Advances in the safety evaluation of mineral medicines - Cinnabar and Realgar

Mercuric sulfide nanoparticles suppress the neurobehavioral functions of Caenorhabditis elegans through a Skp1-dependent mechanism

Cinnabar is the naturally occurring mercuric sulfide (HgS) and concerns about its safety have been grown. However, the molecular mechanism of HgS-related neurotoxicity remains unclear. S-phase kinase-associated protein 1 (Skp1), identified as the target protein of HgS, plays a crucial role in the development of neurological diseases. This study aims to investigate the neurotoxic effects and molecular mechanism of HgS based on Skp1 using the Caenorhabditis elegans (C. elegans) model. We prepared the HgS nanoparticles and conducted a comparative analysis of neurobehavioral differences in both wild-type C. elegans (N2) and a transgenic strain of C. elegans (VC1241) with a knockout of the SKP1 homologous gene after exposure to HgS nanoparticles. Our results showed that HgS nanoparticles could suppress locomotion, defecation, egg-laying, and associative learning behaviors in N2 C. elegans, while no significant alterations were observed in the VC1241 C. elegans. Furthermore, we conducted a 4D label-free proteomics analysis and screened 504 key proteins significantly affected by HgS nanoparticles through Skp1. These proteins play pivotal roles in various pathways, including SNARE interactions in vesicular transport, TGF-beta signaling pathway, calcium signaling pathway, FoxO signaling pathway, etc. In summary, HgS nanoparticles at high doses suppress the neurobehavioral functions of C. elegans through a Skp1-dependent mechanism.

Neurobehavioral effects of cinnabar and the cinnabar-containing pediatric prescription, Yi-Nian-Jin, in juvenile rats

BACKGROUND

Cinnabar, a mercury-containing mineral medicine, has long been widely used in pediatric prescriptions. The safety of cinnabar-containing prescriptions, particularly for children, is drawing increasing attention worldwide. However, whether cinnabar and these pediatric prescriptions have adverse effects on neurobehavior is unknown. Yi-Nian-Jin (YNJ), a classic pediatric prescription, contains 5.66% (w/w) cinnabar, along with other four herbs. YNJ is widely prescribed to promote digestion, eliminate phlegm, and prevent constipation in children (aged 0-6 years). In this study, we used YNJ as an example of cinnabar-containing pediatric prescriptions to determine mercury absorption, distribution, and accumulation and further investigate its potential neurotoxicity in juvenile rats.

MATERIAL AND METHODS

Low (67.9 mg/kg), middle (169.8 mg/kg), and high dose (339.6 mg/kg) of cinnabar, and low (1.2 g/kg), middle (3.0 g/kg), and high dose (6.0 g/kg) of YNJ were used in this study, corresponding to 3, 7.5, and 15 times the clinically equivalent dose, respectively. Juvenile rats were orally administered different doses of cinnabar or YNJ for 14 consecutive days. The mercury content in rat blood and tissues (brain, liver, and kidney) and serum biochemical changes on day 14 of consecutive administration and on day 14 after cessation were measured. Moreover, a series of behavioral assays (open field, elevated plus-maze, and Morris water maze assays) were performed after 14 consecutive days of administration.

RESULTS

The mercury absorption, distribution, and accumulation of cinnabar and YNJ in juvenile rats were substantially different. Mercury in cinnabar was absorbed to a greater extent than that in YNJ, and the mercury content in cinnabar high-dose group (cinnabar-H) was approximately seven times higher than that in YNJ high-dose group (YNJ-H) on day 14 of administration. In contrast, compared with that of cinnabar, the mercury content in YNJ accumulated more in the tissues, especially in the brain and kidney. Repeated administration of cinnabar or YNJ did not affect liver function, renal function, learning, and memory in juvenile rats. However, repeated administration of YNJ at a high dose (6.0 g/kg) affected locomotor activity in juvenile rats. Repeated administration of cinnabar (339.6 mg/kg) or YNJ (>1.2 g/kg) induced anxiety-related behavior in juvenile rats.

CONCLUSIONS

Mercury in YNJ exhibited lower absorption but higher accumulation in tissues than those of the mercury in cinnabar. Consecutive oral administration of cinnabar or YNJ had no impact on liver function, renal function, learning, and memory, but could cause motor dysfunction and anxiety in juvenile rats.

Pharmacodynamics and acute toxicity studies of Shangke Jiegu tablet with or without cinnabar

Purpose

To evaluate the function of cinnabar in Shangke Jiegu tablet (SKJGT) via pharmacodynamics and toxicity investigations to determine whether cinnabar should be removed from SKJGT.

Materials and methods

The pharmacodynamic differences between SKJGT and cinnabar-free Shangke Jiegu tablet (CFSKJGT) were systematically compared in five animal models. Anti-inflammatory effects were assessed on ear swelling and paw edema by measuring the degree of swelling in each. Then, the acetic acid-induced writhing reaction and hot-water tail-flick were also evaluated by counting pain reactions. The pharmacodynamic effects on soft tissue contusions were identified through histopathological observation. Chemical markers of fracture healing, including osteocytes and the blood calcium and phosphorus level, were determined via radiographic examination and biochemical assay, respectively. In addition, the maximum dosages of SKJGT and CFSKJGT were tested in mice to compare their toxicities.

