Rheediinosides A and B,two antiproliferative and antioxidant triterpene saponins from Entada rheedii

Two triterpenoid saponins have been isolated from the seed kernels of Entada rheedii. Their structures have been established using 1D- and 2D-NMR and mass spectrometry as 3-O-β-d-xylopyranosyl-(1 → 3)-O-α-l-arabinopyranosyl-(1 → 6)-2-acetylamino-2-deoxy-β-d-glucopyranosylentagenic acid 28-O-β-apiofuranosyl-(1 → 3)-β-d-xylopyranosyl-(1 → 2)-β-d-glucopyranoside (Rheediinoside A, 1) and 3-O-β-d-glucopyranosyl-(1 → 3)-O-[β-d-xylopyranosyl-(1 → 3)-α-l-arabinopyranosyl-(1 → 6)]-2-acetylamino-2-deoxy-β-d-glucopyranosylentagenic acid 28-O-β-apiofuranosyl-(1 → 3)-β-d-xylopyranosyl-(1 → 2)-β-d-glucopyranoside (Rheediinoside B, 2). Compounds 1 and 2 were tested for their antiproliferative activity against T98G, A431, PC3 and B16-F1 cell lines, and further for their antioxidant properties. Moderate cytotoxic potency and antioxidant properties were found for these compounds whereas Rheediinoside B was in all assays more active than Rheediinoside A.     

Echinocystic acid 3,16-O-bisglycosides from Albizia procera

Three triterpene glycosides and two known ones were isolated from the bark of Albizia procera by using chromatographic techniques. The structures of the compounds were determined to be 3-O-β-d-xylopyranosyl-(1 → 2)-β-d-galactopyranosyl-(1 → 6)-2-acetamido-2-deoxy-β-d-glucopyranosyl echinocystic acid 16-O-β-d-glucopyranoside, 3-O-β-d-xylopyranosyl-(1 → 2)-α-l-arabinopyranosyl-(1 → 6)-2-acetamido-2-deoxy-β-d-glucopyranosyl echinocystic acid 16-O-β-d-glucopyranoside and 3-O-α-l-arabinopyranosyl-(1 → 2)-α-l-arabinopyranosyl-(1 → 6)-2-acetamido-2-deoxy-β-d-glucopyranosyl echinocystic acid 16-O-β-d-glucopyranoside. Their structures were determined by NMR techniques including HOHAHA, ¹H-¹H COSY, ROE, HMQC and HMBC experiments together with FABMS as well as acid hydrolysis. To the best of our knowledge, the new compounds are considered the first examples of echinocystic acid 3,16-O-bisglycosides. In contrast to other cytotoxic echinocystic acid glycosides with N-acetyl glucosamine unit, the new glycosides were found inactive when assayed by MTT method for their cytotoxicities against the human tumor cell lines HEPG2, A549, HT29 and MCF7. The results showed the importance of the free hydroxyl group at the aglycone C-16 for exhibiting cytotoxic properties.     

Phenylethanoid glycosides from the leaves of Magnolia hodgsonii

Three new phenylethanoid glycosides, 2-(3-hydroxy-4-methoxyphenyl)ethyl 1-O-β-d-allopyranoside (hodgsonialloside A, 1), 2-(3-hydroxy-4-methoxyphenyl)ethyl 1-O-β-d-glucopyranosyl-(1 → 4)-β-d-allopyranoside (hodgsonialloside B, 2) and 2-(3-methoxy-4-hydroxyphenyl)ethyl 1-O-β-d-allopyranoside (hodgsonialloside C, 3) were isolated from the leaves of Magnolia hodgsonii in addition to six known compounds, tyrosol 4-O-β-d-xylopyranosyl-(1 → 6)-β-d-glucopyranoside (4), kaempferol 3-O-neohesperidoside (5), kaempferol 3-O-rutinoside (6), kaempferol 3-O-α-l-rhamnopyranosyl-(1 → 2)-[α-l-rhamnopyranosyl-(1 → 6)]-β-d-glucopyranoside (7), (+)-syringaresinol O-β-d-glucopyranoside (8), and oblongionoside C (9). The structure elucidation of these compounds was based on analyses of physical and spectroscopic data including 1D and 2D NMR experiments.     

