There are many kinds and sources of Chinese herbal medicines, and all kinds of Chinese herbal medicines have many chemical components. According to its pharmacological action and component properties, the components of Chinese herbal medicine can be summarized as follows:
(1) Active ingredients are substances that have biological activity and exert major drug effects, such as alkaloids, glycosides and volatile oils.
(2) The auxiliary ingredients themselves have no special curative effect, but can enhance or reduce the efficacy of the effective ingredients. For example, saponins in digitalis can help digitalis glycoside dissolve or promote its absorption.
(3) Invalid ingredients refer to substances that are ineffective or even harmful, which often affect the dissolution effect, preparation stability, drug efficacy, etc.
(4) Tissue substances constitute insoluble substances of cells, such as fibrin and cork.
Traditional Chinese medicine preparations are mostly compound, and the clinical efficacy of traditional Chinese medicine compound is usually reflected in the comprehensive effect of compound compatibility. Its prescription composition ranges from a few herbs to dozens of herbs, and its ingredients are complex. Leaching is to try to put forward the ingredients that play a medicinal role and try to avoid leaching too many ineffective or even harmful substances. However, with the development of TCM science, the boundary between "invalid" and "effective" is not static, and may change in different prescriptions. Some components that used to be considered invalid are now found to have biological activity, and the best extraction process should be determined according to the composition changes of different components.