Home
 
ABTHOCYANIN-EXTRACT


RESEARCH

Extracted from black seed triggers apoptotic cell death in human colorectal cancer cells via a p53-dependent mechanism.

For centuries, the black seed (Nigella sativa) herb and oil have been used in Asia, Middle East and Africa to promote health and fight disease. Thymoquinone (TQ), the most abundant constituent present in black seed, is a promising dietary chemopreventive agent. We investigated the effects of thymoquinone (TQ) against HCT-116 human colon cancer cells and attempted to identify its potential molecular mechanisms of action. We report that TQ inhibits the growth of colon cancer cells which was correlated with G1 phase arrest of the cell cycle. Furthermore, TUNEL staining and flow cytometry analysis indicate that TQ triggers apoptosis in a dose- and time-dependent manner. Apoptosis induction by TQ was associated with a 2.5-4.5-fold increase in mRNA expression of p53 and the downstream p53 target gene, p21WAF1. Simultaneously, we found a marked increase in p53 and p21WAF1 protein levels but a significant inhibition of anti-apoptotic Bcl-2 protein. Co-incubation with pifithrin-alpha (PFT-alpha), a specific inhibitor of p53, restored Bcl-2, p53 and p21WAF1 levels to the untreated control and suppressed TQ-induced cell cycle arrest and apoptosis. p53-null HCT-116 cells were less sensitive to TQ-induced growth arrest and apoptosis. These results indicate that TQ is antineoplastic and pro-apoptotic against colon cancer cell line HCT116. The apoptotic effects of TQ are modulated by Bcl-2 protein and are linked to and dependent on p53. Our data support the potential for using the agent TQ for the treatment of colon cancer.
Gali-Muhtasib H, Diab-Assaf M, Boltze C, Al-Hmaira J, Hartig R, Roessner A, Schneider-Stock R. Int J Oncol. 2004 Oct;25(4):857-66.
Colorectal Cancer Cell


Lack of p53 augments thymoquinone-induced apoptosis and caspase activation in human osteosarcoma cells.

We have recently shown that thymoquinone (TQ) is an antineoplastic drug that induces p53-dependent apoptosis in human colon cancer cells. This study evaluated the antiproliferative and pro-apoptotic effects of TQ in two human osteosarcoma cell lines with different p53 mutation status. TQ decreased cell survival dose-dependently and, more significantly, in p53-null MG63 cells (IC(50) = 17 muM) than in p53-mutant MNNG/HOS cells (IC(50) = 38 muM). Cell viability was reduced more selectively in MG63 tumor cells than in normal human osteoblasts. Flow cytometric analysis showed that TQ induced a much greater increase in the PreG(1) (apoptotic) cell population, but no cell cycle arrest in MG63. G(2)/M arrest in MNNG/HOS cells was associated with p21(WAF1) upregulation. Using three DNA damage assays, TQ was confirmed to result in a significantly greater extent of apoptosis in p53 null MG63 cells. Although the Bax/Bcl-2 ratios were not differentially modulated in both cell lines, the mitochondrial pathway appeared to be involved in TQ-induced apoptosis in MG63 by showing the cleavage of caspases-9 and -3. Oxidative stress and mitochondrial O(2)(*-) generation in isolated rat mitochondria were enhanced by TQ as measured by the dose-dependent reduction in aconitase enzyme activity and Amplex Red oxidation respectively. TQ-induced oxidative damage, reflected by an increase in gamma-H2AX foci and increased protein expression levels of gamma-H2AX and the DNA repair enzyme, NBS1, was more pronounced in MNNG/HOS than in MG63. We suggest that the resistance of MNNG/HOS cells to drug-induced apoptosis is caused by the up-regulation of p21(WAF1) by the mutant p53 (transcriptional activity was shown by p53 siRNA treatment) which induces cell cycle arrest and allows to repair DNA damage. Collectively, these findings show that TQ induces p53-independent apoptosis in human osteosarcoma cells. As the loss of p53 function is frequently observed in osteosarcoma patients, our data suggest the potential clinical usefulness of TQ for the treatment of these malignancies.
Roepke M, Diestel A, Bajbouj K, Walluscheck D, Schonfeld P, Roessner A, Schneider-Stock R, Gali-Muhtasib H. Cancer Biol Ther. 2007 Feb;6(2):160-9. Epub 2007 Feb 5.




