Clerodane diterpene 3-deoxycaryoptinol (Clerodin) selectively induces apoptosis in human monocytic leukemia (THP-1) cells and upregulates apoptotic protein caspase-3

3-deoxycaryoptinol (Clerodin) is a clerodane diterpene isolated from the leaves of Clerodendrum infortunatum. The present research investigates the anticancer therapeutic efficacy of clerodin in human monocytic leukemic (THP-1) cells for the first time. In vitro assay using THP-1 cells showed the cytotoxic ability of clerodin. Further, Annexin-V(FITC)/PI and intracellular ROS (DCFDA) assays carried out using flow cytometry, and confocal laser scanning microscopy confirmed the apoptotic potential of clerodin. Moreover, the Western blot was used to detect mitochondrial apoptosis of THP-1 cells. RT-PCR, ELISA, and Western blot analysis clearly indicated that clerodin significantly increased the expression of pro-apoptotic marker caspase-3 in THP-1 cells. clerodin also selectively targeted the G2/M phase of THP-1 cells, a key feature for anticancer molecules. Importantly, the clerodin did not exhibit cytotoxicity against human peripheral blood cells. These properties of clerodin make it a potential chemotherapeutic agent that can selectively induce apoptosis in leukemia-like cancer cells.