Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/50829
DC FieldValueLanguage
dc.contributor.advisorGow-Chin Yenen_US
dc.contributor.advisor顏國欽zh_TW
dc.contributor.authorChuang, Da-Yonen_US
dc.contributor.author莊大永zh_TW
dc.date1998zh_TW
dc.date.accessioned2014-06-06T08:53:06Z-
dc.date.available2014-06-06T08:53:06Z-
dc.identifier.urihttp://hdl.handle.net/11455/50829-
dc.description.abstract本研究主要探討不同焙炒程度對決明子(Cassia tora L.)水萃取物抗氧化 性的影響,並探討決明子中成分anthraquinones的抗氧化特性,以及不同 焙炒程度決明子之水萃取物對生物分子的影響。在不同焙炒程度對決明子 水萃取物抗氧化性影響方面,結果顯示,未焙炒決明子之水萃取物於0.2 mg/ml時可抑制94% 亞麻油酸的自氧化,高於a-tocopherol (82%);以175 ℃焙炒80分鐘及200℃焙炒5分鐘的樣品於相同條件下其抑制率分別為83% 與82%,顯示過長時間或過高溫焙炒會降低其抗氧化性。未焙炒決明子之 水萃取物於Fenton reaction誘導liposome氧化系統中IC50為0.41 mg/ml ,優於 a -tocopherol IC50=0.55 mg/ml。未焙炒決明子之水萃取物於 microsome酵素性及非酵素性氧化系統中,同樣具有良好的抗氧化性。焙 炒後決明子其水萃取物褐變程度增加,並產生化學發光,游離胺基酸、總 多酚類含量下降。因此推測決明子之水萃取物隨焙炒程度的增加,其所生 成的梅納褐變產物裂解成不具抗氧化性的氧化產物,同時具抗氧化性的多 酚類含量減少,使得抗氧化能力降低。Anthraquinones為決明子中的主要 成分。在探討數種決明子中anthraquinones及anthrone之抗氧化特性方面 ,以硫氰酸鐵法,在系統濃度0.2 mg/ml下,anthrone可抑制95 %亞麻油 酸自氧化,與BHA (96%)相當。其餘樣品抗氧化性為alizarin (93%) > aloe-emodin (78%) > rhein (71%) > emodin (36%) > anthraquinone (8%),chrysophanol則會促進亞麻油酸的自氧化。Anthrone及alizarin具 較強還原力,其餘anthraquinones則不具還原力。Anthraquinones 及 anthrone螯合Fe2+效果皆不佳,並不能在抗氧化性上提供貢獻。Alizarin 在0.2 mg/ml時可完全清除過氧化氫,顯示其可清除活性氧。在系統濃 度0.25 mg/ml,anthrone、aloe-emodin及emodin分別可清除26.2% 、16.6% 及41.8%由Fenton reaction所產生氫氧自由基(OHh)。 Anthraquinone、alizarin、chrysophaol及rhein則會促進氫氧自由基( OHh)生成。因此推測emodin、aloe-emodin之抗氧化能力主要為清除自由 基;alizarin之抗氧化性為其還原力及清除活性氧;anthrone可清除自由 基及具還原力使其抗氧化性較佳;chrysophanol則會促進自由基的生成, 而具促氧化性。在不同焙炒條件之決明子,其水萃取物對DNA、 deoxyribose及DNA鹽基氧化傷害的影響方面。結果顯示,單獨添加決明子 水萃取物會對DNA造成輕微斷裂,其中以150℃焙炒的決明子之水萃取物傷 害性較大。在Fe3+/H2O2存在下,決明子水萃取物則會促進DNA的氧化傷害 ,其中樣品濃度為2 mg/ml時DNA斷裂情形較強,但隨濃度提高至10 mg/ml 時,DNA斷裂程度則降低。在Fe2+/H2O2存在下,決明子水萃取物可抑制 DNA的氧化傷害,顯示決明子水萃取物可清除Fe2+/H2O2所產生的活性氧。 在以Fe3+-EDTA/H2O2誘導去氧核醣的氧化系統中,加入的決明子水萃取物 在濃度低於0.2 mg/ml時,會促進去氧核醣的氧化,但隨樣品濃度的提高 ,其促氧化性則逐漸降低。在Fe3+-EDTA/H2O2/ascorbic acid誘導去氧核 醣的氧化系統中,則可抑制去氧核醣的氧化作用,顯示決明子水萃取物在 不同誘導氧化系統中會呈現促氧化或抗氧化的結果。同樣以Fe3+-EDTA/H2 O2誘導2*-deoxyguanosine (2*-dG)氧化傷害,不論有無加入抗壞血酸, 決明子水萃取物皆會促進2*-dG氧化生成8-OH-2*-deoxyguanosine (8-OH-2*-dG),其促氧化性大小為未焙炒 > 150℃, 5 min> 200℃, 5 min > 250℃, 5 min。這可能是因其具有多量的anthraquinones glycoside,未焙炒樣品anthraquinones glycoside含量較高(88mg/g), 焙炒後含量會減少,使其促氧化性下降。決明子水萃取物具有抗氧化及促 氧化的兩種結果,可能是其同時具有還原金屬離子、清除氫氧自由基及螯 合亞鐵離子等抗氧化特性。zh_TW
dc.description.abstractThe objects of this research were to investigate the effects of different roasting degrees on the antioxidant properties of water extracts from Cassia tora L. (WECT), and the antioxidant properties of anthraquinones and anthrone, and the effects of WECT on oxidative damage to deoxyribose, DNA and DNA base in vitro.The antioxidant properties of WECT prepared under different degrees of roasting were investigated. The water extracts of unroasted Cassia tora L. (WEUCT) showed 94 % inhibition of peroxidation of linoleic acid at a dose of 0.2 mg/ ml, which was higher than that of a-tocopherol (82%). Water extracts prepared from Cassia tora L. roasted at 175 ℃for 5 min and at 200℃for 5 min exhibited 83% and 82%, respectively, inhibition of linoleic acid peroxidation. This result indicated that the antioxidant activities of WECT decreased with longer roasting time or higher roasting temperature. The IC50 of WEUCT in liposome oxidation induced by Fenton reaction was 0.41 mg/ml, which was higher than that of a-tocopherol (IC50=0.55 mg/ml). WEUCT also exhibited good antioxidant activity in enzymatic and nonezymatic microsome oxidative systems. The water extracts of roasted Cassia tora L. increased with the degree of browning and produced chemiluminescence when compared with the unroasted sample. However, the total polyphenolic compounds of WECT decreased after