Biomedical subjects

Christophe Long

Publications and source records attributed to Christophe Long.

8 recordsLinked to original sources

PubMed2006

Triterpenoid saponins from the fruits of Caryocar glabrum.

Twenty-one new triterpenoid saponins, named caryocarosides (1-21), glycosides of 2beta-hydroxyoleanolic acid, hederagenin, bayogenin, and gypsogenic acid, have been isolated from the fruits of Caryocar glabrum along with nine known triterpenoid saponins (22-30) that are described for the first time from a plant in the Caryocaraceae. Their structures were established by 1D and 2D NMR techniques ((13)C, COSY, TOCSY, HSQC, HMBC, and ROESY experiments), ESIMS, and acid hydrolysis. The isolated compounds could be classified into two series: glucosides (1-8, 22, 27, and 30) derived from the 3-O-monoglucoside and glucuronides (9-21, 23-26, 28, and 29) derived from the 3-O-monoglucuronide. In 22 of the saponins (1-8, 12-22, and 24-26), a galactose moiety was linked to C-3 of a glucuronic acid or a glucose moiety. The galactose was substituted in position 3 by a second galactose unit (6, 7, 20, and 21) or by a xylose unit (8). Seven saponins (4, 5, 16-19, and 26) were found to be bidesmosides with one glucose unit linked to C-28 of the aglycon. The hemolytic activity of the major saponins (2, 3, 5, 12-15, 17, 24, and 28) was measured on sheep erythrocytes in order to establish structure-activity relationships based on the type of sugar attached to the aglycon and on the structure of this aglycon.

Animals↗

PubMed2006

Antimalarial activity of sesquiterpene lactones from Vernonia cinerea.

Two new sesquiterpene lactones, vernolides C and D as well as six known ones were isolated from the dichloromethane fraction of an aqueous extract from Vernonia cinerea. Their structures were elucidated by spectroscopic methods. Among the known sesquiterpene lactones, three of them were described in this plant for the first time. In vitro antiplasmodial evaluation showed that the three major compounds 1, 7 and 8 were active against chloroquine resistant Plasmodium falciparum strain (W2) with IC(50) 3.9, 3.7 and 3.5 microM, respectively.

Animals↗

PubMed2005

Saponins from the leaves of Mimusops laurifolia.

Fifteen new bidesmosidic triterpenoid saponins (1-15) were isolated from a methanol extract of the leaves of Mimusops laurifolia. Their structures were established using one- and two-dimensional NMR spectroscopy and mass spectrometry and determined to be bidesmosides of protobassic acid (2-4, 11, 12, and 15) and of 16alpha-hydroxyprotobassic acid (1, 5-10, 13, and 14).

Egypt↗

PubMed2005

Acylphloroglucinol derivatives from Mahurea palustris.

Five new acylphloroglucinol derivatives, mahureones A-E (1, 3-6), have been isolated from the leaves of Mahurea palustris, and their structures determined by spectroscopic means. During the isolation process, several byproducts (7-9) were formed by reaction of one of the isoprenyl side chains with TFA, water, and acetonitrile. All the compounds were assayed for their ability to inhibit human DNA polymerase beta. The most active compounds, mahureones A (1) and D (5), exhibited IC50 values in the 10 microM range.

Clusiaceae↗

PubMed2004

Alkylated isocoumarins from Pituranthos scoparius.

Two isocoumarins have been isolated from the ethyl acetate extract of the root of Pituranthos scoparius: 3-n-propyl-5-methoxy-6-hydroxy-isocoumarin and 3-n-propyl-5,7-dimethoxy-6-hydroxy-isocoumarin. Their structures were assigned by spectral analysis.

Apiaceae↗

PubMed2003

Bioactive flavonoids of Tanacetum parthenium revisited.

Bio-guided fractionation of an extract from Tanacetum parthenium showing activity as mitotic blocker allowed the isolation and identification of santin 3, jaceidin 2 and centaureidin 1. The latter two closely related flavonols, which, to the best of our knowledge, are isolated here together for the first time, form a mixture difficult to resolve and which is probably the reason for the confusion in the literature regarding their occurrence. Centaureidin 1 had an IC50 of 1 microM while jaceidin 2 and santin 3 were 200 times less active.

Animals↗

PubMed2003

Acylated flavonol glycosides from leaves of Planchonia grandis.

Three acylated flavonol glycosides have been identified from leaves of Planchonia grandis Ridley. They possess kaempferol as aglycone and two triglycosidic chains substituting hydroxyl groups at the 3- and 7-positions. The first glycosidic unit of each chain is esterified by a cis or trans p-coumaric acid. Structural elucidation was achieved by means of UV, NMR and mass spectrometry.

Acylation↗

PubMed2003

Yardenone A and B: new cytotoxic triterpenes from the Indian Ocean sponge Axinella cf. bidderi.

Two new polyepoxysqualene-derived triterpenes, yardenone A (1) and B (2), together with the known yardenone (3) and sodwanone A (4), have been isolated from the marine sponge Axinella cf. bidderi from Yemen's Socotra Island in the Indian Ocean. The structures were elucidated using spectroscopic data. The relative stereochemistry was established by the analysis of ROESY spectra as well as coupling constants and molecular modeling. Furthermore, the absolute configuration of 1 was confirmed by the advanced Mosher's method. The cytotoxicity of these compounds was evaluated against a NSCLC cell line.

Animals↗