Triterpenoid saponins and C-glycosyl flavones from stem bark of Erythrina abyssinica Lam and their cytotoxic effects.

Six new compounds including two oleanane-type triterpenoid saponins (1, 2) and four C-glycosyl flavones (3–6), along with a known saponin (7), three di-C-glycosyl flavones (8–10) and a glycosyl auronol (11), were isolated from the stem bark of Erythrina abyssinica Lam. The structures of the new compounds, identified as 3-O-[α-l-rhamnopyranosyl-(1 → 2)-β-d-galactopyranosyl-(1 → 2)-β-d-glucuronopyranosyl]-22-O-β-d-glucopyranosyl sophoradiol (1), 3-O-[α-l-rhamnopyranosyl-(1 → 2)-β-d-glucopyranosyl-(1 → 2)-β-d-glucuronopyranosyl]-22-O-β-d-glucopyranosyl sophoradiol (2), 6-C-β-glucopyranosyl-8-C-β-quinovopyranosyl apigenin (3), 6-C-β-quinovopyranosyl-8-C-β-glucopyranosyl apigenin (4), 8-C-[6″-O-α-l-rhamnopyranosyl-(1‴ → 6″)]-β-glucopyranosyl 7,4′-dihydroxyflavone (5) and 8-C-[6″-O-β-d-xylopyranosyl-(1‴ → 6″)]-β-glucopyranosyl 7,4′-dihydroxyflavone (6), were determined by comprehensive spectroscopic analysis, including 1D and 2D NMR techniques, mass spectrometry and acid hydrolysis. These new compounds together with the known saponins 7 were evaluated for their cytotoxic activity against MCF-7 (estrogen dependent) and MDA-MB-231 (estrogen independent) cell lines. The new saponin 2 exhibited the highest cytotoxic activity among tested compounds, exerting a selective inhibitory effect against the proliferation of MCF-7 cells, with lower IC₅₀ value (12.90 μM) than that of the positive control, resveratrol (13.91 μM). Structure–activity relationship of these compounds is also discussed.     

Chemical constituents from Saussurea cordifolia

Thirty-six naturally occurring compounds, including four C₁₀-acetylenic glycosides and a lignan, were isolated from the whole plants of Saussurea cordifolia. Their structures were elucidated by means of spectroscopic and chemical methods to be 4,6-decadiyne-1-O-β-d-apiofuranosyl-(1 → 6)-β-d-glucopyranoside (1), 4,6-decadiyne-1-O-α-l-rhamnopyranosyl-(1 → 6)-β-d-glucopyranoside (2), (8E)-decaene-4, 6-diyn-1-O-α-l-rhamnopyranosyl-(1 → 6)-β-d-glucopyranoside (3), (8Z)-decaene-4,6-diyn-1-O-β-d-apiofuranosyl-(1 → 6)-β-d-glucopyranoside (4), and (2R, 3S, 4S)-4-(4-hydroxy-3-methoxybenzyl)-2-(5-hydroxy-3-methoxyphenyl)-3-(hydroxymethyl)-tetrahydrofuran-3-ol (5).     