the roasting process finished. In conclusion, the decreased in the antioxidant activity of water extracts from roasted Cassia tora L. might have been due to the degradation of Maillard reaction products and the decreased of polyphenolic compounds.Anthraquinones are the major compounds found in Cassia tora L. The antioxidant properties of anthraquinones (AQs) and anthrone were evaluated using different model systems. The antioxidant activity of these compounds (200 ppm) on the inhibition of peroxidation of linoleic acid were found to follow the order BHA (96%)≒anthrone (95%)≒alizarin (93%) > aloe- emodin (78%) > rhein (71%) > emodin (36%) > anthraquinone (8%). Chrysophanol accelerated the peroxidation of linoleic acid. Anthrone and alizarin exhibited a reducing power, but the other AQs did not show any reducing power. AQs and anthrone exhibited a weak chelating ability on iron(II). Alizarin completely scavenged hydrogen peroxide at a concentration of 0.2 mg/ml. At a concentration of 0.25 mg/ml, anthrone, aloe-emodin and emodin exhibited 26.2, 16.6 and 41.8% scavenging effects, respectively, on hydroxyl radicals produced by the Fenton reaction. However, anthraquinone, alizarin, chrysophanol and rhein accelerated the production of hydroxyl radicals at the same concentration. These results suggested that the antioxidant mechanism for emodin and aloe-emodin is most likely due to scavenge free radicals. The strong antioxidant activities showed by anthrone and alizarin could be due to their reducing power and scavenging effects on reactive oxygens. The prooxidant activity exhibited by chrysophanol might be due to enhanced the production of free radicals. The effects of WECT on oxidative damage to deoxyribose, DNA and DNA base in vitro were investigated. WECT alone caused a slight strand-breaking of DNA. In the presence of Fe3+/H2O2, WECT accelerated the strand-breaking of DNA under the concentration of 2 mg/ml, but it decreased with an increasing concentration of WECT. WECT inhibited oxidative damage to DNA induced by Fe2+/H2O2, perhaps due to scavenge reactive oxygen species. WECT accelerated the oxidation of deoxyribose induced by Fe3+-EDTA/H2O2 under a concentration of 0.2 mg/ml, but inhibited the oxidation of deoxyribose induced by Fe3+-EDTA/H2O2/ascorbic acid. WECT also caused the oxidation of 2*-deoxyguanosine (2*-dG) to form 8-OH-2*-dG induced by Fe3+- EDTA /H2O2. The prooxidant action of WECT on the oxidation of 2*-dG was in the order of unroasted > roasted at 150℃ > roasted at 200℃> roasted at 250℃. The decrease in prooxidant activity of roasted sample might be due to the reduction of its anthraquinone glycoside content after roasting. WECT exhibited either prooxidant or antioxidant property in the model system that was dependent on the ability of reducing metal ions, scavenging hydroxyl radical and chelating ferrous ion.en_US
dc.language.isoen_USzh_TW
dc.publisher食品科學系zh_TW
dc.subject決明子zh_TW
dc.subjectanthraquinonesen_US
dc.subject抗氧化性zh_TW
dc.subject焙炒程度zh_TW
dc.subject促氧化性zh_TW
dc.subjectDNAen_US
dc.subjectCassia tora L.en_US
dc.subjectantioxidant activityen_US
dc.subjectroasting degreeen_US
dc.subjectanthraquinonesen_US
dc.subjectprooxidanten_US
dc.subjectDNAen_US
dc.titleAntioxidative properties of water extracts from jue ming zi (Cassia tora L.) prepared under different degrees of roastingen_US
dc.title不同焙炒程度決明子之水萃取物抗氧化特性之研究zh_TW
dc.typeThesis and Dissertationzh_TW
item.openairetypeThesis and Dissertation-
item.fulltextno fulltext-
item.cerifentitytypePublications-
item.grantfulltextnone-
item.openairecristypehttp://purl.org/coar/resource_type/c_18cf-
item.languageiso639-1en_US-
Appears in Collections:食品暨應用生物科技學系
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