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.     

Oleanane glycosides from the roots of Alhagi maurorum

Three new oleanane-type triterpene glycosides (1–3), along with four known compounds (4–7) glycosides, were isolated from the roots of Alhagi maurorum. Their structures were elucidated by 1D and 2D-NMR experiments as well as ESI-MS analysis. The antiproliferative activity of the isolated compounds was evaluated against a small panel of cancer cell lines including human breast cancer (MCF-7), human lung adenocarcinoma (A549), human prostate cancer (PC-3) and human leukemia (U937) cell lines. None of the tested compounds, in a range of concentrations between 1 and 50 μM, caused a significant reduction of the cell number.     

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.     

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.     

Three new flavonoids from the leaves of oriental tobacco and their cytotoxicity

Three new flavonoids, 6,7-dimethoxy-4′-hydroxy-8-formylflavon (1), 8-formyl-4′,6,7-trimethoxyflavon (2), 4′,7-dihydroxy-8-formyl-6-methoxyflavon (3), together with fifteen known flavonoids (4–18) were isolated from the leaves of oriental tobacco (a variety of Nicotiana tabacum L). Their structures were determined by means of HRESIMS, extensive 1D and 2D NMR spectroscopic studies and chemical evidences. The cytotoxicity against five human tumor (NB4, A549, SHSY5Y, PC3, and MCF7) cell lines of compounds 1–3 were also evaluated. The results showed that compounds 1 and 3 showed high cytotoxicity against PC3 and A549 cell lines with IC₅₀ values of 2.6 and 1.6 μM, respectively.     

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.     

Limonoids from the leaves of Toona ciliata var. yunnanensis

Twelve limonoids, toonayunnanins A–L (1–12) and eleven known compounds (13–23) were isolated from the leaves of Toona ciliata var. yunnanensis, and their structures were elucidated by means of extensive spectroscopic analyses, particularly 1D and 2D NMR techniques. The inhibitory effects of all the isolated compounds were evaluated on human tumor cell lines, such as HL-60, SMMC-7721, A-549, MCF-7 and SW480. Cedrelone (13) and dysobinin (18) showed significant cytotoxicity, and toonayunnanin B (2) and epoxyazadiradione (14), were found to be slightly cytotoxic against the above cell lines. Furthermore, this study provides valuable information for the chemotaxonomy of T. ciliata varieties.     

New biphenyl derivatives from the leaves of Nicotiana tabacum and their cytotoxic activity

With the aim of searching for new bioactive metabolites from medicinal plants, three new biphenyls, tababiphenyls G–I (1–3), together with four known ones (4–7) were isolated from the leaves of Nicotiana tabacum. Their structures were elucidated by extensive NMR and MS spectroscopic analyses. All the isolated compounds were evaluated for their cytotoxicity against NB4, A549, SHSY5Y, PC3, and MCF7 human cancer cell lines, and some of them showed moderate inhibitory activities against several human tumor cell lines with IC₅₀ values ranging from 2.8 to 9.4 μM.     

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.     

Cytotoxic cardiac glycosides and coumarins from Antiaris toxicaria

Eight new cardiac glycosides/aglycones (antiaritoxiosides A–G, 1–7, and antiarotoxinin B, 8), two new coumarins (anticarins A–B, 41–42), and two new flavanones (antiarones L–K, 43–44) were isolated from trunk bark of Antiaris toxicaria together with 53 known compounds. The new structures were established by extensive analysis of spectroscopic data. Compound 1 (10-carboxy and 3α-hydroxy) and compounds 3–6 (10-hydroxy) contain unique substituents that are rarely found in cardiac glycosides. The cytotoxic effects of isolated compounds against ten human cancer cell lines, KB, KB-VIN, A549, MCF-7, U-87-MG, PC-3, 1A9, CAKI-1, HCT-9 and S-KMEL-2, were tested using the sulforhodamine B assay. Five compounds (12, 16, 20, 22, and 31) showed significant cytotoxicity against all ten cancer cell lines, with notable potency at the ng/mL level against some cell lines, which merits further development as clinical trial candidates.     

Three new abietane diterpenoids from Podocarpus fleuryi

Three new abietane diterpenoids, fleuryinols A–C (1–3), together with fourteen known compounds, were isolated from the twigs and leaves of Podocarpus fleuryi. Their structures were established by spectroscopic analysis, including 1D- and 2D-NMR spectroscopic techniques. Compounds 1–8 were tested cytotoxic activity against five human cancer cell lines, HL-60, SMMC-772, A-549, MCF-7, and SW480, of which fleuryinol B (2) and 19-hydroxyferruginol (4) exhibited moderate cytotoxic activity against some cell lines.     

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.     

New cassane diterpenes from the fruits of Caesalpinia mimosoides Lam.

Six new cassane diterpenes, caesmimosins A-F (1–6) were isolated from the fruits of Caesalpinia mimosoides Lam. Their structures were identified by 1D and 2D NMR spectral data. Compounds 1–6 were evaluated for their cytotoxicity on HL-60, SMMC-7721, A-549, MCF-7 and SW-480 human cancer cell lines, they did not show inhibitory cytotoxic activities at a concentration of 40 μM against the five cell lines.     

