Studies On Components From The Flowers Of Eiobotrya. Japonica L. And Its Biological Activity

Loquat flower is the flower of Eriobotrya japonica which belongs to Rosaseae category. Loquat leaf is a widely used Chinese medicine which has been much studied about its chemical components and biological activities. However, the reports of loquat flower are scarce and there is no report about its components and biological activities. Therefore,the dissertation preliminary study on the chemical components and biological activities of loquat flower.The loquat flower was extracted with systematic solvents, such as ethyl acetate, 95% ethanol, 50% ethanol and water. Flavonoids were identified and their contents determined in those extractives. Flovonoids were mainly contained in the 50% ethanol extractive. They are mainly flavones, flavanols, and flavonvones.In our experiment, the compounds in ethyl acetate extractive of loquat flower were separated and purified with column chromatography on silica gel, C18 and sephadex LH-20 gel, TLC, semipreparative chromatography and recrystallization. Seven components were separated and their structures were identified using NMR and MS and their physical &chemical constants were determined. They areβ-sitostero (l), Oleanic acid (2), Ursolic acid (3), 3β,19α-dihydroxyursolic-4-aldehyde-12-en-28-acid (4),β-daucosteriol (5), quercetin-3-O-α-L-galactoside(6), 2α-hydroxyursolic acid and 2α- maslinic acid (7). Among them, compound 1, 4, 5, 6 and 7 are first time separated from this plant.The antibacterial and antineoplastic effects of the compounds and extractive fractions were measured by Kirby-Bauer and MTT method. Our experiment indicated that the ethyl acetate extractive had poor antibiotic activities on Escherichiacoli and Staphylococcus aureus; compounds and extractive fractions except compound 6 had different antibiotic activities on Candidaabbicans. Compound 2, 4, 5 and 7 were better than the positive comparison. Section E2-2-1 and compound 2, 3, 7 were fairly effective to prohibit leukemia cell K562, the effect depending on their concentration. Compound 3 has an inhibitive rate of 91.96% to leukemia cell K562 in a 20μg/ml concentration. Triperpenoids were discovered as the main anti-tumor active component on K562 in this plant.