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|Section2= |Section3= }} (+)-Costunolide is a naturally occurring sesquiterpene lactone, first isolated in ''Saussurea costus'' roots in 1960.〔 It is also found in lettuce.〔 ==Synthesis== It is synthesized through the mevalonate pathway, seen in Figure 1. The synthesis begins with the cyclization of compound 1, farnesyl pyrophosphate (FPP), which is mediated by a sesquiterpene cyclase, (+)-germacrene A synthase, to form compound 2, (+)-germacryl cation. Inside this same enzyme, a proton is lost to form 3, (+)-germacrene A.〔 〕 The isoprenyl side chain of (+)-germacrene A is then hydroxylated by (+)-germacrene A hydroxylase, which is a cytochrome P450 enzyme, to form 4.〔 NAD(P)+ dependent hydrogenase(s) then oxidize 4, germacra-1(10),4,11(13)-trien-12-ol, through the intermediate 5, germacra-1(10),4,11(13)-trien-12-al to form compound 6, germacrene acid. The cyctochrome P450 enzyme, (+)-costunolide synthase, which is a NADPH and O2 dependent enzyme, then oxidizes germacrene acid to give the alcohol intermediate, 7, which then cyclizes to form the lactone 8, (+)-costunolide.〔 〕 Figure 1. Biosynthesis of (+)-Costunolide.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Costunolide」の詳細全文を読む スポンサード リンク
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