Study on effects of sweating treatment and different drying methods on the quality of Gentianae macrophyllae Radix.

To provide basis for improving the quality of Gentianae macrophyllae Radix and optimising the field processing method. Gentianae macrophyllae Radix samples were collected from Long County. Five main active iridoids were determined by using HPLC. The HPLC fingerprints were measured and analysed by the traditional Chinese medicine chromatographic fingerprint similarity evaluation system. Water, total ash, acid insoluble ash and ethanol extract contents were determined in accordance with Chinese Pharmacopoeia (2015). Colour of the surface and powdered samples were determined by using a colorimeter. Data were analysed by SPSS11.0. Notable differences were found among samples from different sweating and drying processes, in spite of the relatively consistent overall chemical characteristics. Sweating and drying methods influenced the contents of some active ingredients and colour very significantly; moreover, they also showed significant effects on the water, ash, and ethanol extract contents. The necessity of sweating treatment in the field processing of Gentianae macrophyllae Radix may be insufficient. Drying in the shade and oven drying are more profitable for preserving the active constituents. Gentianae macrophyllae Radix should be dried directly without sweating, and drying in the shade and oven drying should be adopted preferentially to improve the quality.