Bamboo leaf extract inhibits the malignant growth of human breast cancer MCF-7 cells by regulating the Akt/HIF-1α pathway under hypoxic microenvironment / 西安交通大学学报(医学版)

Objective To investigate the effects of bamboo leaf extract on the malignant growth of human breast cancer MCF-7 cells under hypoxic microenvironment and the molecular mechanism .Methods Cultured human breast cancer MCF-7 cells were randomized into six groups :control group , hypoxia group ,0 .2 μg/mL bamboo leaf extract group ,0 .4μg/mL bamboo leaf extract group ,0 .8μg/mL bamboo leaf extract group and 0 .8μg/mL bamboo leaf extract group treated with IGF-1 .The cell proliferation activity in each group was determined using cell counting Kit-8 (CCK-8) assay .The expressions of proliferation markers PCNA ,Ki-67 and CCK-8 MCM2 in MCF-7 cells were detected by RT-PCR and Western blot .Flow cytometer was used to analyze the cell cycle arrest and cell apoptosis .The protein expressions of Bax ,Bcl-2 ,caspase-3 and survivin were measured by Western blot . Furthermore ,the effect of Akt/HIF-1αpathway underlying bamboo leaf extract-mediated inhibition on cancer cell growth was also explored .Results After treatment with bamboo leaf extract ,cell proliferation activity and the expressions of PCNA ,Ki-67 and MCM2 under hypoxia were obviously inhibited in a dose-dependent manner ( P<0 .01) . The proportion of MCF-7 cells upon hypoxia in the G2/M phase of the cell cycle was increased after treatment with bamboo leaf extract (P<0 .01) .The apoptosis rate of MCF-7 cells was enhanced after bamboo leaf extract stimulation ,accompanied with an increased protein levels of Bax and caspase-3 ,and decreased expressions of Bcl-2 and survivin (both P< 0 .01) .Moreover ,bamboo leaf extract down-regulated the expressions of p-Akt and HIF-1αin MCF-7 cells under hypoxia .IGF-1 ,an Akt/HIF-1α pathway agonist ,reversed the inhibiting effect of bamboo leaf extract on the malignant growth of MCF-7 cells under hypoxia .Conclusion Bamboo leaf extract inhibits the malignant growth of human breast cancer MCF-7 cells by suppressing the Akt/HIF-1αsignaling pathway under hypoxic microenvironment .

Study for anti-tumor and neuroprotection of extract from bamboo leaf / 中草药

In this study, we selected two types of tumor cell lines, HepG2 (VEGF-dependent) and SH-SY5Y (VEGF-independent) to investigate the anti-tumor activity of flavones extract from bamboo leaf (bamboo-leaf flavones) and their molecular mechanism. The bamboo-leaf flavones were used to treat HepG2 and SH-SY5Y cells. The activity of bamboo-leaf flavones in inhibition of the proliferation of HepG2 and SH-SY5Y cells was determined by MTT method. Gene expression of VEGF and VEGFR2 in HepG2 and SH-SY5Y cells was determined by RT-PCR method, so did gene expression of VEGF in HepG2 cells and NGF in SH-SY5Y cells after cells treated by bamboo-leaf flavones. Outgrowth of neurite in SH-SY5Y cells after treated by bamboo-leaf flavones was investigated by inverted fluorescence microscope. Data showed that bamboo-leaf flavones had a significantly higher inhibition to the proliferation of HepG2 cells than that of SH-SY5Y cells. We further observed that HepG2 cells expressed higher levels of VEGF and VEGFR2 cells than those of SH-SY5Y cells and bamboo-leaf flavones down-regulated VEGF expression in HepG2 cells. In addition, we also found bamboo-leaf flavones stimulate the neurite outgrowth in SH-SY5Ycells and up-regulated their NGF expression. Bamboo-leaf flavones could inhibit the proliferation of VEGF-dependent tumor cells by the probable down-regulation of VEGF expression. Meanwhile, bamboo-leaf flavones could stimulate the neurite outgrowth of neurons by the probable up-regulation of the NGF expression. Therefore, bamboo-leaf flavones probably have the dual functions in anti-tumor and neuroprotection.

Isolation of isoorientin and orientin from bamboo leaf flavones using preparative high-performance liquid chromatography / 中草药

Objective: To establish a method for preparation of orientin and isoorientin from bamboo leaf flavones (BLF) using preparative high-performance liquid chromatography (PHPLC). Methods: After BLF was purified by AB-8 resin-based column chromatography, PHPLC was employed to isolate orientin and isoorientin, using a mobile phase consisting of methyl alcohol-water with 0.3% acetic acid (32:68). The flow rate was 5 mL/min while the column temperature was maintained at 20℃. The injection volume was 400 μL and the concentration of sample was 15.3 mg/mL. Signal was monitored at 330 nm with the diode array detector. Results: HPLC analysis showed that the purities of isoorientin and orientin were >99% and >93%, respectively, and the recovery rates were (92.7±2.92)% and (85.1±3.45)%, respectively. The confirmation of chemical structures was performed by 1H-NMR and 13C-NMR. Conclusion: The method is simple, with low toxicity but high recovery rate, and can be applied to the separation and preparation of isoorientin and orientin.

A standardized bamboo leaf extract inhibits monocyte adhesion to endothelial cells by modulating vascular cell adhesion protein-1

Bamboo leaves (Phyllostachys pubescens Mazel ex J. Houz (Poacea)) have a long history of food and medical applications in Asia, including Japan and Korea. They have been used as a traditional medicine for centuries. We investigated the mechanism of anti-inflammatory activity of a bamboo leaf extract (BLE) on tumor necrosis factor-alpha (TNF-alpha)-induced monocyte adhesion in human umbilical vein endothelial cells (HUVECs). Exposure of HUVECs to BLE did not inhibit cell viability or cause morphological changes at concentrations ranging from 1 microg/ml to 1 mg/ml. Treatment with 0.1 mg/ml BLE caused 63% inhibition of monocyte adhesion in TNF-alpha-activated HUVECs, which was associated with 38.4% suppression of vascular cell adhesion molecule-1 expression. Furthermore, TNF-alpha-induced reactive oxygen species generation was decreased to 47.9% in BLE treated TNF-alpha-activated HUVECs. BLE (0.05 mg/ml) also caused about 50% inhibition of interleukin-6 secretion from lipopolysaccharide-stimulated monocyte. The results indicate that BLE may be clinically useful as an anti-inflammatory or anti-oxidant for human cardiovascular disease including atherosclerosis.

Determination of orientin,isoorientin,isovitexin in Bamboo Leaf from different sources by HPLC / 中成药

AIM: To determine the contents of orientin,isoorientin,isovitexin in Bamboo Leaf from different sources. METHODS : Orientin,isoorientin,isovitexin were determined by HPLC. The mobile phase was MeOH-H_2O-HAc (35∶65∶1). The detective wavelength was at 340nm. RESULTS : The highest content of three favonoids was 0.89% and the lowest content was 0.07% from different sources. CONCLUSION : This method is simple,quick and accurate for determination of the three favonoids in Bamboo Leaf from different sources.