Natural & Herbal Remedy

Currently, the primary natural source for astaxanthin is the microalgae Haematococcus pluvialis.^[13] It seems to accumulate the highest levels of astaxanthin in nature;^[14] Commercially more than 40 g of astaxanthin can be obtained from one kg of dry biomass.^[15] It has the advantage of the population doubling every week, which means scaling up is not an issue. However, it does require some expertise to grow the algae with a high astaxanthin content. Specifically, the microalgae is grown in two phases. First, in the green phase, the cells are given an abundance of nutrients to promote proliferation of the cells. In the subsequent red phase, the cells are deprived of nutrients and subjected to intense sunlight to induce encystment (carotogenesis), during which the cells produce high levels of astaxanthin as a protective mechanism against the environmental stress. The cells, with their high concentrations of astaxanthin, are then harvested.^[16]

Phaffia yeast Xanthophyllomyces dendrorhous exhibits 100% free, non-esterified astaxanthin, which is considered advantageous because it is readily absorbable and need not be hydrolysed in the digestive tract of the fish. In contrast to synthetic and bacteria sources of astaxanthin, yeast sources of astaxanthin consist virtually all in 3R, 3’R form, an important astaxanthin source in nature. Finally, the geometrical isomer, all-E, is higher in yeast sources of astaxanthin, as compared to synthetic sources. This contributes to greater efficacy because the all-E (trans) isomer has greater bio-availability than the cis isomer.^[17]

For obtaining astaxanthin from Euphausia superba (Antarctic krill), there are a number of issues:^[18]

Krill

The Krill fishing operation is complex. It is done in Antarctic waters, under extreme weather conditions and far away from ports with substantial operational complexities. Krill's fishing location and the difficult weather conditions in the main fishing area, together with the costs involved in the operation, have contributed to a slow development of the industry. Krill fishing is by far different than any other fishing operation today known. The knowledge to work with it belongs to very few people in the world.

However, In recent years, the ocean krill population has become threatened due to commercial demands, which has created a sustainability problem.

Astaxanthin is commercially collected from shrimp processing waste. 12,000 pounds of wet shrimp shells can yield a 6-8 gallon astaxanthin/triglyceride oil mixture.^[19]

Synthetic sources

Nearly all commercial astaxanthin for aquaculture is produced synthetically, with an annual turnover of over $200 million and a selling price of ~$2000 per kilo.^[15] However, synthetic production of astaxanthin is not preferred in some cases because synthetic astaxanthin contains a mixture of stereoisomers. Astaxanthin is fairly abundant and obtainable from natural sources, and some consumers prefer natural products over synthetic ones.^[16] Synthetic astaxanthin fetches $2000 per kg, while the natural product is sold for over $7000 per kg.^[20]

An efficient synthesis from isophorone, cis-3-methyl-2-penten-4-yn-1-ol and a symmetrical C₁₀-dialdehyde has been discovered and is used commercially. It combines these chemicals together with an ethynylation and then a Wittig reaction.^[21] Two equivalents of the proper ylide combined with the proper dialdehyde