ABSTRACT
Objective: To study the changes rule of active ingredients content and moisture status during the process of dry (drying/steaming) and rehydration (decoction), which could provide technical support for optimizing the dry/rehydration conditions of Chinese medicine and scientifically determine the end point of the process, and it also provides a new scientific perspective for exploring the differences in fresh/dry/processing of traditional Chinese medicine. Methods: Low-field NMR and imaging techniques (LF-NMR, MRI) were used to determine the change of water with time; The content changes of main composition of ginsenosides in different samples were determined by HPLC. Results: The results of determination of moisture and chemical composition showed that: The fresh ginseng was steamed for 180 min. At this time, the water was saturated, the ginsenosides tended to be stable, and the content of total ginsenosides was high. When fresh ginseng and red ginseng were dried at different temperatures for 12.5 h, they were not completely dried at 40 ℃ hot-air drying; The sun-dried ginseng still contained 3.02% water at 50 ℃ hot-air drying, and the red ginseng has been dried; Both of them have been dried at 60 ℃, but the content of total ginsenosides in ginseng and red ginseng was the highest at 50 ℃. The comprehensive results showed that ginseng and red ginseng were better at 50 ℃ hot-air drying. During rehydration (decocting), the moisture content of the decoction for 60 min was fully saturated and the content of total ginsenosides was higher, better than 30 min and 120 min, which was a better decocting condition. The moisture content and total ginsenosides content of fresh ginseng were higher than those of steaming/drying/decocting ginseng, suggesting that fresh ginseng is great significance for preserving and exerting the basic state of the initial pharmacodynamics of traditional Chinese medicine. Conclusion: In this study, ginseng was used as an example. LF-NMR/MRI and HPLC techniques were used to focus on the changes of moisture and chemical contents during the drying (drying, processing) and rehydration (decocting) of traditional Chinese medicines. It provides a new technical method for the determination of the dry/rehydration end point and the optimization of process conditions for traditional Chinese medicine, and also provides a new scientific basis for the interpretation and exploration of the theory of fresh/drying/processing of traditional Chinese medicine.