The antioxidant ability and cytotoxicity of extracted and purified R-phycoerythrin from commercial porphyra haitanensis

Abstract Porphyra haitanensis was popular as healthy food source. People mainly absorbed nutrient by intaking porphyra haitanensis foods, which leaded to poor utilization of the fluorescence characteristics of R-phycoerythrin(R-PE) in porphyra haitanensis. In this study, the R-PE protein was extracted by freeze-thawing cycle assisted with sonication and then purified from commercial porphyra haitanensis. For the purified R-PE, there was a maximum absorbance peak at 565 nm and a maximum fluorescence peak at 575 nm. SDS-PAGE result showed there were three bands-α, β, γ corresponded to 19 kDa, 20 kDa and 32 kDa. And the LC-MS results showed it was corresponded to the wild type R-PE. The purified R-PE was stable between the pH from 5 to 10 and temperature from 25 ℃ to 55 ℃. It was sensitive to Cu² ⁺ at the limitation of 65 nM. Also, the purified R-PE behaved the good antioxidant activity of 1 mg/mL concentration and little cytotoxicity of L02 cells. These results indicated the R-PE extracted and purified from commercial porphyra haitanensis could be used as fluorescent probe to detect Cu²⁺ and antioxidant raw material in vitro and in vivo potentially.