New cytotoxic dihydrochalcone and steroidal saponins from the aerial parts of Sansevieria cylindrica Bojer ex Hook

A new dihydrochalcone, 2‘,4‘-dihydroxy-3‘-methoxy-3,4-methylenedioxy-8-hydroxymethylene dihydrochalcone 1 and two new steroidal saponins, (25S)-ruscogenin-1-O-α-l-rhamnopyranosyl-(1 → 2)-β-d-glucopyranoside 2, (25S)-ruscogenin-3-O-α-l-rhamnopyranosyl-(1 → 4)-β-d-glucopyranoside 3, together with three known steroidal saponins (25S)-ruscogenin-3-O-β-d-glucopyranoside 4, (25S)-ruscogenin-1-O-α-l-rhamnopyranosyl-(1 → 2)-[β-d-xylopyranosyl-(1 → 3)]-α-l-arabinopyranoside 5 and (25R)-26-O-β-d-glucopyranosyl-furost-5-ene-1β,3β,22α,26-tetrol-1-O-α-L-rhamnopyranosyl-(1 → 2)-[β-d-xylopyranosyl-(1 → 3)]-α-l-arabinopyranoside 6 were isolated from the aerial parts of Sansevieria cylindrica. The structures of the new compounds were established by UV, IR, EI-MS, HR-ESI–MS as well as 1D (¹H,¹³C and DEPT-135) and 2D (HSQC, HMBC and TOCSY) NMR spectral analysis. The isolated compounds 1-6 were assayed for in vitro cytotoxicities against the three human tumor cell lines HT116, MCF7 and HepG2. Compound 1 showed a moderate cytotoxicity against MCF7. Compounds 2, 3 and 6 exhibited moderate cytotoxicities against the three used cell lines and compound 5 showed marked cytotoxicities against all used cell lines.     

Two new penterpenoid saponins and a new diterpenoid glycoside from Hemsleya chinensis

Two new penterpenoid saponins, hemsloside-Ma4 (1) hemsloside-Ma5 (2), and a new diterpenoid glycoside, hemsloside-Ma6 (3), were isolated from the rhizomes of Hemsleya chinensis. By detailed analysis of the NMR spectra and chemical methods, the structures of new compounds were determined to be 3-O-β-l-arabinopyranosyl-(1 → 3)-O-(6′-methyl ester)-β-d-glucuropyranosyl-oleanolic acid-28-O-β-d-glucopyranosyl-(1 → 6)-O-β-d-glucopyranoside (1), 3-O-β-l-arabinopyranosyl-(1 → 3)-O-(6′-methyl ester)-β-d-glucuropyranosyl-oleanolic acid-28-O-β-d-xylopyranosyl-(1 → 6)-O-β-d-glucopy-ranoside (2), and 13ϵ-hydroxylabda-8(17), 14-dien-18-oic acid-18-O-α-l-rhamnopyranosyl-(1 → 2)-O-β-d-glucopyranosyl-(1 → 4)-O-α-l-rhamnopyranoside (3). Diterpenoid-type compound (3) was isolated from Hemsleya genus for the first time.     

Triterpene glycosides from Agrostemma gracilis

Four triterpene saponins, agrostemmosides A–D were isolated from the methanol extract of Agrostemma gracilis. The structures of the compounds were determined as 3-O-β-d-xylopyranosyloleanolic acid 28-O-β-d-glucopyranosyl-(1 → 2)-[β-d-xylopyranosyl-(1 → 6)]-β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranosyl ester, 3-O-α-l-rhamnopyranosyl-(1 → 2)-β-d-xylopyranosyloleanolic acid 28-O-β-d-glucopyranosyl-(1 → 2)-[β-d-xylopyranosyl-(1 → 6)]-β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranosyl ester, 3-O-β-d-xylopyranosylechinocystic acid 28-O-β-d-glucopyranosyl-(1 → 2)-β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranosyl ester, 3-O-β-d-xylopyranosylechinocystic acid 28-O-β-d-glucopyranosyl-(1 → 2)-[β-d-xylopyranosyl-(1 → 6)]-β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranosyl ester by a combination of one- and two-dimensional NMR techniques, and mass spectrometry. To the best of our knowledge this is the first phytochemical report on A. gracilis, and echinocystic acid saponins were encountered for the first time in Caryophyllaceae family.     

Saponins in aerial parts of Helleborus viridis L.

