Triterpenoid saponins from Albizia boromoensis Aubrév. & Pellegr

As part of our search of new bioactive saponins from Cameroonian medicinal plants, phytochemical investigation of the roots of Albizia boromoensis led to the isolation of four new oleanane-type saponins, named boromoenosides A–D (1–4). Their structures were established by direct interpretation of their spectral data, mainly HRESIMS, 1D NMR (¹H, ¹³C NMR, and DEPT) and 2D NMR (COSY, NOESY, HSQC and HMBC), and by comparison with the literature data. All isolated saponins were assayed for their cytotoxicity against U-87 MG human glioblastoma cell lines and TG1 glioblastoma stem-like cells with no positive activity detected.     

Steroidal saponins with cytotoxic activity from the rhizomes of Paris polyphylla var. yunnanensis

Two previously unreported spirostanol saponins, dianchonglouosides A and B (1 and 2), along with 7 known steroidal saponins (3–9) were isolated from the rhizomes of Paris polyphylla var. yunnanensis. Their structures were elucidated by extensive spectroscopic analysis (MS, 1D, and 2D NMR), and chemical methods. The cytotoxic activities of the isolated compounds 1–9 were also evaluated against two human cancer cell lines (HEK293 and HepG2). The results showed that compound 7 had the strongest cytotoxic activity against the two cancer cell lines with the IC₅₀ values of 0.6 and 0.9 μM, respectively.     

Bioactive triterpenoids from twigs of Betula schmidtii

Investigation of the MeOH extract of Betula schmidtii twigs resulted in the isolation and identification of three new triterpenoids (1–3), along with ten known ones (4–13). The structures of new compounds (1–3) were elucidated by spectroscopic methods, including 1D, 2D NMR (¹H and ¹³C NMR, COSY, HSQC, HMBC, and NOESY), HR-MS, and chemical methods. All the isolated compounds were evaluated for their cytotoxicity against A549, SK-OV-3, SK-MEL-2, and HCT-15 cell lines. Compound 11 exhibited potent cytotoxic activities against four cell lines, and compounds 5 and 13 significantly induced nerve growth factor secretion in a C6 rat glioma cell line. Their anti-inflammatory effects were also assessed by measuring nitric oxide production in lipopolysaccharide–activated BV-2 cells. Compounds 7 and 12 displayed potent inhibition of nitric oxide production, without significant cell toxicity.     

Bioactive oleanane-type saponins from the rhizomes of Anemone taipaiensis

Investigation of the n-BuOH extract of the rhizomes of Anemone taipaiensis led to the isolation of five new oleanane-type triterpenoid saponins (1–5), together with seven known saponins (6–12). Their structures were determined by the extensive use of ¹D and ²D NMR experiments along with ESIMS analyses and acid hydrolysis. The aglycone of 1, 2 and 4 was determined as siaresinolic acid, which was reported in this genus for the first time. The cytotoxicities of the saponins 1–12, prosapogenins 4a, 5a, 10a–12a and sapogenins siaresinolic acid (SA), oleanolic acid (OA), hederagenin (HE) were evaluated against five human cancer cell lines, including HepG2, HL-60, A549, HeLa and U87MG. The monodesmosidic saponins 6–8, 5a, 10a–12a and sapogenins SA, OA, HE exhibited cytotoxic activity toward all cancer cell lines, with IC₅₀ values ranging from 2.25 to 57.28 μM. Remarkably, the bisdesmosidic saponins 1–4 and 9 showed selective cytotoxicity against the U87MG cells.     

Phytochemical investigation of labdane diterpenes from the rhizomes of Hedychium spicatum and their cytotoxic activity

A comprehensive reinvestigation of chemical constituents from the rhizomes of Hedychium spicatum led to the isolation of two new labdane-type diterpene (1, 2), together with six known compounds (3–8). Their structures were established on the basis of extensive spectroscopic (IR, MS, 2D NMR) data analysis and by comparison with the spectroscopic data reported in the literature. In addition, all the isolates were tested for their cytotoxicity against the THP-1 (human acute monocytic leukemia), HL-60 (human promyelocytic leukemia), A-375 (human malignant melanoma) and A-549 (human lung carcinoma) cancerous cell lines.     

