Considering that as many as 80% of the anticancer drugs have their roots in natural products derived from
traditional medicine, we examined compounds other than
curcumin from turmeric (Curcuma longa) that could exhibit anticancer potential. Present study describes the isolation and characterization of another turmeric-derived compound, β-sesquiphellandrene (SQP) that exhibits anticancer potential comparable to that of
curcumin. We isolated several compounds from turmeric, including SQP, α-curcumene,
ar-turmerone, α-turmerone, β-turmerone, and γ-turmerone, only SQP was found to have antiproliferative effects comparable to those of
curcumin in human
leukemia,
multiple myeloma, and
colorectal cancer cells. While lack of the NF-κB-p65
protein had no effect on the activity of SQP,
lung cancer cells that expressed p53 were more susceptible to the cytotoxic effect of SQP than were cells that lacked p53 expression. SQP was also found to be highly effective in suppressing
cancer cell colony formation and inducing apoptosis, as shown by assays of intracellular
esterase activity, plasma membrane integrity, and cell-cycle phase. SQP was found to induce
cytochrome c release and activate
caspases that lead to
poly ADP ribose polymerase cleavage. SQP exposure was associated with downregulation of cell survival
proteins such cFLIP, Bcl-xL, Bcl-2, c-IAP1, and
survivin. Furthermore, SQP was found to be synergistic with the chemotherapeutic agents
velcade,
thalidomide and
capecitabine. Overall, our results indicate that SQP has anticancer potential comparable to that of
curcumin.