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Journal ArticleDOI

Querspicatins A and B, two pentacyclic triterpenes from Quercus spicata

01 Jan 1989-Phytochemistry (Pergamon)-Vol. 28, Iss: 12, pp 3437-3442
Abstract: Two new triterpenes designated querspicatin A and querspicatin B have been isolated from the bark of Quercus spicata . They have been shown to be 3β-(3′,4′-dihydroxycinnamoyloxy)-9α-hydroxy-7-oxo-lup-20 (30)-ene and 3β,9α-dihydroxy-7-oxo-lup-20(30)-ene on the basis of their 1 H NMR, 13 C NMR and mass spectral data and chemical evidence.

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Topics: Pentacyclic Triterpenes (61%), Triterpene (53%)
Citations
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Journal ArticleDOI
Shashi B. Mahato1, Sucharita Sen1Institutions (1)
01 Apr 1997-Phytochemistry
TL;DR: A compilation of the triterpenoids isolated during the period 1990-1994 along with their occurrence, physical data, spectroscopy and X-ray analysis used for their characterization, is included.

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Abstract: Triterpenoids isolated and characterized from various sources are reviewed. The newer spectroscopic techniques used in their structure elucidation, the new skeleta characterized, their total chemical synthesis, and their biosynthesis are discussed. A compilation of the triterpenoids isolated during the period 1990-1994 along with their occurrence, physical data, spectroscopy and X-ray analysis used for their characterization, is included. The biological activities of the triterpenoids are also discussed.

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173 citations


Journal ArticleDOI
Nguyen Tien Dat1, Xing Fu Cai1, Quanghai Shen1, Im Seon Lee1  +1 moreInstitutions (1)
TL;DR: Two new compounds were isolated from the stem and twigs of Ribes fasciculatum var.

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Abstract: Two new compounds were isolated from the stem and twigs of Ribes fasciculatum var. chinense and their structures were identified to be threo-(7S,8R)-1-(4-hydroxyphenyl)-2-[4-(E)-propenylphenoxy]-propan-1-ol (1), and 5,4'-dihydroxy-7-methoxyflavone-3-O-[alpha-L-rhamnopyranosyl(1-->3)-O-alpha-L-rhamnopyranosyl(1-->6)-O-beta-D-glucopyranoside] (2). With nine other known components, they were tested on inhibitory activity against nuclear factor of activated T cells (NFAT) transcription factor. Compound 1 showed a potent inhibitory activity (IC50=15.6 microM), while compounds 4, 5 and 9 showed moderate inhibitory activity (IC50 22.4, 24.5 and 25.7 microM, respectively).

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17 citations


Journal ArticleDOI
TL;DR: Two new pentacyclic triterpene esters, peltastine A and B, have been isolated from the stem of Peltastes peltatus (Vell.) Woodson along with the previously reported beta-amyrin juarezate.

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Abstract: Two new pentacyclic triterpene esters, peltastine A [3beta-[5-phenyl-(2E,4E)-penta-2,4-dienoyloxy]-urs-12-ene] and peltastine B [3beta-[5-phenyl-(2E,4E)-penta-2,4-dienoyloxy]-lup-20(29)-ene], have been isolated from the stem of Peltastes peltatus (Vell.) Woodson along with the previously reported beta-amyrin juarezate [3-[5-phenyl-(2E,4E)-penta-2,4-dienoyloxy]-olean-12-ene]. The structures of these compounds were established by MS, 1D- and 2D-NMR experiments as well as by chemical degradation.

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9 citations


Journal ArticleDOI
Abstract: New lupane-type triterpenoids with 5(6) double bond were prepared using the method of partial demethylation on carbon C-4. Hydroboration of the double bond led to 6α-hydroxy derivative. By the oxidation and following reduction of 6α-hydroxy derivative the 6-oxo and 6β-hydroxy derivatives were prepared. A new method for selective oxidation of secondary hydroxy group in the presence of primary hydroxy group was performed. The conformation of ring A of new lupane-type 3-oxo derivatives with a substituent on ring B was elucidated on the bases of 1 H and 13 C NMR spectra and molecular modelling.

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5 citations


References
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Journal ArticleDOI
01 Jan 1981-Phytochemistry
TL;DR: Rubicoumaric acid and rubifolic acid isolated from Rubia cordifolia have been shown to be 30-hydroxy-3β-p-Hydroxycoumaryloxy-urs-12-ene-28-oic acid or 3β,30-dihydroxy-urs 12-ene,28- oic acid respectively on the basis of 1H NMR, 13C NMR and mass spectral and chemical evidence.

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Abstract: Rubicoumaric acid and rubifolic acid isolated from Rubia cordifolia have been shown to be 30-hydroxy-3β-p-hydroxycoumaryloxy-urs-12-ene-28-oic acid and 3β,30-dihydroxy-urs-12-ene-28-oic acid(30-hydroxyursolic acid) respectively on the basis of 1H NMR, 13C NMR and mass spectral and chemical evidence.

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32 citations


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No. of citations received by the Paper in previous years
YearCitations
20061
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20041
19971