Synthesis of novel guttiferone E and xanthochymol derivatives with cytotoxicities by inducing cell apoptosis and arresting the cell cycle phase.
Lin X, Tian D, Fu Y, Li Y, Huang L, Gu W, Song J, Li Y, Ben-David Y, Wen M, Yuan C, Hao X.
The mixture of GX (guttiferone E and xanthochymol), an inseparable polycyclic polyprenylated acylphloroglucinol (PPAP), showed moderate cytotoxic activities. The chemical transformation of GX yielded three different types of PPAPs (1, 2, and 3/4). A series of analogs were prepared, and the structures of the 40 newly synthesized compounds were elucidated by 1D and 2D NMR and HR-ESI-MS. The derivatives were screened in vitro for antiproliferative activity against five human cancer cell lines: human leukemic cell lines (HEL and K562), cervical cancer cell line (Hela), human breast adenocarcinoma cell line (MCF-7), and human non-small cell lung cancer cell line (A549), using the MTT assay, and most of the derivatives showed good cytotoxic activities. Noticeably, compound 2, a novel tautomer with a hemiketal, exhibited selective cytotoxic activities against HEL (IC<sub>50</sub> = 4.79 ± 0.23 μM) and K562 (IC<sub>50</sub> = 7.69 ± 0.34 μM) leukemia cells. The mechanism studies indicated that compound 2 induced apoptosis and arrested the cell cycle at the G0/G1 phase in the HEL cell line. Furthermore, compound 2 activated the intrinsic pathway by reducing the expression of anti-apoptotic protein Bcl-2 and cell cycle-specific cyclin D1 and by enhancing the pro-apoptotic protein Bax. Moreover, the caspase-3 and PPRP1 levels were also upregulated. Our present results suggest that compound 2 is a potential candidate for developing novel anti-leukemia agents in the future.