Common name: Thymoquinone
Synonyms: Thymoquinone, Thymoquinon, p-Cymene-2,5-dione, Nigella sativa Extract, black cumin Extract, black seed Extract
Active ingredients: Thymoquinone
CAS NO.: 490-91-5
Molecular Formula: C10H12O2
Molecular Weight: 164.20
Main Specifications: 3%, 5%, 10%, 20%, 30%, 60%, 98%
Test method: HPLC
Resource: The seeds of Nigella sativa
Appearance: Brown fine powder to Yellow powder
Heavy Metals: NMT10ppm
Residue on Ignition: NMT2%
Residual solvent: Conform to USP39, EP8.0
Packing: 25KG/ cardboard drum
Storage: Store in cool and dry place and keep away from strong direct light and heat
Shelf Life: Two years when properly stored
Thymoquinone is a phytochemical compound found in the plant Nigella sativa. It is also found in select cultivated Monarda fistulosa plants which can be steam distilled to produce an essential oil. Nigella sativa, commonly known as black cumin or black seed, is one of the most revered, health-promoting seeds in the history of mankind. This plant is native to the eastern Mediterranean and parts of Asia.
Health Benefits of Thymoquinone
1. Hepatoprotective effects
To investigate the cytoprotective effects of TQ against acetaminophen-induced hepatotoxicity, Wistar albino rats were given 500 mg/kg acetaminophen orally, followed by three doses of TQ at a total dose of 15 mg/kg within an 18 hr time interval (three times 5 mg/kg oral thymoquinone for every six hr). The levels of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), tissue levels of malondialdehyde (MDA), oxidized glutathione (GSSG), and superoxide dismutase (SOD) activity were found to be lower compared to that of rats treated with acetaminophen only. Histopathological studies further revealed significant liver necrosis and toxicity with acetaminophen treatment, whereas those of TQ treatment significantly lowered liver injury scores.
Supplementation of TQ (2 mg/kg/day) for 5 days before acetaminophen administration reversed the acetaminophen-induced increase in ALT, total nitrate/nitrite and lipid peroxide, and the decrease of reduced GSH and ATP. TQ was effective in protecting mice against acetaminophen-induced hepatotoxicity possibly via increased resistance to oxidative and nitrosative stress.
Treatment with anti-cancer drugs like the alkylating agent 5-(Aziridin-1-yl)-2,4-dinitrobenzamide (CB 1954) is associated with significant hepatotoxicity. BALB/c mice transplanted with the mouse mammary cancer cell line (66CL-4-GFP) were treated in vivo with the antitumor drug CB 1954 (141 mg/kg), TQ (10 mg/kg), and a combination of CB 1954 and TQ. Histological examination revealed significant tumor regression and maintenance of the liver enzymes ALT and AST in the combined treatment compared to CB 1954 alone. Furthermore, the effects of aqueous extracts of N. sativa seeds (50 mg/kg) or TQ (5 mg/kg in corn oil) applied by gavage for 5 days were investigated on detoxifying enzymes and glutathione by comparing healthy and CCl4-challenged (1 ml/kg in corn oil, intraperitoneally, a single dose) rats. Both N. sativa and TQ reduced the increased levels of serum ALT activity, the levels of oxidized glutathione, and the stress ratio caused by CCl4. Both N. sativa and TQ also ameliorated the reduced messenger RNA (mRNA) levels of glutathione S-transferase (GST), NAD (P) H-quinone oxido-reductase (NQO1), and microsomal epoxide hydrolase (EPHX1), as well as the reductions in reduced glutathione and cysteine levels caused by CCl4. This protection may be attributed to the increased transcription of chemoprotective enzyme mRNAs. TQ supplementation also normalized liver reduced glutathione (GSH) and decreased the levels of MDA and caspase-3 activity in the liver, and reduced serum tumor necrosis factor-alpha (TNF-alpha), serum total bilirubin and the activities of alkaline phosphatase (ALP) and gamma-glutamyl transferase (gamma-GT) enzymes. Histopathological examination revealed that TQ administration improved lipopolysaccharide (LPS)-induced pathological abnormalities in liver tissues. Summarizing these investigations revealed a protective effect of TQ against the cytotoxicity of different agents in vivo.
