Nutr Res Pract.  2013 Feb;7(1):9-14.

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

• Choi S
• Park MS
• Lee YR
• Lee YC
• Kim TW
• Do SG
• Kim DS
• Jeon BH

Abstract

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.

Keyword

Bamboo leaf extracts; anti-inflammation; reactive oxygen species; interleukin-6; endothelial cells

MeSH Terms

Asia
Atherosclerosis
Cardiovascular Diseases
Cell Adhesion
Cell Survival
Endothelial Cells
Human Umbilical Vein Endothelial Cells
Humans
Interleukin-6
Japan
Korea
Medicine, Traditional
Monocytes
Reactive Oxygen Species
Tumor Necrosis Factor-alpha
Vascular Cell Adhesion Molecule-1
Interleukin-6
Reactive Oxygen Species
Tumor Necrosis Factor-alpha
Vascular Cell Adhesion Molecule-1

Figure

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  Fig. 1 Bamboo leaf extract (BLE) treatment at 0.001-1 mg/ml did not reduce viability in human umbilical vein endothelial cells (HUVECs). (A) Effect of BLE treatment on viability of HUVECs. (B) HUVEC morphological changes in response to BLE (magnification, × 200). Data are presented as means ± SEMs (n = 3). *P < 0.05, significantly different compared with the control (DMSO) by one-way analysis of variance followed by Dunnett's test.

• 

  Fig. 2 Bamboo leaf extract (BLE) inhibited reactive oxygen species (ROS) generation in tumor necrosis factor-α (TNF-α)-stimulated human umbilical vein endothelial cells (HUVECs). (A) Fluorescence intensity of ROS in TNF-α-stimulated HUVECs following BLE treatment. Cells were labeled with the H2O2-sensitive fluorescent probe DCF-DA. (B) Representative fluorescent images show ROS levels in control cells and HUVECs stimulated with TNF-α in the absence or presence of BLE. Cells were observed under a fluorescent microscope at × 100 magnification. Data are presented as means ± SEMs (n = 3). *P < 0.05, significantly different compared with control (DMSO) by one-way analysis of variance followed by Dunnett's test.

• 

  Fig. 3 Quantitative U937 monocyte adhesion assay in tumor necrosis factor-α (TNF-α)-stimulated human umbilical vein endothelial cells (HUVECs). (A) The intensity of fluorescence labeled-adherent U937 monocytes was measured with a fluorometer (ex 485/em 530 nm). (B) U937 cells adherent to HUVECs observed under a fluorescent microscope at × 100 magnification. Data are presented as means ± SEMs (n = 5). *P < 0.01 compared with TNF-α-treated group as determined by one-way analysis of variance followed by Dunnett's test.

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  Fig. 4 Bamboo leaf extract (BLE) results in altered vascular cell adhesion molecule-1 (VCAM-1) expression in tumor necrosis factor-α (TNF-α)-stimulated human umbilical vein endothelial cells (HUVECs). (A) Immunoblotting for VCAM-1 using lysates from TNF-α-stimulated HUVECs treated with DMSO or BLE at the indicated concentrations. (B) Relative VCAM-1 expression was calculated based on densitometric scanning data of each band. Immunoblotting for each protein was performed at least twice using independently prepared lysates, and the results were consistent.

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  Fig. 5 Interleukin (IL)-6 secretion from lipopolysaccharide (LPS)-stimulated monocytes was partially but significantly attenuated by BLE. U937 monocytes were treated with LPS in the presence of 0.05 mg/ml BLE for the indicated time periods. IL-6 levels in the culture supernatant were measured by ELISA. Data are shown as means ± SEM (n = 3). *P < 0.05 compared to LPS alone as determined by one-way analysis of variance followed by Bonferroni's multiple comparison test.

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