Pure total flavonoids from Citrus paradisi Macfad induce leukemia cell apoptosis in vitro.

OBJECTIVE: To investigate the potential effect of pure total flavonoids from Citrus paradisi Macfad peel (PTFC) on the proliferation of human myeloid leukemia cells Kasumi-1, HL-60 and K562, and the underlying mechanisms. METHODS: PTFC was extracted from Citrus paradisi Macfad peel and was identified by high performance liquid chromatography. The effect of PTFC on the proliferation and apoptosis of leukemia cells were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, fluorescent microscopy and flow cytometry, respectively. The effect of PTFC on the expression levels of apoptosis-related regulators was determined by Western blot assay. RESULTS: Treatment with PTFC inhibited leukemia cell proliferation in a dose- and time-dependent manner and triggered Kasumi-1 cell apoptosis. Treatment with PTFC significantly increased the levels of activated poly adenosine diphosphate-ribosepolymerase and caspase-3/-9, but reduced the levels of Mcl-1 expression in Kasumi-1 cells. However, PTFC did not obviously induce HL-60 cell apoptosis. CONCLUSION: PTFC inhibited leukemia cell proliferation and induced their apoptosis by modulating apoptosisrelated regulator expression in leukemia cells in vitro.

[Apoptosis of multiple myeloid cells induced by polysaccharides extracts from Hedyotis diffusa and its mechanism].

OBJECTIVE: To explore the proliferation inhibition and apoptosis effects of polysaccharides extracts from Hedyotis diffusa (PEHD) on multiple myeloma (MM) cell line RPMI 8226 cells in vitro, so as to provide experimental theory for the clinical application in the treatment of MM. METHODS: MTT assay was used to examine the effects of PEHD on cell growth. The apoptotic cells were analyzed by flow cytometry with AnnexinⅤ/PI staining. Hoechst staining was used to observe the morphological changes of RPMI 8226 cell apoptosis. The expression levels of caspase-3,-8,-9, PARP, nucleoprotein NF-κB protein and other channel protein were assayed by Western blotting method. RESULTS: The growth of RPMI 8226 cells were suppressed after treatment with PEHD, the highest inhibition rate reached to 92.3%, the results in the doses from 1 to 4 mg/ml showed a dose-and-time-dependent manner. The proportion of apoptotic cells in 1, 2 and 3 mg/ml PEHD treatment groups for 24 h were 22.52%, 62.31% and 69.94%, respectively, and significantly higher than that of control 8.93%. After treated with PEHD, apoptotic body appeared in RPMI 8226 cells nucleus and the number of apoptotic body increased in a dose-dependent manner. With the increasing of PEHD concentration, the expression of caspase-8,-9,-3 and PARP protein increased. The expression of Mcl-1, Bcl-xl, Bid and Bim protein decreased gradually, but the expression of Bax, Bak and Bad protein increased, and the expression of p-AKT protein (60 kDa) and NF-κB obviously decreased. CONCLUSION: PEHD could inhibited the growth of RPMI 8226 cells and displayed a dose-and-time-dependent manner, its mechanism may involve cell apoptosis induction, which was associated with the activation of caspase-8, caspase-9, and caspase-3 protein and the down-regulation of p-AKT and NF-κB protein expression.