Study On Secondary Metabolites From The Flower Of Michelia Alba And Antimicrobial & Antifeedant Activities Of Volatile Oil

Michelia alba DC.is an evergreen tree of the genus Magnolia,which is warm and bitter,as well as have antitussive and turbid properties.Most of researches focus on the analysis of the extracts of the essential oil and the improvement of extraction methods of M.alba.There are few studies on the antimicrobial and antifeedant activity of the essential oil,and the isolation and extraction of compounds from the non-volatile part of M.alba.In this dissertation,the volatile components were extracted by steam distillation and analyzed by GC-MS,the non-volatile components were purified characterized by spectroscopic analysis.The antimicrobial and antifeedant activity of essential oil of M.alba were assayed in a primary screen.The main findings are as follows:1.Extraction of volatile oil from M.alba:The volatile oil was extracted by steam distillation,and the extraction rate was 4.18%.The obtained volatile oil was analyzed by gas chromatography-mass spectrometry and identified through the wiley7n.l standard library.A total of 81 components were detected in the volatile oil of M.alba by GC-MS analysis,and 76 compounds were identified and characterized,including37 terpenoids,17 alcohols,and 6 alkanes.The relative mass fraction of the components was 93.026%of the total peak area.The main components were linalool,caryophyllene oxide,and?-elemene.2.Antimicrobial activity of volatile oil from M.alba:The antibacterial and antifungal activity of volatile oil were evaluated in a primary screen by the disc diffusion assay against four bacteria,Bacillus subtilis ATCC 6633,Staphylococcus aureus ATCC 6538,Escherichia coli ATCC 8099,and Xanthomonas oryzae pv.oryzae RS105,and eight fungi,Penicillium decumbens ATCC 10436,Saccharomyces cerevisiae,Candidaalbicans,Gibberellazeae,Fusariumoxysporum Schl.f.sp.vasinfectum,Fusarium oxysporum,Curvularia lunata?Walk?Boed and Rhizoctonia solani Kühn.The volatile oil of Michelia alba DC.displayed significant activity against Bacillus subtilis ATCC 6633 and Xanthomonas oryzae pv.oryzae RS105 and minor activity against Escherichia coli ATCC 8099 and Staphylococcus aureus ATCC 6538.It also exhibited inhibitory activity against six kinds of fungi including Penicillium officinalis,Candida albicans,Gibberella zeae,soybean root rot pathogen,corn fungal spores,and Rhizoctonia solani.Among them,the extracted oil had the best inhibition effect against Rhizoctonia solani Kühn,and had no inhibitory effecton Fusarium oxysporum Schl.f.sp.vasinfectum and Saccharomyces cerevisiae.3.Antifeedant activity of volatile oil from M.alba:When the concentration was greater than 0.1 m L/mL,the tested insects Mythimna separata did not eat,and the antifeeding rate was close to 100%.When the concentration was less than 0.05mL/mL,the anti-feeding activity fluctuate.4.Extraction and separation of non-volatile components from M.alba:The powdered flower was extracted by methanol,the generated extract was partitioned with petroleum ether,ethyl acetate,and n-butanol,respectively,and concentrated in vacuo to remove the solvent.The resulting materials were subjected to the column chromatography and finally purified by semipreparative HPLC.Fourteen compounds were isolated and their structures were determined by mass spectrometry?MS?,nuclear magnetic resonance spectrum(¹H-NMR and ¹³C-NMR)analysis and comparison of the data with those reported in literatures.The isolates were identified as,parthenolide?1?,1,10-epoxyparthenolide?2?,magnograndiolide?3?,?7S,8S?-3-methoxy-3?,7-epoxy-8,4?-oxyneoligna-4,9,9?-triol?4?,?6-hydroxy-1H-indol-3-yl?oxoacetic acid methyl ester?5?,?1H-indol-3-yl?oxoacetamide?6?,4-methoxy-benzaldehyde?7?,7-hydroxy-5-methoxychromone?7?,3,4-dihydroxybenzoic acid?9?,1H-Indole-3-carboxaldehyde?10?,arteminorin D?11?2-?benzotriazol-1-yl?tetrahydropyrans?12?,bis?2-ethylhexyl?phthalate?13?,diisobutyl phthalate?14?,?-sitosterol?15?.5.Review of the research progress of essential oils and the chemical constituents from the M.alba.This chapter introduces the essential oil traits,extraction,pharmacological activity,and the research on the main chemical components of the M.alba,At the same time,the prospects for the research of the M.alba are discussed.