A New Triterpenoid Saponin from Albizia zygia Induced Apoptosis by Reduction of Mitochondrial Potential Status in Malignant Melanoma Cells.

In our ongoing research program on the proapoptotic function of saponins, two previously undescribed saponins, named zygiaosides E (1: ) and F (2: ), were isolated from the leaves of Albizia zygia. Their structures were established based on extensive analysis of 1D and 2D NMR data, HR-ESI-MS analysis, and by chemical degradation. The proapoptotic effect of zygiaoside E (1: ) was evaluated on human malignant melanoma (A375), human epidermoid cancer (A431), and normal Homo sapiens skin tissue (TE 353.SK.) cell lines by cytometric analysis. Zygiaoside E (1: ) induced apoptosis of the two human cancer cell lines (A375 and A431) in a dose-dependent manner at 1 µM but did not induce apoptosis in noncancerous skin cells (TE 353.Sk), even when treated with concentrations up to 15 µM. The underlying mechanism of the apoptosis induction activity of zygiaoside E (1: ) on the mitochondrial membrane potential status in A375 cells was further assessed by monitoring the uptake rate of DiOC6, a mitochondrial specific and voltage-dependent fluorescent dye. The number of malignant melanoma cells emitting high fluorescence levels was decreased when cells were treated with 3 or 5 µM of zygiaoside E (1: ) during either 12 or 24 h, thereby revealing a drop of mitochondrial membrane potential in A375 cells upon treatment, which indicated mitochondrial perturbation.

New Cytotoxic Triterpenoid Saponins from the Roots of Albizia gummifera (J.F.Gmel.) C.A.Sm.

As part of our search for new bioactive saponins from Cameroonian medicinal plants, two new oleanane-type saponins, named gummiferaosides D and E (1 and 2), along with one known saponin, julibroside J8 (3), were isolated from the roots of Albizia gummifera. Their structures were established on the basis of extensive 1D- and 2D-NMR (1 H- and 13 C-NMR, DEPT, COSY, TOCSY, NOESY, HSQC, HSQC-TOCSY, and HMBC) and HR-ESI-MS studies, and by chemical evidence. The apoptotic effect of saponins 1 - 3 was evaluated on the A431 human epidermoid cancer cell. Flow cytometric analyses showed that saponins 1 - 3 induced apoptosis of human epidermoid cancer cell (A431) in a dose-dependent manner.

New acylated triterpenoid saponins from the roots of Acacia polyacantha Willd. (Fabaceae).

In our continuing search of saponins from the plants of Fabaceae family, phytochemical investigation of the roots of Acacia polyacantha, led to the isolation and structural characterization of six undescribed triterpenoid saponins, named polyacosides A-F (1-6). Their structures were established, using extensive analysis by NMR techniques, mainly 1D NMR (1H, 13C, and DEPT) and 2D NMR (COSY, NOESY, HSQC, TOCSY and HMBC) experiments, HRESIMS and by comparison with the literature data, as 3-O-[ß-d-xylopyranosyl-(1 â†’ 4)- [ß-d-galactopyranosyl-(1 â†’ 2)-ß-d-xylopyranosyl-(1 â†’ 2)]-α-l-arabinopyranosyl]-21-O-[Cis-2-methoxycinnamoyl] machaerinic acid (1), 3-O-[ß-d-xylopyranosyl-(1 â†’ 4)- [ß-d-galactopyranosyl-(1 â†’ 2)-ß-d-xylopyranosyl-(1 â†’ 2)]-α-l-arabinopyranosyl]-21-O- [Cis-3,4-dimethoxycinnamoyl] machaerinic acid. (2), 3-O- [ß-d-galactopyranosyl-(1 â†’ 2)-ß-d-xylopyranosyl-(1 â†’ 2)-α-l-arabinopyranosyl]-21-O- [Trans-4-methoxycinnamoyl] machaerinic acid (3), 3-O- [ß-d-glucopyranosyl-(1 â†’ 2)-ß-d-glucopyranosyl] -21-O- [Cis-3,4-dimethoxycinnamoyl] machaerinic acid (4), 3-O- [ß-d-glucopyranosyl-(1 â†’ 2)-ß-d-glucopyranosyl] -21-O- [Cis-2-methoxycinnamoyl] machaerinic acid (5) and 3-O- [ß-d-glucopyranosyl-(1 â†’ 2)-ß-d-glucopyranosyl] -21-O- [Trans-4-methoxycinnamoyl] machaerinic acid (6). Our findings highlight the presence of methoxycinnamoyl group linked to C-21 of the machaerinic acid aglycone moiety as first report of 21-methoxycinnamoyl-machaerinic acid derivative from the plants of Acacia genus (Fabaceae). This represents therefore a valuable contribution to the chemotaxonomy of the Acacia genus of Fabaceae family, which is known to be a rich source of triterpenoid saponins.

