Proliferation of lymphocyte cells was measured using MTT method. The yellow color of MTT changed to purple by mitochondrial succinate dehydrogenase of living cells. Briefly, 5 × 105 cells per well in a 96-well plate were stimulated with different concentration of extract (Table 1 for the details of extract concentration) and mitogen as positive control which were 5 µg/mL of Phytohaemagglutinin (PHA) and Concanavaline A (Con A). Control wells received only medium without extract or mitogen addition. After 72 h of culturing at 37 oC in a humidified incubator with 5% CO , 10
µL of 5 mg/mL MTT was added to each well. After incubation at 37 °C with 5% CO for 4 h, 100 μL of 10% SDS was added and mixed to release the purple colour from the cells. Optical density at 570 nm was measured using microplate reader (Arokiyaraj et al. 2007)