Sailuotong (SLT), a standardised Chinese herbal medicine formula, enhances working memory in healthy adults : a pilot study

Purpose: Sailuotong (SLT) is a standardised Chinese herbal medicine formula consisting of Panax ginseng, Ginkgo biloba, and Crocus sativus. Substantive preclinical work has shown that this formula has neuroprotective, antioxidant, and anti-hypertensive properties. A recent human trial demonstrated that SLT significantly improved Alzheimer’s Disease Assessment Scale cognitive subscale (ADAS-cog) scores and increased cerebral blood flow (relative to placebo) in participants with probable or possible vascular dementia. The current pilot study tested whether SLT could improve cognition in a healthy population. Methods: Sixteen healthy adults (49.2±14.3 years) participated in this randomised, placebo-controlled, double-blind crossover design pilot study. The participants were randomised to receive either SLT or placebo for 1 week, and then switched to the other treatment after a 7 day washout period. Before and after each treatment, participants completed a computerised neurocognitive test battery (Compass), and had their electroencephalograph (EEG activity) recorded whilst completing auditory and visual oddball tasks. Results: Among the Compass tasks, 1 week treatment with SLT, compared to placebo, resulted in improvements in visuospatial short-term memory (Corsi Block Span task) and working memory (N-Back task) that approached statistical significance (p<.10). In the auditory oddball task, the N1 event-related potential (ERP) component showed a significant reduction after treatment with SLT that was larger for targets than nontargets (p<.05). There was also a small effect (p<.10) on auditory P3a, where a target enhancement was larger following SLT than placebo. Conclusion: Though the effects were small, SLT enhanced visuospatial short-term memory and working memory. Electrophysiological findings indicate that treatment with SLT resulted in more efficient attentional processing of auditory information, and increased activation ofworkingmemory processes. Findings are consistent with preclinical and recent clinical work, and suggest that SLT could potentially improve memory function in healthy volunteers, however, a larger sample size is needed to demonstrate this.