New triterpenoid saponin from the stems of Albizia adianthifolia (Schumach.) W.Wight.

As part of our continuing study of apoptosis-inducing saponins from Cameroonian Albizia genus, one new triterpenoid saponin, named adianthifolioside J (1), together with the known gummiferaoside E (2), were isolated from Albizia adianthifolia stems. The structure of the new saponin (1), was established on the basis of extensive analysis of 1 D and 2 D NMR (1H-, 13C-NMR, DEPT, COSY, TOCSY, NOESY, HSQC, HSQC-TOCSY and HMBC) and HRESIMS experiments, and by chemical evidence as 3-O-[ß-D-xylopyranosyl-(1→2)-ß-D-fucopyranosyl-(1→6)-ß-D-glucopyranosyl]-21-O-{(2E,6S)-2-(hydroxymethyl)-6-methyl-6-O-{4-O-[(2E,6S)-2,6-dimethyl-6-O-(ß-D-quinovopyranosyl)octa-2,7-dienoyl]-(ß-D-quinovopyranosyl)octa-2,7-dienoyl]}acacic acid-28-O-ß-D-glucopyranosyl-(1→3)-[5-O-acetyl-α-L-arabinofuranosyl-(1→4)]-α-L-rhamnopyranosyl-(1→2)-ß-D-glucopyranosyl ester (1). The pro-apoptotic activity of the new isolated saponin 1 was evaluated, using Annexin V-FITC binding assay, on the A431 human epidermoid cancer cell. The result showed that adianthifolioside J (1) displayed weak pro-apoptotic activity.

Triterpenoid saponins and others glycosides from the stem barks of Pancovia turbinata Radlk.

In our continuing search of saponins from the plant of Sapindaceae family, phytochemical investigation of the stem barks of Pancovia turbinata Radlk., led to the isolation and structural characterization of two new triterpenoid saponins, named turbinatosides A-B (1-2), one new farnesyl glycoside, named turbinoside A (3), one new coumarin glucoside, named panturboside A (4), together with a known saponin (5). The structures of the new compounds were established, using extensive analysis of NMR techniques, mainly 1D NMR (1H, 13C, and DEPT) and 2D NMR (COSY, NOESY, HSQC, HSQC-TOCSY and HMBC) experiments, HRESIMS and by comparison with the literature data, as 3-O-ß-d-xylopyranosyl-(1 â†’ 3)-α-l-arabinopyranosyl-(1 â†’ 4)-ß-d-glucopyranosyl-(1 â†’ 3)-α-l-rhamnopyranosyl-(1 â†’ 2)-α-l-arabinopyranosylhederagenin 28-O-ß-d-glucopyranosyl ester (1), 3-O-α-l-arabinopyranosyl-(1 â†’ 4)-ß-d-glucopyranosyl-(1 â†’ 3)-α-l-rhamnopyranosyl-(1 â†’ 2)-α-l-arabinopyranosylhederagenin 28-O-ß-d-xylopyranosyl-(1 â†’ 4)-ß-d-glucopyranosyl ester (2), 1-O-{ß-d-glucopyranosyl-(1 â†’ 3)-α-l-rhamnopyranosyl-(1 â†’ 2)-[α-l-rhamnopyranosyl-(1 â†’ 6)]-ß-d-glucopyranosyl}-(2E,6E)-farnes-1,12-diol (3), and 5-O-ß-d-glucopyranosyl-5,6,7-trihydroxy-8-methoxycoumarin (4), respectively. Our findings highlight the presence of -3Rha-2Ara-3hederagenin oligosaccharidic sequence usually described in saponins from Sapindoideae subfamily of Sapindaceae family, as well as farnesol glycosides, and represent therefore a valuable contribution to the chemotaxonomy of the Sapindoideae subfamily.

Glycosides of polygalacic acid from the stem barks of Piper guineense Schum and Thonn.

