Isolation and syntheses of polymethoxyflavones and hydroxylated polymethoxyflavones as inhibitors of HL-60 cell lines.

Fifteen polymethoxyflavones (PMFs) and hydroxylated PMFs were isolated from sweet orange (Citrus sinensis) peel extract and synthesized to investigate their biological activity. All obtained compounds were tested in HL-60 cancer cell proliferation and apoptosis induction assays. While some PMFs and hydroxylated PMFs had moderate anti-carcinogenic activities, 5-hydroxy-6,7,8,3',4'-pentamethoxyflavone and 5-hydroxy-3,6,7,8,3',4'-hexamethoxyflavone showed strong inhibitory activities against the proliferation and induced apoptosis of HL-60 cell lines.