Relationship between maceration and extraction yield in the production of Chinese herbal medicine

Abstract The relationship between maceration and extraction yield in the production of Chinese herbal medicine has been studied. There is a general belief that swelling of herb tissue by maceration enhances the extraction yield of a chemical marker in the afterward extraction; however, this may not be true in general. The extraction of chrysophanol from a seed grounded into powder, Semen Cassiae , served as an example to show how maceration enhances the extraction yield of a chemical marker. It is possibly due to the fact that there are so many water soluble substances like starch, sugar and protein in seeds. When water is used as the maceration solvent, it dissolves and removes the water soluble substances, and therefore increases the availability of chemical marker to be extracted by the mixture of ethanol and water. In some other cases, it was found that maceration had no effect on the extraction yield of chemical marker, like the extraction of danshesu from Radix Salviae Miltiorrhizae (herb of root) and peaonol from Cortex Moutan (herb of root bark). Also, chemical markers may decompose during maceration and extraction, such as extractions of pinoresinol diglucoside from Cortex Eucommiae (herb of stem bark) and chlorogenic acid from Flos Lonicerae (herb of flower), leading to a decrease of the extraction yield. Based on these experimental results, this study provides general considerations to evaluate if it is cost and time effective to carry out maceration in the production process of Chinese herbal medicine. These considerations include whether the chemical marker is stable during maceration, and whether any substance present in the herb would affect extraction and can be removed during maceration.