Results

SKJGT and CFSKJGT showed anti-inflammation effects (swelling inhibition ratios of 40.8% and 44.0%, respectively), analgesia (pain threshold ratios of 48.2% and 44.1%, respectively, at 60 min in the hot-water tail-flick test), and soft tissue contusion repair compared with the control (p < 0.05), and the degree of swelling inhibition and the number of pain reactions were dose-dependent. SKJGT and CFSKJGT both significantly improved the bone healing in the rat fracture model, as indicated by the increased osteocyte size during weeks 1-6 and elevated blood calcium and blood phosphorus levels (reaching maximum concentrations of 7.5 mmol/L and 6.8 mmol/L, respectively) during weeks 1-2. The maximum doses for the SKJGT and CFSKJGT groups were 9.0 g/kg in the acute toxicity experiment. The seizure rate of the SKJGT group (25.0%) was lower than that of the CFSKJGT group (50.0%) when the toxicity was observed after administration.

Conclusion

This is the first report to investigate the pharmacodynamics and acute toxicity of cinnabar in SKJGT. Broadly, this study offers novel, valuable insights into the efficacy of cinnabar in prescribed SKJGT.

Antiviral and cytotoxic effects of a traditional drug KanthaRasaVillai with a cocktail of metallic nanoparticles

Objective

Alternative medicine plays an important role today in searching for therapeutics for cancer and viral infection. So, a scientific validation to characterize constituents in the alternative medicines and therapeutic testing is warranted using modern instrumentation.

Methods

In the present study, an old herbomineral formulation, KanthaRasavillai [KRV], was characterized using UV-vis spectrometry, FT-IR, XRD, SEM, and TEM study. Also, In vitro and in vivo studies were done to evaluate their antiviral and anticancer activity. FT-IR and XRD studies revealed a cocktail of nanoparticles of mercury, magnetic oxide, cinnabar, and arsenic.Results.Based on SEM, TEM, and XRD report, KRV contains nanoparticles in the size range of 9.1 nm to 25.0 nm. FT-IR analysis exposed the presence of several anti-cancerous bioactive compounds.Further in vitro testing against HCV virus proved KRV to inhibit HCV virus a close relative to SARS-CoV-2. MTT assay confirmed the anticancer effect of KRV against Huh-7 and MCF-7 cell lines.

Conclusion

The anticancer and antiviral properties in the ancient herbomineral drug with a cocktail of metal nanoparticles acknowledge the traditional medical practice as a pioneering approach for present-day ailments. However, the study concludes that the use of KRV depends on safety dosage and genuine preparation as described by ancient saints.

Understanding the hepatoxicity of inorganic mercury through guts: Perturbance to gut microbiota, alteration of gut-liver axis related metabolites and damage to gut integrity

Mercury (Hg) brings adverse effects to the environment and human beings and inorganic mercury (IHg) is a typical hepatic toxin. This work studied the impacts of IHg on gut microbes and metabolome together with its damage to liver and gut in rats through gut microbiome, metabolomics and metallomics. Sprague Dawley (SD) rats were orally exposed to 0.4 μg/mL IHg and sacrificed after 24 h. It was found that IHg perturbed greatly on the gut microbiota, such as increased pathogenic bacteria like G. bacillus. In addition, IHg also changed gut-liver axis related metabolites, which was confirmed by the secretion of a large number of inflammatory factors in both the gut and the liver. The changed gut-liver axis related metabolites correlated well to the changes of gut microbiome. In all, besides the direct deposition in liver of Hg, the perturbance to gut microbiome and alteration of gut-liver axis related metabolites by IHg also contributed to its hepatoxicity, which provides new insights about the hepatoxicity of chemicals. The strategy applied in this work may also be used to understand the hepatoxicity of other chemicals.

Minerals in biology and medicine

Natural minerals ('stone drugs') have been used in traditional Chinese medicines for over 2000 years, but there is potential for modern-day use of inorganic minerals to combat viral infections, antimicrobial resistance, and for other areas in need of new therapies and diagnostic aids. Metal and mineral surfaces on scales from milli-to nanometres, either natural or synthetic, are patterned or can be modified with hydrophilic/hydrophobic and ionic/covalent target-recognition sites. They introduce new strategies for medical applications. Such surfaces have novel properties compared to single metal centres. Moreover, 3D mineral particles (including hybrid organo-minerals) can have reactive cavities, and some minerals have dynamic movement of metal ions, anions, and other molecules within their structures. Minerals have a unique ability to interact with viruses, microbes and macro-biomolecules through multipoint ionic and/or non-covalent contacts, with potential for novel applications in therapy and biotechnology. Investigations of mineral deposits in biology, with their often inherent heterogeneity and tendency to become chemically-modified on isolation, are highly challenging, but new methods for their study, including in intact tissues, hold promise for future advances.