Progress in the chemistry of the cycloartanes

Исаев, М. И.; Gorovits, M. B.; Abubakirov, N. K.

doi:10.1007/bf00598398

Cited by 35 publications

(40 citation statements)

References 33 publications

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“…. lH and 13C-NMR data for H-24 and C-24 were comparable with those reported for compounds having the 24S configuration (Isaev et al, 1988 and. The FABMS of 42 was 42 mass units higher than those of 43, indicating the presence of an acetoxy group (lH: ~ 2.11 s, 3H, COCH3).…”

Section: Oh Chart 2 Heteronuclear Multiple Bond Correlations (Hmbc) supporting

confidence: 75%

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Triterpene Saponins from Plants of the Flora of Turkey

Çalış¹,

Sticher²

1996

Advances in Experimental Medicine and Biology

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Section: Oh Chart 2 Heteronuclear Multiple Bond Correlations (Hmbc) supporting

confidence: 75%

“…anti-inflammatory, analgesic, diuretic, hypotensive, and sedative effects (Isaev et al, 1988). During our studies, we observed that an aqueous extract of the roots of an Astragalus species is used against leukemia and for its wound-healing activity in the S.E.…”

Section: Oh Chart 2 Heteronuclear Multiple Bond Correlations (Hmbc) mentioning

confidence: 95%

Triterpene Saponins from Plants of the Flora of Turkey

Çalış¹,

Sticher²

1996

Advances in Experimental Medicine and Biology

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“…As expected, the 13 C NMR spectrum of this same glycoside showed resonances at G 21.12, 29.03, and 30.23 for quaternary C-9 and C-10 and methylene C-19 composing the three-membered ring, indicating that the studied glycoside was a cycloartane triterpenoid [2][3][4][5]. 1 2 -4, 6 5 OH OH OH OH O O HO OH OH O HO HO O OH OH O CH 2 OH OH O CH 3 OOC 2 -5 6 Enzyme Í + OH OH OH OH RO R 1 O OH OH OH OH O O HO O OH OH OH O O HO HO HO O OH OH O CH 2 OH OH O HOOC 2: R = R 1 = H; 3: R = E-D-Xylp, R 1 = H 4: R = H, R 1 = E-D-GlcUA(1o2)-E-D-Glcp 6: R = D-L-Arap(1o2)-E-D-Xylp, R 1 = E-D-Glcp…”

mentioning

confidence: 54%

Triterpene glycosides from Astragalus and their genins. XC. Askendoside K from Astragalus taschkendicus

Isaev

Исаев

2011

Chem Nat Compd

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A new triterpene cycloartane glycoside called askendoside K was isolated from roots of Astragalus taschkendicus Bunge (Leguminosae). The structure of this glycoside was established using chemical and biochemical transformations and spectral data.In continuation of research on polar triterpene glycosides from Astragalus taschkendicus Bunge (Leguminosae) [1], we isolated one more new glycoside from roots of this plant and called it askendoside K (1). Herein we report the structure determination of this glycoside.The PMR spectrum of 1 (Table 1) exhibited at strong field 1H doublets for an AX system at G 0.06 and 0.35 that belonged to the isopropane methylene of a cyclopropane ring in addition to resonances for seven methyls. As expected, the 13 C NMR spectrum of this same glycoside showed resonances at G 21.12, 29.03, and 30.23 for quaternary C-9 and C-10 and methylene C-19 composing the three-membered ring, indicating that the studied glycoside was a cycloartane triterpenoid [2][3][4][5]. 1 2 -4, 6 5 OH OH OH OH O O HO OH OH O HO HO O OH OH O CH 2 OH OH O CH 3 OOC 2 -5 6 Enzyme Í + OH OH OH OH RO R 1 O OH OH OH OH O O HO O OH OH OH O O HO HO HO O OH OH O CH 2 OH OH O HOOC 2: R = R 1 = H; 3: R = E-D-Xylp, R 1 = H 4: R = H, R 1 = E-D-GlcUA(1o2)-E-D-Glcp 6: R = D-L-Arap(1o2)-E-D-Xylp, R 1 = E-D-Glcp

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“…Also, it is noted that all the calculated distances between the protons in this preferred conformation that show NOE correlations listed in Table 2 are less than 2.6 Å. To our knowledge, this is the most comprehensive NOE analysis of cycloartan-3-one derivatives, [8][9][10][11][12][13][14][15][16][17][18][19] and thus leading to the assignment of a preferred conformation of compound 2 in solution with the aid of advanced computational methods (B3LYP/6-31G*). This information indeed furnished the foundation for the theoretical calculation of its ECD spectrum.…”

mentioning

confidence: 88%

Capisterones A and B, which Enhance Fluconazole Activity in Saccharomyces cerevisiae, from the Marine Green Alga Penicillus capitatus

Jacob

Ding

et al. 2006

J. Nat. Prod.

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A whole cell-based assay using Saccharomyces cerevisiae strains that overexpress Candida albicans CDR1 and MDR1 efflux pumps has been employed to screen natural product extracts for reversal of fluconazole resistance. The tropical green alga Penicillus capitatus was selected for bioassay-guided isolation, leading to the identification of capisterones A and B (1 and 2), which were recently isolated from this alga and shown to possess antifungal activity against the marine pathogen Lindra thallasiae. Current work has assigned their absolute configurations using electronic circular dichroism and determined their preferred conformations in solution based on detailed NOE analysis. Compounds 1 and 2 significantly enhanced fluconazole activity in S. cerevisiae, but did not show inherent antifungal activity when tested against several opportunistic pathogens, or cytotoxicity to several human cancer and non-cancerous cell lines (up to 35 μM). These compounds may have a potential for combination therapy of fungal infections caused by clinically relevant azole-resistant strains.The molecular mechanisms of antifungal drug resistance may involve a variety of factors such as mutation of target genes and decreased drug concentrations in the cells due to overexpression of efflux pumps. 1,2 In recent years, the rapid development of such drug resistance, particularly for azole antifungals, has highlighted the need for new strategies in antimycotic therapies. 1-5 Efflux pump inhibition has been considered as a promising approach in this regard. Two families of efflux pumps found in Candida albicans include the major facilitators (multidrug resistance, MDR) that are fueled by a proton gradient and the P-glycoprotein ABC transporters (Candida drug resistance, CDR) that require ATP hydrolysis for energy. Within each family, several subtypes have been discovered (i.e., CDR1, CDR2, MDR1). 1,2 We have established a whole cell-based assay using Saccharomyces cerevisiae strains that overexpress C. albicans CDR1 and MDR1 efflux pumps to screen for natural products that can reverse fluconazole resistance and may not be necessarily antifungal. 6In a continuing effort to search for new efflux inhibitors from natural sources, we have screened over 5000 marine extracts from the National Cancer Institute Open Repository. In the presence of a subinhibitory concentration of fluconazole, an extract of the tropical green alga Penicillus capitatus (Halimedaceae) that had an IC 50 value of 55 μg/mL against S. cerevisiae DSY 415 strain (overexpressing the CDR1 efflux pump) and an IC 50 value of < 6 μg/mL against S.

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Progress in the chemistry of the cycloartanes

Cited by 35 publications

References 33 publications

Triterpene Saponins from Plants of the Flora of Turkey

Triterpene Saponins from Plants of the Flora of Turkey

Triterpene glycosides from Astragalus and their genins. XC. Askendoside K from Astragalus taschkendicus

Capisterones A and B, which Enhance Fluconazole Activity in Saccharomyces cerevisiae, from the Marine Green Alga Penicillus capitatus

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