Indigo Naturalis has a long history of medicinal use with particularity and complexity in its processing. Before the Ming dynasty,
Indigo Naturalis was extracted from the top layer of zymotic fluid,called " purified
Indigo Naturalis". In modern processing,the precipitate " crude
Indigo Naturalis" is dried to produce
Indigo Naturalis after impurity removal. The form of
Indigo Naturalis slices has undergone significant changes in ancient and modern times. In view of this,the quality comparison between crude
Indigo Naturalis and purified
Indigo Naturalis was conducted in this study with modern analytical techniques. Firstly,chemical composition was analyzed with UPLC-Q-TOF-MS,and the chemical composition of scent with HS-
SPME/GC-MS/MS. The content of
indigo,
indirubin,total ash,and water-soluble extract was determined as well as the inorganic composition in crude
Indigo Naturalis and purified
Indigo Naturalis. Then,their microscopic morphology was observed and the surface
element composition was investigated. Finally,the
antipyretic activities of crude
Indigo Naturalis and purified
Indigo Naturalis were compared in the
fever rat model induced by
lipopolysaccharide and
2,4-dinitrophenol. The results demonstrated that the purified
Indigo Naturalis had a faster and more lasting
antipyretic effect,while the crude
Indigo Naturalis had almost no
antipyretic effect. This study is of great significance to the research on processing technology of
Indigo Naturalis and provides reference for the formulation of its quality standards,production specifications and calibration procedures.