Realgar increases defenses against infection by Enterococcus faecalis in Caenorhabditis elegans
Authors: Wenjuan Ma
Shu Liang
Xin Wang
Juan Yue
Hongyu Li
Meng Gao
Dejuan Zhi
Na Cui
Journal: Journal of Ethnopharmacology (2021)
Discipline: PHARMACOLOGY & TOXICOLOGY
Keywords: Caenorhabditis elegans; DAF-2 /DAF-16 insulin like pathway; Enterococcus faecalis; Realgar; p38 MAPK pathway.
Affiliations: School of Pharmacy, Lanzhou University, Lanzhou, PR China., Gansu Provincial Centre for Disease Control and Prevention, Lanzhou University, Lanzhou, PR China., School of Pharmacy, Lanzhou University, Lanzhou, PR China. Electronic address: .

Abstract:  Ethnopharmacological relevance: Realgar has been used in traditional remedies for a long history in China and India. It is clinically used to treat diverse cancers, especially acute promyelocytic leukemia (APL), chronic myelogenous leukemia (CML) in China. However, paradoxic roles of realgar to increase or decrease immunity are reported. It is urgent to address this question, due to immune depression can be strongly benefit to cancer development, but detrimental to patients. Aim of the study: This present work is to explore whether realgar promote or suppress immune responses, and shed light on its mode of action. Our results should provide cues for rational strategy to explore realgar for clinical use. Material and methods: Infection model in vivo was established by using Enterococcus faecalis to attack Caenorhabditis elegans, then realgar was used to treat the infected worms to investigate its effects on infectivity and the underlying mechanism. Killing analysis was carried out to test whether realgar can mitigate worm infection. Thermotolerance resistance analysis was used to evaluate if realgar functions hormetic effect. Quantification of live E. faecalis in nematode intestine was employed to ascertain if realgar alleviate the bacterial load in worm gut. Quantitative real-time PCR (qRT-PCR) was used to test the expression of antibacterial effectors. Western blot was used to test the effect of realgar on the expressions of p38 and phospho-p38 in worms infected by E. faecalis. Results: Realgar alleviated the infected worms in strains of N2, glp-4, and daf-2, but failed in sek-1, glp-4; sek-1, and daf-2; daf-16 when p38 MAPK or daf-16 was blocked or inactivated. Western blot assay demonstrated that realgar increased the expression of phosph-p38. Thermotolerance assay showed that realgar played a hormetic role on nemtodes, triggered protective response and reduced bacterial load after realgar treatment for 120 h qRT-PCR demonstrated that realgar significantly increased antibacterial effectors, thus leading to pathogen elimination. Conclusion: Realgar increased defenses against E. faecalis in C. elegans by inducing both immune responses and protective responses. It was regulated by p38 MAPK pathway and DAF-16. 

Retracted: No

PubPeer comments:
 Could the authors explain how C. Zhao s papers on processing waste foliage to maximise the production of biofuels could possibly bring  unexpected insights to the supposed medical value of a **highly toxic arsenical mineral**? I mean, the  active components of realgar are simply **realgar**. No  extraction is involved.  The emerging potential methods of pretreatment and extraction of active components with ammonia and hydrogen peroxide (Zhao et al., 2017a; 2020a, b) and pre-soaking (Zhao et al., 2017b) may bring unexpected insights into the effects of realgar on immunity responses. - Zhao, C., Cao, Y., Ma, Z., Shao, Q. 2017a. Optimization of liquid ammonia pretreatment conditions for maximizing sugar release from giant reed (Arundo donax L.). Biomass and0 Bioenergy 98, 61-69. - Zhao, C., Qiao, X., Shao, Q., Hassan, M., Ma, Z., Yao, L. 2020a. Synergistic effect of hydrogen peroxide and ammonia on lignin. Industrial Crops Products 146, 112177. - Zhao, C., Qiao, X., Shao, Q., Hassan, M., Ma, Z., 2020b. Evolution of the lignin chemical structure during the bioethanol production process and its inhibition to enzymatic hydrolysis. Energy Fuels 34, 5938-5947. - Zhao, C., Qiao, X., Cao, Y., Shao, Q. 2017b. Application of hydrogen peroxide presoaking prior to ammonia fiber expansion pretreatment of energy crops. Fuel 205, 184-191. The wording is surprisingly similar to [Ma et al (2021)] :  The emerging potential methods of pretreatment and extraction of active components with hydrogen peroxide presoaking may bring unexpected insights into the material basis of FKQJ [21]. - [21]. Zhao C., Qiao X., Shao Q., Hassan M., Ma Z. Evolution of the lignin chemical structure during the bioethanol production process and its inhibition to enzymatic hydrolysis. Energy Fuels. 