In a continuation of our study on constituents of P. guineense now focusing on the search for saponins, phytochemical investigation of the n-BuOH fraction of P. guineense stem bark led to the isolation of three previously undescribed triterpenoid saponins, named guineenosides A─C (1─3). Their structures were established on the basis of extensive analysis of 1D and 2D NMR (1H, 13C NMR, DEPT, COSY, TOCSY, NOESY, HSQC, HSQC-TOCSY and HMBC) and HRESIMS experiments, and by chemical evidence as 3-O-{α-l-rhamnopyranosyl-(1 â†’ 3)-ß-d-xylopyranosyl-(1 â†’ 2)-α-l-arabinopyranosyl-(1 â†’ 4)-α-l-rhamnopyranosyl-(1 â†’ 3)-[α-l-arabinofuranosyl-(1 â†’ 4)]-α-l-rhamnopyranosyl-(1 â†’ 3)-ß-d-fucopyranosyl} polygalacic acid 28-O-α-l-rhamnopyranosyl-(1 â†’ 4)-α-l-rhamnopyranosyl-(1 â†’ 3)-ß-d-xylopyranosyl ester (1), 3-O-{α-l-rhamnopyranosyl-(1 â†’ 3)-ß-d-xylopyranosyl-(1 â†’ 2)-α-l-arabinopyranosyl-(1 â†’ 4)-α-l-rhamnopyranosyl-(1 â†’ 3)-[α-l-arabinofuranosyl-(1 â†’ 4)]-α-l-rhamnopyranosyl-(1 â†’ 3)-ß-d-fucopyranosyl} polygalacic acid 28-O-ß-d-glucopyranosyl-(1 â†’ 3)-α-l-rhamnopyranosyl-(1 â†’ 4)-α-l-rhamnopyranosyl-(1 â†’ 3)-ß-d-xylopyranosyl ester (2), and 3-O-{α-l-rhamnopyranosyl-(1 â†’ 2)-ß-d-xylopyranosyl-(1 â†’ 3)-ß-d-fucopyranosyl} polygalacic acid 28-O-[α-l-rhamnopyranosyl-(1 â†’ 4)-α-l-rhamnopyranosyl-(1 â†’ 3)-ß-d-xylopyranosyl ester (3). This is the first report of triterpenoid saponins from P. guineense.

Structure elucidation of new acacic acid-type saponins from Albizia coriaria.

Three new acacic acid derivatives, named coriariosides C, D, and E (1-3) were isolated from the roots of Albizia coriaria. Their structures were elucidated on the basis of extensive 1D- and 2D-NMR studies and mass spectrometry as 3-O-[ß-D-xylopyranosyl-(1 → 2)-ß-D-fucopyranosyl-(1 → 6)-2-(acetamido)-2-deoxy-ß-D-glucopyranosyl]-21-O-{(2E,6S)-6-O-{4-O-[(2E,6S)-2,6-dimethyl- 6-O-(ß-D-quinovopyranosyl)octa-2,7-dienoyl]-4-O-[(2E,6S)-2,6-dimethyl-6-O-(ß-D-quinovopyranosyl)octa-2,7-dienoyl]-ß-D-quinovopyranosyl}-2,6-dimethylocta-2,7-dienoyl}acacic acid 28-O-ß-D-xylopyranosyl-(1 → 4)-α-L-rhamnopyranosyl-(1 → 2)-ß-D-glucopyranosyl ester (1), 3-O-{ß-D-fucopyranosyl-(1 → 6)-[ß-D-glucopyranosyl-(1 → 2)]-ß-D-glucopyranosyl}-21-O-{(2E,6S)-6-O-{4-O-[(2E,6S)-2,6-dimethyl-6-O-(ß-D-quinovopyranosyl)octa-2,7-dienoyl]-4-O-[(2E,6S)-2,6-dimethyl-6-O-(ß-D-quinovopyranosyl)octa-2,7-dienoyl]-ß-D-quinovopyranosyl}-2,6-dimethylocta-2,7-dienoyl}acacic acid 28-O-α-L-rhamno pyranosyl-(1 → 2)-ß-D-glucopyranosyl ester (2), and 3-O-[ß-D-fucopyranosyl-(1 → 6)-ß-D-glucopyranosyl]-21-O-{(2E,6S)-6-O-{4-O-[(2E,6S)-2,6-dimethyl-6-O-(ß-D-quinovopyranosyl)octa-2,7-dienoyl)-ß-D-quinovopyranosyl]octa-2,7-dienoyl}acacic acid 28-O-ß-D-glucopyranosyl ester (3).

Farnesyl glycosides and one new triterpenoid saponin from the roots of Lecaniodiscus cupanioides Planch. ex Benth.