2. Anti-inflammatory effects
There are many reports on the anti-inflammatory activity of TQ (30-50). Kundu et al, stated that the anti-inflammatory effect of TQ is caused by the upregulated expression of heme-oxygenase 1 (HO-1) in human keratinocytes (HaCaT) by activating nuclear factor (NF)-erythroid2-(E2)-related factor-2 (Nrf2) via reactive oxygen species (ROS)-mediated phosphorylation of protein kinase B (PKB/Akt) and cyclic AMP-activated protein kinase-alpha (AMPKalpha). According to Bai et al (37), TQ attenuated thioacetamide (TAA)-induced liver fibrosis accompanied by reduced protein and mRNA expression of of α-smooth muscle actin (α-SMA), collagen-I and tissue inhibitor of toll-like receptor 4 (TLR4) and decreased pro-inflammatory cytokine levels. It also inhibited phosphatidylinositol 3-kinase phosphorylation and enhanced the phosphorylation of adenosine monophosphate-activated protein kinase (AMPK) and liver kinase B (LKB).
TQ has also been reported to inhibit the effects of 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced expression of cyclooxygenase-2 (COX-2) and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) (38). N. sativa and TQ treatment also suppressed the expression of the COX-2 enzyme in the pancreatic tissue of streptozotocin (STZ)-induced diabetic rats (39). The anti-ulcerative effect of N. sativa and TQ was demonstrated by Kanter et al by investigating ethanol induced mucosal ulceration in rats, which was inhibited by pretreatment with TQ and N. sativa. Furthermore, oral administration of TQ in Wistar rats at 5mg/kg body weight for 21 days led to a significant reduction of the levels of different pro-inflammatory mediators (IL-1β, IL-6, TNFα, IFNγ and PGE(2)). Intraperitoneal treatment of mice with thymoquinone (6 mg/kg; IP), 24 and 1 hr before intratracheal treatment with Diesel exhaust particles (DEP) (30 µg/mouse), prevented pulmonary inflammation and the increase of airway resistance caused by DEP, and inhibited the increase of blood leukocyte numbers and plasma IL-6 concentrations (43). The effects of TQ on airway inflammation in a mouse model of allergic asthma were investigated by intraperitoneal injection of TQ before airway challenge of ovalbumin (OVA)-sensitized mice, and caused a marked decrease in lung eosinophilia and elevated Th2 cytokines - both in vivo and in vitro - following stimulation of lung cells with OVA. TQ also decreased the elevated serum levels of OVA-specific IgE and IgG1. Histological examination of lung tissue demonstrated that the compound significantly inhibited allergen-induced lung eosinophilic inflammation and mucus-producing goblet cells. Using an asthmatic murine model, TQ has also been demonstrated to have a high potential in inhibiting the inflammatory changes associated with asthma, especially the aggregation of inflammatory cells in bronchoalveolar lavage (BAL) fluid and in lung tissues. In addition it inhibited mRNA expression of inducible nitric oxide synthase (iNOS) and transforming growth factor-β1 (TGF-β1).
3. Antioxidant effects
TQ has been intensively studied for its antioxidant effects. Thymoquinone and thymohydroquinone inhibited in vitro non-enzymatic lipid peroxidation in hippocampal homogenates induced by iron-ascorbate. Pretreatment of male NMRI rats with TQ and N. sativa oil significantly decreased lipid peroxidation levels measured as MDA in hippocampus portion following cerebral ischemia-reperfusion injury (IRI).
