Preparative separation of TL1-1 from Daldinia eschscholzii extract by macroporous resin and evaluation of its antimicrobial activities.

Abstract

2,3-Dihydro-5-hydroxy-2-methylchromen-4-one (TL1-1) has already been reported to exhibit significant activities such as cytotoxicity, antifungal activity and growth inhibitory activity. In order to simply and efficiently separate TL1-1 from crude extracts of Daldinia eschscholzii on a large-preparative scale, XAD-16 resin was selected from ten types of resin based on its superior adsorption and desorption performance. Adsorption equilibrium data for this resin fitted well with pseudo-first order kinetics and the Freundlich model, which were elucidated from kinetic experiments and adsorption isotherms. Under optimized conditions, the purity of TL1-1 increased from 19.21% (w/w) in the crude extract, to 84.64% (w/w) in the final product, with a recovery yield of 75.06% (w/w) by a one-step treatment. Moreover, in a large-scale separation, the purity and recovery of TL1-1 was 80.33% and 72.02% (w/w), respectively. These results demonstrated that a simple adsorption-desorption strategy, using XAD-16 resin, was efficient, which also highlighted its potential for the future large-scale purification and preparation of TL1-1. In addition, studies showed that the purified TL1-1 exhibited moderate antibacterial activity against Ralstonia solanacearum.