34(5):5938u20135947. [Liu et al (2021)] :  Furthermore, the emerging potential methods of pretreatment and extraction of active components [34u201336] may bring unexpected insights into the material basis of PALF. - [35] C. Zhao, Y. Cao, Z. Ma, and Q. Shao, u201cOptimization of liquid ammonia pretreatment conditions for maximizing sugar release from giant reed (*Arundo donax* L.),u201d Biomass and Bioenergy, vol. 98, pp. 61u201369, 2017. - [36] C. Zhao, X. Qiao, Y. Cao, and Q. Shao, u201cApplication of hydrogen peroxide presoaking prior to ammonia fiber expansion pretreatment of energy crops,u201d Fuel, vol. 205, no. 10, pp. 184u2013191, 2017. [Su et al (2020)] :  The emerging potential methods of pretreatment and extraction of active components with ammonia and hydrogen peroxide (Zhao et al., 2017a, 2020a,b) and pre-soaking (Zhao et al., 2017b; Qiao et al., 2018) may bring unexpected insights into the material basis of Schisandra chinensis. - Zhao, C., Cao, Y., Ma, Z. Q., and Shao, Q. J. (2017a). Optimization of liquid ammonia pretreatment conditions for maximizing sugar release from giant reed (*Arundo donax* L.). Biomass Bioenergy 98, 61u201369. doi: 10.1016 j.biombioe.2017.01.001 - Zhao, C., Qiao, X. L., Shao, Q. J., Hassan, M., and Ma, Z. Q. (2020a). Evolution of the lignin chemical structure during the bioethanol production process and its inhibition to enzymatic hydrolysis. Energy Fuels 34, 5938u20135947. doi: 10.1021 acs.energyfuels.0c00293 - Zhao, C., Qiao, X. L., Shao, Q. J., Hassan, M., Ma, Z. Q., and Yao, L. J. (2020b). Synergistic effect of hydrogen peroxide and ammonia on lignin. Ind. Crops Prod. 146:112177. doi: 10.1016 j.indcrop.2020.112177 - Zhao, C., Qiao, X. L., Cao, Y., and Shao, Q. J. (2017b). Application of hydrogen peroxide presoaking prior to ammonia fiber expansion pretreatment of energy crops. Fuel 205, 184u2013191. doi: 10.1016 j.fuel.2017.05.073 - Qiao, X. L., Zhao, C., Shao, Q. J., and Hassan, M. (2018). Structural characterization of corn stover lignin after hydrogen peroxide presoaking prior to ammonia fiber expansion pretreatment. Energy Fuels 32, 6022u20136030. doi: 10.1021 acs.energyfuels.8b00951 [Xia et al (2021)] :  The emerging potential methods of pretreatment and extraction of active components [30] may bring unexpected insights into the material basis of *Glycyrrhiza uralensis*. - [30] C. Zhao, X. Qiao, Q. Shao, M. Hassan, and Z. Ma, u201cEvolution of the lignin chemical structure during the bioethanol production process and its inhibition to enzymatic hydrolysis,u201d Energy Fuels, vol. 34, no. 5, pp. 5938u20135947, 2020. ---and many other papers. The most charitable interpretation is that this irrelevant bolus of Zhao papers was forced on the authors as a condition of publication. , 
 The introductory passage creates the impression that this rather unpleasant mineral is currently prescribed as a treatment for various forms of cancer.  Nowadays, realgar is used to fight against acute promyelocytic leukemia (APL) (Wang et al., 2008; Lu et al., 2002; Zhang et al., 2003), chronic myelogenous leukemia (CML) (Mao et al., 2010) and other cancers in China (Balu00e1u017e and Sedlu00e1k, 2010). Given the broad-spectrum lethality of realgar, I would prefer to see this claim supported by more than decades-old pilot and in-vitro studies.  To date, realgar is still used externally to cure skin problems such as carbuncle, lump and furuncle, even to treat bites by insects or snakes, and internally to remedy convulsive epilepsy, malaria and abdominal pain resulting from parasitic infection (Chinese Pharmacopeia, 2015). The citation is missing from the References. , 
 #1 The following 22 papers are a subset of [a larger group of 30-odd papers] , all from the Traditional Chinese Medicine genre, and all citing the work of C. Zhao and colleagues, under the misapprehension that this work is about extracting active phytochemical ingredients from herbs. What singles out these 22 entries is the presence of identical passages, to contain these irrelevant citations. This is consistent with some kind of citation manipulation. It would be helpful if the authors of any of these papers could explain whether the references and repeated passages were their own idea, and if not, who suggested them. The irrelevance is particularly obvious in the case of Ma et al (#8 in the list), which purports to apply herbal-ingredient extraction methods to a mineral substance, Realgar. -------------------------- The relevant canon of C. Zhao papers is - A. Hassan, M., Umar, M., Ding, W., Mehryar, E., Zhao, C. (2017). Methane enhancement through co-digestion of chicken manure and oxidative cleaved wheat straw: Stability performance and kinetic modeling perspectives. Energy, 141, 2314u20132320. - B. Qiao, X. L., Zhao, C., Shao, Q. J., Hassan, M., Energy Fuel 2018, 32, 6022-6030.  