Bioactive jatrophane diterpenes from Euphorbia guyoniana

Chromatographic investigation of the methylenechloride/methanol extract of the aerial parts of Euphorbia guyoniana afforded two jatrophane diterpenes, designated guyonianins E and F, in addition to a known jatrophane diterpene. The structures of the compounds were determined by comprehensive NMR analyses, including DEPT, COSY, HMQC, HMBC, NOESY and HRMS. These compounds exhibited cytotoxicity against human embryonic kidney 293 (HEK293) cells with IC₅₀ values of 35–100 μM.     

Synthesis,Cytotoxicity and Antimicrobial Evaluation of New Coumarin‐Tagged β‐Lactam Triazole Hybrid

A series of coumarin‐tagged β‐lactam triazole hybrids ( 10a – 10o ) were synthesized and tested for their cytotoxic activity against MDA‐MB‐231 (triple negative breast cancer), MCF‐7 (estrogen receptor positive breast cancer (ER+)) and A549 (human lung carcinoma) cancer cell lines including one normal cell line, HEK‐293 (human embryonic kidney). Two compounds 10b and 10d exhibited substantial cytotoxic effect against MCF‐7 cancer cell lines with IC₅₀ values of 53.55 and 58.62 μm , respectively. More importantly, compounds 10b and 10d were non‐cytotoxic against HEK‐293 cell lines. Structure–activity relationship (SAR) studies suggested that the nitro and chloro group at the C‐3 position of phenyl ring are favorable for anticancer activity, particularly against MCF‐7 cell lines. Furthermore, antimicrobial evaluation of these compounds revealed modest inhibition of examined pathogenic strains with compounds 10c and 10i being the most promising antimicrobial agents against Pseudomonas aeruginosa and Candida albicans, respectively.     

Hexane Extract of Echinops spinosissimus Turra subsp. spinosus from Tunisia: A Potential Source of Acetylated Sterols – Investigation of its Biological Activities

The hexane extract of Echinops spinosissimus Turra subsp. spinosus flower heads was analyzed for its fatty acid and sterol composition. Its physicochemical characteristics were also studied. The saponification, iodine and peroxide values were determined as 255 mg KOH/g, 42.57 g I₂/100 g and 110 m equiv. O₂/kg of oil, respectively. The oleic (C18:1; 61.14%), palmitic (C16:0; 21.36%) and linoleic (C18:2; 10.45%) acids were the dominant fatty acids. This extract was also found to contain high levels of β‐sitosterol and stigmasterol (44.97% and 34.95% of total sterols, respectively). On the other hand, the identification of terpenoid compounds was investigated by using GC/MS, which revealed fourteen major terpenoids mainly taraxasterol, lupeol, pseudotaraxasterol, lup‐22(29)‐en‐3‐yl acetate, taraxasteryl acetate, α‐amyrin, β‐amyrin, pseudotaraxasteryl acetate, hop‐20(29)‐en3‐β‐ol, α‐amirenone, along with β‐sitosterol and stigmasterol. Moreover, we have evaluated the in vitro antibacterial and antifungal activities of the unsaponifiable matter and a fraction isolated from this extract. These activities were conducted using the diffusion disc methods and broth microdilution assay. The resulted fraction from this extract showed the highest antibacterial activity with significant minimum inhibitory concentrations (MIC) values 125.0 μg/ml against Staphylococcus aureus, Micrococcus luteus and Bacillus cereus. However, it did exhibit no substantial antifungal activity.     

Triterpenoid,coumarin and quinone constituents of eleven Diospyros species (Ebenaceae)

From the bark and/or timber extracts of Diospyros hirsuta, D. moonii, D. quaesita, D. spinescens, D. thwaitesii and D. walkeri, the following compounds have been isolated; lupeol, betulin, betulinic acid sitosterol, taraxerol, taraxerone, ursolic acid, oleanolic acid scopoletin, plumbagin, elliptinone, diospyrin and diosindigo A. TLC examination of the bark and timber extract of D. acuta, D. chaetocarpa, D. oblongifolia, D. oppositifolia and D. rheophytica is reported. Lupeol betulin, oleanolic acid and sitosterol have been isolated from the fruit of D. oblongfolia.     

