Thymoquinone prevents endoplasmic reticulum stress and mitochondria-induced apoptosis in a rat model of partial hepatic warm ischemia reperfusion

Therapeutic potential of monoterpene molecules acts against 7KCh-mediated oxidative stress and neuroinflammatory amyloidogenic signalling pathways

Alzheimer's disease (AD) is a degenerative disorder characterised by amyloid-beta aggregates activated by the accumulation of lipid molecules and their derivatives, especially 7-ketocholesterol (7KCh), an oxidised lipid that plays a great part in the progression of AD. The current therapeutics need bio-potential molecules and their biomedical application preventing 7KCh-induced cytotoxicity. In this study, bornyl acetate (BA) and menthol (ME), the natural monoterpenes were investigated for their neuroprotective effects against 7KCh-induced SH-SY5Y cells and their effects were compared to the standard drug galantamine (GA). 7KCh-induced changes like lipid accumulation, amyloid generation, free radical generation, acetylcholinesterase levels, calcium accumulation and mitochondrial membrane integrity were analysed in SH-SY5Y cells with or without BA and ME treatment. Furthermore, various mediators involved in the amyloidogenic, inflammatory and apoptotic pathways were studied. In our results, the cells induced with 7KCh upon co-treatment with BA and ME significantly reduced lipid accumulation and amyloid generation through toll-like receptor (TLR) 4 suppression and enhanced ATP binding cassette (ABCA) 1-mediated clearance. Co-treatment with BA and ME concurrently regulated oxidative stress, acetylcholinesterase activity, mitochondrial membrane potential and intracellular calcification altered by 7KCh-induced SH-SY5Y cells. Moreover, 7KCh-induced cells showed elevated mRNA levels of misfolded protein markers and apoptotic mediators which were significantly downregulated by BA and ME co-treatment. In addition, the protein expression of amyloidogenic, proinflammatory as well as pro-apoptotic markers was decreased by BA and ME co-treatment in 7KCh-induced cells. Overall, BA and ME mediated inhibition of amyloidogenic activation and cell survival against 7KCh-induced inflammation, thereby preventing the onset and progression of AD in comparison to GA.

Comparison of the protective effects of silymarin and thymoquinone in the focal cerebral ischemia-reperfusion rat model

Silymarin and thymoquinone exert neuroprotective effects, although their combined effects in focal cerebral ischemia/reperfusion (I/R) models are unknown. We compared the effect of silymarin and thymoquinone in an I/R rat model. Wistar rats were divided into five groups: SHAM, REP (I/R), SIR (200 mg/kg silymarin+I/R), TIR (3 mg/kg thymoquinone+I/R), and STIR (200 mg/kg silymarin+3-mg thymoquinone+I/R). The rats underwent bilateral carotid artery occlusion for 30 min and neurological assessments 24 h thereafter. Apoptosis was evaluated using anti-caspase-3 and terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL) assays. Astrocyte activation was determined using an anti-GFAP antibody. Total antioxidant status (TAS), total oxidant status (TOS), and trimethylamine N-oxide (TMAO) levels were measured. SHAM and REP rats had the lowest and highest neurological scores, respectively (p = 0.001). REP rats showed greater deterioration than SIR, TIR, and STIR rats. SIR, TIR, and STIR rats had fewer TUNEL and caspase-3-positive cells than REP rats (p<0.05). GFAP expression was higher in REP rats (p<0.05) than in SIR, TIR, and STIR rats (p<0.05). SIR and TIR rats showed higher TAS than REP rats (p<0.05). SIR, TIR, and STIR rats had lower TMAO values than REP and SHAM rats (p<0.05). Silymarin/thymoquinone reduces impairment, apoptosis, and astrocyte activation. Combination therapy reduces TMAO levels.

Emodin alleviates intestinal ischemia/reperfusion-induced lung injury by upregulating HO-1 expression via PI3K/AkT pathway

BACKGROUND

Emodin, a natural anthraquinone derivative found in various Chinese medicinal herbs, has been proved to be an effective therapeutic agent in the treatment of many diseases. However, its effect on lung injury after intestinal ischemia/reperfusion injury remains unknown. This research was designed to investigate whether emodin protects against intestinal ischemia/reperfusion-induced lung injury and to elucidate the underlying molecular mechanisms in vivo and in vitro.

METHODS

Intestinal ischemia/reperfusion injury was induced by occluding the superior mesenteric artery in mice, and mouse lung epithelial-12 cells were subjected to oxygen-glucose deprivation and reoxygenation to establish an in vitro model.

RESULTS

Our data indicated that emodin treatment reduced intestinal ischemia/reperfusion-induced oxidative stress, inflammation and apoptosis in lung tissues and alleviated lung injury. However, the protective effects of emodin on intestinal ischemia/reperfusion-induced lung injury were reversed by the protein kinase B inhibitor triciribine or the heme oxygenase-1 inhibitor tin protoporphyrin IX. The protein kinase inhibitor triciribine also downregulated the expression of heme oxygenase-1.

CONCLUSION

In conclusion, our data suggest that emodin treatment protects against intestinal ischemia/reperfusion-induced lung injury by enhancing heme oxygenase-1 expression via activation of the PI3K/protein kinase pathway. Emodin may act as a potential therapeutic agent for the prevention and treatment of lung injury induced by intestinal ischemia/reperfusion.

Alpha-pinene neutralizes cisplatin-induced reproductive toxicity in male rats through activation of Nrf2 pathway

PURPOSE

Testicular toxicity is one of the most important side effects of cisplatin (CP) therapy. Alpha-pinene (AP) is a naturally occurring monoterpene with antioxidant character in plants. Here, we aimed to evaluate the therapeutic activity of AP against CP-induced testicular toxicity by including the nuclear factor erythroid 2-associated factor 2 (Nrf2) pathway in rats.

METHODS

Thirty male rats were divided into 5 groups: control, CP, CP + AP (5 and 10 mg/kg) and only AP (10 mg/kg). CP was administered intraperitoneally at a dose of 5 mg/kg on the first day, followed by three consecutive injections of AP. Serum reproductive hormone levels were evaluated using ELISA kits. Oxidative stress (OS), inflammation, endoplasmic reticulum stress (ERS) and apoptosis markers in testicular tissue were also determined colorimetrically. In addition, how CP affects Nrf2 pathway and the effect of AP on this situation were also addressed.

