Our previous research showed that standardized extract from the flowers of the Gossypium herbaceam labeled GHE had been used in clinical trials for its beneficial effects on brain functions, particularly in connection with age-related dementia and Alzheimer's disease (AD). The aim of this work was to determine the components of this herb and the individual constituents of GHE. In order to better understand this herb for AD treatment, we investigated the acetylcholinesterase (AChE) inhibition and antioxidant activity of GHE as well as the protective effects to PC12 cells against cytotoxicity induced by tertiary butyl hydroperoxide (tBHP) using in vitro assays. The antioxidant activities were assessed by measuring their capabilities for scavenging 1,1-diphenyl-2-picylhydrazyl (DPPH) and 2-2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) free radical as well as in inhibiting lipid peroxidation. Our data showed that GHE exhibited certain activities against AChE and also is an efficient free radical scavenger, which may be helpful in preventing or alleviating patients suffering from AD.