Chemical Composition Isolation Of Malus Melliana Leaves And Antimicrobial, Antioxidant Activity Research Of Its Extract

In present study, a variety of chromatographic processes, structure elucidationmethods and AB-8macroporous absorbent resin technology have been used toinvestigate the chemical constituents of TCM in order to provide definite theoreticalbasis for the further physiological avtivities (antibacterial activity and antioxidantactivity) study of Malus melliana leaves. The main contents of present study are asfollows:①Malus melliana leaves has been reported to possesses antibiosis, antioxidant,antitumor activities and liver protection. The chemical components of Malus mellianaleaves, however, have not been systematically investigated. Flavonoids, terpenes,organic acids, steroids and saponins compounds have been found by a series ofchemical qualitative experiments. The present study conducted the first phytochemicalresearch of Malus melliana leaves and led to the isolation of nine known compounds.By using physical-chemical data and spectra data, these nine compounds are identifiedas follows: β-sitosterol (1), daucosterol (2), oleanolic acid (3), ursolic acid (4), arjunolicacid (5), chrysin (6), phlorizin (7), trilobatin (8) and isoetin5′-glucoside (9). All thecompounds were isolated from Malus melliana leaves for the first time. Among them,compound5was isolated from the genus of Malus for the first time and compound9was isolated from the family of Rosaceae for the first time. In addition, phlorizin andtrilobatin (approximately5.3‰and3.3‰, respectively) were considered as the mainchemical constituents of this plant according to calculation (quality of compound/quality of Malus melliana leaves). This research was significant for plant systematics ofMalus melliana leaves.②The present study reported Malus melliana leaves total flavonoids were enrichedand purified by AB-8macroporous resin. According to content of flavonoids, AB-8macroporous resin were used to make an on-the-spot investigation onabsorption-desorption time、absoring capacity、absorption temperature and desorptionethanol concentration. After the treatment with AB-8resin and parameter optimization,the amount of total flavonoids from Malus melliana leaves in the product increased torecovery yields of91.77%, and the enrichment ratio was75.26%. The results wereexpected to present certain material base for physiological activities study of totalflavonoids from Malus melliana leaves. ③The present study performed the antibacterial activity study of Malus mellianaleaves extract by using Bacillus subtilis, Escherichia coli and Staphyloccocus aureu.Malus melliana leaves total flavonoids presented the much higher antibacterial andactivity than90%ethanol crude extract. Consequently, flavonoids were responsible foractive ingredients, possibly. It was meaningful that Malus melliana leaves totalflavonoids were enriched and purified by AB-8macroporous absorbent resin technology.Besides, the antioxidant properties of Malus melliana leaves crude extract, totalflavonoids and four compounds (chrysin, phloridzin, trilobatin and isoetin5′-glucoside)were evaluated using the DPPH radical scavenging activity and ferric reducingantioxidant power (FRAP) assay. Purified total flavonoids presented the much higherantioxidant activity than crude extract. Isoetin5′-glucoside showed strong antioxidantactivities, both its DPPH-scavenging activity and reducing power were better than thoseof standard (ascorbic acid). The present study was expected to present certain theoreticbasis for developing flavonoids of Malus melliana leave as an inexpensive, natural andreadily available source of dietary antioxidants with remarkable benefits for human oranimal health instead of synthetic ones included in foods.