Arcapitins A - C, First Dammarane-Type Triterpenes from the Convolvulaceae<sup>§</sup>

Tofern, Britta; Jenett‐Siems, Kristina; Siems, Karsten; Jakupovic, Jasmin; Eich, Eckart

doi:10.1515/znc-1999-1202

Cited by 7 publications

(5 citation statements)

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“…In the 20 S -series, the resonance of C-21 has a higher δ value and that of C-22 has a lower δ value than in the 20 R -series . A compound identified as the 20 S epimer of 1 was described by Tofern et al The 13 C NMR chemical shift differences between the latter and 1 were less than 0.3 ppm (in most cases much less) for all carbons, except for C-16, C-17, and C-20 to C-23, the differences for C-21 and C-22 (Δδ = δ S − δ R 2.3 and −1.7 ppm, respectively) being the largest and in agreement with the rule 14 mentioned above. Consistent chemical shifts were reported for other 20 S -hydroxydammaranes. − Thus, 1 has the R -configuration at C-20.…”

Section: Resultsmentioning

confidence: 98%

New Dammarane and Malabaricane Triterpenes from Caloncoba echinata

Ziegler¹,

Christensen²,

Olsen³

et al. 2002

J. Nat. Prod.

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Three novel triterpenes, (11R,20R)-11,20-dihydroxy-24-dammaren-3-one (1), (17S,20R,24R)-17,25-dihydroxy-20,24-epoxy-14(18)-malabaricen-3-one (2), and (17R,20S,24R)-17,25-dihydroxy-20,24-epoxy-14(18)-malabaricen-3-one (3), were isolated from leaves of Caloncoba echinata. The structures were established using mainly 800 MHz NOESY and HMBC connectivities. The absolute stereochemistry of C-11 in 1 and that of C-17 in 2 were established by the Mosher method. The stereochemistry of the side chains of the malabaricanes is compatible with their biosynthesis by a cascade opening of diepoxides. The isolated triterpenes inhibited growth of Plasmodium falciparum parasites in vitro apparently via incorporation into erythrocyte membrane, as suggested by transformation of erythrocytes into stomatocytes at a concentration level at which the growth inhibition was observed.

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Section: Resultsmentioning

confidence: 98%

New Dammarane and Malabaricane Triterpenes from Caloncoba echinata

Ziegler¹,

Christensen²,

Olsen³

et al. 2002

J. Nat. Prod.

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“…The occurrence of dammarane-type triterpenoids in the family Convolvulaceae was previously only reported from Argyreia capitata. 11 Compounds 1 and 2 are the first two dammaranetype triterpenoids having an oxymethyl group substituted at C-24.…”

Section: ' Results and Discussionmentioning

confidence: 99%

Bioactive Dammarane-Type Saponins from Operculina turpethum

Ding

Zeng

et al. 2011

J. Nat. Prod.

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Four new dammarane-type saponins, operculinosides A-D (1-4), were isolated from the aerial parts of Operculina turpethum, of which 1 and 2 are the first two dammarane-type triterpenoids having an oxymethyl group at C-24. Their structures were determined by spectroscopic analysis and acid hydrolysis. The absolute configuration of operculinoside A (1) was confirmed by X-ray crystallography. Compounds 1 and 3 showed significant protective activities against d-galactosamine-induced toxicity in L-02 human hepatic cells.

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“…Arcaptins A, B and C, from the roots of Argyreia capitata, are 11α-acetoxy-20S-hydroxydammar-24-en-3-one 81, 11α,20S-dihydroxydammar-24-en-3-one 82 and 11α-acetoxydammar-24ene-3β,20S-diol 83 respectively. 65 The ring A cleaved dammaranes aglinins A 84 and B 85, from Aglaia lawii, may be derived biogenetically from the corresponding ketone aglinin D 86 which occurs in A. tomentosa along with the alcohol aglinin C 87. 66 19,3β : 20S,24S-Diepoxy-3α,25-dihydroxydammaran-3-one 88 is a constituent of Cleome gynandra.…”

Section: The Dammarane-euphane Groupmentioning

confidence: 99%