In the search of natural compounds inhibiting methane production in ruminants three novel steroidal saponins have been isolated from the aerial parts of Helleborus viridis L. Their structures have been established based on spectral analyses as: (25R)-26-O-β-d-glucopyranosyl-5β-furostan-3β,22α,26-triol 3-O-β-d-glucopyranosyl-(1 → 6)-O-β-d-glucopyranoside, (25R)-26-O-β-d-glucopyranosyl-5α-furostan-3β,22α,26-triol 3-O-β-d-glucopyranosyl-(1 → 6)-O-β-d-glucopyranoside and (25R)-26-O-β-d-glucopyranosyl-furost-5-ene-1β,3β,22α,26-tetraol 1-O-{α-l-rhamnopyranosyl-(1 → 2)-O-[β-d-glucopyranosyl-(1 → 3)]-6-O-acetoxy-β-d-glucopyranoside}.     

New oleanane-type saponins: Leptocarposide B-D,from Ludwigia leptocarpa (Onagraceae)

Three new oleanane-type saponins, leptocarposide B-D (1–3), were isolated from the whole plant of Ludwigia leptocarpa (Nutt.) Hara, together with ten known compounds 4–13.The structures of these compounds were determined by interpretation of their spectral data, mainly HR-TOFESIMS, 1D-NMR (¹H, ¹³C) and 2D-NMR (¹H–¹H COSY, HSQC, HMBC, and NOESY), and by comparison with the literature data. The structures of the new compounds were established as 28-O-β-d-xylopyranosyl-(1 → 4)-α-l-rhamnopyranosyl-(1 → 2)-[α-l-arabinopyranosyl-(1 → 3)]-4-O-(3′-hydroxybutanoyloxy-3-hydroxybutanoyloxy)-β-d-fucopyranosyl zanhic acid (1); 3-O-β-d-glucopyranosyl-28-O-β-d-xylopyranosyl-(1 → 4)-α-l-rhamnopyranosyl-(1 → 2)-4-O-(3′-hydroxybutanoyloxy-3-hydroxybutanoyloxy)-β-d-fucopyranosyl medicagenic acid (2); 3-O-β-d-glucopyranosyl-(1 → 4)-β-d-glucopyranosyl-28-O-β-d-xylopyranosyl-(1 → 4)-α-l-rhamnopyranosyl-(1 → 2)-[α-l- arabinopyranosyl-(1 → 3)]-4-O-(3′-hydroxybutanoyloxy-3-hydroxybutanoyloxy)-β-d-fucopyranosyl zanhic acid (3).     

Highly glycosylated flavonols with an O-linked branched pentasaccharide from Iberis saxatilis (Brassicaceae)

Four flavonol glycosides isolated from non-flowering leafy shoots of Iberis saxatilis (Brassicaceae) were characterised by spectroscopic and chemical methods as saxatilisins A–D, the 3-O-β-d-glucopyranosyl-(1 → 3)-α-l-rhamnopyranosyl-(1 → 2)[β-d-glucopyranosyl-(1 → 2)-α-l-rhamnopyranosyl-(1 → 6)]-β-d-glucopyranoside, 3-O-β-d-glucopyranosyl-(1 → 3)-α-l-rhamnopyranosyl-(1 → 2)[α-l-rhamnopyranosyl-(1 → 6)]-β-d-glucopyranoside, 3-O-(6-O-E-sinapoyl)-β-d-glucopyranosyl-(1 → 3)-α-l-rhamnopyranosyl-(1 → 2)[β-d-glucopyranosyl-(1 → 2)-α-l-rhamnopyranosyl-(1 → 6)]-β-d-glucopyranoside, and 3-O-(6-O-E-feruloyl)-β-d-glucopyranosyl-(1 → 3)-α-l-rhamnopyranosyl-(1 → 2)[β-d-glucopyranosyl-(1 → 2)-α-l-rhamnopyranosyl-(1 → 6)]-β-d-glucopyranoside of isorhamnetin (3,5,7,4′-tetrahydroxy-3′-methoxyflavone), respectively. Analysis of ²J_HC correlations detected with the H2BC (heteronuclear two-bond correlation) pulse sequence aided the unambiguous assignment of glycosidic resonances in the ¹H and ¹³C NMR spectra of these compounds. Saxatilisins A, C, and D, are the first flavonol glycosides to be described with a pentasaccharide chain at a single glycosylation site. Several pentaglycosides of kaempferol and quercetin, tentatively assigned as saxatilisin analogues from LC–MS/MS analyses, were present as minor constituents of the extracts.     

