Curvularin derivatives from the soil-derived fungus Aspergillus polyporicola PSU-RSPG187

Two new curvularin derivatives, curvulopyran (1) and ent-curvulone A (2), along with ten known compounds including five cytochalasins and five curvularins, were isolated from a culture broth of the soil-derived fungus Aspergillus polyporicola PSU-RSPG187. Their structures were determined by spectroscopic methods. Known aspochalasin D displayed moderate antifungal activity against flucytosine–resistant Cryptococcus neoformans with an MIC value of 32 μg/mL and showed no cytotoxic activity against noncancerous cell lines. In addition, known α,β–dehydrocurvularin exhibited potential cytotoxic activity against both KB and MCF-7 cell lines with the IC₅₀ values of 11.26 and 19.50 μM. Unfortunately, it was strongly active against Vero cell lines.     

A new benzophenone from Mesua congestiflora,an inhibitor against human B lymphocyte cancer cell line

An investigation on the secondary metabolites from the roots of Mesua congestiflora was carried out. A new benzophenone–congestiflorone (1) and one xanthone, α-mangostin (2) were obtained. Structures of these compounds were determined using spectroscopic methods which included 1D and 2D NMR, GC–MS, IR and UV techniques. The cytotoxic activities of this new metabolite against cancer cell lines such as SNU-1, LS-174T, HeLa, SK-MEL-28, NCI-H23, IMR-32, Hep-G2 and K562 were evaluated using the MTT assays. Congestiflorone (1) gave good cytotoxic activity against Raji lymphoma cell line.     

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.     

Cytotoxic quassinoids from Ailanthus altissima

Two new quassinoids, altissinol A (1) and B (7), together with 12 known quassinoids, were isolated from the 95% ethanol extract of the barks of Ailanthus altissima. The structures of the new compounds (1 and 7) were determined on the basis of the spectroscopic methods including UV, IR, HR-ESI-MS, 1D and 2D NMR. The cytotoxic potential of all isolates were evaluated in vitro against three human hepatoma cell lines. Quassinoids 1–7 displayed potent cytotoxic activities against human hepatoma Hep3B and HepG2 cell lines. Interestingly, compounds 2, 3, and 5 exhibited cytotoxic activity against multidrug resistance HepG2/ADM cell line with IC₅₀ value 4.3-fold more sensitive to Doxorubicin (DOX).     

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.     

The cytotoxicity of 8-O-4′ neolignans from the seeds of Crataegus pinnatifida

Nine new 8-O-4′ neolignans, named pinnatifidanin B I–IX (1–9), together with 9 known analogs (10–18) were isolated from the seeds of Crataegus pinnatifida. The structures of 1–18 were determined by spectroscopic methods, including 1D, 2D NMR, CD and HRESIMS analysis. Compounds 8–11, 17 and 18 displayed potent cytotoxic activities against human cancer cell lines, and most interestingly, none of the 6 compounds displayed inhibitory activity against human lung cell line (Mrc5). The 6 cytotoxic compounds are considered to be potential as antitumor agents, which could significantly inhibit the cancer cell growth in a dose-dependent manner and are probably safer than positive control drug.     

Cytotoxic ent-Abietane-type diterpenoids from the roots of Euphorbia ebracteolata

Euphoroids A–C (1–3), three new ent-abietane-type diterpenoids, together with ten known analogues (4–13) were obtained from the roots of Euphorbia ebracteolata. The structures of these compounds were determined by extensive spectroscopic data analysis, including UV, HRESIMS, 1D-, and 2D-NMR data. The inhibitory effects of compounds 1–13 on human cancer cells were determined using the MTT assay. The results revealed that new compounds 2 and 3 showed moderate cytotoxic activities against human cancer cell lines. Especially, compound 3 displayed selective cytotoxic effect agains cancer cell lines.     

Tomensides A–D,new antiproliferative phenylpropanoid sucrose esters from Prunus tomentosa leaves

To search for novel cytotoxic constituents against cancer cells as lead structures for drug development, four new 3-phenylpropanoid-triacetyl sucrose esters, named tomensides A–D (1–4), and three known analogs (5–7) were isolated from the leaves of Prunus tomentosa. Their structures were elucidated by spectroscopic analyses (1D, 2D NMR, CD and HRESIMS). The cytotoxic activities of all isolates against four human cancer cell lines (MCF-7, A549, HeLa and HT-29) were assayed, and the results showed that these isolates displayed stronger inhibitory activities compared with positive control 5-fluorouracil. Tomenside A (1) was the most active compound with IC₅₀ values of 0.11–0.62 μM against the four tested cell lines. The structure–activity relationship (SAR) of the isolates was also discussed. The primary screening results indicated that these 3-phenylpropanoid-triacetyl sucrose esters might be valuable source for new potent anticancer drug candidates.     

