Anti-malarial drug: the emerging role of artemisinin and its derivatives in liver disease treatment

Chemical and spectroscopic characterization of (Artemisinin/Querctin/ Zinc) novel mixed ligand complex with assessment of its potent high antiviral activity against SARS-CoV-2 and antioxidant capacity against toxicity induced by acrylamide in male rats

A novel Artemisinin/Quercetin/Zinc (Art/Q/Zn) mixed ligand complex was synthesized, tested for its antiviral activity against coronavirus (SARS-CoV-2), and investigated for its effect against toxicity and oxidative stress induced by acrylamide (Acy), which develops upon cooking starchy foods at high temperatures. The synthesized complex was chemically characterized by performing elemental analysis, conductance measurements, FT-IR, UV, magnetic measurements, and XRD. The morphological surface of the complex Art/Q/Zn was investigated using scanning and transmission electron microscopy (SEM and TEM) and energy dispersive X-ray analysis (XRD). The in vitro antiviral activity of the complex Art/Q/Zn against SARS-CoV-2 and its in vivo activity against Acy-induced toxicity in hepatic and pulmonary tissues were analyzed. An experimental model was used to evaluate the beneficial effects of the novel Art/Q/Zn novel complex on lung and liver toxicities of Acy. Forty male rats were randomly divided into four groups: control, Acy (500 mg/Kg), Art/Q/Zn (30 mg/kg), and a combination of Acy and Art/Q/Zn. The complex was orally administered for 30 days. Hepatic function and inflammation marker (CRP), tumor necrosis factor, interleukin-6 (IL-6), antioxidant enzyme (CAT, SOD, and GPx), marker of oxidative stress (MDA), and blood pressure levels were investigated. Histological and ultrastructure alterations and caspase-3 variations (immunological marker) were also investigated. FT-IR spectra revealed that Zn (II) is able to chelate through C=O and C-OH (Ring II) which are the carbonyl oxygen atoms of the quercetin ligand and carbonyl oxygen atom C=O of the Art ligand, forming Art/Q/Zn complex with the chemical formula [Zn(Q)(Art)(Cl)(H2O)2]⋅3H2O. The novel complex exhibited a potent anti-SARS-CoV-2 activity even at a low concentration (IC50 = 10.14 µg/ml) and was not cytotoxic to the cellular host (CC50 = 208.5 µg/ml). Art/Q/Zn may inhibit the viral replication and binding to the angiotensin-converting enzyme-2 (ACE2) receptor and the main protease inhibitor (MPro), thereby inhibiting the activity of SARS-CoV-2 and this proved by the molecular dynamics simulation. It alleviated Acy hepatic and pulmonary toxicity by improving all biochemical markers. Therefore, it can be concluded that the novel formula Art/Q/Zn complex is an effective antioxidant agent against the oxidative stress series, and it has high inhibitory effect against SARS-CoV-2.

Palmitoylation of PKCδ by ZDHHC5 in hypothalamic microglia presents as a therapeutic target for fatty liver disease

The hypothalamus plays a fundamental role in controlling lipid metabolism through neuroendocrine signals. However, there are currently no available drug targets in the hypothalamus that can effectively improve human lipid metabolism. In this study, we found that the antimalarial drug artemether (ART) significantly improved lipid metabolism by specifically inhibiting microglial activation in the hypothalamus of high-fat diet-induced mice. Mechanically, ART protects the thyrotropin-releasing hormone (TRH) neurons surrounding microglial cells from inflammatory damage and promotes the release of TRH into the peripheral circulation. As a result, TRH stimulates the synthesis of thyroid hormone (TH), leading to a significant improvement in hepatic lipid disorders. Subsequently, we employed a biotin-labeled ART chemical probe to identify the direct cellular target in microglial cells as protein kinase Cδ (PKCδ). Importantly, ART directly targeted PKCδ to inhibit its palmitoylation modification by blocking the binding of zinc finger DHHC-type palmitoyltransferase 5 (ZDHHC5), which resulted in the inhibition of downstream neuroinflammation signaling. In vivo, hypothalamic microglia-specific PKCδ knockdown markedly impaired ART-dependent neuroendocrine regulation and lipid metabolism improvement in mice. Furthermore, single-cell transcriptomics analysis in human brain tissues revealed that the level of PKCδ in microglia positively correlated with individuals who had hyperlipemia, thereby highlighting a clinical translational value. Collectively, these data suggest that the palmitoylation of microglial PKCδ in the hypothalamus plays a role in modulating peripheral lipid metabolism through hypothalamus-liver communication, and provides a promising therapeutic target for fatty liver diseases.

TPN10475 alleviates concanavalin A-induced autoimmune hepatitis by limiting T cell development and function through inhibition of PI3K-AKT pathway

Autoimmune hepatitis (AIH) is an inflammatory liver disease in which the autoimmune system instigates an attack on the liver, causing inflammation and liver injury, and its incidence has increased worldwide in recent years. The mouse model of acute hepatitis established by concanavalin A (Con A) is a typical and recognized mouse model for the study of T-cell-dependent liver injury. In this study, we aimed to investigate whether the artemisinin derivative TPN10475 could alleviate AIH and its possible mechanisms. TPN10475 effectively inhibited lymphocyte proliferation and IFN-γ+ T cells production in vitro, alleviated liver injury by decreasing infiltrating inflammatory T cells producing IFN-γ in the liver and peripheral immune tissues, and demonstrated that TPN10475 weakened the activation and function of T cells by inhibiting PI3K-AKT signaling pathway. These results suggested that TPN10475 may be a potential drug for the treatment of AIH, and the inhibition of PI3K-AKT signaling pathway may provide new ideas for the study of the pathogenesis of AIH.