A furan-2-carbonyl C-glucoside and an alkyl glucoside from the parasitic plant,Dendrophthoe pentandra

A new furan-2-carbonyl C-(6′-O-galloyl)-β-glucopyranoside (scleropentaside F, 1) and a new alkyl glucoside [butane-2,3-diol 2-(6′-O-galloyl)-O-β-glucopyranoside, 2] were isolated from the entire hemi-parasitic plant, Dendrophthoe pentandra growing on Tectona grandis together with ten known compounds including, benzyl-O-β-d-glucopyranoside (3), benzyl-O-α-l-rhamnopyranosyl-(1 → 6)-β-d-glucopyranoside (4), benzyl-O-β-d-apiofuranosyl-(1 → 6)-β-d-glucopyranoside (5), methyl gallate 3-O-β-d-glucopyranoside (6), methyl gallate 3-O-(6′-O-galloyl)-β-d-glucopyranoside (7), (+)-catechin (8), procyanidin B-1 (9) and procyanidin B-3 (10), bridelionoside A (11), and kiwiionoside (12). In addition, compounds 1, 3–9 were isolated from this species growing on the different host, Mangifera indica. The structure elucidations were based on physical data and spectroscopic evidence including 1D and 2D experiments.     

Phytochemical screening of flavonoids with their antioxidant activities from rapeseed (Brassica napus L.)

Ten flavone compounds, including three new flavonoid glycosides, were isolated from defatted rapeseed, and their protective antioxidant effect on H₂O₂-induced oxidative damage in human umbilical vein endothelial cells (ECV-304) was investigated. Three new flavonoid glycosides were identified as kaempferol-3-O-[(6-O-sinapoyl)-β-d-glucopyranosyl-(1 → 2)-β-d-glucopyranoside]-7-O-β-d-glucopyranoside (8), kaempferol-3,7-di-O-β-d-glucopyranoside-4'-O-(6-O-sinapoyl)-β-d-glucopyranoside (9), and kaempferol-3-O-[(3-O-sinapoyl)-β-d-glucopyranosyl-(1 → 2)-β-d-glucopyranoside]-7-O-β-d-glucopyranoside (10). The protective effects of all of the isolated compounds on H₂O₂-induced oxidative damage were assessed, and the activities of superoxide dismutase (SOD) and lactate dehydrogenase (LDH) were measured. All of compounds had a protective effect on H₂O₂-induced oxidative damage in ECV-304 cells and the presence of a substituted sinapoyl group and its position in the structures were used to elucidate the activity differences.     

Constituents of the leaves of Pseuderanthemum carruthersii (Seem.) Guill. var. atropurpureum (Bull.) Fosb.