Structural characterization of corn stover lignin after hydrogen peroxide presoaking prior to ammonia fiber expansion pretreatment - C. Zhang, M. Q., Zhao, C., Shao, Q. J., Yang, Z. D., Int. J. Agr. Biol. Eng. 2019, 12, 143-148.  Determination of water content in corn stover silage using near-infrared spectroscopy - D. Zhao, C., Shao, Q. J., Ma, Z. Q., Li, B., Zhao, X. J., Ind. Crop. Prod. 2016, 83, 86-93.  Physical and chemical characterizations of corn stalk resulting from hydrogen peroxide presoaking prior to ammonia fiber expansion pretreatment - E. Zhao, C., Cao, Y., Ma, Z. Q., Shao, Q. J., Biomass Bioenergy 2017, 98, 61-69.  Optimization of liquid ammonia pretreatment conditions for maximizing sugar release from giant reed (*Arundo donax* L.). - F. C. Zhao, X.L. Qiao, Y. Cao, Q.J. Shao, Methane enhancement through co-digestion of chicken manure and oxidative cleaved wheat straw: stability performance and kinetic modeling perspectives, Energy 141 (2017) 2314u20132320. - G. Zhao, C., Qiao, X. L., Cao, Y., Shao, Q. L., Fuel 2017, 205, 184-191.  Application of hydrogen peroxide presoaking prior to ammonia fiber expansion pretreatment of energy crops - H. Zhao, C., Qiao, X., Shao, Q., Hassan, M., Ma, Z., 2020a, Evolution of the lignin chemical structure during the bioethanol production process and its inhibition to enzymatic hydrolysis, Energ. Fuel., 2020, 34, 5938-5947. - I. Zhao, C., Qiao, X. L., Shao, Q. J., Hassan, M., Ma, Z. Q., Yao, L. J., Ind. Crop. Prod. 2020, 146, 112177.  Synergistic effect of hydrogen peroxide and ammonia on lignin ----------------------------------------------- 1. [Wang et al (2020)] .  Simultaneous determination of 20 bioactive components in Chuanxiong Rhizoma from different production origins in Sichuan province by ultrau2010highu2010performance liquid chromatography coupled with triple quadrupole mass spectrometry combined with multivariate statistical analysis . -  TCM is usually prepared by boiling herbs in water, and it is impossible to obtain all the chemical components of herbs. ... Meanwhile, The emerging potential methods of pretreatment and extraction of active components with ammonia and hydrogen peroxide [36, 37] and pre-soaking [38-40] may bring unexpected insights into the material basis of TCM. -  In addition, Chuanxiong Rhizoma contains water, and the determination of water content may be performed before extraction [41], which contribute to accurate determination of active components in future research. 2. [Li et al (2020)] .  Metabonomics approach reveals the vital role of Huangqi in Huangqi Jianzhong tang against chronic atrophic gastritis coupled with molecular docking and BAWP . -  Additionally, TCM was usually prepared by reflowing the herbs in water, which could not obtain their whole chemical constitutes. The emerging potential approaches to pre-treat and extract the active compounds with presoaking [32], CO2 extraction [33], ammonia and hydrogen peroxide, etc [34u201336]. might introduce unexpected insights into its chemicalome and material basis research for TCM, which depicted the compound compatibility environment of single herb in a whole TCM formula. 3. [Wang et al (2021)] .  Geographical traceability of Eucommia ulmoides leaves using attenuated total reflection Fourier transform infrared and ultraviolet-visible spectroscopy combined with chemometrics and data fusion . -  The emerging potential methods of pretreatment and extraction of active components with ammonia and hydrogen peroxide (Zhao et al., 2020a; Zhao et al., 2017a; Zhao et al., 2020b) and pre-soaking (Zhao et al., 2016; Zhao et al., 2017b) may bring unexpected insights into the material basis of *E. ulmoides*. -  The EULs may contain water, and the determination of water content may be performed before experiment (Zhang et al., 2019), which contribute to accurate determination of active components in future research. 4. [Liu et al (2020)] .  UHPLC Q-Exactive MS-based spleen metabolomics and lipidomics to explore the effect mechanisms of Danggui Buxue Decoction in anemia mice . -  However, the sample pretreatment also might be potential hot spots for increasing the metabolic coverage of the tissue samples, which might better reveal the pathological location and specific metabolic mechanism of DBD. The emerging potential approaches to pre-treat and extract the active compounds with Solid Phase Extraction (SPE) [26], supercritical fluid extraction [27], ammonia and hydrogen peroxide, etc [28]., etc. from tissue sample might introduce unexpected insights into its metabolic mechanism of TCM [29]. 