Studies on Chemical Constituents and Antioxidant Activity of Eriobotrya japonica L. The medicinal material of Eriobotrya japonica L. is the dry aboveground part of Ficus tikoua Bur. It is widely distributed in Hubei, Yunnan, Guizhou, Guangxi, Sichuan, Xizang and other places in China. Diloquat is a national medicine widely used by Yi, Zhuang, Miao, Hani and other ethnic minorities. It is a traditional medicinal material of Miao in Guizhou, and a common medicine of Yi, Hani and other ethnic minorities in Yunnan. It has a long medicinal history and is a unique local herbal medicine. This medicinal herb was first recorded in the book “Dian Nan Ben Cao” (1977) written by Lan Mao in the early Ming Dynasty. The “National Compilation of Chinese Herbal Medicines” records that its main functions are clearing heat, removing dampness, promoting blood circulation, and detoxifying. In the 2018 edition of the Quality Standards for Traditional Chinese Medicine in Hubei Province, which our research group participated in compiling, the characteristics and identification methods of loquat were detailed. At the same time, its functions of clearing heat and detoxifying, clearing lungs and stopping cough, moistening dryness and stopping diarrhea were also recorded.
According to domestic and foreign literature records, the chemical components of loquat mainly include flavonoids, steroids, coumarins, triterpenes, etc. There is relatively little modern pharmacological research on this medicinal herb, mainly focusing on its antibacterial and tyrosinase activity effects. In addition, Yang et al. used the DPPH method to determine the antioxidant activity of loquat extracts and different solvent extracts, and found that their ethyl acetate extract and n-butanol extract both have good DPPH free radical scavenging ability. Based on this, this study comprehensively evaluated the antioxidant activity of compounds isolated from this medicinal herb using three antioxidant activity evaluation methods: DPPH free radical scavenging ability, total antioxidant capacity determination, and superoxide anion scavenging ability. It is expected to provide some guidance for the development of natural antioxidants. Reference value.

The excessive free radicals produced in the human body can attack biomolecules such as lipids, proteins, and DNA, disrupt the normal structure of cells, interfere with normal metabolic activities, and cause diseases and accelerate human aging. Therefore, it is necessary to search for exogenous antioxidants to maintain normal metabolism in the human body. Natural antioxidants have gradually entered the field of researchers due to their low toxicity and high efficiency.
This study isolated and identified 17 compounds from loquat, a folk medicine of the Tujia ethnic group, including flavonoids, coumarins, lignans, polyphenols, and other structural types. Due to the diversity and complexity of antioxidant experiments, it is usually required to use two or more antioxidant activity methods to determine antioxidant activity. This experiment conducted a simple activity assay on compounds isolated from loquat by measuring their DP-PH clearance rate, total antioxidant capacity, and superoxide anion scavenging capacity. It was found that lignans, polyphenols, and phenolic acid compounds have strong antioxidant activity, even exceeding the antioxidant capacity of positive controls at the same concentration. This indicates that lignans and polyphenolic compounds in loquat may serve as the basis for its antioxidant activity and pharmacological properties. This study further enriched the chemical composition and pharmacological activity of loquat, suggesting that loquat may have great potential to be developed as a natural antioxidant, laying the foundation for the development and utilization of folk medicine loquat in the Tujia ethnic group.