Synthesis of reduced graphene oxide using methanolic extract of Sargassum tenerrimum and its antiproliferative activity against human colorectal adenocarcinoma HT-29 cell lines

Biosynthesis of reduced graphene oxide (rGO) nanosheets through functionalization of bioactive molecules from plant sources is considered therapeutically more effective in the field of nanomedicine. In this study, a green and one-pot method of synthesizing reduced GO nanosheets using methanol extract of brown seaweed species—Sargassum tenerrimum—was investigated for its anticancer properties. The synthesized SrGO nanosheets were spectroscopically characterized using UV–Visible spectrophotometer, XRD, FTIR, DLS, TEM, and EDX techniques. In UV–Visible spectrophotometry analysis, the absorption maxima were shifted 251 nm (GO) to 263 nm (SrGO) which confirms the bioreduction. Particularly, in FTIR analysis of SrGO observation of peaks at 1377 cm−1 and 1048 cm−1 confirms the bioreduction. TEM reveals the existence of thin silky nanosheets with folded structures. The in vitro antiproliferative activity of GO and SrGO evaluated against HT29 cell lines shows concentration-dependent cytotoxic effects. The inhibitory concentration (IC50) of GO and SrGO was found to be 62.5 µg/ml and 15.75 µg/ml respectively. The results signify that enhanced cytotoxic effects involve capping of biomolecules on surface of reduced GO nanosheets. The cell viability was high in SrGO than GO which were statistically significant. The antiproliferative effects of SrGO could be attributed to the presence of benzoic acid, 4-phenoxy and benzamide, N,N-didecyl-2,6-difluoro derivatives detected in the ESI spectra. The findings of the study revealed that Sargassum tenerrimum can be used as a strong reducing agent to produced stabilized rGO nanosheets for various biomedical applications.