Thymoquinone has a synergistic effect with PHD inhibitors to ameliorate ischemic brain damage in mice

BACKGROUND

A blockage in a blood vessel can cause reduced blood flow to the brain, which eventually leads to the death of surrounding tissue. Several studies have attempted to develop an effective intervention to reverse this process and improve the health status of affected individuals. Due to its indirect effect on cellular functions and metabolism, the hypoxia-inducible factor (HIF-1α) protein has been proposed as a promising transcription factor in the treatment of stroke.

PURPOSE

The current study aims to explore the relation between HIF-1 α and thymoquinone (TQ) in the attenuation of ischemic brain damage and the possible mechanism of this relation to reduce cell death.

METHODS

For this purpose, dimethyloxallyl glycine (DMOG), 8 mg/kg, Acriflavine (ACF), 1.5 mg/kg, and both combined with TQ (5 mg/kg) were assessed. Male C57 mice were used to establish an ischemic stroke model by using endothelin-1 (ET-1) (400 pmole/μl) intra- cranial injection. The ultrastructure alterations of neuronal soma, axons, and mitochondria after stroke and treatment were well addressed. Besides, the expression levels of VEGF, HIF-1α, Nrf2, and HO-1 were evaluated. Meanwhile, apoptosis and autophagy-related proteins were also investigated.

RESULTS

Treatment of ischemic stroke by TQ can activate the HIF-1α pathway and its downstream genes such as VEGF, TrkB, and PI3K, which in turn enhance angiogenesis and neurogenesis. Our study revealed that TQ has the same effect as DMOG to activate HIF-1 α and can improve motor dysfunction after ischemic stroke. Further, we demonstrated that both TQ and DMOG effectively attenuate the organelle's damage following ischemic stroke, which was confirmed by the cryogenic transmission electron microscope. The synergistic effect of TQ and DMOG may lead to a chemo-modulation action in the autophagy process after stroke onset and this result is validated by the western blot and rt-qPCR techniques.

CONCLUSION

Our finding revealed the potential role of TQ as a HIF-1 α activator to reduce cell death, modulate autophagy and decrease the infarct volume after ischemic stroke onset. The neuroprotective effect of TQ is achieved by decreasing the inflammation and increasing angiogenesis as well as neurogenesis via induction of the HIF-1α-VEGF/Nrf2-HO-1-TrkB-PI3K pathway.

Thymoquinone Augments Cyclophosphamide-Mediated Inhibition of Cell Proliferation in Breast Cancer Cells

Objective:

Cancer chemotherapy at the recommended doses is largely associated with toxicity, and also it is not effective enough to reduce the advancement of the disease at lower doses. Thymoquinone (TQ) is an active compound derived from black seeds (Nigella sativa) which exhibits anticancer activities. The aim of the present study was to investigate the synergistic effect of TQ alone and in combination with cyclophosphamide (cyclo), and to unravel the role of TQ in fatty acid synthase (FASN) mediated molecular signaling in Her2 + and Her2- breast cancer cell lines.

Methods:

The effect of TQ on the growth of Her2+ SKBR-3 and Her2- MDA-231 breast cancer lines were evaluated as percent cell viability by cytotoxicity-based MTT assay. The analysis of cell cycle arrest was done through flow-cytometry followed by Western blot and RT-PCR to detect signaling events in the cells.

Results:

The data showed that TQ-cyclo (0.5mM-10µM) combination significantly inhibited the proliferation through the 5.49% and 57.72% accumulation of cells in sub-G1 and G1 respectively as 12% cells were shifted from G2/M phase in Her2+ breast cancer cells. Similarly, TQ-cyclo (0.5mM-20µM) combination exhibited that the 16.6% cells were arrested in Sub-G1 and only 3.54% cells were remained in G2/M phase as it was 22.89% in DMSO control in Her-2- breast cancers cells. Though TQ alone or in combination with cyclo alleviated the PI3K/Akt signaling by downregulating the phosphorylation of Akt and upregulating the PTEN, no changes was observed in FASN and Her-2 as well in both type of cells. The significant decreased expression of cyclin D1 was found in TQ-cyclo combinations.

Conclusion:

The current findings suggested that TQ can alter the cell cycle progression and induce cell death independent of FASN mediated signaling. In terms of clinical perspective, the present study clearly showed that TQ can broadly augment the effect of cyclo in breast cancer cases irrespective of Her-2+ or Her-.

