| Morus nigra L. is a unique black mulberry germplasm resources in xinjiang and also the only twenty-two ploidy mulberry varieties in domestic.The deteriorated ecological environment and different chromosome multiple resulting either in morphological character and biological feature compared with other regions of mulberry are obviously different, which contains various nutrients and other secondary metabolite production is different from other counterparts of mulberry variety, study on the chemical constituents will be favorable to the research of physiological and biochemical characteristics and resistant mechanism. Normal celluar metabolism process will produce a large number of free radicals which caused the organism aging, therefore, looking for natural and low toxicity antioxidants has became an important part of the research and development of anti-aging functional foods and medicines at present, the study found it has radical scavenging abilities and antioxidant activities.There are many reports about pharmacological activi-ty of the chemical composition from other mulberry varieties at home and abroad, but the Morus nigra L.for free radical scavenging and antioxi-dantactivity components are rarely reported. In this paper with DPPH radical scavenging activity tracking,which studied the Morus nigra L. on antioxidant activity and chemical composition,the contents and results are as follows:1Determination of antioxidant activity parts of the Morus nigra L.In order to fast separate strong antioxidant activity compounds, firstly, in the ways of polyph-enolics and flavonoids contents and DPPH, OH radical scavenging activity and reducing power were screened for antioxidant activity from mulberry organs (branches, leaves),the results showed that the Morus nigra L. branch and leaf ethanolic extract have significant difference (p<0.01). The mass ratio of active ingredients of total polyphenolics and total flavonoids of branches (170.49+1.68mg/g)was significantly higher than that in leaves (31.96±0.73mg/g); DPPH, OH radical scavenging activity of branches(the inhibitory concentration50%of scavenging activity to DPPH and OH free radical were0.52±0.03mg/mL and0.59±0.06mg/mL) is far better than the leaves (the inhibitory concentration50%of scavenging activity to DPPH and OH free radical were0.95±0.01mg/mL and1.17±0.03mg/mL); the reducing power of branches(the reducing power of vitamin C equivalent is58.25±0.04mg/g) is also better than the leaves(the reducing power of vitamin C equivalent is25.33±1.22mg/g). Therefore, Morus nigra L. branch was choosed for antioxidant materials in the further study.The petroleum ether, ethyl acetate, n-butanol and water were applied for extracting the mulberry branch ethanolic extract, and the polyphenolics and flavonoids contents of evey fractions were detected.The yield was2.85%,27.81%,36.63%and31.02%, respectively, the mass ratio of active ingredients of total polyphenolics and total flavonoids was211.75±0.08mg/g,764.27±1.41mg/g,137.66±1.53mg/g and120.18±1.20mg/g, respectively, it showed that the petroleum ether and ethyl acetate extraction fractions had higher antioxidant activity components.TLC-autography was applied to detect the scavenging activity to free radical of mulberry branch ethanolic extract fractions, the results showed that mulberry branch ethanolic extract, petroleum ether extraction fractions,ethyl acetate extraction fractions had obvious white spots TLC plate purple background than n-butanol and residue water phase fractions, it could judge that the petroleum ether and ethyl acetate extraction fractions had higher DPPH free radical scavenging activity. Then tested the antioxidant activity of extraction fractions, the results showed that DPPH and OH radical scavenging activity:ethyl acetate extraction fractions> petroleum ether extraction fractions>n-butanol extraction fractions>residue water phase fractions;the mass ratio of active ingredients of total polyphenolics and total flavonoids was positively related to DPPH and OH radical scavenging activity.Ethyl acetate fractions of DPPH free radical scavenging ability has significant difference with other fractions (p<0.01), and OH free radical scavenging capacity has significant difference(p<0.01) with and n-butanol and water fractions, the reducing power:ethyl acetate extraction fractions>n-butanol extraction fractions>residue water phase fractions>petroleum ether extraction fractions. Therefore, petroleum ether and ethyl acetate extraction fractions were choosed to isolate the antioxidant components.2DPPH radical scavenging activity tracking for seperating antioxidant chemical composition With the separation technology of silica gel, Sephadex LH-20gel column chromatography and recrystallization, the antioxidant chemical composition of petroleum ether and ethyl acetate extrac-tion fractions were isolated.This research established arapid detection and tracking separation met-hods which suitable for the antioxidant activity components of mulberry, namely TLC-autography of DPPH free radical scavenging activity method for combination of separation and purification. The method can be simple, rapid separation of target compounds with antioxidant activity from thousands of compounds in Morus nigra L. branch From18.41g petroleum ether extraction fractions two compounds were isolated, nine compounds were isolated from175g ethyl acetate extraction fractions.TLC-autoradiography, color reaction,nuclear magnetic resonance instrument were applied to determine the eleven compounds with physics and chemistry nature analysis, spectral determination and structural analysis, six compounds structures were determined. They were linolenic acid (fatty acid,31mg), uvaol (three terpenoids,16mg), sanggenon M (flavo-noids,29mg),sanggenon A (flavonoids,18mg), monostearin(esterofglycerol,37mg), isoscopoletin (coumarin,13mg),five unidentified compounds of the two (MN7, MN10) may be sterols, one (M-N8) may be flavonoid, one (MN9) may be lignin compound, one(MN11)may be coumarins. The-se compounds include fatty acids, three terpenes, flavonoids, coumarins,glyceride, lignin, sterols, linolenic acid and isoscopoletin were first seperated from Morus nigra L.branch, isoscopoletin is one of the anti-inflammatory activity materials of Morus nigra L.3Antioxidant activity of monomeric compound from Morus nigra L.With BHT as control, monomer compounds isolated from Morus nigra L.were determined the radical scavenging activity on DPPH,OH and reducing power,the results showed that, linolenic acid (MN1, DPPH:IC50=26.04±0.04u.g/mL, OH:39.47±0.08μg/mL), sanggenon M (MN3, DPPH: IC50=39.87±0.05μg/mL, OH:57.21μ0.09μg/mL), flavonoid (MN8, DPPH:IC50=45.63±0.07μg/mL, OH:59.46±0.04μg/mL), sanggenon A (MN4,DPPH:IC5o=54.54±0.03μg/mL.OH:IC50=80.13±0.02μg/mL), lignin (MN9, DPPH:IC50=57.82±0.02μg/mL, OH:IC50=99.92±0.05μg/mL) and isoscopoleti-n (MN6, DPPH:IC50=61.56±0.07μg/mL,OH:100.20±0.01μg/mL) in the DPPH,OH radical scaven-ging activity and reducing power were higher than that in the control BHT. Each compound has significant difference (p<0.01)with DPPH and OH free radical of scavenging activity. Through the research, finding a series of good scavenging free radicals antioxidant constituents from the Morus nigra L., which laid the foundation for Morus nigra L.of further exploration research and utiliza-... |
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