Sinopestalotiollides A–D,cytotoxic diphenyl ether derivatives from plant endophytic fungus Pestalotiopsis palmarum

Four new diphenyl ether derivatives, sinopestalotiollides A–D (1–4), one new natural α-pyrone product (11), as well as twelve known compounds (5–1?7), were obtained from the ethyl acetate extract of the endophytic fungus Pestalotiopsis palmarum isolated from the leaves of medicinal plant Sinomenium acutum (Thunb.) Rehd et Wils. The structures were elucidated by HR-ESI-MS and NMR spectrometry data. Bioassay experiments revealed that compounds 1–4 and 11 exhibited strong to weak cytotoxicities against three human tumor cell lines Hela, HCT116 and A549.     

Cytotoxic polyketides from endophytic fungus Phoma bellidis harbored in Ttricyrtis maculate

Four new polyketides, namely bellidisins A-D (1-4), were isolated from rice fermentation extract of endophytic fungus Phoma bellidis, along with three known compounds pinolidoxin (5), 5,6-epoxypinolidoxin (6), and 2-epi-herbarumin II (7). Their structures and absolute configurations were determined by 1D and 2D NMR, HRESIMS and ECD calculation. Their cytotoxicity was evaluated against human cancer cell lines HL-60, A549, SMMC-7721, MCF-7, and SW480. Compound 4 showed significant cytotoxicity on these five cell lines with IC₅₀ value ranged from 3.40 to 15.25 μM, which is stronger than cisplatin (4.86–27.70 μM).     

Ceramide,cerebroside and triterpenoid saponin from the bark of aerial roots of Ficus elastica (Moraceae)

Three compounds, ficusamide (1), ficusoside (2) and elasticoside (3), were isolated from the bark of aerial roots of Ficus elastica (Moraceae), together with nine known compounds, including four triterpenes, three steroids and two aliphatic linear alcohols. The chemical structures of the three compounds were established by extensive 1D and 2D NMR spectroscopy, mass spectrometry and by comparison with published data. The growth inhibitory effect of the crude extract and isolated compounds was evaluated against several microorganisms and fungi. The cytotoxicity against human cancer cell lines was also assessed. Ficusamide (1) displayed a moderate in vitro growth inhibitory activity against the human A549 lung cancer cell line and a strong activity against Staphylococcus saprophyticus, while elasticoside (3) showed a potent activity on Enterococcus faecalis.     

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.     

Lactarane sesquiterpenoids from Lactarius subvellereus and their cytotoxicity

Subvellerolactones B (1), D (2), and E (3), structurally unusual lactarane sesquiterpenoids, were isolated from the fruiting bodies of Lactarius subvellereus together with four known lactarane sesquiterpenes (4–7). The chemical structures and stereochemistries of compounds 1–3 were determined on the basis of spectroscopic analyses, including 1D and 2D NMR experiments and a convenient Mosher ester procedure. Subvellerolactone B (1) exhibited cytotoxicity against the A549, SK-MEL-2, and HCT-15 cell lines with IC₅₀ values of 26.5, 18.3, and 14.2 μM, respectively, and subvellerolactones D (2) and E (3) showed cytotoxicity against the A549 and HCT-15 cell lines (IC₅₀ (2): 25.1 and 17.8 μM, and IC₅₀ (3): 19.6 and 28.7 μM, respectively).     

Incrassamarin A–D: Four new 4-substituted coumarins from Calophyllum incrassatum and their biological activities

Four new 4-substituted coumarins, incrassamarin A (1), B (2), C (3) and D (4) with (7S,8S)-7,8-dihydro-5-hydroxy-7,8-dimethyl-4-propyl-2H,6H-benzo[1,2-b;5,4-b’]dipyran-2,6-dione (5), friedelin, carpachromene, amentoflavone, epiafzelechin and L-quercitrin were isolated from the barks and leaves of Calophyllum incrassatum (Guttiferae). The compounds were isolated and purified by size-exclusion recycling HPLC and column chromatographic techniques. The structures of the compounds were determined by spectroscopic means. The compounds were tested for their cytotoxic activity towards MCF-7 and A-549 cell lines and α-glucosidase enzymatic inhibitory activity. Compound (1) displayed cytotoxic activity against A-549 cell lines with IC₅₀ 87.71 μg/mL and showed inhibition towards α-glucosidase enzymatic activity with IC₅₀ 93.25 μM. This is the first report on the isolation of phytochemicals from the barks and leaves of C. incrassatum and their bioactivities.     

Three new labdane diterpenes from Loxocalyx urticifolius

Three new labdane diterpenes, namely loxocalyxin D (1), loxocalyxin E (2) and 13-epiloxocalyxin E (3), were isolated from the whole plants of Loxocalyx urticifolius Hemsl. Their structures were elucidated by extensive spectral analysis and chemical methods. The absolute configuration of loxocalyxin D (1) was confirmed by X-ray crystallographic analysis. The cytotoxic activities of the isolated labdane diterpenes were evaluated against the four human cancer cell lines A549, HepG2, HL-60 and MCF-7. 13-epiloxocalyxin E (3) exhibited selective cytotoxicity against A549 and MCF-7 with the IC₅₀ values of 22.4 and 47.3 μM, respectively.