Purpose: To investigate the anti-proliferative, apoptotic and differentiating activities of
Eurycoma
longifolia
root extracts on HL-60 leukemic cells.
Methods: HL-60 cells were treated with different partially purified sub-fractions (F1 – F3) derived from
the resin chromatography of the crude methanol root extract of
E. longifolia roots, at different doses and
time points. The anti-proliferative activity of
E. longifolia was assessed via cell counting and trypan blue
exclusion. Apoptosis was evaluated via Annexin-V FITC/IP and Hoechst staining. Flow cytometry and
Wright staining were used to assess its differentiation activities.
Results: F1 showed unremarkable growth inhibition rate while F2 and F3 showed growth inhibitory
effects with median inhibitory concentration (IC
50) values of 15.2 and 28.6 μg/ml, respectively.
Treatment with F2 and F3 (100 μg/ml) for 96 h increased cell death from 3.3 to 95.5 and 76.3 %,
respectively. Treatment with F2 (50 μg/ml) induced apoptosis by 14, 19.5 and 25 % after 24, 48 and
72 h, respectively. No differentiation activity was observed, as indicated by absence of myeloid
maturation and a non-significant CD14 positivity (p > 0.05).
Conclusion: E. longifolia extract (F2) showed promising anti-leukemic activity and can be a candidate
for the development of a drug for the treatment of acute promyelocytic leukemia (APL).
