Antiproliferative and apoptosis-inducing activities of extracts from Sargassum binderi sonder on human cervical cancer cells

Abstract

Brown seaweeds contain a wide variety of compounds that inhibit cell proliferation and stimulate apoptosis. In this study, we investigated the antiproliferative and apoptotic properties of Sargassum binderi Sonder(SB)from the east coast of the Gulf of Thailand using human cervical cancer cell line(HeLa)as a model system. The fresh samples were extracted with dichloromethane and ethyl acetate(1:1)to afford crude extracts. The SB extraction were treated with HeLa cells (72hours) and cell proliferation was determined by MTT assay. The quantitation of apoptotic nuclear morphology was counted using fluorescent double staining: 4'-6-Diamidino-2phenylindole (DAPI) and Propidium iodide (PI). Qualitative analysis of DNA fragmentation by agarose gel electrophoresis was observed. The SB extraction inhibited the proliferation of HeLa cells in a dose-dependent manner with an IC50 of 90 ± 6.35 µg/m. Morphological alteration in SB-treated HeLa cells were detached from the surface and rounded with apoptotic body when compared with cuboid and polygonal in control cells. Nuclear morphology stained with DAPI and PI exhibited chromatin condensation and nuclear fragmentation as compared to control with rounded nuclei. Quantitative estimation were 3.66 ± 3.2% (apoptotic nuclei). 17.01±1.82% (late apoptotic nuclei), and 46.33±4.27%(normal nuclei). Qualitative DNA fragmentation by agarose gel electrophoresis showed undefined outline due to DNA diffusing into agarose. These result indicated that SB-induced cell death via morphological changes typical of apoptosis including membrane blebbing, chromatin condensation, nuclear and DNA fragmentation. Because apoptosis may have a major inpact on the therapy of cancer, further investigation is needed to confirm and characterize the apoptotic pathway.