Chemical investigation of the methanol extract of the roots of Lecaniodiscus cupanioides led to the isolation and characterisation of three new sesquiterpene glycosides, named cupanioidesosides A (1), B (2) and C (3), together with one new triterpenoid saponin named lecanioside A (4), Their structures were established by extensive analysis of spectroscopic methods including 1D and 2D NMR techniques (COSY, NOESY, TOCSY, HSQC, and HMBC) and HRESIMS. The four new compounds were evaluated for their antiproliferative activity against the Caco-2 cell line (human epithelial cell line). None of the isolated compounds showed positive activity in our assay. Our findings represent a valuable contribution to the chemotaxonomy Lecaniodiscus genus of the subfamily of Sapindoideae of Sapindaceae family, known to be a rich source of farnesol glycosides.

Triterpenoid saponins from Calliandra calothyrsus Meisn. and their antiproliferative activity against two digestive carcinoma human cell lines.

The chemical investigation of the flowers and twigs of Calliandra calothyrsus (Fabaceae) led to the isolation of three new oleanane-type triterpenoid saponins, named calothyrsusosides AC (13). Their structures were established by direct interpretation of their spectral data, mainly HRESIMS, 1D NMR and 2D NMR (1H, 1H NMR DOSY, 13C NMR, COSY, HSQC, HMBC, HSQC-TOCSY and NOESY) and by comparison with literature data. Compounds 1 and 2 were tested for their antiproliferative activity against two digestive carcinoma human cell lines: Hep3B (hepatocellular carcinoma) and Caco-2 (epithelial colorectal adenocarcinoma). Both compounds exhibited an antiproliferative activity against the Hep3B cell line, with IC50 values of 6.0 and 6.5 µM, respectively, while no effect was detected against the epithelial colorectal adenocarcinoma Caco-2 (CC50 > 25 µM).

Cytotoxic acacic acid glycosides from the roots of Albizia coriaria.

Two new oleanane-type saponins, coriariosides A (1) and B (2), along with a known saponin, gummiferaoside C (3), were isolated from the roots of Albizia coriaria. Their structures were established by extensive analysis of 1D and 2D NMR experiments (COSY, ROESY, TOCSY, HSQC, and HMBC) and mass spectrometry. Compounds 1 and 3 when tested for cytotoxicity against two colorectal human cancer cells showed activity against the HCT 116 (IC50 4.2 microM for 1 and 2.7 microM for 3) and HT-29 (IC50 6.7 microM for 1 and 7.9 microM for 3) cell lines.

Tetrapterosides A and B, two new oleanane-type saponins from Tetrapleura tetraptera.

From the stem bark of Tetrapleura tetraptera, two new oleanane-type saponins, tetrapteroside A 3-O-{6-O-[(2E,6S)-2,6-dimethyl-6-hydroxyocta-2,7-dienoyl]-beta-D-glucopyranosyl-(1 --> 2)-beta-D-glucopyranosyl-(1 --> 3)-beta-D-glucopyranosyl-(1 --> 4)-[beta-D-glucopyranosyl-(1 --> 2)]-beta-D-glucopyranosyl}-3,27-dihydroxyoleanolic acid (1), and tetrapteroside B 3-O-{ beta-D-glucopyranosyl-(1 --> 2)-6-O-[(E)-feruloyl]-beta-D-glucopyranosyl-(1 --> 3)-beta-D-glucopyranosyl-(1 --> 4)-[beta-D-glucopyranosyl-(1 --> 2)]-beta-D-glucopyranosyl}-3,27-dihydroxyoleanolic acid (2), were isolated. Further extractions from the roots led to the isolation of four known oleanane-type saponins. Their structures were elucidated by the combination of mass spectrometry (MS), one and two-dimensional NMR experiments.

Lebbeckoside C, a new triterpenoid saponin from the stem barks of Albizia lebbeck inhibits the growth of human glioblastoma cells.