RESULTS

Treatment with CP significantly increased OS, inflammation, ERS and apoptosis in testicular tissue. Administrations of AP resulted in an amelioration of these altered parameters. The mechanism of therapeutic effect of AP appeared to involve induction of Nrf2. Furthermore, these results were also confirmed by histological data.

CONCLUSION

Results suggest that AP can exhibit therapeutic effects against CP-induced testicular toxicity. It can be concluded that AP may be a potential molecule to abolish reproductive toxicity after chemotherapy.

Thymoquinone-loaded self-nano-emulsifying drug delivery system against ischemia/reperfusion injury

In the present study, a self-nano-emulsifying drug delivery system (SNEDDS) was developed to evaluate the efficiency of thymoquinone (TQ) in hepatic ischemia/reperfusion. SNEDDS was pharmaceutically characterized to evaluate droplet size, morphology, zeta potential, thermodynamic stability, and dissolution/diffusion capacity. Animals were orally pre-treated during 10 days with TQ-loaded SNEDDS. Biochemical analyses, hematoxylin-eosin staining, indirect immunofluorescence, and reverse transcription polymerase chain reaction (RT-PCR) were carried out to assess cell injury, oxidative stress, inflammation, and apoptosis. The TQ formulation showed good in vitro characteristics, including stable nanoparticle structure and size with high drug release rate. In vivo determinations revealed that TQ-loaded SNEDDS pre-treatment of rats maintained cellular integrity by decreasing transaminase (ALT and AST) release and preserving the histological characteristics of their liver. The antioxidant ability of the formulation was proven by increased SOD activity, reduced MDA concentration, and iNOS protein expression. In addition, this formulation exerted an anti-inflammatory effect evidenced by reduced plasma CRP concentration, MPO activity, and gene expressions of TLR-4, TNF-α, NF-κB, and IL-6. Finally, the TQ-loaded SNEDDS formulation promoted cell survival by enhancing the Bcl-2/Bax ratio. In conclusion, our results indicate that TQ encapsulated in SNEDDS significantly protects rat liver from I/R injury.

Thymoquinone, a Novel Multi-Strike Inhibitor of Pro-Tumorigenic Breast Cancer (BC) Markers: CALR, NLRP3 Pathway and sPD-L1 in PBMCs of HR+ and TNBC Patients

Breast cancer (BC) is not only a mass of malignant cells but also a systemic inflammatory disease. BC pro-tumorigenic inflammation has been shown to promote immune evasion and provoke BC progression. The NOD-like receptor (NLR) family pyrin domain-containing protein 3 (NLRP3) inflammasome is activated when pattern recognition receptors (PRRs) sense danger signals such as calreticulin (CALR) from damaged/dying cells, leading to the secretion of interleukin-1β (IL-1β). CALR is a novel BC biological marker, and its high levels are associated with advanced tumors. NLRP3 expression is strongly correlated with an elevated proliferative index Ki67, BC progression, metastasis, and recurrence in patients with hormone receptor-positive (HR+) and triple-negative BC (TNBC). Tumor-associated macrophages (TAMs) secrete high levels of IL-1β promoting endocrine resistance in HR+ BC. Recently, an immunosuppressive soluble form of programmed death ligand 1 (sPD-L1) has been identified as a novel prognostic biomarker in triple-negative breast cancer (TNBC) patients. Interestingly, IL-1β induces sPD-L1 release. BC Patients with elevated IL-1β and sPD-L1 levels show significantly short progression-free survival. For the first time, this study aims to investigate the inhibitory impact of thymoquinone (TQ) on CALR, the NLRP3 pathway and sPD-L1 in HR+ and TNBC. Blood samples were collected from 45 patients with BC. The effect of differing TQ concentrations for different durations on the expression of CALR, NLRP3 complex components and IL-1β as well as the protein levels of sPD-L1 and IL-1β were investigated in the peripheral blood mononuclear cells (PBMCs) and TAMs of TNBC and HR+ BC patients, respectively. The findings showed that TQ significantly downregulated the expression of CALR, NLRP3 components and IL-1β together with the protein levels of secreted IL-1β and sPD-L1. The current findings demonstrated novel immunomodulatory effects of TQ, highlighting its potential role not only as an excellent adjuvant but also as a possible immunotherapeutic agent in HR+ and TNBC patients.

Hypothermic oxygenated perfusion attenuates DCD liver ischemia-reperfusion injury by activating the JAK2/STAT3/HAX1 pathway to regulate endoplasmic reticulum stress

BACKGROUND

Hepatic ischemia-reperfusion injury (IRI) in donation after cardiac death (DCD) donors is a major determinant of transplantation success. Endoplasmic reticulum (ER) stress plays a key role in hepatic IRI, with potential involvement of the Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) pathway and the antiapoptotic protein hematopoietic-lineage substrate-1-associated protein X-1 (HAX1). In this study, we aimed to investigate the effects of hypothermic oxygenated perfusion (HOPE), an organ preservation modality, on ER stress and apoptosis during hepatic IRI in a DCD rat model.

METHODS

To investigate whether HOPE could improve IRI in DCD livers, levels of different related proteins were examined by western blotting and quantitative real-time polymerase chain reaction. Further expression analyses, immunohistochemical analyses, immunofluorescence staining, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining, and transmission electron microscopy were conducted to analyze the effects of HOPE on ER stress and apoptosis. To clarify the role of the JAK2/STAT3 pathway and HAX1 in this process, AG490 inhibitor, JAX1 plasmid transfection, co-immunoprecipitation (CO-IP), and flow cytometry analyses were conducted.

RESULTS

HOPE reduced liver injury and inflammation while alleviating ER stress and apoptosis in the DCD rat model. Mechanistically, HOPE inhibited unfolded protein responses by activating the JAK2/STAT3 pathway, thus reducing ER stress and apoptosis. Moreover, the activated JAK2/STAT3 pathway upregulated HAX1, promoting the interaction between HAX1 and SERCA2b to maintain ER calcium homeostasis. Upregulated HAX1 also modulated ER stress and apoptosis by inhibiting the inositol-requiring enzyme 1 (IRE1) pathway.

