Planta Med 2003; 69(1): 3-8
DOI: 10.1055/s-2003-37040
Original Paper
Pharmacology
© Georg Thieme Verlag Stuttgart · New York

Antioxidant Activity of Piperlactam S: Prevention of Copper-Induced LDL Peroxidation and Amelioration of Free Radical-Induced Oxidative Stress of Endothelial Cells

Jeng-Yan Tsai1 , Cheng-Jeng Chou2 , Chieh-Fu Chen1 , 2 , Wen-Fei Chiou2
  • 1Institute of Pharmacology, School of Life Sciences, National Yang-Ming University, Taipei, R.O.C.
  • 2National Research Institute of Chinese Medicine, Taipei, Taiwan, R.O.C.
Further Information

Publication History

Received: March 25, 2002

Accepted: September 22, 2002

Publication Date:
04 February 2003 (online)

Abstract

The protective effects of piperlactam S, an alkaloid isolated from Piper kadsura (Choisy) Ohwi, on lipid peroxidation and free radical-mediated cell injuries were investigated. Piperlactam S (1 to 20 μM) concentration-dependently prevented the copper-catalyzed oxidative modification of human low-density lipoproteins (LDL) measured through (i) the lag period, (ii) the slope of the propagation phase, (iii) the total amount of conjugated dienes formed, and (iv) the electrophoretic mobility of LDL. Fe2+-induced oxidative modification of cell membrane was also significantly attenuated by piperlactam S as measured by thiobarbituric acid-reactive substances (TBARS). Furthermore, piperlactam S effectively minimized the loss of cell viability induced by Fenton’s reagent (H2O2/FeSO4) in cultured endothelial cells and significantly reversed H2O2/FeSO4-induced impairment of endothelium-dependent relaxation to acetylcholine in rat aorta. Since the oxidative modification of LDL plays an important role in the genesis of atherosclerosis, piperlactam S may help to reduce the risk of atherosclerosis, not only by protecting LDL and membrane lipids from oxidative modification but also by reducing free radical-induced endothelial injury and/or dysfunction.

Abbreviations

LDL:low-density lipoprotein

MDA:malondialdehyde

PAECs:pulmonary artery endothelial cells

PE:phenylephrine

REM:relative electrophoretic mobility

TBARS:thiobarbituric acid-reactive substances

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Dr. Wen-Fei Chiou

National Research Institute of Chinese Medicine

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