Isolation and identification of bioactive proteins from the brown algae Sargassum, Sp. and their potential as anticancer agents

Abstract

A study was conducted on the bioactivity as anticancer agents of protein fractions isolated from the brown algae Sargassum, sp. collected from Laikang Island, Takalar, South Sulawesi, Indonesia. The proteins were isolated using buffer Tris-HCl pH 8.3 containing 0.2 M NaCl; 0.01 M CaCl2 1% β-mercaptoethanol; and 0.5% Triton X-100. Fractionation of bioactive proteins from crude extract used the salting out method with the addition of a (NH4)2SO4 salt powder at percent saturation rates of 0-20%, 20-40%, 40-60%, and 60-80%. Pre-purification of the proteins through dialysis was carried out in cellophane bags. Protein concentration was determined by the Lowry method using BSA (Bovine Serum Albumin) as a standard solution. The anticancer activity test used the Brine Shrimp Lethality Test (BSLT) preliminary test method, with further confirmation from antimitotic testing using urchin zygote cells. The protein concentration of the crude extract of brown alga Sargassum, sp. was 2.89 mg/mL.The 60-80% saturation fraction (F4) had the highest protein concentration (2.545 mg/mL). The 0-20% saturation protein fraction (F1) showed the highest activity in the anticancer tests, with an LC50 value of 55.62 µg/mL and IC50 value of 53.80 µg/mL. The 0-20% saturation protein fraction (F1) showed potential for development as an alternative anticancer agents in the future.