| 摘要: | 火炭母草 (Polygonum chinensis L.，PC，屬蓼科) 在台灣民間常用於發燒、扁桃腺炎及腹瀉等疾病之治療。本研究之主要目的為利用DPPH (2,2-diphenyl-1-picrylhydrazyl) 自由基清除能力試驗、Trolox當量抗氧化能力試驗及總酚含量測定試驗等三個篩選平台，以活性目標分離方式進行分離火炭母草之抗氧化活性成分。在台灣採集PC全草，經陰乾後，以水及95% 乙醇進行萃取，得到PCW (水萃取物) 及PCE (乙醇萃取物) 二種萃取物。並將此兩種萃取物分別經由DPPH自由基清除能力試驗、Trolox當量抗氧化能力試驗及總酚含量測定試驗，結果顯示，PCW的抗氧化能力較高。因此，再以水進行 PC之大量 (680g) 萃取，所得到之水萃取物 (PCW) 分別以二氯甲烷、乙酸乙酯及正丁醇等三種溶媒做分配萃取，除了分別可得到二氯甲烷層萃取物 (PCWC)、乙酸乙酯層萃取物 (PCWA)、正丁醇層萃取物 (PCWB) 及水層萃取物 (PCWW) 等四層萃取物外，另外也可得到乳化層萃取物 (PCWE)及沉澱物層萃取物 (PCWP)。將這六層不同的分配萃取物進行DPPH自由基清除能力、Trolox當量抗氧化能力及總酚含量測定試驗後，結果顯示，PCWA萃取層具有最佳抗氧化能力。PCWA萃取層再經由管柱層析分離，可獲得PCWA 1~6六個分層，將此分層進行抗氧化能力試驗，其結果顯示，PCWA 2分層為具有最佳抗氧化能力。PCWA 2 (190.7 mg) 分層經由再結晶及各種光譜分析，及與標準品比對構造鑑定為Gallic acid。
Polygonum chinensis L. (PC, Polygonaceae) has been used as a folk medicine in Taiwan to treat infection related symptoms such as the fever, tonsillitis and diarrhea. The aim of this study is to isolate the antioxidant constituents from PC according to the activity-guided isolation process. DPPH radical scavenging ability, Trolox equivalent antioxidant capacity and total phenol contents were applied as screening platforms. The dry herbs of PC were collected in Taiwan. The PC was extracted with H2O and 95% EtOH to obtain PCW and PCE extract, respectively. The two layer extracts were determined by DPPH radicals scavenging ability, Trolox equivalent antioxidant capacity and total phenolic contents, and the results showed that the most potent antioxidant layer was H2O extract. A large amount (680g) of PC was extracted with H2O, and obtained PCW extract. PCW was then partitioned with CH2Cl2, EtOAc, n-BuOH and H2O solvents, respectively, to obtain extracts. Emulsion layer and precipitation layer extracts were also collected. The six different partitioned extracts were evaluated by DPPH radical scavenging ability, Trolox equivalent antioxidant capacity and total phenol contents. The results indicated that EtOAc layer extract (PCWA) had the strongest antioxidant activity. PCWA extract was subjected a column chromatography and six fractions, PCWA1～6, were collected. The antioxidant activity assays of the six fractions were evaluated. The results all demonstrated that Fraction 2, PCWA 2, exhibited the most effective antioxidant activity. After recrystalization of PCWA 2, it was elucidated to be gallic acid (190.7 mg) using spectroscopic analysis and comparing with authentic sample of gallic acid. |