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.     

Five new triterpenoid saponins from the Roots of Camellia oleifera C. Abel with cytotoxic activities

Five new triterpenoid saponins, oleiferosides P–T (1–5) were isolated from the EtOH extract of the roots of Camellia oleifera C. Abel. The structures of saponins 1–5 were elucidated on the basis of integrated spectroscopic techniques. All the compounds were characterized to be oleanane-type saponins with sugar moieties linked to the C-3 of the aglycone. By using the MTT assay, an in vitro analysis of the cytotoxic activities of these saponins on the human tumor cell lines (lung adenocarcinoma A549 cells, hepatic carcinoma SMMC-7721 cells and breast cancer MCF-7 cells). Among them, compound 4 showed a certain cytotoxic activity against all the tested cell lines.     

Dimeric antioxidant and cytotoxic triterpenoid saponins from Terminalia ivorensis A. Chev.

Three saponins, including two dimeric triterpenoid glucosides possessing an unusual skeleton, ivorenosides A and B, and a monomeric triterpenoid saponin (ivorenoside C), together with the known sericoside, were isolated from the bark of Terminalia ivorensis. Their structures were established on the basis of 1D and 2D NMR data, chemical methods and tandem MS–MS spectrometry as a dimer of β-d-glucopyranosyl-18,19-seco-2α,3β,19,19,24-pentahydroxyolean-12-en-28-oate and β-d-glucopyranosyl-2α,3β,19α,24-tetrahydroxyolean-12-en-28-oate (ivorenoside A, 1), a dimer of β-d-glucopyranosyl-18,19-seco-24-carboxyl-2α,3β,19,19-tetrahydroxyolean-12-en-28-oate and β-d-glucopyranosyl-2α,3β,19α,24-tetrahydroxyolean-12-en-28-oate (ivorenoside B, 2) and β-d-glucopyranosyl-2α,3β,19β,24-tetrahydroxyolean-11-oxo-olean-12-en-28-oate (ivorenoside C, 3). Ivorenosides A and B are the first examples in nature of dimeric triterpenoid saponins with a 18,19-seco E ring of one of the two units. These isolated compounds were evaluated for their antioxidant properties and further for their cytotoxic activity against four human cancer cell lines. Ivorenoside B and C exhibited scavenging activity against DPPH and ABTS⁺ radicals with IC₅₀ values comparable with that of the standard drug Trolox and ivorenoside A showed antiproliferative activity against MDA-MB-231 and HCT116 human cancer cell lines with IC₅₀ values of 3.96 and 3.43 μM, respectively.     

Triterpenoid saponins from Piptadeniastrum africanum (Hook. f.) Brenan

One new triterpenoid saponin, named piptadeniaoside (1), along with two known saponins (2–3) have been isolated from the stem bark of Piptadeniastrum africanum. After previous isolation of flavone derivatives from this plant, new phytochemical investigations were performed for its saponin content. Their structures were established by direct interpretation of their spectral data, mainly HRESIMS, 1D NMR (¹H, ¹³C NMR, DEPT) and 2D NMR (COSY, NOESY, HSQC and HMBC), and by comparison with the literature data.     

Novel dammarane saponins from Gynostemma pentaphyllum and their cytotoxic activities against HepG2 cells

Two new dammarane saponins, 2α,3β,12β-trihydroxydammar-20(22),24-diene-3-O-[β-d-glucopyranoxyl(1→2)-β-d-6″-O-acetylglucopyranoside (1, namely damulin C) and 2α,3β,12β-trihydroxydammar-20(21),24-diene-3-O-[β-d-glucopyranoxyl(1→2)-β-d-6″-O-acetylglucopyranoside (2, namely damulin D), were isolated from the ethanol extract of Gynostemma pentaphyllum, which had been heat processed by steaming at 125 °C. The NMR spectroscopic data of the novel saponins were completely assigned by using a combination of 2D NMR experiments including ¹H–¹H COSY, HSQC, and HMBC. Their cytotoxic activities of human liver adenocarcinoma HepG2 cells were evaluated in vitro. They showed cytotoxicities against HepG2 cell line with IC₅₀ of 40 ± 0.7 and 38 ± 0.5 μg/ml, respectively.     