5. [Liu, Ma Cai (2020)] .  Fecal metabonomics study of raw and bran-fried Atractylodis Rhizoma in spleen-deficiency rats . -  In this study, because of the uncertainty of material basis, we used the powder solution of traditional Chinese medicine. It has been reported that the emerging potential methods of pretreatment and extraction of active components with ammonia and hydrogen peroxide [24-26] and pre-soaking [27-29] may bring unexpected insights into the material basis of TCM. Novel extraction method may be helpful for our future material basis research. -  It also should be noted that AR contains water, and the determination of water content may be performed before extraction [30], which contribute to accurate determination of active components in future research. 6. [Zhao et al (2021)] .  Tissue-specific metabolite profiling of Fallopia multiflora (Heshouwu) and Fallopia multiflora var. angulata by mass spectrometry imaging and laser microdissection combined with UPLC-Q TOF-MS . -  However,the secondary metabolites identified from *F. multiflora* in this study are not as abundant as previously reported [30], which may be related to samples volume and or the extraction method. The emerging potential methods of pretreatment and extraction of active components with ammonia and hydrogen peroxide and presoaking [34] may bring unexpected insights into the material basis of *F. multiflora* and *F. multiflora var. angulata*. 7. [Cheng et al (2021)] .  Involvement of mTOR Survivin signaling pathway in TUA(2u03b2, 3u03b2, 23-trihydroxy-urs-12-ene-28-olic acid)-induced apoptosis in human gastric cancer cell line BGC823 cells . -  In the study, the *A. fulvicoma* Hance extracts were extracted by 95 % ethanol, and it may not be the most effective method for extracting TUA from the herb. The emerging potential methods of pretreatment and extraction of active components with ammonia and hydrogen peroxide (Zhao,et al.,2020; Zhao, et al.,2017; Zhao, et al.,2020)and pre-soaking (Zhao, et al.,2017)may bring unexpected insights into the material basis of the herb. -  The herbal material of *A. fulvicoma* Hance contained water, and the determination of water content may be performed before extraction (Zhang et al.,2019), which contribute to accurate analysis of TUA in future research. 8. [Ma et al (2021)] . ** Realgar increases defenses against infection by Enterococcus faecalis in Caenorhabditis elegans **. -  In present work, the realgar is prepared by 0.1 M NaOH, and it may not be the most effective method for extracting active components from the realgar. The emerging potential methods of pretreatment and extraction of active components with ammonia and hydrogen peroxide (Zhao et al., 2017a; 2020a, b) and pre-soaking (Zhao et al., 2017b) may bring unexpected insights into the effects of realgar on immunity responses. 9. [Fu et al (2021)] .  Deciphering the metabolic profile and pharmacological mechanisms of Achyranthes bidentata blume saponins using ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry coupled with network pharmacology-based investigation . -  Meanwhile, the development of instrumentations and postacquisition data mining platforms (Wu et al., 2015, 2020; Yu et al., 2016) as well as the emerging potential methods of pretreatment and extraction of active components (Zhao et al., 2020) may bring unexpected insights into the material basis of herbal medicine. 10. [Liu et al (2020)] .  Urinary metabolomics research for Huangqi Jianzhong Tang against chronic atrophic gastritis rats based on H NMR and UPLC-Q TOF MS -  In addition, HQJZ was prepared by reflowing the herbs in water with a TCM classical method. The emerging potential approaches to pretreat and extract the active compounds with CO2 extraction, ammonia and hydrogen peroxide, etc. from herbs might introduce unexpected insights into its chemical constituents and material basis research in future.[40,41] 11. [Guo et al (2020)] .  Chemical Comparison of White Ginseng before and after Extrusion by UHPLC-Q-Orbitrap-MS MS and Multivariate Statistical Analysis . -  Meanwhile, the sample of ginseng contains water, and the determination of water content may be performed before extraction [35, 36], which contribute to accurate determination of polysaccharide in future research. 12. [Li et al (2020)] .  