CONCLUSIONS

JAK2/STAT3-mediated upregulation of HAX1 during HOPE alleviates hepatic ER stress and apoptosis, indicating the JAK2/STAT3/HAX1 pathway as a potential target for IRI management during DCD liver transplantation.

Nigella sativa seeds mitigate the hepatic histo-architectural and ultrastructural changes induced by 4-nonylphenol in Clarias gariepinus

Due to its prevalence in aquatic environments and potential cytotoxicity, 4-nonylphenol (4-NP) has garnered considerable attention. As a medicinal plant with numerous biological activities, Nigella sativa (black seed or black cumin) seed (NSS) is widely utilized throughout the world. Consequently, this study aimed to examine the potential protective effects of NSS against 4-NP-induced hepatotoxicity in African catfish (Clarias gariepinus). To achieve this objective, 18 fish (351 ± 3 g) were randomly divided into three equal groups for 21 days. The first group serves as a control which did not receive any treatment except the basal diet. The second and third groups were exposed to 4-NP at a dose of 0.1 mg L-1 of aquarium water and fed a basal diet only or supplemented with 2.5% NSS, respectively. The histological, histochemical, and ultrastructural features of the liver were subsequently evaluated as a damage biomarker of the hepatic tissue. Our results confirmed that 4-NP was a potent hepatotoxic agent, as 4-NP-intoxicated fish exhibited many lesions. Steatohepatitis, ballooning degeneration, sclerosing cholangitis, and coagulative necrosis of melanomacrophagecenters (MMCs) were observed. Hemosiderin, lipofuscin pigments, and proliferation of fibroblasts, kupffer cells, and telocytes were also demonstrated in the livers of 4-NP-intoxicated fish. In addition, decreased glycogen content and increased collagen deposition were observed in the hepatic tissue. Hepatocytes exhibited ultrastructural alterations in the chromatin, rough endoplasmic reticulum, smooth endoplasmic reticulum, mitochondria, lysosomes, and peroxisomes. Co-administration of 2.5% NSS to 4-NP-intoxicated fish significantly reduced these hepatotoxic effects. It nearly preserved the histological, histochemical, and ultrastructural integrity of hepatic tissue.

ADSCs-exo attenuates hepatic ischemia-reperfusion injury after hepatectomy by inhibiting endoplasmic reticulum stress and inflammation

Hepatic ischemia-reperfusion (I/R) injury commonly occurs during liver surgery. Exosomes from adipose-derived stem cells (ADSCs-exo) induce a hepatoprotective effect during hepatic I/R injury. This study aimed to investigate the possible mechanism by which ADSCs-exo attenuates hepatic I/R injury in rats. Rats were randomly divided into four groups: Sham, I30R + PH, ADSCs, and ADSCs-exo groups. Liver tissues were collected immediately after 24 h of reperfusion for further analyses. The content of inflammatory factors in liver tissue was detected using enzyme-linked immunosorbent assay. The pathological changes in liver tissue were analyzed using HE staining. Transmission electron microscopy was used to visualize the ultrastructural changes of hepatocytes. Real-time quantitative polymerase chain reaction (RT-qPCR) and western blot analysis were used to detect the expression of endoplasmic reticulum stress (ERS)-related genes and proteins. Liver histomorphology and hepatocyte ultrastructure changes improved after ADSCs-exo treatment. Moreover, ADSCs-exo treatment significantly downregulated tumor necrosis factor-α, interleukin-1β (IL-1β), and IL-6 levels while upregulating IL-10 levels. Western blot analysis suggested that the protein expressions of GRP78, p-PERK, p-eIF2α, p-IRE1α, XBP1s, ATF-6, ATF-4, CHOP, p-JNK, cleaved-Caspase-3, cleaved Caspase-9, and cleaved Caspase-12 significantly decreased after ADSCs-exo treatment. RT-qPCR results demonstrated that mRNA expression of GRP78, IRE1α, XBP1, ATF-6, ATF-4, CHOP, JNK, Caspase-3, Caspase-9, and Caspase-12 markedly reduced after ADSCs-exo treatment. In conclusion, ADSCs-exo protects against hepatic I/R injury after hepatectomy by inhibiting ERS and inflammation. Therefore, ADSCs-exo can be considered as a viable option for the treatment of hepatic I/R injury.

Thymoquinone alleviates doxorubicin induced acute kidney injury by decreasing endoplasmic reticulum stress, inflammation and apoptosis

Doxorubicin (DOX) is used as an anticancer drug despite its many side effects. Thymoquinone (THQ) is a plant-derived substance that exhibits antioxidant and anti-inflammatory properties. We investigated the protective effects of THQ on DOX induced nephrotoxicity in rats. Rats were divided into five groups of eight: group 1, untreated control; group 2, olive oil group given olive oil intraperitoneally (i.p.) for 14 days; group 3, THQ group given 10 mg/kg THQ i.p. for 14 days; group 4, DOX group given a single dose of 15 mg/kg DOX i.p. on day 7 of experiment; group 5, DOX + THQ given 10 mg/kg THQ i.p. for 14 days and 15 mg/kg DOX i.p. on day 7. Kidney tissues were evaluated for histopathology. Caspase-3, IL-17, GRP78 and TNF-α immunostaining was used to determine the expression levels of these proteins among the groups. The TUNEL method was used to determine the apoptotic index. Total antioxidant status (TAS), total oxidant status (TOS), and TNF-α and TGF-β1 levels in kidney tissue were measured using ELISA assay. Histopathologic damage, caspase-3, IL-17, GRP78 and TNF-α immunoreactivity, TUNEL positive cells, TOS, TNF-α and TGF-β1 levels were increased in group 4 compared to group 1. The TAS of group 4 decreased compared to group 1. We found decreased caspase-3, IL-17, GRP78 and TNF-α expressions and TUNEL positive cells in group 5 compared to group 4. In rats given DOX, THQ reduced kidney damage by suppressing endoplasmic reticulum stress, inflammation and apoptosis pathways.

