phytochemicals Phytochemicals
 
 

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Anti-cancer effects of astaxanthin


Numerous studies have demonstrated the anti-cancer effects of astaxanthin. This phytochemical may be involved in the regulation of cell communication at gap junctions, induction of apoptosis, modulation of immune response and induction of xenobiotic metabolizing enzymes.

Already in 1994 Tanaka and co-workers at the Gifu University School of Medicine, Japan, published in Carcinogenesis about the possible chemopreventive activity of astaxanthin against bladder carcinogenesis [1]. The scientists showed that the phytochemical reduced the incidence of chemically induced carcinoma by suppression of cell proliferation.



Growth inhibition by astaxanthin was observed in different cancer cell lines [2]. Researchers from the Catholic University School of Medicine, Rome, explored the growth-inhibitory effects of the astaxanthin-rich extract of Haematococcus pluvialis on colon cancer cells and found that the extract inhibited cell growth in a dose dependent manner. Astaxanthin increased the expression of several proteins such as p53, p21 and p27, but decreased the expression of cyclin D1 and AKT phosphorylation.

Several studies with mammals also indicate that astaxanthin may have anti-cancer effects. A study conducted at the Washington State University found that an adequate blood astaxanthin level protected mice against tumor initiation [3]. The team of scientists lead by Nakoa injected mice with mammary tumor cells and observed that mice fed with 0.005% astaxathin for 8 weeks before the injection showed extended tumor latency and lower tumor volume. However, when the astaxanthin was administered after injection of tumor cells the tumor growth was enhanced. A study conducted at the University of Madras, India, explored the protective effects of astaxanthin against 1, 2 dimethyl hydrazine (DMH) induced rat colon carcinogenesis [4]. The carcinogen upregulated the expression of several proteins involved in colon carcinogenesis, such as nuclear factor kappa B-p65, cyclooxygenase-2, matrixmetallo proteinases, proliferating cell nuclear antigen and extracellular signal-regulated kinase-2. The expression of these proteins was decreased by astaxanthin treatment. Another study conducted at the same university found that astaxanthin had a protective effect against DMH-induced colonic pre-neoplastic progression in rats [5]. The Indian researchers explored the chemopreventive efficacy of astaxanthin in DMH-induced colon carcinogenesis in rats and found that the phytochemical reduced lipid peroxidation, total number of aberrant crypt foci and cell proliferation.

[1] Chemoprevention of mouse urinary bladder carcinogenesis by the naturally occurring carotenoid astaxanthin. Carcinogenesis. 1994 Jan;15(1):15-9.
[2] Growth-inhibitory effects of the astaxanthin-rich alga Haematococcus pluvialis in human colon cancer cells. Cancer Letters. 2009 Sep 28;283(1):108-17.
[3] Effect of dietary astaxanthin at different stages of mammary tumor initiation in BALB/c mice. Anticancer Research. 2010 Jun;30(6):2171-5.
[4] Astaxanthin inhibits tumor invasion by decreasing extracellular matrix production and induces apoptosis in experimental rat colon carcinogenesis by modulating the expressions of ERK-2, NFkB and COX-2. Invest New Drugs. 2009 Oct 30.
[5] Antioxidative and antiproliferative effects of astaxanthin during the initiation stages of 1,2-dimethyl hydrazine-induced experimental colon carcinogenesis. Fundam Clin Pharmacol. 2009 Apr;23(2):225-34.




 
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