Les présents travaux concernent deux plantes du genre Sedum (Crassulaceae). S. caeruleum et S. pubescens. L’extraction et les séparations chromatographiques (CC, CCM) des fractions chloroformique, acétate d’éthyle et n-butanol de S. caeruleum ont permis d’isoler 6 produits qui ont été identifiés grâce aux méthodes spectroscopiques (UV, RMN 1D et 2D) : 1- Acide ursolique 2- Daucosterol (β-sitosterol-3-O-β-D-glucopyranoside) 3- β-sitosterol-3-O-β-D-galactopyranoside 4- Apigénine 5- Apigétrine 6- Apiine L’analyse LC-ESI-MS/MS de la fraction butanolique de Sedum caeruleum nous a permis d’identifier 23 composés dont 11 acides phénoliques et 12 flavonoïdes glycosides Les résultats d’étude des activités biologiques de S. caeruleum et S. pubescens sont comme suit : - Les fractions n-butanol des espèces S. caeruleum et S. pubescens ont montré la meilleure activité antiradicalaire avec le test du DPPH. - Les fractions chloroformique de S. caeruleum et butanolique de S. pubescens ont manifesté la meilleure activité avec le test CUPRAC. - La fraction butanolique de S. caeruleum a montré la meilleure activité avec le test du métal chélate. - Les fractions butanolique de S. caeruleum et butanolique de S. pubescens ont manifesté la meilleure activité avec le test du β-carotène. - La fraction butanolique de S. caeruleum a inhibé l’activité de la butyrylcholinesterase. - La fraction chloroformique de S. caeruleum a montré une excellente activité antiinflammatoire supérieure à celle du standard (l’ibuprofène). - La fraction chloroformique de S. caeruleum a moyennement inhibé la croissance des souches bactériennes testées.

Saponins are bioactive compounds occurring in many plant species having a wide range of biological activities such as immunoadjuvant, cytotoxic, analgesic, antimicrobial and anti-inflammatory activities, just to mention a few. The aim of our researches concerns the isolation, structural elucidation and biological investigation of saponins from various plant species [1]. In this context, the study of the roots and leaves of Weigela stelzneri(Caprifoliaceae) led to isolation of four new and two known oleanane-type saponins mainly by medium pressure- and vacuum-liquid chromatography on silica gel (normal and reversed-phase RP-18) [1]. The new compounds were elucidated by a combination of spectroscopic techniques including 1D-, 2D-NMR, and mass spectrometry as glycosides of oleanolic acid, three of them being monodesmosides at C-3 with a branched oligosaccharidic chain made of six sugar units, whereas the known ones were hederagenin derivatives. The six compounds were evaluated for their cytotoxicity against a human cancer cell line (colorectal SW480) and a mouse cancer cell line (mammary EMT6), and for their anti-inflammatory activity. The results show that two new compounds differing only by the first sugar unit of the hexasaccharidic chain at C-3 (arabinopyranosyl instead of xylopyranosyl) exhibited the strongest cytotoxicity on both cell lines (IC₅₀ 5.41 µM and 1.54 µM, respectively), which was better than those of the positive controls etoposide and methotrexate. Furthermore, they revealed a significant modulatory effect of the IL-1β production on human lymphocytes stimulated with endotoxins, showing therefore a strong anti-inflammatory potential.

Three steroidal glycosides were isolated from the bark of Dracaena fragrans (L.) Ker Gawl. "Yellow Coast", and a fourth from the roots and the leaves. Their structures were characterized on the basis of extensive 1D and 2D NMR experiments and mass spectrometry, and by comparison with NMR data of the literature. These saponins have the spirostane-type skeleton and are reported in this species for the first time.