Thymoquinone in Ocular Neurodegeneration: Modulation of Pathological Mechanisms via Multiple Pathways

Thymoquinone is a naturally occurring compound and is the major component of Nigella sativa, also known as black seed or black cumin. For centuries thymoquinone has been used especially in the Middle East traditionally to treat wounds, asthma, allergies, fever, headache, cough, hypertension, and diabetes. Studies have suggested beneficial effects of thymoquinone to be attributed to its antioxidant, antibacterial, anti-oxidative stress, anti-inflammatory, and neuroprotective properties. Recently, there has been a surge of interest in thymoquinone as a treatment for neurodegeneration in the brain, such as that seen in Alzheimer’s (AD) and Parkinson’s diseases (PD). In vitro and in vivo studies on animal models of AD and PD suggest the main neuroprotective mechanisms are based on the anti-inflammatory and anti-oxidative properties of thymoquinone. Neurodegenerative conditions of the eye, such as Age-related Macular Degeneration (AMD) and glaucoma share at least in part similar mechanisms of neuronal cell death with those occurring in AD and PD. This review aims to summarize and critically analyze the evidence to date of the effects and potential neuroprotective actions of thymoquinone in the eye and ocular neurodegenerations.

Thymoquinone attenuates isoproterenol-induced myocardial infarction by inhibiting cytochrome C and matrix metalloproteinase-9 expression

Thymoquinone (TQ) is the main active constituent of Nigella sativa. The present study aimed to investigate the effect of TQ on apoptotic parameters and MMP-9 expression in isoproterenol (ISP)-induced myocardial infarction (MI). TQ was given once daily for 7 days at doses of 10 and 20 mg/kg orally with ISP (86 mg/kg; s.c.) administered on the sixth and seventh days. TQ pre-treatment protected against ISP-induced MI as approved by normalisation of electrocardiogram (ECG) and b (CK)-MB, minimal histopathological changes, and reduction of the infarction size. Effects of TQ could be supported by its antioxidant activity, evidenced by the increase of cardiac reduced glutathione and total serum antioxidant capacity, and the inhibition of ISO-induced lipid peroxidation. TQ anti-inflammatory activity was associated with reduced expression of NF-κB and TNF-α. TQ ameliorated cardiomyocytes, apoptotic pathways by inhibiting both the intrinsic pathway, via reducing cytoplasmic cytochrome C, and the extrinsic pathway, by inhibiting TNF-α and caspases, and the effect of TQ was dose-dependent. Moreover, TQ reduced the expression of metalloproteinase (MMP)-9, which is considered as a prognostic marker of ventricular remodelling, recommending that TQ can be used as a possible supplement to minimise post-MI changes. So, we conclude that TQ antiapoptotic activity and the inhibitory modulation of MMP-9 expression contribute to TQ protective effects in MI. To our knowledge, this is the first study reporting the effect of TQ on cytochrome c activity and MMP-9 expression in MI.

The Dietary Supplement γ-Oryzanol Attenuates Hepatic Ischemia Reperfusion Injury via Inhibiting Endoplasmic Reticulum Stress and HMGB1/NLRP3 Inflammasome

The purpose of this study is to investigate the protective effect of γ-oryzanol (ORY) against hepatic ischemia reperfusion (HIR) injury and the potential protective mechanisms of ORY. ORY is an important biologically active ingredient isolated from rice bran oil, which has anti-inflammatory and antiapoptotic effects. However, it is still unknown whether ORY can protect the liver from the HIR damage. In this study, ORY was administered orally for seven days, after which the animals were subjected to liver ischemia for 60 minutes and reperfused for 6 hours. Related indicators were analyzed. The results showed that ORY pretreatment significantly reduced the levels of AST and ALT, relieved hepatocellular damage and apoptosis, and attenuated the exhaustion of SOD and GSH and accumulation of MDA and MPO. Interestingly, ORY treatment could significantly decreased ER stress. Furthermore, ORY pretreatment remarkably reduced the protein expressions of HMGB1, NLRP3, caspase-1 (p20), and IL-1β to protect the liver from I/R-induced inflammasome activation and apoptosis. In conclusion, we demonstrated the potential effect of ORY in modulating oxidative stress, endoplasmic reticulum stress, and inflammasome activation during HIR.

d-Pinitol protects against endoplasmic reticulum stress and apoptosis in hepatic ischemia-reperfusion injury via modulation of AFT4-CHOP/GRP78 and caspase-3 signaling pathways

Hepatic ischemia-reperfusion injury (IRI) is a major unavoidable clinical problem often accompanying various liver surgery and transplantation. d-Pinitol, a cyclic polyol, exhibits hepatoprotective efficacy. The objective of this study is to determine the possible mechanism of action of pinitol against endoplasmic reticulum (ER) stress regulation-mediated hepatic IRI and compare its effects with thymoquinone (TQ) in experimental rats. Male Sprague Dawley rats were pre-treated orally with either vehicle (DMSO) or d-Pinitol (5, 10, and 20 mg/kg) or TQ (30 mg/kg) for 21 days and subjected to 60 min of partial hepatic ischemia followed by 24 h of reperfusion. Pre-treatment with pinitol (10 and 20 mg/kg) effectively (P < 0.05) protected against IRI-induced hepatic damage reflected by attenuation of elevated oxidative stress and pro-inflammatory cytokines. Additionally, western blot and ELISA analyses suggested that pinitol significantly (P < 0.05) down-regulated expression of endoplasmic reticulum stress apoptotic markers, namely glucose-regulated protein (GRP)-78, CCAAT/enhancer-binding protein homologous protein (CHOP), activating transcription factor (AFT)-4 and -6α, X-box binding protein-1, and caspase-3, 9, and 12. Additionally, pinitol pre-treatment effectively (P < 0.05) improved mitochondrial function and phosphorylation of Extracellular signal-regulated kinase (ERK)-1/2 and p38. Pinitol markedly (P < 0.05) protected hepatic apoptosis determined by flow cytometry. Further, pinitol provided effective (P < 0.05) protection against hepatic histological and ultrastructural aberrations induced by IRI. TQ showed more pronounced protective effect against attenuation of IRI-induced hepatic injury as compared to d-Pinitol. Pinitol offered protection against endoplasmic reticulum stress-mediated phosphorylation of ERK1/2 and p38, thereby inhibiting AFT4-CHOP/GRP78 signaling response and caspase-3 induced hepatocellular apoptosis during hepatic ischemia-reperfusion insults. Thus, Pinitol can be considered as a viable option for the management of hepatic IRI.