A new iridoid, 5β,6β-dihydroxyantirrhide (1) was isolated from the dried leaves of Pseuderanthemum carruthersii (Seem.) Guill. var. atropurpureum (Bull.) Fosb. (Acanthaceae), together with 13 known compounds, including two iridoids, linarioside and antirrhinoside; five phenylethanoids, echipuroside A, verbascoside, isoverbascoside, isomartynoside and osmanthuside B; and six flavonoids, luteolin 7-O-β-d-glucopyranoside, luteolin 7-O-rutinoside, apigenin 7-O-rutinoside, apigenin 6-C-α-l-arabinopyranosyl–8-C-β-l-arabinopyranoside, apigenin 6,8-di-C-α-l-arabinopyranoside and apigenin 6-C-β-d-xylopyranosyl–8-C-α-l-arabinopyranoside. Their chemical structures were elucidated by 1D and 2D NMR as well as HR-ESI-MS spectroscopic analysis. Some purified compounds were evaluated the acetylcholinesterase inhibition and cytotoxic activities against the HeLa cervical cancer cell line and the MCF-7 breast cancer cell line at the concentration of 100 μg/mL. Luteolin 7-O-β-d-glucopyranoside exhibited cytotoxic activities against both the HeLa cervical cancer cell line and the MCF-7 breast cancer cell line. Verbascoside and isoverbascoside showed strong cytotoxic activity against the MCF-7 breast cancer cell line. The tested compounds showed the AChE inhibitory activity fairly weak.     

Three new flavonoid glycosides from the aerial parts of Graptophyllum grandulosum Turril (Acanthaceae)

Grandulosides A-C, three new flavonoid glycosides, were isolated from the aerial parts of Graptophyllum grandulosum Turill and identified as chrysoeriol-7-O-β-d-apiofuranosyl-(1 → 2)-β-d-xylopyranoside (1), chrysoeriol-7-O-[4′′′-O-acetyl-β-d-apiofuranosyl-(1 → 2)]-β-d-xylopyranoside (2) and 7-O-α-l-rhamnopyranosyl-(1 → 6)-β-d-(4′′-Sodium hydrogeno sulfate) glucopyranoside (3). Four known compounds, chrysoeriol-7-O-β-d-xyloside (4), isorhamnetin-3-O-α-l-rhamnopyranosyl-(1 → 6)-β-d-glucopyranoside (5), luteolin-7-O-β-d-apiofuranosyl-(1 → 2)-β-d-xylopyranoside (6) and sucrose (7) were also obtained. The structures of these compounds were established by interpretation of their spectral data, mainly HR-TOFESIMS, 1D-NMR (¹H, ¹³C) and 2D-NMR (COSY, NOESY, HSQC and HMBC) and by comparison with the literature data.     

A new semiterpenoid glycoside and a new benzofuran derivative glycoside from the roots of Heracleum dissectum

A new semiterpenoid glycoside, 3-methylbutan-1, 3-diol-1-O-β-d-glucopyranoside (1) and a new benzofuran derivative glycoside, 6-carboxylethyl-benzofuran-5-O-β-d-xylopyranosyl-(1 → 2)-β-d-glucopyranoside (2), together with seven known compounds (3-9) were isolated from the roots of Heracleum dissectum Ledeb. Their structures were elucidated on the basis of physicochemical properties and the detailed interpretation of various spectroscopic data. All the isolated compounds were screened for anti-inflammatory activity in vitro. And the result showed that compound 2 exhibited significantly inhibitory activity on nitric oxide production in RAW264.7 cells, which IC₅₀ value was equivalent to that of the positive control indomethacin.     

Cycloartane-type glycosides from Astragalus schottianus

Three new cycloartane-type triterpene glycosides were isolated from the roots of Astragalus schottianus Boiss. Their structures were established as 20(R),25-epoxy-3-O-β-d-xylopyranosyl-24-O-β-d-glucopyranosyl-3β,6α,16β,24α-tetrahydroxycycloartane (1), 20(R),25-epoxy-3-O-[β-d-glucopyranosyl(1 → 2)]-β-d-xylopyranosyl-24-O-β-d-glucopyranosyl-3β,6α,16β,24α-tetrahydroxycycloartane (2), 3-O-β-d-xylopyranosyl-3β,6α,16β,20(S),24(S),25-hexahydroxycycloartane (3) by the extensive use of 1D and 2D-NMR techniques and mass spectrometry.     