Chemical constituents from Abrus cantoniensis and their cytotoxic effects on cancer cells

Two new compounds named 4-(4-hydroxybenzyl)-isofraxidin (1) and 1''-methoxyl-bavacoumestan B (2), along with five known compounds (3–7) were isolated from the EtOAc-soluble extract of Abrus cantoniensis. Their structures were elucidated with spectroscopic and physico-chemical analyses. All isolates were evaluated for their cytotoxic activities against four cancer cell lines including HepG2, SMMC-7721, A549 and MCF-7. Among them, compounds 1 and 5 exhibited significant cytotoxic activity on the above four cell lines. In particular, 1 showed the potent cytotoxic activity on HepG2 and SMMC-7721 cells with IC₅₀ values of 4.31 ± 0.5 and 3.24 ± 0.9 μM, respectively.     

Steroidal alkaloids from Solanum erianthum and their anti-breast cancer properties

Two new glycoalkaloids, erianosides A (1) and B (2) along with five known compounds (3–7) were isolated from the leaves of Solanum erianthum. Their structures were elucidated from analyses of spectroscopic data and all isolates were tested for in vitro cytotoxic activity against human breast cancer cell lines (BT-549, MDA-MB-231, T74D, and MCF-7). Solasonine (5) and solamargine (6) were active against the aforementioned four cancer cell lines with IC₅₀ values of 27.26–35.89 and 5.84–10.13 μM, respectively. Erianoside A (1) (T74D: IC₅₀, 56.39 µM) and solasodine (3) (BT-549 and MDA-MB-231: IC₅₀, 59.15 and 75.63 µM, respectively) had moderate cytotoxic effects towards some cell lines in the panel.     

Bibenzyl and phenolic glycosides from Pterospermum heterophyllum

A new bibenzyl, heterophyllic acid (1), and three new phenolic glycosides, heterophylloside A–C (2–4), along with two known phenolic glycosides oldhamioside (5) and 6′-O-vanilloylisotachioside (6) were isolated from Pterospermum heterophyllum. The structures of these compounds were elucidated on the basis of 1D, 2D NMR, MS spectroscopic analysis, and chemical methods. Their cytotoxic activities against KB and MCF-7 cancer cell lines were evaluated. Compound 2 showed significant cytotoxic activities.     

Phenylpropanoids from Juglans mandshurica exhibit cytotoxicities on liver cancer cell lines through apoptosis induction

Three new phenylpropanoids (1–3) together with six known congeners (4–9) were isolated from the bark of Juglans mandshurica Maxim using anti-hepatoma activity as a guide. Their structures were determined by comprehensive NMR and HRESIMS spectroscopic data analyses. All the isolated compounds were evaluated for their growth inhibitory activities against two kinds of liver cancer cell lines (HepG2 and Hep3B). Among them, compound 4 showed moderate cytotoxic activities against HepG2 and Hep3B cell lines with IC₅₀ values of 58.58 and 69.87 μM. Compound 5 exhibited 50% cell death rate in HepG2 and Hep3B cell lines at 63.70 and 46.45 μM, respectively. Further observation of morphological changes and Western blot demonstrated that compounds 4 and 5 exhibited their cytotoxic activities through the induction of apoptosis. A structure-activity relationship study suggested that an α, β-unsaturated aldehyde might be the most important functional group.     

Tricycloalternarene derivatives from the endophytic fungus Guignardia bidwellii PSU-G11

Four new tricycloalternarene derivatives, guignarenones A–D (1–4), along with known (6S,9R)-vomifoliol were isolated from the endophytic fungus Guignardia bidwellii PSU-G11. Their structures were determined on the basis of spectroscopic data. The absolute configurations in 1 were assigned using a combination of the modified Mosher's method and NOEDIFF data. Compound 1 displayed mild cytotoxic activity against oral cavity cancer and African green monkey kidney fibroblast (Vero) cell lines.     

Diarylpropanes and lignans from Horsfieldia tetratepala

Two new diarylpropanes (1–2), four known compounds, and a new artifact, were isolated from 70% aqueous acetone extract of the twigs of Horsfieldia tetratepala. Their structures were elucidated by spectroscopic analysis. Cytotoxicity evaluation against five cancer cell lines showed that none of these compounds was cytotoxic.     