Natural products may interfere with SARS-CoV-2 attachment to the host cell

SARS-CoV-2 has been emerged in December 2019 in China, causing deadly (5% mortality) pandemic pneumonia, termed COVID-19. More than one host-cell receptor is reported to be recognized by the viral spike protein, among them is the cell-surface Heat Shock Protein A5 (HSPA5), also termed GRP78 or BiP. Upon viral infection, HSPA5 is upregulated, then translocating to the cell membrane where it is subjected to be recognized by the SARS-CoV-2 spike. In this study, some natural product compounds are tested against the HSPA5 substrate-binding domain β (SBDβ), which reported to be the recognition site for the SARS-CoV-2 spike. Molecular docking and molecular dynamics simulations are used to test some natural compounds binding to HSPA5 SBDβ. The results show high to a moderate binding affinity for the phytoestrogens (Diadiazin, Genistein, Formontein, and Biochanin A), chlorogenic acid, linolenic acid, palmitic acid, caffeic acid, caffeic acid phenethyl ester, hydroxytyrosol, cis-p-Coumaric acid, cinnamaldehyde, thymoquinone, and some physiological hormones such as estrogens, progesterone, testosterone, and cholesterol to the HSPA5 SBDβ. Based on its binding affinities, the phytoestrogens and estrogens are the best in binding HSPA5, hence may interfere with SARS-CoV-2 attachment to the stressed cells. These compounds can be successful as anti-COVID-19 agents for people with a high risk of cell stress like elders, cancer patients, and front-line medical staff.Communicated by Ramaswamy H. Sarma.

Neuroprotective Effects of Thymoquinone by the Modulation of ER Stress and Apoptotic Pathway in In Vitro Model of Excitotoxicity

Experimental evidence indicates that the activation of ionotropic glutamate receptors plays an important role in neurological disorders’ models such as epilepsy, cerebral ischemia and trauma. The glutamate receptor agonist kainic acid (KA) induces seizures and excitotoxic cell death in the CA3 region of the hippocampus. Thymoquinone (TQ) is the most important component of the essential oil obtained from black cumin (Nigella sativa L.) seeds. It has many pharmacological actions including antioxidant, anti-inflammatory, and anti-apoptotic effects. TQ was used in an in vitro experimental model of primary cultures where excitotoxicity was induced. Briefly, rat organotypic hippocampal slices were exposed to 5 µM KA for 24 h. Cell death in the CA3 subregions of slices was quantified by measuring propidium iodide fluorescence. The cross-talk between TQ, ER stress and apoptotic pathways was investigated by Western blot. In untreated slices TQ (10 µM) induced a significant increase on the PSD95 levels and it decreased the excitotoxic injury induced by KA. Additionally, TQ was able to ameliorate the KA-induced increase in unfolded proteins GRP78 and GRP94 expression. Finally, TQ was able to partially rescue the reduction of the KA-induced apoptotic pathway activation. Our results suggest that TQ modulates the processes leading to post-kainate neuronal death in the CA3 hippocampal area.

Thymoquinone: A Tie-Breaker in SARS-CoV2-Infected Cancer Patients?

Since the beginning of the SARS-CoV-2(severe acute respiratory syndrome-coronavirus-2) pandemic, arace to develop a vaccine has been initiated, considering the massive and rather significant economic and healthcare hits that this virus has caused. The pathophysiology occurring following COVID-19(coronavirus disease-2019) infection has givenhints regarding the supportive and symptomatic treatments to establish for patients, as no specific anti-SARS-CoV-2 is available yet. Patient symptoms vary greatly and range from mild symptoms to severe fatal complications. Supportive treatments include antipyretics, antiviral therapies, different combinations of broad-spectrum antibiotics, hydroxychloroquine and plasma transfusion. Unfortunately, cancer patients are at higher risk of viral infection and more likely to develop serious complications due to their immunocompromised state, the fact that they are already administering multiple medications, as well as combined comorbidity compared to the general population. It may seem impossible to find a drug that possesses both potent antiviral and anticancer effects specifically against COVID-19 infection and its complications and the existing malignancy, respectively. Thymoquinone (TQ) is the most pharmacologically active ingredient in Nigella sativa seeds (black seeds); it is reported to have anticancer, anti-inflammatory and antioxidant effects in various settings. In this review, we will discuss the multiple effects of TQ specifically against COVID-19, its beneficial effects against COVID-19 pathophysiology and multiple-organ complications, its use as an adjuvant for supportive COVID-19 therapy and cancer therapy, and finally, its anticancer effects.

Effect of oleuropein on oxidative stress, inflammation and apoptosis induced by ischemia-reperfusion injury in rat kidney

AIMS

This study aimed to evaluate the effect of oleuropein (OLE), the main phenolic compound present in olive leaves, on kidney ischemia-reperfusion injury (IRI) and to explore the underlying protective mechanism.

MAIN METHODS

Rat kidneys were subjected to 60 min of bilateral warm ischemia followed by 120 min of reperfusion. OLE was administered orally 48 h, 24 h and 30 min prior to ischemia at doses of 10, 50 and 100 mg/kg body weight. The creatinine, urea, uric acid concentrations and lactate dehydrogenase (LDH) activity in plasma were evaluated. Oxidative stress and inflammation parameters were also assessed. Renal expression of AMP-activated protein kinase (p-AMPK), endothelial nitric oxide synthase (eNOS), mitogen-activated protein kinases (MAPK), inflammatory proteins and apoptotic proteins were evaluated using Western blot.