Steroidal saponins from the fresh tubers of Ophiopogon japonicus

Eleven novel furostanol saponins, named ophiofurospisides C–E, G–N (1–3, 5–12), one new spirostanol saponin, named ophiopogonin R (13), were isolated from the fresh tubers of Ophiopogon japonicus. Their structures were determined on the basis of spectroscopic techniques (1D and 2D NMR) and HRESIMS. The isolated furostanol saponins possessed two sugar chains located at C-3 and C-26, respectively. Six furostanol saponins (1, 5–9) with disaccharide moiety linked at position C-26 of the aglycone were rare in the plant kingdom.     

Cytotoxic clerodane diterpenoids from Croton crassifolius

Hepatocellular carcinoma (HCC) is the most common type of liver cancer, and treatment options for HCC are limited. In addition, the discovery of new natural compounds with anti-hepatocarcinoma activity is attracting increasing attention. For this reason, phytochemical investigation of Croton crassifolius led to the isolation of 17 diterpenoids, including three new clerodane diterpenoids, named crassifolius A-C (1–3), along with 14 known ones (4–17). Their structures were established by 1D, 2D NMR, HR-ESI-MS, detailed calculated electronic circular dichroism (ECD) spectra and the assistance of quantum chemical predictions (QCP) of ¹³C NMR chemical shifts. The cytotoxicities of all these compounds against human liver cancer lines (HepG2 and Hep3B) were determined. Among them, compound 1 exhibited good cytotoxicity with IC₅₀ value of 17.91 μM against human liver tumor cells Hep3B. Following further studies of the anti-tumor mechanism of compound 1-induced cell growth inhibition, we found that compound 1 caused apoptotic cell death in Hep3B cells by detecting morphologic changes and Western blotting analysis.     

Mandshunosides C–E from the roots and rhizomes of Clematis mandshurica

Three new triterpene saponins, mandshunosides C–E (1–3) together with four known triterpene saponins (4–7) were isolated from the roots and rhizomes of Clematis mandshurica. Their structures were elucidated on the basis of spectroscopic evidence and hydrolysis products. Those compounds showed inhibitory activities against two human colorectal cancer cell lines HCT-116 and HT-29.     

New ursane-type triterpenes from the root bark of Calotropis procera

As a part of our continuing interest in identifying anticancer drug leads from natural sources, we have investigated the in vitro growth inhibitory effects of the hexane fraction of the root bark of Calotropis procera (Ait) R. Br. (Asclepiadaceae). This study reports the isolation and structure elucidation of four new ursane-type triterpenes named calotroprocerol A (1), calotroproceryl acetate A (2), calotroprocerone A (3) and calotroproceryl acetate B (4) in addition to five known compounds including pseudo-taraxasterol acetate (5), taraxasterol (6), calotropursenyl acetate B (7), stigmasterol (8) and (E)-octadec-7-enoic acid (9). Their structures were established on the basis of 1D and 2D NMR studies (¹H–¹H COSY, HSQC, and HMBC) and HRMS spectral data. The in vitro growth inhibitory activity of the isolated compounds was evaluated against three human cancer cell lines including the A549 non-small cell lung cancer (NSCLC), the U373 glioblastoma (GBM) and the PC-3 prostate cancer cell lines.     

Triterpene glycosides with in vitro anti-inflammatory activity from Cyclamen repandum tubers

A new triterpene glycoside, repandoside (1) was isolated together with six known saponins (2-7) from the methanol extract of Cyclamen repandum tubers. The isolated saponins were characterized by high resolution mass spectrometry and both 1D and 2D NMR experiments. The in vitro effect of saponins on LPS-induced IL-8 and TNF-α mRNA level (by quantitative RT-PCR) and protein release (by ELISA) was evaluated in human THP-1 macrophages. We found that compounds 1 (repandoside), 2 (deglucocyclamin) and 4 (anagalloside B) at 100 μM inhibited the LPS-induced IL-8 and TNF-α expressions.     

