- Br?nsted acid-induced transannulation of the phytochemical zerumbone
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The sesquiterpene zerumbone was treated with HCl in ethyl acetate under the light-protected condition, and the time-dependent conversions were analyzed by gas chromatography. Nine products were isolated, and their structures were revealed by several NMR m
- Kashiwazaki, Gengo,Kawai, Yasushi,Kitamura, Yuto,Kitayama, Takashi,Nishikawa, Atsuya,Ohtomo, Satoru,Tsuchida, Noriko,Tsuzuki, Terutaka,Utaka, Yoshimi,Watanabe, Ryo,Yamamoto, Chieko,Yoshikawa, Tomomi
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p. 10444 - 10454
(2021/12/17)
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- A short-chain dehydrogenase involved in terpene metabolism from Zingiber zerumbet
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The rhizome oil of Zingiber zerumbet Smith contains an exceptionally high content of sesquiterpenoids with zerumbone, a predominating potential multi-anticancer agent. Biosynthetic pathways of zerumbone have been proposed, and two genes ZSS1 and CYP71BA1 that encode the enzymes catalyzing the first two steps have been cloned. In this paper, we isolated a cDNA clone (ZSD1) that encodes an alcohol dehydrogenase capable of catalyzing the final step of zerumbone biosynthesis. ZSD1 has an open reading frame of 804 bp that encodes a 267-residue enzyme with a calculated molecular mass of 28.7 kDa. After expression in Escherichia coli, the recombinant enzyme was found to catalyze 8-hydroxy-α-humulene into zerumbone. ZSD1 is a member of the short-chain dehydrogenase/reductase superfamily (SDR) and shares high identities with other plant SDRs involved in secondary metabolism, stress responses and phytosteroid biosynthesis. In contrast to the transcripts of ZSS1 and CYP71BA1, which are almost exclusively expressed in rhizomes, ZSD1 transcripts are detected in leaves, stems and rhizomes, suggesting that ZSD1 may also be involved in other biological processes. Consistent with its proposed flexible substrate-binding pocket, ZSD1 also converts borneol to camphor with Km and k cat values of 22.8 μm and 4.1 s-1, displaying its bisubstrate feature.
- Okamoto, Sho,Yu, Fengnian,Harada, Hisashi,Okajima, Toshihide,Hattan, Jun-Ichiro,Misawa, Norihiko,Utsumi, Ryutaro
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experimental part
p. 2892 - 2900
(2012/04/11)
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- The chemistry of zerumbone. Part 5: Structural transformation of the dimethylamine derivatives
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Zerumbone (1) and its 6,7-epoxide (2) react with ammonia and dimethylamine regio- and stereospecifically, affording monoamines 3, 4, 7 and 8. All adducts have the same relative configuration at C2 and C3. The conjugate amination is thermodynamically controlled to arrive at a single diastereomer. At 15°C 7 reacts with cyanide to give aminonitrile 10 as the single product, while at 30°C, acyclic aminonitrile 11 is also formed. The reaction with 8 affords at 0°C bicyclic aminonitrile 12 of the asteriscane skeleton, while at 30°C or higher temperature, mixtures of 12 and tricyclic nitriles 13 and 13′ are obtained. Refluxing of 7, 8 and 10 in aqueous acetonitrile promotes scission of the zerumbone ring by retro-Mannich reaction to provide acyclic aldehydes 16-18, respectively. The dimethylamino group of 7, 8 and 10 is eliminated stereospecifically by Cope- and base-catalyzed eliminations to regenerate the zerumbone skeleton in the products 1, 2 and 21. Cope elimination of 12 results in a mixture of 13 and 13′ by deaminative transannular etherification.
- Kitayama, Takashi,Yokoi, Taketo,Kawai, Yasushi,Hill, Richard K.,Morita, Masanori,Okamoto, Tadashi,Yamamoto, Yukio,Fokin, Valery V.,Sharpless, K. Barry,Sawada, Seiji
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p. 4857 - 4866
(2007/10/03)
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- CONVERSION OF HUMULENE TO ZERUMBONE
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Humulene was first converted to zerumbone through a sequence of chemical reactions.
- Shirahama, Haruhisa,Chhabra, Baldev R.,Matsumoto, Takeshi
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p. 717 - 718
(2007/10/02)
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