KEY FINDINGS

Our results showed that OLE at 50 mg/kg reduced kidney IRI as revealed by a significant decrease of plasmatic creatinine, urea, uric acid concentrations and LDH activity. In parallel, OLE up-regulated antioxidant capacities. Moreover, OLE diminished the level of CRP and the expression of cyclooxygenase 2 (COX-2). Finally, OLE enhanced AMPK phosphorylation as well as eNOS expression whereas MAPK, and cleaved caspase-3 implicated in cellular apoptosis were attenuated in the ischemic kidneys.

SIGNIFICANCE

In conclusion, this study shows that OLE could be used as therapeutic agent to reduce IRI through its anti-oxidative, anti-inflammatory and anti-apoptotic properties.

Natural Products Targeting ER Stress, and the Functional Link to Mitochondria

The endoplasmic reticulum (ER) is a dynamic organelle essential for intracellular homeostasis maintenance, controlling synthesis, the folding of secreted and membrane-bound proteins, and transport of Ca²⁺. During cellular stress, ER dysfunction leads to the activation of unfolded protein response (UPR) due to accumulated misfolded proteins in the ER. This condition is referred as ER stress. Mitochondria and ER form a site of close contact (the mitochondria-associated membrane, MAM) which is a major platform exerting important physiological roles in the regulation of intracellular Ca²⁺ homeostasis, lipid metabolism, mitochondrial fission, autophagosome formation, and apoptosis progression. Natural products have been receiving increasing attention for their ability to interfere with ER stress. Research works have focused on the capacity of these bioactive compounds to induce apoptosis by activating ER stress through the ER stress-mediated mitochondrial apoptotic pathway. In this review we discuss the role of natural products in the signaling communication between ER and mitochondria, focusing on the effects induced by ER stress including Ca²⁺ permeability transition and UPR signaling (protein kinase R-like ER kinase/mitofusin 2).

Thymoquinone reduces ischemia and reperfusion-induced intestinal injury in rats, through anti-oxidative and anti-inflammatory effects

OBJECTIVES

The aim of the present study was to investigate the effect of thymoquinone on ischemia/reperfusion (I/R) injury at 150 min or/and 24 h of reperfusion in male Wistar Rats.

MATERIAL AND METHODS

The therapeutic value of thymoquinone on cellular damage caused by reactive oxygene species or inflammatory processes during intestinal ischemia/reperfusion was investigated using pharmacological function studies on smooth muscle contractile responses of acetylcholine (Ach) and KCl, along with myeloperoxidase activity, malondialdehyhde, glutathione and cytokine levels such as tumor necrosis factor (TNF)-α and interleukin (IL)-1β in serum and ileum tissue of rats. Thymoquinone was administered at a dose of 50 mg/kg orally for three times: 30 min, 24 h and 48 h prior to the surgical procedure. Soon after reperfusion timing (150 min or 24 h), the contractility traces to KCl and acetylcholine of the ileum smooth muscle were recorded through isolated organ bath.

RESULTS

Pretreatment with thymoquinone reversed the disrupted contractility of the ileum smooth muscle at the 24 h reperfusion. Increased malondialdehyde and depleted glutathione levels and high myeloperoxidase activity determined in the ileum I/R tissue returned to reasonable amounts by pretreatment of Thymoquinone, which attenuated malondialdehyde quantity, restored glutathione level and inhibited myeloperoxidase activity. In addition, both serum and tissue TNF-α and IL-1β activities were modulated by thymoquinone at 24 h of intestinal I/R.

CONCLUSION

The results indicate that thymoquinone may have therapeutic value due to its immunomodulating, radical scavenging and/or antioxidant effects in intestinal I/R injury including oxidant damage mechanisms.

Cerium oxide nanoparticles improve liver regeneration after acetaminophen-induced liver injury and partial hepatectomy in rats

Background and aims

Cerium oxide nanoparticles are effective scavengers of reactive oxygen species and have been proposed as a treatment for oxidative stress-related diseases. Consequently, we aimed to investigate the effect of these nanoparticles on hepatic regeneration after liver injury by partial hepatectomy and acetaminophen overdose.

Methods

All the in vitro experiments were performed in HepG2 cells. For the acetaminophen and partial hepatectomy experimental models, male Wistar rats were divided into three groups: (1) nanoparticles group, which received 0.1 mg/kg cerium nanoparticles i.v. twice a week for 2 weeks before 1 g/kg acetaminophen treatment, (2) N-acetyl-cysteine group, which received 300 mg/kg of N-acetyl-cysteine i.p. 1 h after APAP treatment and (3) partial hepatectomy group, which received the same nanoparticles treatment before partial hepatectomy. Each group was matched with vehicle-controlled rats.

Results

In the partial hepatectomy model, rats treated with cerium oxide nanoparticles showed a significant increase in liver regeneration, compared with control rats. In the acetaminophen experimental model, nanoparticles and N-acetyl-cysteine treatments decreased early liver damage in hepatic tissue. However, only the effect of cerium oxide nanoparticles was associated with a significant increment in hepatocellular proliferation. This treatment also reduced stress markers and increased cell cycle progression in hepatocytes and the activation of the transcription factor NF-κB in vitro and in vivo.

Conclusions

Our results demonstrate that the nanomaterial cerium oxide, besides their known antioxidant capacities, can enhance hepatocellular proliferation in experimental models of liver regeneration and drug-induced hepatotoxicity.