One new acacic acid-type saponin, named lebbeckoside C (1), was isolated from the stem barks of Albizia lebbeck. Its structure was established on the basis of extensive analysis of 1D and 2D NMR (1H, 13C NMR, DEPT, COSY, TOCSY, ROESY, HSQC and HMBC) experiments, HRESIMS studies, and by chemical evidence as 3-O-[ß-d-xylopyranosyl-(l→2)-ß-d-fucopyranosyl-(1→6)-[ß-d-glucopyranosyl(1→2)]-ß-d-glucopyranosyl]-21-O-{(2E,6S)-6-O-{4-O-[(2E,6S)-2,6-dimethyl-6-O-(ß-d-quinovopyranosyl)octa-2,7-dienoyl]-4-O-[(2E,6S)-2,6-dimethyl-6-O-(ß-d-quinovopyranosyl)octa-2,7-dienoyl]-ß-d-quinovopyranosyl}-2,6-dimethylocta-2,7-dienoyl}acacic acid 28 O-[ß-d-quinovopyranosyl-(l→3)-[α-l-arabinofuranosyl-(l→4)]-α-l-rhamnopyranosyl-(l→2)-ß-d-glucopyranosyl] ester. The isolated saponin (1) displayed significant cytotoxic activity against the human glioblastoma cell line U-87 MG and TG1 stem-like glioma cells isolated from a patient tumor with IC50 values of 1.69 and 1.44 µM, respectively.

Structural determination of two new acacic acid-type saponins from the stem barks of Albizia zygia (DC.) J. F. Macbr.

As a continuation of our interest in the study of triterpenoid saponins from Albizia zygia, phytochemical investigation of its stem barks led to the isolation of two new oleanane-type saponins, named zygiaosides C-D (1-2). Their structures were established on the basis of extensive analysis of 1D and 2D NMR (1H-, 13C NMR, DEPT, COSY, TOCSY, ROESY, HSQC and HMBC) experiments, HRESIMS studies, and by chemical evidence as, 3-O-[ ß-d-glucopyranosyl-(1→2)-[α-l-arabinopyranosyl-(1→6)]-ß-d-glucopyranosyl]-21-O-[(2E,6S)-2,6-dimethyl-6-O-(ß-d-quinovopyranosyl) octa-2,7-dienoyl]acacic acid 28-O-α-l-arabinofuranosyl-(1→4)-[ß-d-glucopyranosyl-(1→3)]-α-l-rhamnopyranosyl-(1→2)-ß-d-glucopyranosyl ester (1) and 3- O-[ß-d-glucopyranosyl-(1→2) -[ ß-d-fucopyranosyl-(1→6)]-ß-d-glucopyranosyl]-21-O-[(2E,6S)-2,6-dimethyl-6-O-(ß-D-quinovopyranosyl) octa-2,7-dienoyl]acacic acid 28-O-α-l-arabinofuranosyl-(1→4)-[ß-d-glucopyranosyl-(1→3)]-α-l-rhamnopyranosyl-(1→2)-ß-d-glucopyranosyl ester (2).

Pro-apoptotic activity of new triterpenoid saponins from the roots of Albizia adianthifolia (Schumach.) W.Wight.

As part of our study of the proapoptotic function of saponins from Cameroonian's Albizia genus, phytochemical investigation of the roots of Albizia adianthifolia led to the isolation of three new triterpenoid saponins, named adianthifoliosides GI (13). Their structures were established on the basis of extensive analysis of 1D and 2D NMR (1H-, 13C NMR, DEPT, COSY, TOCSY, NOESY, HSQC, HSQC-TOCSY and HMBC) and HRESIMS experiments, and by chemical evidence as 3-O-[ß-d-glucopyranosyl-(1 → 2)-ß-D-fucopyranosyl-(1 → 6)-ß-d-glucopyranosyl]-21-O-{(2E,6S)-2-(hydroxymethyl)-6-methyl-6-O-{4-O-[(2E,6S)-2,6-dimethyl-6-O-(ß-D-quinovopyranosyl)octa-2,7-dienoyl]-(ß-D-quinovopyranosyl)octa-2,7-dienoyl]}acacic acid-28-O-ß-d-xylopyranosyl-(1 → 3)-[5-O-acetyl-α-L-arabinofuranosyl-(1 → 4)]-α-L-rhamnopyranosyl-(1 → 2)-ß-d-glucopyranosyl ester (1), 3-O-[ß-d-glucopyranosyl-(1 → 2)-ß-D-fucopyranosyl-(1 → 6)-ß-d-glucopyranosyl]-21-O-{(2E,6S)-2-(hydroxymethyl)-6-methyl-6-O-{4-O-[(2E,6S)-2,6-dimethyl-6-O-(ß-D-quinovopyranosyl)octa-2,7-dienoyl]-(ß-D-quinovopyranosyl)octa-2,7-dienoyl]}acacic acid 28-O-ß-d-xylopyranosyl-(1 → 3)-[α-L-arabinofuranosyl-1 → 4)]-α-L-rhamnopyranosyl-(1 → 2)-ß-d-glucopyranosyl ester (2), and 3-O-[ß-d-glucopyranosyl-(1 → 2)-ß-D-fucopyranosyl-(1 → 6)-ß-d-glucopyranosyl]-21-O-{(2E,6S)-2-(hydroxymethyl)-6-methyl-6-O-{4-O-[(2E,6S)-2,6-dimethyl-6-O-(ß-D-quinovopyranosyl)octa-2,7-dienoyl]-4-O-[(2E,6S)-2,6-dimethyl-6-O-(ß-D-quinovopyranosyl)octa-2,7-dienoyl]-ß-D-quinovopyranosyl}-2,6-dimethylocta-2,7-dienoyl}acacic acid 28-O-ß-d-xylopyranosyl-(1 → 3)-[α-L-arabinofuranosyl-1 → 4)]-α-L-rhamnopyranosyl-(1 → 2)-ß-d-glucopyranosyl ester (3). The apoptotic effect of saponins 1-3 was evaluated on the A431 human epidermoid cancer cell. Flow cytometric analyses showed that saponins 1-3 induced apoptosis of human epidermoid cancer cell (A431) in a dose-dependent manner.

