2.4. Quantification of apoptosis using flow cytometry

To determine the mechanistic approach of cell death, using the Annexin-V FITC/DAPI apoptosis kit (Calbiochem, CA, USA) (Bhanja et al., 2017) was employed. Briefly, γ-rays were introduced into berberine pre-treated SKOV-3 cells. Berberine treatment was given for 2 h prior to the irradiation. After the 2 h of berberine treatment, treated cells were washed by PBS twice for irradiation. After irradiation, cells were incubated for 24 h. Then the incubated cells were washed and stained with Annexin-V-FITC as per company’s protocols. The measurement of FITC appearance was carried out by Flow cytometer (BD LSRFortessa TM San Jose, CA, USA) to ensure the apoptosis.