Aim: Grasses are an important group of monocotyledonous plants that are utilized as healthy foods as well as remedies against diseases for both humans and livestock. Themeda triandra Forssk. is a grass, which belongs to the family Poaceae. It was collected from the forest and grassland regions of Chikkamagaluru District, Karnataka. The goal of the present investigation is to identify the metabolites and in vitro cytotoxic properties against Osteosarcoma cancer (MG- 63) cell lines. Materials and Methods: The phytochemical investigations were done by preliminary qualitative and quantitative GCMS analysis. In vitro cytotoxic potential against MG-63 cells was examined by MTT assay. Results: Qualitative phytochemical investigations showed the existence of various metabolites such as alkaloids, phenols, tannins, flavonoids, glycosides, steroids, terpenoids, proteins and carbohydrates. GCMS profiling of methanolic whole plant extract exhibited the occurrence of 5 phytocompounds, with valuable pharmacological properties. The whole plant different solvent extracts showed moderate cytotoxicity against MG-63 cell lines at higher concentrations. Among the different solvent extracts petroleum ether extracts showed significant potential with an IC50 value of 28.82 μg/mL. Conclusion: It was concluded that Themeda triandra consists of several phytoconstituents and is also a proven effective cytotoxic agent for MG-63 cell lines, further investigations need to determine the molecular mechanism behind cytotoxic potential and elucidation of the potential pharmacological properties required further investigation
