- Biotransformation of cycloartane-type triterpenes by the fungus Glomerella fusarioides
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Biotransformation of three cycloartane-type triterpenes, cycloartenol (1), 24-methylenecycloartanol (2), and cycloartenone (3), by the fungus Glomerella fusarioides was studied. Compound 1 was converted to 3, cycloart-25-ene-3β, 24-diol (4), and cycloartane-3β,24,25-triol (5). Compound 2 was metabolized to cycloeucalenol (6) and two new compounds, 24-methylcycloartane-3β,24, 241-triol (7) and 241-methoxy-24-methylcycloartane- 3β,24-diol (8). Compound 3 was converted into two new metabolites, 4α,4β,14α-trimethyl-9β,19-cyclopregnane-3,20-dione (9) and 25-hydroxy-24-methoxycycloartan-3-one (14), and four known compounds, viz., cycloartane-3,24-dione (10), 24-hydroxycycloart-25-en-3-one (11), (23E)-25-hydroxycycloart-23-en-3-one (12), and 24,25-dihydroxycycloartan-3-one (13). The structures of four new metabolites, 7, 8, 9, and 14, were established by spectroscopic methods.
- Akihisa, Toshihiro,Watanabe, Kenji,Yoneima, Risa,Suzuki, Takashi,Kimura, Yumiko
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p. 604 - 607
(2008/09/20)
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- Microwave assisted acetylation and deacetylation studies on the triterpenes isolated from Dysoxylum malabaricum and Dysoxylum beddomei
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Phytochemical investigations on the leaves of Dysoxylum malabaricum and Dysoxylum beddomei result in the isolation of a number of triterpenes. Acetylation and deacetylation studies on some of the representative triterpenes show appreciable rate enhancement and increase of yield in the presence of microwave radiation. Details of isolation of triterpenes, acetylation and deacetylation procedures and their results form the subject of the paper. Triterpenes of three skeletal types namely lupane, tirucallane and cycloartane are examined. All the triterpenes examined indicate an increase of cytotoxicity with acetylation.
- Jayakumar,Ajithabai,Santhosh,Veena,Nairt, Mangalam S.
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p. 429 - 431
(2007/10/03)
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- Cytotoxic triterpenoids from the leaves of Euphorbia pulcherrima
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Two cytotoxic triterpenes have been isolated from Euphorbia pulcherrima. Their structures and stereochemistry have been established from NMR, IR, and EI-mass spectroscopy. The compounds were identified as 9,19-cycloart-23-ene-3β,25-diol and 9,19-cycloart-25-ene-3β,24-diol. Cytotoxicity evaluation was performed using Ehrlich ascites tumor cells. While cycloartenol induced no cytotoxic activity against Ehrlich ascites tumor cells, both isolated triterpenes exhibited cell inactivating effects. The IC50 is approximately 7.5 μM, while the IC90 is approximately 13.5 μM for 9,19-cycloart-25-ene-3β,24-diol. The 3β,25-diol compound is 50% less active.
- Smith-Kielland,Dornish,Malterud,Hvistendahl,R?mming,B?ckman,Kolsaker,Stenstr?m,Nordal
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p. 322 - 325
(2007/10/03)
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