Identification and biological activity of secondary metabolites from Dryobalanops beccarii

A new trimeric oligostilbene, malaysianol D (1) and galloylglucoside, malaysin A (2), together with twelve known compounds (3–14) have been isolated from the methanol extract of the stem bark of Dryobalanops beccarii by combination of vacuum and radial chromatography techniques. Their structures were established on the basis of their spectroscopic evidence and comparison with the published data. The cytotoxic activity of isolated compounds was tested against A549 and MCF-7 cancer cell lines.     

Venezuelines A–G,new phenoxazine-based alkaloids and aminophenols from Streptomyces venezuelae and the regulation of gene target Nur77

Five new phenoxazine-based alkaloids venezuelines A–E (1–5) and two new aminophenols venezuelines F–G (6–7), as well as three known analogues exfoliazone, chandrananimycin D and carboxyexfoliazone were isolated from the fermentation broth of the marine-derived bacterium Streptomyces venezuelae. The structures of new compounds were determined on the basis of extensive spectroscopic analysis. The cytotoxic activity of these compounds against a panel of tumor cell lines were tested, while the regulation of gene target Nur77 of 2 and exfoliazone (8) were evaluated.     

New phenylpropanoids with cytotoxic activities from Drypetes hainanensis

Phytochemical investigation on Drypetes hainanensis has resulted in the isolation of three new phenylpropanoids, named drypetesins A–C (1–3). Their structures were elucidated by applying various spectroscopic techniques (NMR, UV, IR, MS, and CD). The antiproliferative activities of these compounds were evaluated in vitro against three cultured cancer cell lines. Those new isolates exhibited potent cytotoxic activities against human hepatoma (HepG2), human breast adenocarcinoma (MCF-7), and human lung carcinoma (A-549) cancer cell lines with IC₅₀ value range 5.6–14.8 μM.     

New cytotoxic quinone analogues from the rhizomes of Arnebia euchroma

Two new quinone analogues, given the trivial names arneromas A–B (1–2) were isolated from the rhizome of Arnebia euchroma. Their structures were elucidated on the basis of extensive spectroscopic analyses. The absolute configurations of both compounds were determined by comparison of their calculated and experimental CD curves. In addition, compounds 1–2 were tested for their cytotoxic activities against HCT-8 and HL-60 cancer cell lines, and both of the compounds showed moderate inhibitory activities against HL-60 cell line with IC₅₀ values of 9.1 and 7.2 μM, respectively.     

C21 steroidal glycosides with cytotoxic activities from Cynanchum otophyllum

Eight new C21 steroidal glycosides, namely cynanotins A–H (1–8), together with fifteen known analogues, were isolated from the roots of Cynanchum otophyllum. Their structures were elucidated by spectroscopic analysis and chemical methods. In this study, all of isolates were tested for their vitro inhibitory activities against five human tumor cell lines (HL-60, SMMC-7721, A-549, MCF-7 and SW480). Compounds 3–15 showed moderate cytotoxic activities against HL-60 cell lines with IC₅₀ values ranging from 11.4 to 37.9?µM. Compounds 5, 9, and 10 showed marked or moderate cytotoxic activities against five human tumor cell lines with IC₅₀ values ranging from 11.4 to 36.7?µM. Compound 11 displayed moderate cytotoxic activities against HL-60, SMMC-7721, MCF-7 and SW480 cell lines with IC₅₀ values of 12.2–30.8?µM. Compared to the positive control (IC₅₀: 35.0?µM), compounds 5, 9–11 exhibited more potential inhibitory activity against MCF-7 cells (IC₅₀: 16.1–25.6?µM).     

Cytotoxic clerodane diterpenoids from the leaves of Casearia kurzii

A phytochemical investigation to obtain bioactive substances as lead compounds or agents for cancer led to the obtainment of six new clerodane diterpenoids, designated as kurzipenes A–F (1–6), from the leaves of Casearia kurzii. Their structures were elucidated on the basis of NMR spectroscopic data analysis and the absolute configurations were confirmed by the time-dependent density functional theory (TDDFT) electronic circular dichroism (ECD) calculations. The cytotoxic activities of compounds 1–6 were evaluated against human lung cancer A549 cell line, human cervical cancer Hela cell line, and human hepatocellular carcinoma HepG2 cell line. Most diterpenoids showed potent cytotoxicities against the three selected cancer cell lines. The preliminary mechanism studies revealed that the most active compound 2, with an IC₅₀ value of 5.3 μM against Hela cells, induced apoptosis and arrested the Hela cell cycle at the G0/G1 stage to exert cytotoxic effects.