Dynamic changes in chemical components during sweating processing of Magnolia officinalis cortex based on...

Magnolia Officinalis Cortex (MOC), originated from the dried bark of Magnolia officinalis Rehd. et Wils., has often been used in clinical practice to treat various gastrointestinal disorders. The so called "sweating processing" endowed MOC with unique chemical qualities and specific clinical efficacy. Although previous studies have confirmed that sweating processing could change the chemical composition of MOC to affect its pharmacological effects, there is few research available so far on the dynamic chemical variations that occur during the sweating processing of MOC. In study, the method of spatial metabolomics combined with UPLC-Q-TOF-MS and MALDI-MSI was adopted to analyze the chemical components, transformation mechanisms and in situ spatial distribution during the dynamic sweating processing of MOC. The components in MOC at different sweating processing points included 36 lignans, 33 phenolic glycosides and phenolic acids, 36 alkaloids and others. Clear dynamic changes in compounds such as lignans, alkaloids, glycosidic phenols and phenylethanoid glycosides were observed, and 25 metabolic differentiators were identified to distinguish raw MOC and sweated MOC. Seven compounds including (R)-magnocurarine, syringin, (S)-magnoflorine, magnoloside B, magnoloside A, magnolol, and honokiol were quantified by HPLC. Through MALDI-MSI, the dynamic chemical changes in raw MOC and its sweating processing products were visualized. Interestingly, the syringic acid-4-O-α-L-rhamnopyranoside might be converted to magnolol or honokiol during sweating processing of MOC. In conclusion, the spatial metabolomics method based on UPLC-Q-TOF-MS, MALDI-MSI and quantitative analysis approach could effectively characterize the dynamic variations in chemical components of MOC during sweating processing. The wide application of this method would contribute to the process of monitoring and controlling MOC and others Chinese medical herb.