Isolation and characterization of bioactive protein from green algae Halimeda macrobola acting as antioxidant and anticancer agent

A protein fraction isolated from green algae Halimeda macrobola taken from the sea of Selayar and Kapoposang Island in South Sulawesi was tested for antioxidant and anticancer properties. The protein was isolated using buffer Tris (hydroxymethyl) amino methane. Initial purification of protein was conducted by using the fractionation method with ammonium sulphate, followed by dialysis process. Protein concentration was determined by Lowry method. Antioxidant assay was done by using DPPH method and anticancer activity test by Brine Shrimp Lethality Test (BSLT) method. Anticancer activity was further confirmed by antimitotic test using urchin zygote cells. The results showed that the protein concentration of the crude extract was 0.920 mg/mL. The highest concentration of protein fractions was indicated by the fraction 40-60%, with 1.015 mg/mL. The strong antioxidant activity was shown in the protein fraction of 0-20% saturation with IC50 values of 0.110 mg/mL.The highest activity in the anticancer tests was shown in fractions 0-20% saturation with LC50 values of 0.29 μg/mL and IC50 value of 53.80 μg/mL. The protein fraction 0-20% saturation had a potential to be developed as antioxidant and anticancer agent. These results demonstrate that inexpensive green algae Halimeda macrobola could be a new alternative to produce antioxidant and anticancer proteins.