicine (TCM). Angong Niuhuang Wan (AGNHW) is a representative realgar- and cinnabar-containing TCM formula for treating acute ischemic stroke, but its toxicology and neuropharmacological effects are not well addressed. In this study, we compared the neuropharmacological effects of AGNHW and modified AGNHW in an experimental ischemic stroke rat model. Male SD rats were subjected to 2 h of middle cerebral artery occlusion (MCAO) plus 22 h of reperfusion. Although oral administration of AGNHW for 7 days in the rats increased arsenic level in the blood and liver tissue, there were no significant changes in the arsenic level in kidney, mercury level in the blood, liver and kidney as well as hepatic and renal functions in MCAO rats. AGNHW revealed neuroprotective properties by reducing infarction volume, preserving blood-brain barrier integrity and improving neurological functions against cerebral ischemia-reperfusion injury. Interestingly, removing realgar and/or cinnabar from AGNHW abolished the neuroprotective effects. Meanwhile, AGNHW could scavenge peroxynitrite, down-regulate the expression of p47phox, 3-NT and MMP-9 and up-regulate the expression of ZO-1 and claudin-5 in the ischemic brains, which were abolished by removing realgar and/or cinnabar from AGNHW. Notably, realgar or cinnabar had no neuroprotection when used alone. Taken together, oral administration of AGNHW for one week should be safe for treating ischemic stroke with neuroprotective effects. Realgar and cinnabar are necessary elements with synergetic actions with other herbal materials for the neuroprotective effects of AGNHW against cerebral ischemia-reperfusion injury.

Realgar transforming solution as a novel arsenic agent with a lower risk of cardiotoxicity.

QTc prolongation has been observed during arsenic trioxide and realgar's clinical use, and become a huge obstacle for the application. Our lab has obtained the soluble arsenic from realgar named realgar transforming solution or RTS. In this study, we first evaluated the cytotoxicity on NB4 cell and found that RTS could remarkably inhibit proliferation of NB4 than arsenic trioxide. Then we figured out the QTc prolongation of RTS treatment contrasted with arsenic trioxide; results revealed that arsenic trioxide prolonged corrected QTc of mice by 20.1% and showed 1.9-fold higher cytotoxicity on H9c2 cell than RTS. On the contrary, there could not find any QTc prolongation of mice in RTS treatment. Also, arsenic trioxide elevated the intercellular calcium accumulation of H9c2 cell by 2.02-fold v.s control and RTS. HE staining and Masson's trichrome staining had shown that there was no injured section after RTS treatments. IK1 currents of rat ventricular cardiomyocytes were diminished by 45.0% after treating with arsenic trioxide while RTS showed no significance than the control group. The results above indicated that RTS could serve as an alternative arsenic agent on leukemia and had a lower risk of cardiotoxicity.

[Research progress in mineral Chinese medicine realgar].

Realgar is a mineral traditional medicine with definite efficacy. The function of realgar is detoxicating, insecticiding, eliminating dampness and phlegm, etc. It is widely applied in clinical practice by compatibility medicines. However, the safety and scientificalness of clinical application are questioned because of the toxic effect caused by arsenic compounds. At present, there are still many problems in the research of realgar, which are mainly manifested in three areas: the expression of main components and effective substances are inconsistent; the anti-tumor mechanism is difficult to explain at the molecular level; the mechanism of compatibility is not clear. As a result, realgar and realgar-containing Chinese patent medicines are frequently prohibited from entering the international market, and the reputation of traditional Chinese medicine is also damaged. This paper would analyze the research status of realgar at home and abroad as well as its problems from its main components, effective substances, anti-tumor mechanism and compatibility mechanism. In view of these difficulties, quantum chemical calculation method is proposed to solve them, so as to make up for the shortcomings and limitations of experimental technology and experimental conditions, reduce the cost of realgar research and improve research efficiency. Moreover, it provides inspiration for research of other mineral medicine.

Mechanisms of Mineral Substrate Acquisition in a Thermoacidophile.

