Eurycomanol and eurycomanone as potent inducers for cell-cycle arrest and apoptosis in small and large human lung cancer cell lines

Eurycoma longifolia Jack is one of traditional herbal medicines in South-East Asia. This study evaluated the anticancer, cell-cycle arrest, and apoptotic induction potentials of eurycomanone (EONE) and eurycomanol (EOL), highly oxygenated quassinoids previously isolated from its roots, against large (H460) and small (A549) lung cancer cells. EOL and EONE exhibited IC50 of 386 and 424 µg/mL on normal human lung cell line. EONE exhibited higher anticancer activity with an IC50 of 1.78 µg/mL and 20.66 μg/mL than EOL which exhibited an IC50 of 3.22 µg/mL and 38.05 µg/mL against H460 and A549, respectively. Both reduced the viability of H460 and A549 and arrested G0/G1 phase. The increase in the apoptotic rates was mainly in the percentage of late apoptosis. Moreover, they inhibited A549 by inducing the accumulation of S and G2/M phases. This study revealed EOL and EONE potential as novel leads exhibiting cell-cycle arrest and apoptosis induction potentials.