Redox modulating small molecules having antimalarial efficacy

The search for effective antimalarial agents remains a critical priority because malaria is widely spread and drug-resistant strains are becoming more prevalent. In this review, a variety of small molecules capable of modulating redox processes were showcased for their potential as antimalarial agents. The compounds were designed to target the redox balance of Plasmodium parasites, which has a pivotal function in their ability to survive and multiply within the host organism. A thorough screening method was utilized to assess the effectiveness of these compounds against both drug-sensitive and drug-resistant strains of Plasmodium falciparum, the malaria-causing parasite. The results revealed that several of the tested compounds exhibited significant effectiveness against malaria, displaying IC50 values at a low micromolar range. Furthermore, these compounds displayed promising selectivity for the parasite, as they exhibited low cytotoxicity towards mammalian cells. Thorough mechanistic studies were undertaken to clarify how the active compounds exert their mode of action. The findings revealed that these compounds disrupted the parasites' redox balance, causing oxidative stress and interfering with essential cellular functions. Additionally, the compounds showed synergistic effects when combined with existing antimalarial drugs, suggesting their potential for combination therapies to combat drug resistance. Overall, this study highlights the potential of redox-modulating small molecules as effective antimalarial agents. The identified compounds demonstrate promising antimalarial activity, and their mechanism of action offers insights into targeting the redox balance of Plasmodium parasites. Further optimization and preclinical studies are warranted to determine their efficacy, safety, and potential for clinical development as novel antimalarial therapeutics.

Synthesis and spectroscopic study of novel mixed ligand formula "Artemisinin/Zn" and assessment of its inhibitory effect against "SARS-CoV-2″

Background

Herein, a newly synthesised mixed ligand artemisinin/zinc (Art/Zn) is chemically characterised and examined against SARS-CoV-2.

Methods

The synthesised complex was thoroughly characterised using various spectroscopic methods (FT-IR, UV and XRD). Its surface morphology and chemical purity were investigated using transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analysis. The synthesised Art/Zn complex was tested for its inhibitory effects against SARS-CoV-2 using inhibitory concentration 50 (IC₅₀) and cytotoxicity concentration 50 (CC₅₀).

Results

The results reveal that the Art/Zn complex exhibits a moderate in vitro inhibitory effects against SARS-CoV-2, with a CC₅₀ index of 213.6 μg/ml and an IC50 index of 66.79 μg/ml. Notably, it exhibits the inhibitory effect (IC₅₀ = 66.79 μg/ml) at a very low concentration without any observable cytotoxic effects on host cells (CC₅₀ = 213.6 μg/ml). Its mode of action against SARS-CoV-2 involves inhibiting the viral replication. The predicted target classes that Art/Zn may affect include kinases, which can regulate and inhibit the viral replication and binding to the angiotensin-converting enzyme-2 (ACE2) receptor and the main protease inhibitor (M^Pro), thereby inhibiting the activity of SARS-CoV-2 and proved by the molecular dynamics simulation.

Conclusion

We recommend using the Art/Zn complex owing to its moderate inhibitory and antiviral effects against the SARS-CoV-2 with a low cytotoxic effect on host (Vero E6) cells. We suggest conducting further prospective studies to investigate the biological effects of Art/Zn in animal models at different concentrations for testing its clinical efficacy and safety in inhibiting SARS-CoV-2 activities.

Dihydroartemisinin engages liver fatty acid binding protein and suppresses metastatic hepatocellular carcinoma growth

Dihydroartemisinin non-covalently binds liver fatty acid binding protein (FABP1) with micromolar affinity, acts as a FABP1-dependent peroxisome proliferator-activated receptor alpha agonist and inhibits metastatic hepatocellular carcinoma growth.

MADS-box gene AaSEP4 promotes artemisinin biosynthesis in Artemisia annua

The plant Artemisia annua is well known for its production of artemisinin, a sesquiterpene lactone that is an effective antimalarial compound. Although remarkable progress has been made toward understanding artemisinin biosynthesis, the effect of MADS-box family transcription factors on artemisinin biosynthesis is still poorly understood. In this study, we identified a MADS transcription factor, AaSEP4, that was predominantly expressed in trichome. AaSEP4 acts as a nuclear-localized transcriptional activator activating the expression of AaGSW1 (GLANDULAR TRICHOME-SPECIFIC WRKY1). Dual-luciferase and Yeast one-hybrid assays revealed that AaSEP4 directly bound to the CArG motif in the promoter region of AaGSW1. Overexpression of AaSEP4 in A. annua significantly induced the expression of AaGSW1 and four artemisinin biosynthesis genes, including amorpha-4,11-diene synthase (ADS), cytochrome P450 monooxygenase (CYP71AV1), double-bond reductase 2 (DBR2) and aldehyde dehydrogenase 1 (ALDH1). Furthermore, the results of high-performance liquid chromatography (HPLC) showed that the artemisinin content was significantly increased in the AaSEP4-overexpressed plants. In addition, RT-qPCR results showed that AaSEP4 was induced by methyl jasmonic acid (MeJA) treatment. Taken together, these results explicitly demonstrate that AaSEP4 is a positive regulator of artemisinin biosynthesis, which can be used in the development of high-artemisinin yielding A. annua varieties.