The thermoacidophile Acidianus is widely distributed in Yellowstone National Park hot springs that span large gradients in pH (1.60 to 4.84), temperature (42 to 90°C), and mineralogical composition. To characterize the potential role of flexibility in mineral-dependent energy metabolism in contributing to the widespread ecological distribution of this organism, we characterized the spectrum of minerals capable of supporting metabolism and the mechanisms that it uses to access these minerals. The energy metabolism of Acidianus strain DS80 was supported by elemental sulfur (S0), a variety of iron (hydr)oxides, and arsenic sulfide. Strain DS80 reduced, oxidized, and disproportionated S0 Cells growing via S0 reduction and disproportionation did not require direct access to the mineral to reduce it, whereas cells growing via S0 oxidation did require direct access, observations that are attributable to the role of H2S produced by S0 reduction/disproportionation in solubilizing and increasing the bioavailability of S0 Cells growing via iron (hydr)oxide reduction did not require access to the mineral, suggesting that the cells reduce Fe(III) that is being leached by the acidic growth medium. Cells growing via oxidation of arsenic sulfide with Fe(III) did not require access to the mineral to grow. The stoichiometry of reactants to products indicates that cells oxidize soluble As(III) released from oxidation of arsenic sulfide by aqueous Fe(III). Taken together, these observations underscore the importance of feedbacks between abiotic and biotic reactions in influencing the bioavailability of mineral substrates and defining ecological niches capable of supporting microbial metabolism.IMPORTANCE Mineral sources of electron donor and acceptor that support microbial metabolism are abundant in the natural environment. However, the spectrum of minerals capable of supporting a given microbial strain and the mechanisms that are used to access these minerals in support of microbial energy metabolism are often unknown, in particular among thermoacidophiles. Here, we show that the thermoacidophile Acidianus strain DS80 is adapted to use a variety of iron (hydro)oxide minerals, elemental sulfur, and arsenic sulfide to support growth. Cells rely on a complex interplay of abiologically and biologically catalyzed reactions that increase the solubility or bioavailability of minerals, thereby enabling their use in microbial metabolism.

Realgar nanoparticles versus ATO arsenic compounds induce in vitro and in vivo activity against multiple myeloma.

Multiple myeloma (MM), a B cell malignancy characterized by clonal proliferation of plasma cells in the bone marrow, remains incurable despite the use of novel and conventional therapies. In this study, we demonstrated MM cell cytotoxicity triggered by realgar (REA; As4 S4 ) nanoparticles (NREA) versus Arsenic trioxide (ATO) against MM cell lines and patient cells. Both NREA and ATO showed in vivo anti-MM activity, resulting in significantly decreased tumour burden. The anti-MM activity of NREA and ATO is associated with apoptosis, evidenced by DNA fragmentation, depletion of mitochondrial membrane potential, cleavage of caspases and anti-apoptotic proteins. NREA induced G2 /M cell cycle arrest and modulation of cyclin B1, p53 (TP53), p21 (CDKN1A), Puma (BBC3) and Wee-1 (WEE1). Moreover, NREA induced modulation of key regulatory molecules in MM pathogenesis including JNK activation, c-Myc (MYC), BRD4, and histones. Importantly, NREA, but not ATO, significantly depleted the proportion and clonogenicity of the MM stem-like side population, even in the context of the bone marrow stromal cells. Finally, our study showed that both NREA and ATO triggered synergistic anti-MM activity when combined with lenalidomide or melphalan. Taken together, the anti-MM activity of NREA was more potent compared to ATO, providing the preclinical framework for clinical trials to improve patient outcome in MM.

Properties of realgar bioleaching using an extremely acidophilic bacterium and its antitumor mechanism as an anticancer agent.

