Extraction and isolation of potential anti-stroke compounds from flowers of Pueraria lobata guided by in vitro PC12 cell model

A simple and efficient method based on ultrafiltration liquid chromatography-mass spectrometry (UFLC-MS) was applied to rapidly screen and identify ligands for lactate dehydrogenase (LDH) from the flowers of Pueraria lobata, and the compounds were assessed for anti-stroke activity using a PC12 cell model. Seven major isoflavones, kakkalide, 3′-hydroxy puerarin, puerarin, puerarin xyloside, tectoridin, tectorigenin, and ononin, were identified as potent LDH inhibitors. A continuous online method, which consisted of microwave-assisted extraction and countercurrent chromatography (MAE-CCC), was newly developed for scaled-up production of these compounds with high purity and efficiency. This novel approach, using UFLC-MS coupled with MAE-CCC and a PC12 cell model, provided a powerful tool for screening, extraction, and separation of LDH inhibitors from complex samples, and a useful platform for the large-scale production of functional food and nutraceutical ingredients.