Nature has gifted us with abundant plants possessing medicinal virtues which can cure several illnesses. Currently, diabetes mellitus is a severe threat to human well-being across the world due to the rapidly increasing incidence of diabetes. New effective bioactive drugs are in need, as plants do harbour and are proven to have potential antidiabetic activity than the present hypoglycemic medicines used in clinical therapy. In this study, in vitro cytotoxicity, glucose uptake, and anti-adipogenic activities of the plant extract (methanolic extract) of S. brevistigma were examined using 3T3L1 cell lines. The studies interpreted by MTT cytotoxicity assay and glucose uptake assay by using 3T3-L1 cell lines, it was found that a very low dosage (1 ng/mL) of plant extract showed lesser cytotoxicity effect (1.42%) and considerably higher glucose uptake activity of 38.04% which is equivalent to the glucose uptake shown by 100 nm insulin (40.10%). Though plant extract has antidiabetic activity, it is important to study whether it has any other related side effects when used at higher concentrations. Therefore, in this study, the appropriate non-toxic concentration was optimized.