The synthesis of cholestane and furostan saponin analogues and the determination of sapogenin's absolute configuration at C-22

A facile and efficient way for the synthesis of cholestane and furostan saponin analogues was established and adopted for the first time. Following this strategy, starting from diosgenin, three novel cholestane saponin analogues: (22S,25R)-3β,22,26-trihydroxy-cholest-5-ene-16-one 22-O-[O-α-l-rhamnopyranosyl-(1 → 2)-β-d-glucopyranoside] 11, (25R)-3β,16β,26-trihydroxy-cholest-5-ene-22-one 16-O-[O-α-l-rhamnopyranosyl-(1 → 2)-α-d-glucopyranoside] 14 and (25R)-3β,16β,26-trihydroxy-cholest-5-ene-22-one 16-O-[O-α-l-rhamnopyranosyl-(1 → 2)-β-d-glucopyranoside] 17, three novel furostan saponin analogues: (22S,25R)-furost-5-ene-3β,22,26-triol 22-O-(α-d-glucopyranoside) 23, (22R,25R)-furost-5-ene-3β,22,26-triol 22-O-(α-d-glucopyranoside) 24 and (22S,25R)-furost-5-ene-3β,22,26-triol 22-O-[O-α-l-rhamnopyranosyl-(1 → 2)-α-d-glucopyranoside] 26, were synthesized ultimately. The structures of all the synthesized analogues were confirmed by spectroscopic methods. The S-chirality at C-22 of cholestane was confirmed by Mosher's method. The absolute configuration at C-22 of furostan saponin analogues was distinguished by conformational analysis combined with the NMR spectroscopy. The cytotoxicities of the synthetic analogues toward four types of tumor cells were shown also.     

New cytotoxic steroidal saponins from Cestrum parqui

Two new steroidal saponins, 25(R)-3β [(O-β-d-glucopyranosyl-(1 → 3)-β-d-glucopyranosyl-(1 → 2)-O-[β-d-xylopyranosyl-(1 → 3)-O-β-d-glucopyranosyl-(1 → 4)-β-d-galactopyranosyl)oxy]-5α, 15β, 22R, 25R-spirostan-3,15-diol (1, named parquispiroside) and 25R-26-[(β-d-glucopyranosyl)Oxy]-(3β [(O-β-d-glucopyranosyl-(1 → 3)-β-d-glucopyranosyl-(1 → 2)-O-[β-d-xylopyranosyl-(1 → 3)-O-β-d-glucopyranosyl-(1 → 4)-β-d-galactopyranosyl)oxy], 5α, 15β, 22R, 25R)-furostane-3,15,22-triol (2, named parquifuroside), along with the known saponins, capsicoside D (3) and 22-OMe-capsicoside D (4) and the known glycoside, benzyl primeveroside (5), were isolated from the leaves of Cestrum parqui. The structures of these compounds were elucidated by careful analysis of 1D and 2D NMR spectra and ESIMS data. Parquispiroside (1) exhibited moderate inhibition of Hela, HepG2, U87, and MCF7 cell lines with IC₅₀ values in the range of 3.3–14.1 μM.     

Flavonoid and cardenolide glycosides and a pentacyclic triterpene from the leaves of Nerium oleander and evaluation of cytotoxicity

A pentacyclic triterpene, oleanderocioic acid, two flavonoidal glycosides, quercetin-5-O-[α-l-rhamnopyranosyl-(1 → 6)]-β-d-glucopyranoside and kaempferol-5-O-[α-l-rhamnopyranosyl-(1 → 6)-β-d-glucopyranoside, and a cardenolide, oleandigoside, together with 11 known compounds, were isolated from the leaves of Nerium oleander. Their structures were elucidated on the basis of spectroscopic analysis. The growth inhibitory and cytotoxic activities of eight compounds were evaluated against the MCF-7 human breast cancer cell line using a sulforhodamine B assay. Three compounds, oleandrin, odoroside A and B were further assayed using a panel of 57 human cancer cell lines.