A new flavanolignan and a new alkane from the Stem bark of Newtonia griffoniana.

Two new compounds a flavanolignan (1), and an alkane (2) along with four known compounds including two fatty acid esters (3-4) and two isocoumarins (5-6) were isolated from the methanolic extract of the stem bark of Newtonia griffoniana. Their structures were elucidated using spectroscopic methods including extensive 1-D and 2-D NMR experiments.

Phenotype-specific apoptosis induced by three new triterpenoid saponins from Albizia glaberrima (Schumach. & Thonn.) Benth.

As part of our search of new bioactive saponins from Cameroonian medicinal plants, phytochemical investigation of the roots of Albizia glaberrima led to the isolation of three new oleanane-type saponins, named glaberrimosides A-C (1-3). Their structures were established by direct interpretation of their spectral data, mainly HRESIMS, 1D NMR (1H, 13C NMR, and DEPT) and 2D NMR (COSY, ROESY, HSQC and HMBC) as 3-O-[α-L-arabinopyranosyl-(1 → 6)-[ß-D-glucopyranosyl-(1 → 2)]-ß-D-glucopyranosyl]-28-O-[ß-D-glucopyranosyl-(1 → 6)-[ß-d-glucopyranosyl-(1 → 2)]-ß-D-glucopyranosyl]-oleanolic acid (1), 3-O-[α-L-arabinopyranosyl-(1 → 6)-[ß-D-glucopyranosyl-(1 → 2)]-ß-D-glucopyranosyl]-28-O-[ß-D-glucopyranosyl-(1 → 6)-ß-D-glucopyranosyl]-oleanolic acid (2), and 3-O-[ß-D-glucopyranosyl-(1→2)-ß-D-glucopyranosyl]-28-O-[ß-D-glucopyranosyl-(1 → 6)-[ß-D-fucopyranosyl-(1 → 2)]-ß-D-glucopyranosyl]-oleanolic acid (3). The pro-apoptotic effect of the three saponins was evaluated on three human cell lines (pancreatic carcinoma AsPC-1, hematopoietic monocytic THP-1, and human fibroblast cell line BJ). Saponins 1-3 specifically induced apoptosis of pancreatic carcinoma cell (AsPC-1) in a dose-dependent manner. More interestingly, there were inactive on monocytic (THP-1) and normal human fibroblast (BJ) cell lines.

Triterpenoid saponins from Albizia lebbeck (L.) Benth and their inhibitory effect on the survival of high grade human brain tumor cells.

As part of our search of new bioactive triterpenoid saponins from Cameroonian Mimosaceae plants, phytochemical investigation of the roots of Albizia lebbeck led to the isolation of two new oleanane-type saponins, named lebbeckosides A-B (1-2). Their structures were established on the basis of extensive 1D and 2D NMR ((1)H, (13)C NMR, DEPT, COSY, TOCSY, ROESY, HSQC, and HMBC) and HRESIMS studies, and by chemical evidence. Compounds 1-2 were evaluated for their inhibitory effect on the metabolism of high grade human brain tumor cells, the human glioblastoma U-87 MG cell lines and the glioblastoma stem-like TG1 cells isolated from a patient tumor, and known to be particularly resistant to standard therapies. The isolated saponins showed significant cytotoxic activity against U-87 MG and TG1 cancer cells with IC50 values of 3.46 µM and 1.36 µM for 1, and 2.10 µM and 2.24 µM for 2, respectively.