Received for review August 19, 2004. Revised manuscript received January 6, 2005. Accepted January 11, 2005. This work was supported in part by the Postdoctoral Fellowship Program of Korea Science and Engineering Foundation (2003) for H. J. Heo at Cornell University.

Abstract:

Because strawberries are known to contain higher concentrations of phytochemicals and have higher antioxidant capacity among common fruits, their neuroprotective activity was tested in vitro on PC12 cells treated with H₂O₂. Their protective effect and antioxidant capacity were also compared with those of banana and orange, which are the fresh fruits consumed at highest levels in the United States. The cell viability test using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction assay showed that strawberry phenolics significantly reduced oxidative stress-induced neurotoxicity. Because oxidative stress is also known to increase neuronal cell membrane breakdown, lactate dehydrogenase (LDH) and trypan blue exclusion assays were also performed. Strawberry showed the highest cell protective effects among the samples. The overall relative neuronal cell protective activity of three fruits by three tests followed the decreasing order strawberry > banana > orange. The protective effects appeared to be due to the higher phenolic contents including anthocyanins, and anthocyanins in strawberries seemed to be the major contributors.

Keywords: Alzheimer's disease; strawberry; phenolics; anthocyanins

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