Published by Maney Publishing (c) W.S Maney & Son Limited Nutritional Neuroscience 2009 Vol 12 No 3 123 Anti-inflammatory effects of daidzein on primary astroglial cell culture Man-Hai Liu 1 , Yu-Shan Lin 1 , Shiow-Yunn Sheu 2 , Jui-Sheng Sun 3,4 1 Graduate Institute of Pharmacy and 2 School of Pharmacy, Taipei Medical University, Taipei, Taiwan, Republic of China 3 Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan, Republic of China 4 Department of Orthopedic Surgery, National Taiwan University Hospital, Taipei, Taiwan, Republic of China Introduction: Alzheimer’s disease is the common cause of dementia in old people. The pathological hallmarks of Alzheimer’s disease include neuronal loss, deposition of amyloid-β, and presence of neurofibrillary tangles. The endogenous steroid estrogen has been shown to affect neuronal growth, differentiation and survival, while isoflavones also have a neuroprotective effect on human cortical neurons. Daidzein, however, has a superior neuron-protective effect to other isoflavones. The present study is to determine whether daidzein is able to inhibit the production of pro-inflammatory mediators under amyloid-β and lipopolysaccharide stimulation. Materials and methods: Astrocyte cells were stimulated with amyloid-β or lipopolysaccharide in the absence and presence of diadzein. Nitric oxide released into the culture media was determined using the Griess reaction, and concentrations of IL-1, IL-6, TNF-α and estrogen receptor gene expression were measured by semi-quantitative real-time polymerase chain reaction assay. Results: Diadzein-treatment increases astrocyte cell counts and attains its maximal effect at the 10 –12 M concentration. The addition of 20 μM amyloid-β or 10 –6 g/ml LPS can significantly decrease the viability of astrocytes, up-regulated IL-1, IL-6, TNF-α mRNA and estrogen receptor expression; in addition, 1-h daidzein pre-treatment can restore the decreased viability of astrocytes induced by amyloid-β or lipopolysaccharide as well as down-regulate their mRNA expression. Conclusions: It seems that this response is estrogen receptor-mediated. These results further increase the possibility that daidzein may have potential to ameliorate the inflammatory process and also alleviate the risk of Alzheimer’s disease progression. Keywords: neuroprotective effect, diadzein, amyloid beta-peptide, lipopolysaccharide Introduction Alzheimer’s disease is a progressive neurodegenerative disorder characterized by excessive deposition of amyloid-β peptides in the brain. One of the earliest neuropathological changes in Alzheimer’s disease is the accumulation of astrocytes at sites of amyloid-β Research article Correspondence to: Correspondence to: Jui-Sheng Sun MD PhD, Institute of Clinical Medicine, National Yang-Ming University, No.155, Sec. 2, Linong Street, Beitou District, Taipei City 11221, Taiwan, Republic of China. E-mail: jssun@ym.edu.tw or Shiow-Yunn Sheu, School of Pharmacology, Taipei Medical University, No. 250, Wu-Shin Street, Taipei, Taiwan, Republic of China E-mail: amel@tmu.edu.tw Received 17 Oct. 2008; revised manuscript accepted 12 Jan. 2009 © W. S. Maney & Son Ltd 2009 DOI 10.1179/147683009X423274