Realgar is a naturally occurring arsenic sulfide (or Xionghuang, in Chinese). It contains over 90% tetra-arsenic tetra-sulfide (As4S4). Currently, realgar has been confirmed the antitumor activities, both in vitro and in vivo, of realgar extracted using Acidithiobacillus ferrooxidans (A. ferrooxidans). Bioleaching, a new technology to greatly improve the use rate of arsenic extraction from realgar using bacteria, is a novel methodology that addressed a limitation of the traditional method for realgar preparation. The present systematic review reports on the research progress in realgar bioleaching and its antitumor mechanism as an anticancer agent. A total of 93 research articles that report on the biological activity of extracts from realgar using bacteria and its preparation were presented in this review. The realgar bioleaching solution (RBS) works by inducing apoptosis when it is used to treat tumor cells in vitro and in vivo. When it is used to treat animal model organisms in vivo, such as mice and Caenorhabditis elegans, tumor tissues grew more slowly, with mass necrosis. Meanwhile, the agent also showed obvious inhibition of tumor cell growth. Bioleaching technology greatly improves the utilization of realgar and is a novel methodology to improve the traditional method.

[Effect of clinical doses of Realgar-Indigo Naturalis formula and large-dose of realgar on CYP450s of rat liver].

To investigate the effect of clinical dose of Realgar-Indigo Naturais formula (RIF) and large-dose of Realgar on main drug-metabolizing enzymes CYP450s of rat liver, as well as its regulatory effect on mRNA expression. Wistar rats were administrated orally with tested drugs for 14 days. A Cocktail method combined with HPLC-MS/MS was used in the determination of 4 cytochrome P450 isozymes (CYP1A2, CYP2B, CYP3A and CYP2C) in liver of the rats, and the mRNA expression levels of the above subtypes were detected by real-time fluorescent quantitative PCR. The results showed that RIF can significantly induce CYP1A2 and CYP2B enzyme activity, and inhibit CYP3A enzyme activity. This result was consistent with the mRNA expression. However, its single compound showed weaker or even contrary phenomenon. Different doses of Realgar also showed significant inconsistencies on CYP450 enzymes activity and mRNA expression. These phenomena may be relevant with RIF compatibility synergies or toxicity reduction. The results can also prompt drug interactions when RIF is combined with other medicines in application.

[Quality of realgar and its influencing factors based on toxicity].

The results of a toxicity analysis showed differences from those of the existing experimental data. Therefore, HPLC-ICP-MS was used to analyze the soluble arsenic content at different valences in realgar prepared with water grind processing, which were collected from 3 companies. The results showed that the free arsenic of the 3 companies did not exceed the limit of Chinese Pharmacopoeia. However, if the free arsenic was calculated based on the total value of As(Ⅲ) + As(Ⅴ), free arsenic of 1 company exceeded the limit of Chinese Pharmacopoeia. The method of determining free arsenic in Chinese Pharmacopoeia. was ancient Cai's arsenic detection method, which had a certain limitation and failed to effectively avoid the toxicity of remaining arsenics except for trivalent arsenic. Then, we examined the effects of water and temperature on the content and form of soluble arsenic in realgar. The results showed that the content of soluble arsenic increased with the rise of water content, and the form of soluble arsenic did not change, there were only As (Ⅲ) and As (Ⅴ); With the simple temperature factor, there was an increasing trend in the content of soluble arsenic in the samples, the maximum increment was As (Ⅲ) 2.489 mg•g⁻¹ and As (Ⅴ) 0.546 mg•g⁻¹; When water and temperature played an synergistic effect, the increase of soluble arsenic in the samples significantly changed, the maximum increment was As (Ⅲ) 23.690 mg•g⁻¹, As (Ⅴ) 0.468 mg•g⁻¹, respectively. Through comprehensive analysis, we believed that the quality of realgar was susceptible to water content and temperature. Both of the single effect of water content and the synergistic effect of water and temperature can significantly change the content of soluble arsenic in realgar, and the water content was a high-risk factor. In the current Chinese Pharmacopoeia 2015 version, the free arsenic detection method had limitations, hence new techniques shall be introduced; At the same time, realgar does not have a water content inspection item in the current pharmacopoeia, which shall be added. However, due to the limit of water content, more in-depth studies are required.

