October 22, 2011. Send your comment to    
How may astaxanthin function as anti-cancer agent?
When the conjugated keto-carotenoids, astaxanthin was added to rat liver microsomes undergoing radical-initiated
lipid peroxidation under air, astaxanthin is as effective as alpha-tocopherol in inhibiting the process. While,
beta-carotene was a much less potent antioxidant when added in this system. [2] In another study, the inhibitory
effects of beta-carotene and astaxanthin on photosensitized oxidation of phospholipid bilayers were compared. Large
unilamellar liposomes comprising of egg yolk phosphatidylcholine was exposed to photoirradiation in the presence of
photosensitizers.  Without sensitizers, astaxanthin decreased the process much slower than beta-carotene, lycopene,
and alpha-carotene. [4] Another early study showed that astaxanthin (10 nM) was able to protect against UV-induced
oxidative stress in rat kidney fibroblasts. [7] Further, research also shows that astaxanthin is an immunomolulator,
astaxanthin enhances in vitro antibody production to sheep red blood cells in normal B6 mice. [3] With such
immulomodulatory and anti-oxidative effects, one may expect that astaxanthin is an anti-cancer agent. Here, we are
going to review the studies have done to support its benefit claim on people suffered from cancers.

Bladder cancer
In a study, mice were given 250 p.p.m. OH-BBN in drinking water for 20 weeks then, water containing astaxanthin.
Researches found astaxanthin administration after OH-BBN exposure significantly reduced the incidence of bladder
cancer (transitional cell carcinoma). Treatment with astaxanthin also decreased the number/nucleus of silver-stained
nucleolar organizer region proteins, an index of cell proliferation. Astaxanthin may suppress cell proliferation. [5]

Colon Cancer
In one experiment, the effects of astaxanthin on colitis-associated colon carcinogenesis induced by azoxymethane in
mice was studied. Researchers found that dietary astaxanthin significantly inhibited the occurrence of colonic
mucosal ulcers, dysplastic crypts, and colonic adenocarcinoma at week 20. [Yasui Y et al, Chem Biol Interact. 2011
Aug 15;193(1):79-87.]

Oral carcinogenesis
In another study, researchers induced oral carcinogenesis in male F344 rats with 4-nitroquinoline 1-oxide (4-NQO).
Then, they fed the animals with 100 ppm astaxanthin during the initiation or post-initiation phase of 4-NQO-induced
oral carcinogenesis. They found the incidences of preneoplastic lesions and neoplasms in the oral cavity of rats fed
with astaxanthin were significantly smaller than those without astaxanthin treatment. In particular, no oral neoplasms
developed in rats fed with astaxanthin during the 4-NQO exposure. [6]

Mammary tumor cells
One early study demonstrated the anticancer activities of astaxanthin against the growth of mammary tumors were
studied in female eight-wk-old BALB/c mice. Researchers fed the mice with a synthetic diet containing 0, 0.1 or 0.4%
astaxanthin. After 3 weeks, they inoculated all mice with 1 x 10(6) WAZ-2T tumor cells into the mammary fat pad.
They killed all animals on 45 d after inoculation with the tumor cells and they found that astaxanthin decreased
mammary tumor volume in a dose-dependent fashion. [8]

Prostate cancer cells
Astaxanthin also demonstrated 98% inhibition of 5alpha-reductase at 300 microg/mL in vitro. Inhibition of
5alpha-reductase has been reported to decrease the symptoms of benign prostate hyperplasia (BPH) and possibly
inhibit or help treat prostate cancer. [14]

Liver cancer cells
Astaxanthin showed anticancer effect in rat hepatocellular carcinoma CBRH-7919 cells by inducing cell apoptosis
through the regulation of mitochondrial-dependent manner. [Song XD, et al, Biol Pharm Bull. 2011;34(6):839-44].

Discussion and Conclusion
Astaxanthin appears to be a potent anti-cancer agent, and astaxanthin may benefit people at risk or even suffered
from different types of cancers. However, its support is limited to in vitro and animal studies. Clinical studies are
needed to further explore this application.
Astaxanthin Review
Astaxanthin, a naturally occurring carotenoid pigment, is a powerful biological antioxidant. Astaxanthin exhibits strong
free radical scavenging activity and protects against lipid peroxidation and oxidative damage of LDL-cholesterol, cell
membranes, cells, and tissues. Consequently, astaxanthin has important applications in the Nutraceuticals,
Cosmetics, Food and Feed industries.

For last 2 decades. more than 300 articles and patents have been published regarding astaxanthin. Astaxanthin is a
small Lipid soluble molecule that can cross the blood brain and retina barriers easily. Because of its antioxidant
activities and blood brain/retina permeability, astaxanthin was found to have benefits on various health conditions
including inflammation, diabetics, certain cardiovascular, vision and CNS conditions.

Astaxanthin is a naturally occurring molecule and the most abundant carotenoid in the marine world. Astaxanthin can
be found in many of seafood such as salmon, trout, seabream and shrimps. Astaxanthin cannot be synthesized by
animals and must be provided in the diet. The main or richest commercial source for natural astaxanthin is
Haematococcus pluvialis microalgae. Most manufacturers have the advanced biotechnology process to cultivate
large amount of enriched algae cells without the disadvantages of open pond algae systems such as problems
associated with contaminations and salinity. In addition, the Haematococcus microalgae is cultivated in ideal
environmental conditions using the natural sun light as the energy source all year round.

Review / Benefits / Side Effects / Dosage / Cancer / Reference
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