According to Abdel-Wahab and Aly (6), N. sativa oil neutralized the toxicity of aflatoxins, and treatment with N. sativa oil of rats fed an aflatoxin-contaminated diet resulted in significant protection against aflatoxicosis. Recent reports further demonstrate that TQ at a dose of 9 mg/kg body weight protects liver injury induced by aflatoxin B1 (AFB1) as evidenced by a reduction of the serum concentrations of AST, ALT and ALP as marker enzymes for liver injury. When rats were pretreated with TQ followed by AFB1 the GSH content of the liver was restored and MDA production prevented (54). N. sativa oil and its active component, TQ have also been shown to protect brain tissue from radiation-induced nitrosative stress (55). Oral administration of TQ in Wistar rats at 5 mg/kg body weight for 21 days resulted in a significant reduction of the levels of different antioxidant parameters (myeloperoxidase MPO, LPO, GSH, catalase (CAT), SOD and NO) in collagen induced arthritis (CIA), and similarly reduced the Fe(III) nitrilotriacetic acid (Fe-NTA) induced oxidative stress after oral administration in Wistar rats. Furthermore, the glycation of SOD by glucose or methylglyoxal (MG) and its protection by TQ has been investigated. Incubation of SOD with glucose at 37ºC resulted in a progressive decrease in the activity of the enzyme due to fragmentation, evidenced by a decrease in the amount of protein on SDS-PAGE gels. On the other hand, incubation of SOD with MG or both glucose and MG glucose at 37ºC caused protein cross linking evidenced by the formation of high molecular weight aggregates. TQ offered protection against glucose or methylglyoxal (MG) induced loss of SOD activity and fragmentation or cross-linking. Pretreatment of Wistar rats with TQ and 1,2-dimethylhydrazine (DMH) for 10 weeks prevented the depletion of antioxidant enzymes catalase, glutathione peroxidase, and superoxide dismutase in red blood cells and maintained a similar value as the control group. At the same time, it prevented erythrocyte damage in DMH-induced colon post initiation carcinogenesis in rats. TQ and N. sativa oil possess cytoprotective effects against the anti-cancer drugs cyclophosphamide (CTX) via maintenance of hemoglobin and blood sugar levels, and the activities of liver enzymes, bilirubin, urea, creatinine, lipids (triglyceride, cholesterol and low-density lipoprotein (LDL)-cholesterol) and lipid peroxidation in the liver. The cytoprotective effects of N. sativa oil and TQ were associated with induction of antioxidant mechanisms (59). Neuron-protective effects have also been studied in cultured hippocampal and cortical neurons treated with amyloid-β peptide (Aβ1-42) and TQ simultaneously for 72 h. TQ efficiently attenuated Aβ1-42-induced neurotoxicity by improving cell viability. It has also been shown to inhibit mitochondrial membrane potential depolarization and the generation of reactive oxygen species caused by Aβ1-42, and to restore synaptic vesicle recycling inhibition and to partially reverse the loss of spontaneous firing activity, and Aβ1-42 aggregation in vitro.
4. Anti-cancer and antitumor activity
There has been growing interest in natural compounds with anti-cancer properties because they are presumably non-toxic to healthy cells and are available in a readily digestible form. There is a wide consensus in cancer research that TQ has promising anti-cancer activity. Many researchers provided evidence for the chemopreventive or chemotherapeutic activity. Thus it may be useful as a dietary supplement to enhance the effects of anti-cancer drugs.
There is evidence that TQ induces p53-independent apoptosis via the activation of caspase-8 and caspases 9 and 3 in the caspase cascade. Activation of caspase-8 promotes release of cytochrome c from mitochondria into the cytoplasm. It also modulates the Bax/Bcl2 ratio by upregulation of proapoptotic Bax and down-regulation of antiapoptotic Bcl2 proteins in p53-null HL-60 cells during apoptosis (61). Investigating the anti-cancer effects of TQ on A549 non-small cell lung cancer cells exposed to benzo(a)pyrene, Ulasli et al found that TQ treatment up-regulated Bax and down-regulated Bcl2 proteins, and increased the Bax/Bcl2 ratio. It also decreased the expression of cyclin D and increased the expression of p21, and it up-regulated TRAIL receptor 1 and 2 expression. These molecular events lead to regulatory p53 levels affecting the induction of G2/M cell cycle arrest and apoptosis.