Abstract: The inhibitory effects of bamboo leaves flavonoids (BLF) from the species of Pleioblastus amarus (Keng) keng, Indocalamus latifolius (Keng) McClure, Phyllostachys heterocycla (Carr.) Mitford Pubescens and P. glauca McClure on the fatty acid synthase (FAS) and human breast cancer cell MDA-MB-231 in vitro were studied. The inhibitory effects of bamboo leaves flavonoids on FAS were determined by UV spectrophotometry, and the inhibitory effects of MDA-MB-231 were detected by CCK-8 assay. Flow cytometry was used to detect the apoptosis of MDA-MB-231. The results showed that all four bamboo leaves flavonoids had significant inhibitory effects on FAS and MDA-MB-231 cells. The IC₅₀ values of four flavonoids against FAS were 112.43, 153.29, 161.32 and 195.09 mg/L, respectively. The inhibition effects of flavonoids on MDA-MB-231 followed the dose-effect relationship. Further studies showed that the 70% and 95% ethanol fraction of bamboo leaves flavonoids exhibited the strongest cytotoxicity. The inhibition rates against MDA-MB-231 at the mass concentration of 100, 200, 400 mg/L of 95% ethanol fraction of P. amarus were 25%, 44% and 70%, and the apoptosis rates were 11.1%, 23.1% and 38.7%, respectively.

Key words: bamboo leaves flavonoids, FAS, human cacer cells MDA-MB-231, apoptosis