| Pomegranate flower is rich in active substances with high health care and medicinal value. In recent years, resources development of pomegranate flowers has received extensive attention. In this paper, the technology of ultrasonic extraction for the main secondary metabolites in pomegranate flower was established. The biological activities and the main secondary metabolites of different organs of pomegranate flower were compared. Seasonal changes of active components and the biological activities on the active components were studied. Some unknown components of flavonoids from pomegranate flowers were isolated and analyzed. And we analyze the main components of volatiles substances of the pomegranate flower. The main results are as follows:(1) In order to explore the optimum conditions of ultrasonic-assisted extraction of flavonoids from pomegranate flower, the orthogonal experiment was performed with1:60(g/mL) ratios of pomegranate rind and the solvent. The result was as follow:50%ethanol solution as solvent, ultrasound power80W, temperature40℃and extracting for50minutes. Under the conditions, the extraction quantity was58.32mg/g DW. Compared with the conventional soaking method, ultrasonic assisted extraction method has short term and higher efficiency.(2) An ecofriendly ultrasonic-assisted extraction (UAE) technique was developed for rapid extraction of bioactive compounds oleanolic and ursolic acids from pomegranate flowers. Several different influential extraction parameters such as ultrasonic power, extraction time, solvent types, aqueous ethanol concentration, loading ratio and extraction temperature were investigated. The optimum extraction conditions were90%ethanol solution as solvent, ultrasound power150W, the liquid:material ratio of20:1(v/w) and extraction for50min at40℃. Scanning electron microscopy showed that ultrasonic treatment resulted in a number of pits on cells of pomegranate flowers. Extracts obtained from30min of UAE showed higher antioxidant activity than those of other conventional methods. The UAE method was more efficient than classical methods included maceration, stirring extraction and heat reflux extraction.(3) Pomegranate flowers are important sources of bioactive compounds. Twenty four cultivars of pomegranate flowers grown in China were assessed for their phytochemical concentrations and antioxidant activity. The results revealed that total phenolic (61.62-133.84mg/g DW), flavonoid (14.77-54.56mg/g DW), monomeric anthocyanin pigment (0.42-7.05mg/g DW), and triterpenoid concentrations and antioxidant activities were different among the pomegranate cultivars. Pomegranate flower was rich in oleanolic acid (1.00-3.37mg/g DW) and ursolic acid (1.92-13.18mg/g DW). Total phenolic concentration was positively correlated with antioxidant activity. The results of this study indicate that the antioxidant activity of pomegranate flowers can be enhanced by cultivar selection, which provide valuable information for choosing the cultivars with potentially high health value so that the food supplement and functional food industries, as well as breeders, can benefit.(4) The results of the HPLC analysis of Phenolic acids in pomegranate flowers as follow: the content of ellagic acid from pomegranate flowers is higher, and the pomegranate flowers in May have the highest content of ellagic acid, the flowers of Damaya, dahongpao and Gangliu pomegranate which containd ellagic acid can be used as a natural resource materials or as the resources of the crude drug; There are large differences of the contents11kinds of phenolic acids in pomegranate flowers. According to the type of the phenolic acids, we can be targeted to select relevant varieties breeding and cultivation, has reached the pomegranate flowers the best use of resources.(5) Separation by a high performance liquid chromatography-mass spectrometry (HPLC-MS) technology and nuclear magnetic resonance (NMR) technology types for the identification of the flavonoids and components, providing theoretical basis for the development and utilization of the pomegranate flowers.By reverse phase HPLC and gel column chromatography technology for the first time from pomegranate flower of raw flavonoids ingredients, through infrared spectrum, mass spectrometry, nuclear magnetic resonance spectrum analyzing its structure identification, but also need further analysis of the experimental data.(6) The GC-MS analysis on the volatiles components of Qingpitian pomegranate flowers were proceed. Pomegranate flowers detected40kinds of volatiles components; the mainly includes various alcohols, esters, aldehydes, ketones, alkanes and substances such as terpenes class, and got the percentage content of each component relative amount. For the further research and development of pomegranate flowers laid a foundation. |
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