Chinese herbs for memory disorders: a review and systematic analysis of classical herbal literature.

Text mining and other literature-based investigations can assist in identifying natural products for experimental and clinical research. This article details a method for systematically analyzing data derived from the classical Chinese medical literature. We present the results of electronic searches of Zhong Hua Yi Dian ("Encyclopaedia of Traditional Chinese Medicine"), a CD of 1000 premodern (before 1950) medical books, for single herbs, and other natural products used for dementia, memory disorders, and memory improvement. This review explores how the terminology for these disorders has changed over time and which herbs have been used more or less frequently, and compares the results from the premodern literature with the herbs indexed for memory disorders in a modern pharmacopoeia. The searches located 731 citations deriving from 127 different books written between ca. 188 ad and ca. 1920. Of the 110 different natural products identified, those most frequently cited for forgetfulness were yuan zhi (Polygala tenuifolia), fu shen (Poria cocos), and chang pu (Acorus spp.), all of which have been cited repeatedly over the past 1800 years and appear among the 31 herbs indexed in a modern pharmacopoeia. By providing a complete, hierarchically organized list of herbs for a specific disorder, this approach can assist researchers in selecting herbs for research.