| 摘要: | 錫蘭七指蕨中含有許多黃酮類化合物，入地蜈蚣素T (1)為錫蘭七指蕨中被發現的微量黃酮類成分，結構中具有一個二氫呋喃環，具有抗發炎活性，目前為止，入地蜈蚣素T尚未有全合成之報導，本論文建立一有效的合成方法合成入地蜈蚣素T與衍生物，並探討這些化合物的抗氧化活性。
以2’,4’,6’-trihydroxyacetophenone為起始物，經由七個步驟製備含二氫呋喃關鍵中間產物1-(6-hydroxy-4-methoxy-2,3,3-trimethyl-2,3-dihydrobenzofuran-5-yl)ethanone 13，再與methyl 3,4-bis((tert-butyldimethylsilyl)oxy)benzoate 16 進行縮合反應得到衍生物22，再經去甲基化反應得到入地蜈蚣素T，使用相似的方法，合成出4個入地蜈蚣素T衍生物23、24、27、28，抗氧化活性是以清除自由基活性試驗分析，檢測結果顯示化合物1、22、27具有抗氧化活性，其活性程度相當於luteolin與維生素E，然而衍生物23、24、28則顯示無活性，此結果表示在化合物1、22、27及luteolin之B環上的兩個羥基對抗氧化活性是重要的部分。
Several flavonoids were found from Helminthostachys zeylanica. Ugonin T (1) was isolated and characterized as a minor component from the rhizomes of Helminthostachys zeylanica. Ugonin T possesses a flavone skeleton containing a dihydrofuran ring. Ugonin T was found to show anti-inflammatory activity. Until now, the total synthesis of ugonin T has not been reported yet. In this thesis, an efficient synthetic method for the total synthesis of ugonin T and analogues was established.
The key intermediate 1-(6-hydroxy-4-methoxy-2,3,3-trimethyl-2,3-dihydrobenzofuran-5-yl)ethanone 13 was prepared from 2’,4’,6’-trihydroxyacetophenone in seven steps. Reaction of 13 with methyl 3,4-bis((tert-butyldimethylsilyl)oxy)benzoate 16 gave analogue 22, followed by demethylation to yield ugonin T. Using the similar manner, analogues 23, 24, 27, and 28 were obtained. The antioxidative activity of synthesized compounds using DPPH method was evaluated. Compounds 1, 22, and 27 showed similar DPPH radical scavenging activity as those of luteolin and -tocopherol (a positive control). However, analogues 23, 24, and 28 showed no activity. The results indicated with the dihydroxyl group of B ring in 1, 22, 27, and luteolin is important for good antioxidative activity. |
