An Integrated Strategy for Rapid Screening of Multi-target Lead Compounds for the Treatment of Alzheimer's Disease from Traditional Chinese Medicines by UHPLC Combined with High-throughput Screening: A Case Study on Salviae miltiorrhizae Radix et Rhizoma

Background: Salviae miltiorrhizae Radix et Rhizoma (Red Sage root) is widely used in traditional Chinese medicine (TCM) for the treatment of Alzheimer’s disease (AD) with demonstrated curative effects, based on the concept of "one drug with multiple therapeutic targets," which appears to be a good strategy for AD treatment. Objective: This study aimed to develop of high-throughput screening (HTS) method for multitherapeutic target components found in complex TCMs, which are active against AD, using Red Sage root as the case study. Methods: Acetylcholinesterase (AChE) inhibitors (AChEIs) from Red Sage root extracts were pre-screened by ultrafiltration-HPLC (UF-HPLC) analysis, in which AChE was added to the extract and then ultrafiltered to remove non-binding compounds. Potential AChEIs were identified by HPLC analysis of compounds bound to AChE. A microplate-based HTS was then used to quantify the AChE inhibitory activity and antioxidant activity of the pre-screened compounds. Results: Pre-screening found ten potential inhibitors, which were identified by ESI-TOF/MS; six of these were purified by semi-preparative HPLC: Oleoyl neocryptotanshinone (1), Dihydrotanshinone 133; (2), Cryptotanshinone (3), Tanshinone 133; (4), Tanshinone 133;¡A (5) and Miltirone (6). All six compounds had good AChE inhibitory activity and weak DPPH scavenging capacity. Conclusion: This study provides a platform and technology support for the rapid discovery of multi-target components, potentially active against AD, from complex TCMs and with strong potential for adaptation to the discovery of treatments for other diseases.