Macathiohydantoins P–R,three new thiohydantoin derivatives from Maca (Lepidium meyenii)

Three new thiohydantoins with a 2-thioxoimidazolidin-4-one nucleus, named macathiohydantoins P–R (1–3), along with one known analog (4), were isolated from the roots of Lepidium meyenii. Their structures were elucidated by means of analysis of extensive spectroscopic data, including ¹D NMR, ²D NMR and HRESIMS. The thiohydantoins (1–4) were isolated as racemic mixtures, which were further separated by chiral semi-preparative HPLC to afford the corresponding enantiomers. Their absolute configuration of C-5 was assigned by comparison of optical rotation values with those reported in the literature. All thiohydantoin derivatives were evaluated for their cytotoxicities against five human cancer cell lines.     

Three new cytotoxic sesquiterpenoids from Solanum lyratum

In our continuing effort to discover more new cytotoxic sesquiterpenoid from Solanum lyratum collected from different districts of China, three new sesquiterpenoids, attributable to eudesmane-type (1, named solajiangxin D) and vetispirane-type (2–3, named solajiangxins E and 2-hydroxysolajiangxin E), respectively, were isolated. Their structures were elucidated on the basis of integrated spectroscopic techniques, mainly HR-FABMS, 1D and 2D NMR (¹H–¹H COSY, HMQC, HMBC and ROESY). In vitro, compounds 1–3 were found to show significant cytotoxicities against three human cancer lines (P-388, HONE-1, and HT-29), and gave ED₅₀ values in the range 2.1–3.7 μg/ml.     

New acylated triterpene saponins from the roots of Securidaca inappendiculata Hassk

Two new acylated triterpene saponins, named as securioside C (1), securioside D (2), and one pair of isomers 3/4, the (Z)–isomer securioside E (3) being new, together with a known triterpene saponin polygalasaponin XLIV (4) were isolated from the roots of Securidaca inappendiculata Hassk. Their structures were established by HRESIMS, 1D and 2D NMR experiments and comparison of their NMR data with previous reported data. In addition, Compounds 1–2, 3/4, 4 were evaluated for cytotoxicities against LLC (Lewis lung carcinoma) and MCF-7 (human breast cancer) cell lines. Compounds 1 and 2 exhibited moderate cytotoxic activities against LLC cells with IC₅₀ values of 45.56 μM and 85.98 μM.     

Two new hemiterpene glycosides and one new phenolic glycoside from the roots of Securidaca inappendiculata Hassk

Two new hemiterpene glycosides, named as securiterpenoside B (1), and securiterpenoside C (2), and one new phenolic glycoside, named as securiphenoside A (3) were isolated from the roots of Securidaca inappendiculata Hassk. Their structures were elucidated on the basis of 1D and 2D NMR data and HRESIMS and comparisons with published data. Moreover, compounds 1–3 were evaluated for cytotoxicities against A549 (Lewis lung cancer), Hela (human cervical cancer) and MCF-7 (human breast cancer) cell lines.     

Investigation of chemical constituents from Spiraea prunifolia var. simpliciflora and their biological activities

Quantum mechanics (QM)-based calculations for elucidating full structures of natural compounds are growing in importance and reliability. Two new phenolic glycosides (1 and 2) and 11 known compounds were isolated from the twigs of Spiraea prunifolia var. simpliciflora. The chemical structures of the new compounds (1 and 2) were initially established through different NMR techniques (¹H and ¹³C NMR, COSY, HSQC, and HMBC), HRMS data analysis, and chemical hydrolysis. These structure assignments were further verified by QM-based NMR chemical shift calculations. All of the purified compounds (1–13) were evaluated for their cytotoxicity against four human cancer cell lines (A549, SK-OV-3, SK-MEL-2, and BT549). Those phytochemicals were also evaluated for both anti-inflammatory activity through the measurement of nitric oxide (NO) production levels in lipopolysaccharide (LPS)-stimulated murine microglia BV-2 cell lines and neuroprotective effects via induction of nerve growth factor (NGF) in C6 glioma cells.