Effects of BT-11 on memory in healthy humans.

We previously reported that BT-11, the extract of dried roots of Polygala tenuifolia Willdenow, had neuroprotective effects and improved scopolamine- and stress-induced amnesia in rats. It also blocked the activity of acetylcholinesterase and enhanced glucose utilization in the rat brain. Therefore, we examined whether BT-11 could enhance memory in healthy humans. This study was a randomized, double-blind, placebo-controlled, parallel-group study of BT-11 in healthy adults. The participants were given capsules of BT-11 or placebo 3 times daily for 4 weeks. The Korean version of the California Verbal Learning Test (K-CVLT) and the Self-Ordered Pointing Test (SOPT) were used to assess verbal memory and working memory, respectively. The subjects in BT-11-treated group showed more significant increases in immediate recall on the K-CVLT than those in the placebo-treated group. In a comparison within each group, the subjects' scores on most subtests of the K-CVLT were significantly increased by both placebo and BT-11 treatment. Interestingly, the subjects' scores on the recognition subtest of the K-CVLT were significantly increased by BT-11 treatment but not by placebo treatment. Also, BT-11 treatment significantly reduced the number of errors on the SOPT, whereas placebo treatment did not. We are the first to show that BT-11 has memory-enhancing effects and may be a memory-enhancing drug in healthy adults.