Effects of realgar on GSH synthesis in the mouse hippocampus: Involvement of system XAG(-), system XC(-), MRP-1 and Nrf2.

Realgar is a type of mineral drug that contains arsenic and has neurotoxicity. Glutathione (GSH), which is the main antioxidant in the central nervous system, plays a key role in antioxidant defenses and the detoxification of arsenic. However, whether realgar interferes with the synthesis of GSH in the brain and the molecular mechanisms underlying its effects are largely unknown. Here, we used mouse models of exposure to realgar to show that realgar affects the synthesis of GSH in the hippocampus, leading to ultrastructural changes in hippocampal neurons and synapses and deficiencies in cognitive abilities, and that the mechanisms that cause this effect may be associated with alterations in the expression of system XAG(-), system XC(-), multidrug resistance-associated protein 1(MRP-1), nuclear factor E2-related factor 2 (Nrf2), γ-glutamylcysteine synthetase (γ-GCS), and the levels of glutamate (Glu) and cysteine (Cys) in the extracellular fluid. These findings provide a theoretical basis for preventing the drug-induced chronic arsenic poisoning in the nervous system that is triggered by realgar.

Arsenic remediation by formation of arsenic sulfide minerals in a continuous anaerobic bioreactor.

Arsenic (As) is a highly toxic metalloid that has been identified at high concentrations in groundwater in certain locations around the world. Concurrent microbial reduction of arsenate (As(V) ) and sulfate (SO4 (2-) ) can result in the formation of poorly soluble arsenic sulfide minerals (ASM). The objective of this research was to study As biomineralization in a minimal iron environment for the bioremediation of As-contaminated groundwater using simultaneous As(V) and SO4 (2-) reduction. A continuous-flow anaerobic bioreactor was maintained at slightly acidic pH (6.25-6.50) and fed with As(V) and SO4 (2-) , utilizing ethanol as an electron donor for over 250 d. A second bioreactor running under the same conditions but lacking SO4 (2-) was operated as a control to study the fate of As (without S). The reactor fed with SO4 (2-) removed an average 91.2% of the total soluble As at volumetric rates up to 2.9 mg As/(L · h), while less than 5% removal was observed in the control bioreactor. Soluble S removal occurred with an S to As molar ratio of 1.2, suggesting the formation of a mixture of orpiment- (As2 S3 ) and realgar-like (AsS) solid phases. Solid phase characterization using K-edge X-ray absorption spectroscopy confirmed the formation of a mixture of As2 S3 and AsS. These results indicate that a bioremediation process relying on the addition of a simple, low-cost electron donor offers potential to promote the removal of As from groundwater with naturally occurring or added SO4 (2-) by precipitation of ASM.

[¹H-NMR-based metabonomics on chemical component groups with toxicity alleviation effect to Realgar in Niuhuang Jiedu tablet].

To study the chemical component groups with toxicity alleviation effect to Realgar in Niuhuang Jiedu tablet based on ¹H-NMR metabonomics. Twenty-four male Wistar rats were divided into four groups： control group, R group (treated with Realgar), RRSPG group (treated with Realgar, the root and rhizoma of Rheum palmatum, the root of Scutellaria baicalensis, the root of Platycodon grandiflorum and the root and rhizoma of Glycyrrhiza uralensis) and RC group (treated with total anthraquinones from the root and rhizoma of R. palmatum, total flavonoids from the root of S. baicalensis, total saponins from the root of P. grandiflorum, total flavonoids and saponins from the root and rhizoma of G. uralensis). Based on ¹H-NMR spectra of urine and serum from rats, PLS-DA was performed to identify different metabolic profiles.The metabolic profiles of R group were different from that of control group, while the metabolic profiles of RC group were almost similar to control group.Total anthraquinones from the root and rhizoma of R. palmatum, total flavonoids from the root of S. baicalensis, total saponins from the root of P. grandiflorum, total flavonoids and saponins from the root and rhizoma of G. uralensis regulated energy, choline and amino acid metabolism and gut flora disorder affected by realgar's toxicity.