Antiproliferative Potential of GUR Extracts

The antiproliferative activities of GUR extracts and flavonoids were investigated using the MTT assay [14 (link)]. Firstly, B16-F10 cells were cultured in 96-well plates at approximately 7.5 × 10³ cells per well and incubated for 12 h. Then cells were treated with different concentrations of GUR extracts (5, 10, 25, 50, and 100 μg/mL) or GUR flavonoids (10, 20, 40, 60, and 80 μM). After incubation of 48 h, MTT solution (5 mg/mL in PBS) was added to each well, and cells were incubated at 37 °C for 4 h. Subsequently, 150 μL DMSO was added to each well, and the plate was put on a shaker for 5 min, the absorbance were measured at 570 nm using a fluorescence plate reader (Thermo scientific, Waltham, MA, USA). Inhibition percentage (%) was calculated according to the following formula: Inhibition percentage of cell viability (%) = [1−(OD treated well/OD control well)] × 100%. The IC₅₀ value was calculated using the SPSS v. 22.0 Statistics Software (IBM Corp., Armonk, New York, NY, USA).