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Coumarin is an important class of natural organic compounds, which widely exists in a variety of plants and microorganisms. Coumarins have many biological activities and wide clinical applications, such as anti-tumor, anti-HIV, anti-bacterial, anti-inflammatory, anti-oxidation, anti-coagulation, but they have obvious toxic effects in rodents. It was found that the toxicity of coumarins in different animals and organs was significantly different, and high dose oral administration was more likely to produce toxic reactions. Based on the research and analysis of domestic and foreign literatures in recent 60 years, this paper mainly summarized the hepatotoxicity and pulmonary toxicity induced by coumarins, and probed into their possible mechanisms. It was found that the toxicity of coumarins had metabolic differences and species differences. The liver of rats and lungs of mice were more susceptible to coumarins. Toxic reactions occurred mainly in the second metabolic pathway of coumarin metabolism in vivo. In order to put forward safety considerations and evaluate the impact of coumarin on human body, it was found that coumarin is unlikely to produce hepatotoxicity at normal exposure level. It was also suggested that species differences due to different metabolic patterns in model animals should be carefully considered when assessing coumarin toxicity, in order to provide reference for clinical research and rational use of coumarins and improve the rational use of coumarins.

This paper aimed to study the effect nitrogen supplying on biomass accumulation and root respiration dynamic change of Glycyrrhiza uralensis and reveal the metabolic pathway of root respiration impact the biomass accumulating of G. uralensis. Six groups of one-year-old G. uralensis were fertilized with total nutrition containing various nitrogen concentration (0, 0.5, 1, 2, 4, 8 mmol x L(-1)) every week. At the end of every month, from June to October, the volume respiration rate and biomass of different classes of root samples were determined, and the correlation between root respiration and biomass was analyzed. The results indicated a negative correlation between volume respiration rate and biomass, nitrogen supply significantly affected both root respiration and biomass of G. uralensis by reducing root respiration and increasing root biomass. Under 8 mmol x L(-1) nitrogen supplying, there existed the optimal inhibition of root respiration, which has increased biomass of G. uralensis.