Identification Of The Chemical Components Of Pear Peel Using HPLC-MC And NMR Technique

Pear is edible fruit of the shrub species of Rosaceae, Maloideae and Pyrusrich in the family Rosaceae. Pear peels is rich in polyphenol chemicals, which show good anti-bacterial, anti-inflammatory, anti-tumor and some other activities, were deemed to be effective supplementary in the prevention of cardiovascular disease, and are widely used in medicine and health care products. The analytic method of polyphenol chemicals were mainly adapted with high performance liquid chromatography (HPLC) and mass spectrometry, such as quadrupole and/or ion trap mass spectrometer. The quadrupole-time of flight mass spectrometry (Q-TOF MS) has the high resolution, sensitivity, selectivity, and the high accuracy for the wide molecular weight range, and this technique seems have not been used in the chemical identification of pear peels, for no related published paper temporary. In this thesis, high performance liquid chromatography (HPLC)-diode array detector (DAD)-electrospray ionization (ESI)-quadrupole time of flight tandem mass spectrometry (QTOF-MS) and nuclear magnetic resonance (NMR) technology were applied to identification the metabolites of pear peels.The polyphenol compounds in pear peel were qualitatively analyzed by LC-DAD-ESI-MS,25kinds of phenolic compounds was identified. A reversed-phase C18column was used, with gradient elution program using acetonitrile (with0.05%formic acid) and water (with0.05%formic acid) as the mobile phase, the components in the two pear peel extracts were separated well in the chromatogram, the eluents were detected sequentially by ESI-Q-TOF-MS in positive and negative ion mode, spectral data were obtained. The chemicals identification were mainly based on high resolution spectral data, and maxis UV wavelength and related literature. The result demonstrates that HPLC-DAD-ESI-QTOF-MS technique is a simple and effective in the identificaion of phenolic compounds in fragrant pear and snow pear skins.Furthermore, liquid NMR experimental technique was applied in the chemical identification of the snow pear and fragrant pear peel extracts. Based on the analysis of the’H NMR and1H-1H COSY,1H-1H TOCSY,1H-13C HSQC,1H-13C HMBC NMR spectrum, glucose, sucrose, malic acid, caffeic acid, quinic acid and arbutin were abandunt in the peel extracts, and low content flavonoids were also found exist in the extract. Then HPLC-DAD-SPE-NMR experiment was conducted to identify the main flavonids. Based on the1H NMR and’H-’H COSY,1H-13C HSQC,1H-13C HMBC NMR spectrum.5main flavonoids, quercetion-3’-O-rhamnoside-3-O-arabinoglucoside, quercetion-3’-O-rhamnoside-3-O-arabinoglucoside, rutin, luteolin-7-O-glucoside, Isorhamnetin-7-O-glucoside were identified.In this thesis, HPLC-DAD-ESI-QTOF-MS and NMR technique were applied in the chemical identification of the peel of two pears, a total of35chemicals were identified. The result of this research would afford basic data for the comprehensive exploitation and utilization of fruit pear.