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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 ( 1 H-, 13 C-NMR, DEPT, COSY, TOCSY, NOESY, HSQC, HSQC-TOCSY and HMBC) and HRESIMS experiments, and by chemical evidence as 3- O -[ β -D-xylopyranosyl-(1→2)- β -D-fucopyranosyl-(1→6)- β -D-glucopyranosyl]-21- O -{(2E,6S)-2-(hydroxymethyl)-6-methyl-6- O -{4- O -[(2E,6S)-2,6-dimethyl-6- O -( β -D-quinovopyranosyl)octa-2,7-dienoyl]-( β -D-quinovopyranosyl)octa-2,7-dienoyl]}acacic acid-28- O - β -D-glucopyranosyl-(1→3)-[5- O -acetyl- α -L-arabinofuranosyl-(1→4)]- α -L-rhamnopyranosyl-(1→2)- β -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.

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 ( 1 H, 13 C NMR, DEPT, COSY, TOCSY, ROESY, HSQC and HMBC) experiments, HRESIMS studies, and by chemical evidence as 3- O -[ β -d-xylopyranosyl-(l→2)- β -d-fucopyranosyl-(1→6)-[ β -d-glucopyranosyl(1→2)]- β -d-glucopyranosyl]-21- O -{(2 E ,6 S )-6- O -{4- O -[(2 E ,6 S )-2,6-dimethyl-6- O -( β -d-quinovopyranosyl)octa-2,7-dienoyl]-4- O -[(2 E ,6 S )-2,6-dimethyl-6- O -( β -d-quinovopyranosyl)octa-2,7-dienoyl]- β -d-quinovopyranosyl}-2,6-dimethylocta-2,7-dienoyl}acacic acid 28 O -[ β -d-quinovopyranosyl-(l→3)-[ α -l-arabinofuranosyl-(l→4)]- α -l-rhamnopyranosyl-(l→2)- β -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 IC 50 values of 1.69 and 1.44 μM, respectively.

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-[ β-d-glucopyranosyl-(1→2)-[α-l-arabinopyranosyl-(1→6)]-β-d-glucopyranosyl]-21-O-[(2E,6S)-2,6-dimethyl-6-O-(β-d-quinovopyranosyl) octa-2,7-dienoyl]acacic acid 28-O-α-l-arabinofuranosyl-(1→4)-[β-d-glucopyranosyl-(1→3)]-α-l-rhamnopyranosyl-(1→2)-β-d-glucopyranosyl ester (1) and 3- O-[β-d-glucopyranosyl-(1→2) -[ β-d-fucopyranosyl-(1→6)]-β-d-glucopyranosyl]-21-O-[(2E,6S)-2,6-dimethyl-6-O-(β-D-quinovopyranosyl) octa-2,7-dienoyl]acacic acid 28-O-α-l-arabinofuranosyl-(1→4)-[β-d-glucopyranosyl-(1→3)]-α-l-rhamnopyranosyl-(1→2)-β-d-glucopyranosyl ester (2).

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.