Evaluation of in vitro antioxidant activities and antiproliferative activity of green microalgae, Desmococcus olivaceous and Chlorococcum humicola

The potential antioxidant and antiproliferative activities of acetone and methanolic extracts of green micro algae, Desmococcus olivaceous and Chlorococcum humicola, were evaluated in vitro. Total phenolic and flavonoid content were determined in both the extracts. Free radical (DPPH) scavenging potential was higher in Desmococcus olivaceous than cholorococcum humicola. Reducing power ( H2O2 ) scavenging assay, Ferric reducing antioxidant power assay (FRAP), lipid peroxidation inhibition efficiency ( TBAR’s assay) of both extracts were also evaluated. Methanolic extract of D .olivaceous and C.humicola showed higher reducing power and promising activity in preventing lipid peroxidation that might prevent oxidative damage to biomolecules. DNA fragmentation analysis was done by agarose gel electrophoresis. The results obtained suggest that methanolic extract of D.olivaceous and acetone extract of C.humicola were able to protect DNA from oxidative damage. Tested extracts showed strong selective cell proliferation inhibition on Hep-2 cell line, especially the methanolic extract of D. olivaceous with IC50 value of 1.56μg / ml and the acetone extract of C.humicola with IC50 value of 0.625μg / ml. Cell growth inhibition was mainly due to apoptosis proved by fragmentation analysis. The results obtained suggest that the methanolic extracts of D. olivaceous and acetone extracts of C. humicola may be promising alternative to synthetic substances as natural compound with high anti-proliferative activity.