| Elaeagnus angustifolia L. also be named as salix argyracea, is one of defoliation trees or shrubs in Elaeagnaceae, and the height of it is4-15m. It mainly distributes in North China and the northwest area in China, and their distribution center is the desert or the half-desert. E. anqustifolia is not only an excellent tree which can prevent hurricane, stabilize sand and preserve the water and sand but also an economic tree. All parts of the species are highly valued for they are widely used in food, medicine, papermaking, forage grass, timber, furniture, and so on. However, chemical constituents and bioactivities of the tree are still far from fully investigated.This study was carried out to investigate the antioxidant and antibacterial activities of the extracts from of E. angustifolia fruit, bark, wood. Volatile constituents, total phenolic contents, total flavonoids and total tannins of the crude extracts and efficient fractions were also studied in this work. Under activity-guided screening, chemical constituents of E. angustifolia bark were extensively isolated and elucidated.About5kg of each of the dried sample of species was ground, extracted with ethanol-H2O (95:5, v/v) for more than tree days at room temperature, concentrated under reduced pressure and successively fractionated using n-hexane. CH2Ck2, EtOAc, BuOH and H2O on a separation funnel. Finally, each fraction was freeze dried.The results of antibacterial activity showed that all fractions and extracts of E. angustifolia exhibited certain extent of inhibition activity against the four bacteria. The results also indicated that the antibacterial activity showed a dose-dependence trend. Inhibitory capacity from strong to weak as follows:EtOAc fraction, n-BuOH fraction,95%EtOH extract, aqueous fraction CH2Cl2fraction, and n-hexane fraction.In this study, we additionaly undertook a phytochemical investigation of E. angustifolia by gas chromatographic and mass spectrometric (GC-MS) analysis. Results showed that E. angustifoli contained a lot of different volatile components.The total flavonoid. phenolic, tannin contents of each part was determined by UV spectrophotometry method. The results showed that total flavonoid contens of E. angustifolia bark, wood and fruit were around37.0mg/g,14.3mg/g and1.6mg/g, respectively. Total phenolic contens of E. angusiifolici bark, wood and fruit were around51.7mg/g.27.8mg/g and50.7mg/g. respectively. Total tannin contens of E. angustifolia bark, wood fruit were around36.1mg/g,27.4mg/g and45.0mg/g, respectively. This study indicated that flavonoid, phenolic, tannin contents in different parts of Elaeagnus angustifolia varied considerably.EtOAc soluble powders of E. angustifolia bark were chromatographed on a Sephadex LH-20column using a serious of aqueous MeOH and EtOH-hexane as washing solvents to get8pure compounds. The structures of the compounds were elucidated as (1-8):(+)-catechin (1),(-)-epicatechin (2),(+)-gallocatechin (3),(-)-epigallocatechin (4), caffeic acid (5), luteolin (6), kaempferol (7), and quercetin (8) using spectroscopic analysis such as NMR and MS, including cellulose TLC and other physical and chemical evidences. |
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