Thymoquinone (2-Isoprpyl-5-methyl-1, 4-benzoquinone) as a chemopreventive/anticancer agent: Chemistry and biological effects

Cancer remains the topmost disorders of the mankind and number of cases is unceasingly growing at unprecedented rates. Although the synthetic anti-cancer compounds still hold the largest market in the modern treatment of cancer, natural agents have always been tried and tested for potential anti-cancer properties. Thymoquinone (TQ), a monoterpene and main ingredient in the essential oil of Nigella sativa L. has got very eminent rankings in the traditional systems of medicine for its anti-cancer pharmacological properties. In this review we summarized the diverse aspects of TQ including its chemistry, biosynthesis, sources and pharmacological properties with a major concern being attributed to its anti-cancer efficacies. The role of TQ in different aspects involved in the pathogenesis of cancer like inflammation, angiogenesis, apoptosis, cell cycle regulation, proliferation, invasion and migration have been described. The mechanism of action of TQ in different cancer types has been briefly accounted. Other safety and toxicological aspects and some combination therapies involving TQ have also been touched. A detailed literature search was carried out using various online search engines like google scholar and pubmed regarding the available research and review accounts on thymoquinone upto may 2019. All the articles reporting significant addition to the activities of thymoquinone were selected. Additional information was acquired from ethno botanical literature focusing on thymoquinone. The compound has been the centre of attention for a long time period and researched regularly in quite considerable numbers for its various physicochemical, medicinal, biological and pharmacological perspectives. Thymoquinone is studied for various chemical and pharmacological activities and demonstrated promising anti-cancer potential. The reviewed reports confirmed the strong anti-cancer efficacy of thymoquinone. Further in-vitro and in-vivo research is strongly warranted regarding the complete exploration of thymoquinone in ethnopharmacological context.

Hepatoprotective activity of raspberry ketone is mediated via inhibition of the NF-κB/TNF-α/caspase axis and mitochondrial apoptosis in chemically induced acute liver injury

Raspberry Ketone (RK) is a natural phenolic compound which is marketed nowadays as a popular weight-reducing remedy, with reported antioxidant and anti-inflammatory activities. However, its biological activity is not fully elucidated. Hepatotoxicity is the leading cause of acute liver failure in Europe and North America, and its management is still challenging. Therefore, this study aimed to assess the therapeutic detoxification activity of RK against liver injury in vivo and to explore the underlying mechanisms using carbon tetrachloride (CCl4)-induced hepatotoxicity as a model. First, a dose-response study using 4 different doses, 25, 50, 100, and 200 mg kg-1 day-1, of RK was conducted. RK was administered for 5 days as a pretreatment, followed by a single dose of CCl4 (1 ml kg-1, 1 : 1 v/v CCl4 : olive oil). The RK dose of 200 mg kg-1 showed the greatest protective effect and was selected for further investigations. CCl4 hepatotoxicity was confirmed by elevation of liver enzymes, and histopathological examination. CCl4-induced oxidative stress was evident from increased lipid peroxidation measured as thiobarbituric acid reactive substances (TBARS) along with depleted superoxide dismutase (SOD), reduced glutathione (GSH), and total antioxidant capacity (TAC). Increased oxidative stress was associated with increased cytochrome c expression with subsequent activation of caspase-9 and caspase-3, in addition to DNA fragmentation reflecting apoptosis. CCl4 also induced the expression of inflammatory cytokines (NF-κB and TNF-α). Interestingly, RK hepatoprotective activity was evident from the reduction of liver enzymes, and maintenance of hepatocyte integrity and microstructures as evaluated by histopathological examination using H and E, and transmission electron microscopy. The antioxidant activity of RK was demonstrated by the increase of TAC, SOD, and GSH, with a concomitant decrease of the TBARS level. Moreover, RK pretreatment inhibited CCl4-induced upregulation of inflammatory mediators. RK antiapoptotic activity was indicated by the reduction of the expression of cytoplasmic cytochrome-C, a decrease of caspases, and inhibition of DNA fragmentation. In conclusion, this study demonstrates that RK is a promising hepatoprotective agent. The underlying mechanisms include antioxidant, anti-inflammatory, and anti-apoptotic activities. This is the first study reporting RK hepatoprotective activity in acute hepatic injury and approves its antiapoptotic effect in the liver.

Recent Advances in the Pharmacological Activities of Dioscin

Dioscin is a typical saponin with multiple pharmacological activities. The past few years have seen an emerging interest in and growing research on this pleiotropic saponin. Here, we review the emerging pharmacological activities reported recently, with foci on its antitumor, antimicrobial, anti-inflammatory, antioxidative, and tissue-protective properties. The potential use of dioscin in therapies of diverse clinical disorders is also discussed.

Baicalein administered in the subacute phase ameliorates ischemia-reperfusion-induced brain injury by reducing neuroinflammation and neuronal damage

Ischemic stroke is a cerebrovascular disease with high morbidity, high mortality, and high disability, representing a serious threat to human life and health. Clinically, the extensive injury caused by ischemic stroke results from ischemia-reperfusion (I/R) injury thrombolytic treatment. However, there are few reports on the use of medications in the subacute stage of cerebral I/R. Baicalein (5,6,7-trihydroxyflavone) is a biologically active ingredient extracted from the root of Scutellaria baicalensis Georgi. In the present study, we investigated the therapeutic effect of baicalein administered in the subacute phase of cerebral I/R injury in a rat model of ischemia induced by occlusion of the middle cerebral artery (MCA). Rats were treated daily with baicalein (200 mg/kg, i.g.) in the subacute phase (24 h after reperfusion) for 7 days. The results showed that baicalein significantly reduced neurobehavioral deficits and decreased brain infarct volume from 18.99% to 7.41%. Immunofluorescence analysis of the ischemic penumbra showed that baicalein significantly reduced expression of the M1 marker, cluster of differentiation (CD) 16 and CD86, and increased expression of the M2 marker, CD 163 and CD206, indicating that baicalein inhibited M1 transformation and promoted M2 transformation of microglia/macrophage to inhibit neuroinflammation. Moreover, baicalein suppressed NF-κB signaling by reducing IκBα phosphorylation and nuclear translocation of NF-κB/p65, which decreased the release of the pro-inflammatory factors IL-6, IL-18, and TNF-α. In addition, baicalein reduced phosphorylation of JNK, ERK and p38, which are involved modulation of microglia/macrophage M1/M2 polarization. Western blot analysis of apoptosis- and autophagy-related proteins showed that baicalein increased the Bcl-2/Bax ratio and reduced caspase-3 expression to decrease neuronal apoptosis and ameliorate neuronal loss. Baicalein also decreased the LC3-II/LC3-I ratio and promoted phosphorylation of the PI3K/Akt/mTOR signaling pathway which implied inhibition of autophagy. These observations suggest that baicalein exerts neuroprotective effects by reducing neuroinflammation, apoptosis and autophagy, and protects against cerebral I/R injury in the subacute phase in vivo.

