Basic introduction to phycocyanin

Phycocyanin is a dark blue powder isolated from Spirulina. It is mainly found in cyanobacteria, red algae and cryptophytes. Phycocyanin is also usually divided into C- and R- phycocyanin, the former being found mainly in cyanobacteria and the latter in red algae, both of which are found in cryptophytes. Its function is to absorb light (orange-yellow) energy and to transmit it. It is both a protein and an excellent natural food colouring, and a good health food.

Phycocyanin is one of the rare pigmented proteins found in nature. Not only is it brightly coloured, but it is also a nutritious protein in its own right, with a complete amino acid composition and a high content of essential amino acids.

In the early 21st century, it was widely used as a high grade natural pigment in food and cosmetics in Europe, America and Japan, and as a biochemical drug. In 1986, Conpatch (confident) phycocyanin was used as a rehabilitation drug and nutritional food for cancer patients and leukaemia patients, achieving outstanding therapeutic effects.

The blue granules or powder are protein-bound pigments and therefore have the same properties as proteins, with an isoelectric point of 3.4. Soluble in water but insoluble in alcohols and oils. Unstable to heat, light and acids. Stable under weak acidity and neutrality (pH 4.5 to 8), precipitates when acidic (pH 4.2), strong bases to decolourisation.

The application of phycocyanin has been widely studied and can be summarised as follows.

(1) Natural food pigment: algal cyanidin is a water-soluble pigment, non-toxic, pure blue, clear and lovely, and can be used as food colouring agent and additive in cosmetics.

(2) Pharmaceutical health food: algae cyanidin in vitro experiment has the effect of stimulating the production of red blood cell colonies, similar to erythropoietin (EPO). A variety of phycocyanin compounds have been successfully developed overseas, and Japan's Kangpai AIDS Research Institute has successfully reported that phycocyanin can improve anaemia and increase haemoglobin. In 1982, Iijima et al. studied that oral administration of cyanobacteria in mice increased the survival rate of mice injected with liver tumour cells, and the lymphocyte activity of the experimental group was significantly higher than that of the control, they believed that the protein had the function of promoting immunity and anti-disease. 1986, Schwartz and Shklar of Harvard Hospital in the USA found that spirulina cyanobacteria had an inhibitory effect on some cancer cells.

(3) Special reagents for biology, chemistry and cytology experiments: phycocyanin is blue and fluorescent and can be used as a research reagent for some photodynamic studies in biology and cytology.