Thymoquinone: a promising anti-cancer drug from natural sources.

There has been growing interest in naturally occurring compounds with anti-cancer potential. Black seed is one of the most extensively studied plants. This annual herb grows in countries bordering the Mediterranean Sea and India. Thymoquinone (TQ) is the bioactive constituent of the volatile oil of black seed. It has been shown to exert anti-neoplastic and anti-inflammatory effects. The molecular pathways of TQ action are not clear. Nevertheless, TQ is known to induce apoptosis by p53-dependent and p53-independent pathways in cancer cell lines. Growth inhibition is associated with induction of cell cycle arrest. TQ also acts on the immune system by modulating the levels of inflammatory mediators. To date, the chemotherapeutic potential of TQ in the clinic has not been tested, but numerous studies have shown its promising anti-cancer effects in animal models. The combination of TQ with clinically used anti-cancer drugs has led to improvements in their therapeutic index and prevents non-tumor tissues from sustaining chemotherapy-induced damage.
Gali-Muhtasib H, Roessner A, Schneider-Stock R. Int J Biochem Cell Biol. 2006;38(8):1249-53. Epub 2005 Nov 8.
Nigella Sativa Seeds


Is thymoquinone an antioxidant?

Thymoquinone is one of the active ingredients of black cumin (Nigella sativa L.) essential oil possessing anti-inflammatory, antineoplastic, neuro- and hepatoprotective properties. Some of these properties were attributed to an antioxidant activity of thymoquinone, which seems to be unlikely from its structure. Because the lipophilic thymoquinone exhibits a structural similarity with the natural mitochondrial electron carrier, ubiquinone, it was of interest whether the suggested antioxidant effect of thymoquinone in cells can be explained by its interaction with the mitochondrial respiratory chain.

Thymoquinone (oxidized form) possesses a very low antioxidant activity while its reduced form (thymohydroquinone) exerts a high radical-scavenging capacity, comparable to that of pentamethylchromanol, a short-chain tocopherol analogon. We assume that the mitochondrial respiratory chain is significant for the antioxidant properties of thymoquinone in the cell by converting the administered thymoquinone into its hydroquinone.
Staniek, K. & Gille, L. BMC Pharmacology 2010, 10(Suppl 1):A9. doi:10.1186/1471-2210-10-S1-A9

Pancreatic Cancer
MST An Herbal Extract Inhibits the Development of Pancreatic Cancer
Thymoquinone, the major constituent of the oil extract from a Middle Eastern herbal seed called Nigella sativa, exhibited anti-inflammatory properties that reduced the release of inflammatory mediators in pancreatic cancer cells, according to Hwyda Arafat, M.D., Ph.D., associate professor of Surgery at the Jefferson Medical College of Thomas Jefferson University and a member of the Jefferson Pancreatic, Biliary & Related Cancers Center.

Nigella sativa seeds and oil are used in traditional medicine by many Middle Eastern and Asian countries. It helps treat a broad array of diseases, including some immune and inflammatory disorders, Dr. Arafat said. Previous studies have also shown it to have anti-cancer effects on prostate and colon cancers.

Based upon their previously published findings that thymoquinone inhibits histone deacetylases (HDACs), Dr. Arafat and her colleagues compared the anti-inflammatory properties of thymoquinone and trichostatin A, an HDAC inhibitor that has previously shown to ameliorate inflammation-associated cancers.

The researchers used pancreatic ductal adenocarcinoma (PDA) cells, some of which were pretreated with the cytokine TNF-alpha to induce inflammation. Thymoquinone almost completely abolished the expression of several inflammatory cytokines, including TNF-alpha, interleukin-1beta, interleukin-8, Cox-2 and MCP-1, an effect that was more superior to the effect of trichostatin A.

