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% CO2, 10
μL of 5 mg/mL MTT was added to each well. After
incubation at 37 °C with 5% CO2 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)