The cardioprotective effect of thymoquinone on ischemia-reperfusion injury in isolated rat heart via regulation of apoptosis and autophagy

Thymoquinone (TQ), as the active constituents of black cumin (Nigella sativa) seed oil, has been reported to have potential protective effects on the cardiovascular system. This study aimed to investigate the effects and the underlying mechanisms of TQ on myocardial ischemia-reperfusion (I/R) injury in Langendorff-perfused rat hearts. Wister rat hearts were subjected to I/R and the experimental group were pretreated with TQ prior to I/R. Hemodynamic parameters, myocardial infarct size, cardiac marker enzymes, superoxide dismutase (SOD), malondialdehyde (MDA) content, and cardiomyocyte apoptosis were assayed. Compared with the untreated group, TQ preconditioning significantly improved cardiac function, reduced infarct size, decreased cardiac lactate dehydrogenase (LDH) and creatine kinase-MB (CK-MB) levels, suppressed enedoxidative stress, and apoptosis. In addition, TQ treatment promoted autophagy, which was partially reversed by chloroquine (CQ), a kind of autophagy blocker. Our study suggests that TQ can protect heart against I/R injury, which is associated with anti-oxidative and anti-apoptotic effects through activation of autophagy.

Immunomodulatory and anti-inflammatory action of Nigella sativa and thymoquinone: A comprehensive review

Many herbal products are now used as remedies to treat various infectious and non-infectious conditions. Even though the use of herbs and natural products is much more evident in the Eastern world, their use in Western cultures is continuously increasing. Although the immunomodulatory effects of some herbs have been extensively studied, research related to possible immunomodulatory effects of many herbs and various spices is relatively scarce. Here, we provide a comprehensive review of the immunomodulatory and anti-inflammatory properties of Nigella sativa, also known as black seed or black cumin, and its major active ingredient, thymoquinone (TQ). This review article focuses on analyzing in vitro and in vivo experimental findings that were reported with regard to the ability of N. sativa and TQ to modulate inflammation, cellular and humoral adaptive immune responses, and Th1/Th2 paradigm. The reported capability of N. sativa to augment the cytotoxic activity of natural killer (NK) cells against cancer cells is also emphasized. The molecular and cellular mechanisms underlying such immunomodulatory and anti-inflammatory effects of N. sativa and TQ are highlighted. Moreover, the signal transduction pathways implicated in the immunoregulatory functions of N. sativa and TQ are underscored. Experimental evidence suggests that N. sativa extracts and TQ can potentially be employed in the development of effective therapeutic agents towards the regulation of immune reactions implicated in various infectious and non-infectious conditions including different types of allergy, autoimmunity, and cancer.

Thymoquinone-induced reactive oxygen species causes apoptosis of chondrocytes via PI3K/Akt and p38kinase pathway

Thymoquinone (TQ), a bioactive ingredient of the volatile oil of black seed (Nigella sativa), has been shown to possess anti-neoplastic and anti-inflammatory effects on a variety of tumours. However, the precise mechanism of action is not clear in normal cells such as primary chondrocytes. So, we have investigated the effects of TQ on the apoptosis of chondrocytes with a focus on reactive oxygen species (ROS) production. In in vitro experiments, chondrocytes were cultured with increasing concentrations of TQ for 24 h or with 20 µmol/L TQ for the indicated time periods, and various experiments were performed to detect the apoptotic effects caused by TQ. The results showed that TQ significantly increases apoptosis. Apoptosis was dose- and time-dependently expressed, and the generation of ROS also dramatically increased in a dose-dependent manner. Pretreatment of N-acetyl-L-cysteine (NAC), an inhibitor of ROS, inhibited both TQ-induced apoptosis and ROS generation. Also, TQ up-regulated phosphorylation of phosphatidylinositol 3-kinase/Akt (PI3K/Akt) and mitogen-activated protein kinases ([MAPKs] p38kinase, ERK-1/-2, and JNKinase), and these effects were prevented by pretreatment of NAC. However, pretreatment with inhibitors of PI3K/Akt and MAPKs did not inhibit TQ-caused ROS generation. Among the inhibitors of PI3K/Akt, p38kinase, ERK-1/-2, and JNKinase, pretreatment with LY294002 and SB203580 abolished TQ-induced apoptosis, but PD98059 and SP600125 did not have any effect on TQ-caused apoptosis. These findings suggest that TQ-induced ROS generation regulates apoptosis by modulating PI3K/Akt and p38kinase pathways.