The herb also inhibited the activation and synthesis of NF-kappaB, a transcription factor that has been implicated in inflammation-associated cancer. Activation of NF-kappaB has been observed in pancreatic cancer and may be a factor in pancreatic cancer's resistance to chemotherapeutic agents. When animal models of pancreatic cancer were treated with thymoquinone, 67 percent of the tumors were significantly shrunken, and the levels of proinflammatory cytokines in the tumors were significantly reduced.

Inflammation has been implicated in the development of several solid tumor malignancies. Chronic pancreatitis, both hereditary and sporadic, is associated with the risk of developing pancreatic cancer.

"These are very exciting and novel results," Dr. Arafat said. "Not only patients with chronic pancreatitis could benefit from this, but also several other groups with risk of development or recurrence of pancreatic cancer, such as high-risk family members and post-surgical patients. These potent effects show promise for the herb as a potential preventive and therapeutic strategy for pancreatic cancer. More importantly, the herb and oil are safe when used moderately, and have been used for thousands of years without reported toxic effects."

An herb recently found to kill pancreatic cancer cells also appears to inhibit development of pancreatic cancer as a result of its anti-inflammatory properties, according to researchers from the Kimmel Cancer Center at Jefferson. The data were presented at the AACR 100th Annual Meeting 2009 in Denver. (Abstract #494)

Thymoquinone, the major constituent of the oil extract from a Middle Eastern herbal seed called Nigella sativa, exhibited anti-inflammatory properties that reduced the release of inflammatory mediators in pancreatic cancer cells, according to Hwyda Arafat, M.D., Ph.D., associate professor of Surgery at the Jefferson Medical College of Thomas Jefferson University and a member of the Jefferson Pancreatic, Biliary & Related Cancers Center.

Nigella sativa seeds and oil are used in traditional medicine by many Middle Eastern and Asian countries. It helps treat a broad array of diseases, including some immune and inflammatory disorders, Dr. Arafat said. Previous studies have also shown it to have anti-cancer effects on prostate and colon cancers.

Based upon their previously published findings that thymoquinone inhibits histone deacetylases (HDACs), Dr. Arafat and her colleagues compared the anti-inflammatory properties of thymoquinone and trichostatin A, an HDAC inhibitor that has previously shown to ameliorate inflammation-associated cancers. The researchers used pancreatic ductal adenocarcinoma (PDA) cells, some of which were pretreated with the cytokine TNF-a to induce inflammation.

Thymoquinone almost completely abolished the expression of several inflammatory cytokines, including TNF-a, interleukin-1b, interleukin-8, Cox-2 and MCP-1, an effect that was more superior to the effect of trichostatin A.

The herb also inhibited the activation and synthesis of NF-kB, a transcription factor that has been implicated in inflammation-associated cancer. Activation of NF-kB has been observed in pancreatic cancer and may be a factor in pancreatic cancerís resistance to chemotherapeutic agents. When animal models of pancreatic cancer were treated with thymoquinone, 67 percent of the tumors were significantly shrunken, and the levels of proinflammatory cytokines in the tumors were significantly reduced.

Inflammation has been implicated in the development of several solid tumor malignancies. Chronic pancreatitis, both hereditary and sporadic, is associated with the risk of developing pancreatic cancer.

"These are very exciting and novel results," Dr. Arafat said. "Not only patients with chronic pancreatitis could benefit from this, but also several other groups with risk of development or recurrence of pancreatic cancer, such as high-risk family members and post-surgical patients. These potent effects show promise for the herb as a potential preventive and therapeutic strategy for pancreatic cancer. More importantly, the herb and oil are safe when used moderately, and have been used for thousands of years without reported toxic effects."

Pancreatic cancer is the fourth leading cause of cancer death in the United States, with approximately 32,000 deaths a year. Only five percent of individuals with pancreatic cancer live for at least one year after diagnosis.
http://www.jeffersonhospital.org/News/2009-april-mst-herb-inhibits-development-pancreatic-cancer.aspx
 
CopyRight 2011 - ICOP