Protective effects of Nigella sativa oil against carboplatin-induced liver damage in rats

OBJECTIVE

This study aimed to investigate the protective effects of nigella sativa oil (NSO) against liver damage due to intraperitoneal (i.p.) usage of carboplatin which is commonly used as a chemotherapeutic agent.

MATERIAL AND METHOD

Twenty four female Wistar-albino rats (about 200-350 grams each) were divided into 4 groups. Group 1 (n = 6) was administered 4 ml/kg intraperitoneal (i.p.) saline 48 and 24 h before. Group 2 (n = 6) was i.p. administered 4 ml/kg NSO 48 h before and 4 ml/kg saline 24 h before. Group 3 (n = 6) was i.p. administered 4 ml/kg saline 48 h before and 80 mg/kg carboplatin 24 h before. Group 4 (n = 6) was i.p. administered 4 ml/kg NSO 48 h before and 80 mg/kg carboplatin 24 h before. At the end of 48 h, all rats were sacrificed, and liver tissues were put into 10% neutral formalin. After the routine tissue follow-up, histopathological changes and collagen fiber density were evaluated with Hematoxylin-Eosin and Masson's Trichrome staining. Apoptotic index was determined with TUNEL staining.

RESULTS

The degeneration in hepatocytes, fiber distribution and density around central vein and portal space was observed in the carboplatin group compared to the control and NSO groups, hepatocyte cords preserved integrity, partial degeneration in hepatocytes and decreased collagen fiber distribution around central vein was noted in the NSO-carboplatin group compared to the carboplatin group. The apoptosis was lower in the NSO-carboplatin group compare with the carboplatin group, but no statistically significant difference was found between the two groups (p = 0.449).

CONCLUSION

When used NSO before carboplatin exposure, it may protect against liver damage.

The effect of zinc acexamate on oxidative stress, inflammation and mitochondria induced apoptosis in rat model of renal warm ischemia

AIM

Zinc has proved its efficacy in many models of ischemia reperfusion (I/R) injury. In this study, we used zinc acexamate (ZAC) as an exogenous source of zinc against renal I/R injury and we investigated whether its protective effects are mediated by the decrease of oxidative stress, inflammation, and mitochondria induced-apoptosis.

METHODS

Rats were orally pretreated with vehicle or ZAC (10 or 100 mg/kg) 24 h and 30 min prior to 1 h of bilateral renal warm ischemia and 2 h of reperfusion.

RESULTS

Our data showed that 10 mg/kg of ZAC, but not 100 mg/kg, improved renal architecture and function. Also, the low dose of ZAC up-regulated antioxidant enzymes activities and glutathione level and decreased lipids and proteins oxidation. Interestingly, the use of ZAC resulted in a significant reduce of pro-inflammatory cytokines (IL-1ß, IL-6 and MCP-1), enhanced mitochondria integrity and decreased expression of the pro-apoptotic protein caspase-9.

CONCLUSION

We conclude that renal I/R induced oxidative stress, inflammation and apoptosis and that the use of ZAC at 10 mg/kg, but not 100 mg/kg, protects rat kidneys from I/R injury by down-regulating these processes.

Thymoquinone protects rat liver after partial hepatectomy under ischaemia/reperfusion through oxidative stress and endoplasmic reticulum stress prevention

Ischaemia reperfusion (I/R) is associated with liver injury and impaired regeneration during partial hepatectomy (PH). The aim of this study was to investigate the effect of thymoquinone (TQ), the active compound of essential oil obtained from Nigella sativa seeds, on rat liver after PH. Male Wistar rats were divided equally into four groups (n = 6) receiving an oral administration of either vehicle solution (sham and PH groups) or TQ at 30 mg/kg (TQ and TQ + PH groups) for 10 consecutive days. Then, rats underwent PH (70%) with 60 minutes of ischaemia followed by 24 hours of reperfusion (PH and TQ + PH groups). Alanine aminotransferase (ALT) activity and histopathological damage were determined. Also, antioxidant parameters, liver regeneration index, hepatic adenosine triphosphate (ATP) content, endoplasmic reticulum (ER) stress and apoptosis were assessed. In response to PH under I/R, liver damage was significantly alleviated by TQ treatment as evidenced by the decrease in ALT activity (P < .01) and histological findings (P < .001). In parallel, TQ preconditioning increased hepatic antioxidant capacities. Moreover, TQ improved mitochondrial function (ATP, P < .05), attenuated ER stress parameters and repressed the expression of apoptotic effectors. Taken together, our results suggest that TQ preconditioning could be an effective strategy to reduce liver injury after PH under I/R. The protective effects were mediated by the increase of antioxidant capacities and the decrease of ER stress and apoptosis.

Does posttreatment thymoquinone reverse high-dose atorvastatin-induced hepatic oxidative injury in rats?

Atorvastatin (ATO) was commonly used to lower blood cholesterol, but it caused harmful effects to organs, including the liver. Thymoquinone (TQ), a prominent constituent of Nigella sativa, has antioxidant, antiinflammatory, antiapoptotic, antimicrobial, and anticancer activity. The current study investigated the mechanism of ATO-induced hepatotoxicity, whether posttreatment TQ could reverse ATO-induced hepatic injury, and the mechanism of action of TQ as a hepatoprotective agent. Forty adult male Sprague Dawley rats were divided into four equal groups: control, TQ-treated, ATO-treated, and combined ATO/TQ-treated. Rats were treated for 8 weeks and 10 days and euthanized by cervical dislocation 3 days after the last treatment. Blood samples and livers were tested for liver enzymes, oxidative stress, and apoptosis markers and used for histopathological and ultrastructural examination. The ATO-treated group showed an increase in liver enzymes, decreases in reduced glutathione and catalase, and increases in the malondialdehyde lipid peroxidation marker, protein carbonylation, and caspase 3 activity. Posttreatment TQ in the ATO/TQ-treated group seemed to reverse these changes. Histopathological and ultrastructural examination supported these data. Results from the current study suggested that posttreatment TQ may reverse oxidative stress injury in rat liver produced by ATO, suggesting a potential clinical application of using TQ to prevent ATO-induced hepatic injury.