[Chemical and nutrient differences between medicinal material, residues, and residue compost of Moutan Cortex]

Moutan Cortex(MC) residues produced after the extraction of MC can be re-extracted for active components and used to produce organic fertilizer and animal feed. However, they are currently disposed as domestic waste, which pollutes the environment. This study analyzed the chemical composition of the medicinal material, residues, and residue compost of MC by UPLC-UV-Q-TOF-MS. Furthermore, the nutrient composition of MC residues and the residue compost was analyzed. The results showed that:(1)MC residues had lower content of chemicals than the medicinal material, and content of paeonol, gallic acid, and galloylglucose in MC residues were about 1/3 of that in the medicinal material. The content of chemicals were further reduced after residue composting, and the quantitative compounds were all below the limits of detection.(2)Compared with MC residues, the residue compost showed the total nitrogen, total phosphorus, total potassium, and organic matter content increasing by 122.67%, 31.32%, 120.39%, and 32.06%, respectively. Therefore, we concluded that the MC residues can be used to re-extract active compounds such as paeonol, gallic acid, and galloylglucose. The MC residue compost is a high-quality organic fertilizer containing minimal content of chemicals and can be widely used in the cultivation of Chinese medicinal herbs.