Quantification Analysis of 13 Organic Components and 8 Inorganic Elements in Angelica Sinensis Radix and Its Different Parts Combined with Chemical Recognition Pattern . -  TCM is usually prepared by boiling herbs in water, and it is impossible to obtain all the chemical components of herbs. The emerging potential methods of pretreatment and extraction of active components with ammonia and hydrogen peroxide [25u201327] and presoaking [28u201330] may bring unexpected insights into the material basis of TCM -  In addition, TCM contains water, and the determination of water content may be performed before extraction [32], which contributes to accurate determination of active components in future research. 13. [Lia et al (2021)] .  Study on the Spectrum-Effect Relationship of the Traditional Effect of Saponins in Glycyrrhiza uralensis Fisch . -  At first, the enriched GS is usually extracted and prepared in ethanol by sonication, and it may not be the most effective method for extracting active components from the *Glycyrrhiza uralensis*. The emerging potential methods of pretreatment and extraction of active components [30] may bring unexpected insights into the material basis of *Glycyrrhiza uralensis*. 14. [Ma et al (2021)] .  Study on the Bioassay of Anti-Inflammatory Effects of Fuke Qianjin Capsule Based on COX-2 Inhibiting Activity . -  In addition, FKQJ is usually prepared by boiling the eight kinds of TCM in water, and it may not be the most effective method for extracting active components from the TCM. The emerging potential methods of pretreatment and extraction of active components with hydrogen peroxide presoaking may bring unexpected insights into the material basis of FKQJ [21]. 15. [Liu et el (2021)] .  Assessing the Quality of Calyx of Physalis alkekengi L. var. franchetii Based on Quantitative Analysis of Q-Marker Combined with Chemometrics and Machine Learning Algorithms . -  Furthermore, the emerging potential methods of pretreatment and extraction of active components [34u201336] may bring unexpected insights into the material basis of PALF. -  Determination of water content in the experiment material PALF was carried out using some methods before the test [24u201326], which will help the test results to be more accurate 16. [Wu et al (2021)] .  Network Pharmacology-Based Analysis on the Action Mechanism of Oleanolic Acid to Alleviate Osteoporosis . -  The emerging potential methods of pretreatment and extraction of active components may provide guarantee for the sustainable supply of OA in a large scale. (23,24) -  Future studies may explore whether a certain method to measure the water content in OA prior to the experiment would contribute to more accurate results. (50) 17. [Li et al (2022)] .  Mulberry leaves ameliorate diabetes via regulating metabolic profiling and AGEs RAGE and p38 MAPK NF-u03baB pathway . -  The emerging potential methods of pretreatment and extraction of active components with ammonia and hydrogen peroxide and pre-soaking may bring unexpected insights into the... 18. [Wang et al (2022)] .  Shengmai Yin formula exerts cardioprotective effects on rats with chronic heart failure via regulating Linoleic Acid metabolism -  Emerging potential methods of pretreatment and extraction of active components with ammonia and hydrogen peroxide and pre-soaking [25,26] may bring unexpected insights into the u2026 19. [Chen et al (2021)] .  Application of UV-Vis and Infrared Spectroscopy on Wild Edible Bolete Mushrooms Discrimination and Evaluation: A Review . -  The emerging potential methods of pretreatment and extraction of active components with ammonia and hydrogen peroxide and presoaking may bring unexpected insights into the u2026 20. [Zhao et al (2021)] .  Monascus ruber fermented Panax ginseng ameliorates lipid metabolism disorders and modulate gut microbiota in rats fed a high-fat diet . -  The emerging potential new methods, such as ammonia pretreatment, enzymatic hydrolysis and so on (Zhao et al., 2020), may bring unexpected insights into the material basis of ginseng. 21. [Hu et al (2021)] .  Determination and analysis of monosaccharides in Polygonatum cyrtonema Hua polysaccharides from different areas by ultrau2010highu2010performance liquid chromatography quadrupole trap tandem mass spectrometry . -  The emerging potential methods of pretreatment and extraction [42] may provide unexpected insights into the active material bases of herbal medicine. 22. Gong et al (2021)] .  Anti-angiogenesis Function of Ononin via Suppressing the MEK Erk Signaling Pathway . -  The emerging potential methods of pretreatment and extraction of ononin with ammonia and hydrogen peroxide and presoaking may bring unexpected insights into the material basis of the herbs.52 , 
 #2 Arsenic trioxide is FDA approved for very specific forms of cancer and is sold under the brand name Trisenox Realgar is not approved for any medical use AFIK however ,