A naphthalene glucoside lactone from Rhamnus wightii

A new naphthalene glucoside lactone was isolated from the acetone extract of the stem bark of Rhamnus wightii. Cynodontin, chrysophanol, physcion, musizin, lupeol, sitosterol, 7-hydroxy-5-methoxyphthalide, emodin, sitosterol glycoside, β-sorigenin are the known compounds; β-sorigenin may be an artifact of its glucoside. The co-occurrence of two lactone ring compounds, 7-hydroxy-5-methoxyphthalide and the naphthalide glucoside is the significant feature of this plant.     

A New Aromatic Amide from the Roots of Zanthoxylum tessmannii (Rutaceae)

Phytochemical investigation of the methanolic extract of the roots of Zanthoxylum tessmannii Zepernick and Timler (Rutaceae) led to the isolation and characterization of one new aromatic amide named tessmamide ( 1 ) along with twelve known compounds, N‐benzoyltyramine methyl ether ( 2 ), 7,8,9‐trimethoxycoumarin ( 3 ), 7,8‐dimethoxycoumarin ( 4 ), integrifoliodiol ( 5 ), robustin ( 6 ), skimmianine ( 7 ), lupeol ( 8 ), lupenone ( 9 ), a mixture of stigmasterol and β‐sitosterol, and a mixture of their glucosides. The structures of all compounds were determined by comprehensive spectroscopic analyses (1D‐ and 2D‐NMR, EI‐MS, and ESI‐MS) and comparison with known analogs. The determination of the radical scavenging activity using the 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) assay gave moderate antioxidant values for the crude extracts of the roots of Zanthoxylum tessmannii (IC₅₀ 0.8 mg/mL), tessmamide ( 1 ; IC₅₀ 31.8 μm ), and 7,8,9‐trimethoxycoumarin ( 3 ; IC₅₀ 29.3 μm ), compared to the standard ascorbic acid (IC₅₀ 11.6 μm ).     

Lignans and Terpenoids from the Leaves of Schisandra chinensis

Fifteen constituents, including one new lignan (schisandroside E) and one new terpenoid (schisandenoid A) as well as nine known lignans and four known terpenoids, were isolated from Schisandra chinensis leaves. The structures of schisandroside E and schisandenoid A were established by entirely meticulous spectroscopic analysis (NMR, MS, CD, IR and UV). All compounds were tested for cytotoxicity against MGC‐803, Caco‐2 and Ishikawa cell lines. Some compounds showed strong cytotoxicity against these three cancer cell lines with IC₅₀<1 μm .     

Functional Expression of Odorant Receptors of the Zebrafish Danio rerio and of the Nematode C. elegans in HEK293 Cells

Odorant receptors of zebrafish and C. elegans were functionallyexpressed in vertebrate kidney cells (HEK293) using the eucaryoticexpression vector pSMyc. Receptor-encoding cDNA cloned intothis vector was expressed as a fusion protein with the N-terminalmembrane import sequence of the guinea-pig serotonin receptorfollowed by a myc tag. Immunocytochemical evidence indicatesthat this strategy directs a protein with the predicted immunoreactivityand approximate molecular weight to the plasma membrane. Fishfood extract (TetraMin) evoked a transient increase in intracellular[Ca²⁺] in HEK293 cells transiently transfected with plasmidscontaining cDNA for three fish odorant receptors and convertedto stable cell lines. The effect of the extract was concentrationdependent and limited to the fraction of the extract <5 kDa.Pretreating the transfected cells with the PLC inhibitor U73122reduced the odor-evoked signal. Fish food extract also evokeda transient increase in intracellular [Ca²⁺] in HEK293 cellstransiently transfected with plasmids containing cDNA for singlefish odorant receptors. Diacetyl evoked a transient increasein intracellular [Ca²⁺] in HEK293 cells transiently transfectedwith plasmids encoding the cDNA of ODR10, an odorant receptorof C. elegans suggested in other work to be specific for diacetyl.These results strongly imply that odorant receptors can be functionallyexpressed in HEK293 cells using this novel expression protocol.Chem. Senses 22: 467–476, 1997.     

GC/MS and LC/MS Phytochemical Analysis of Vigna unguiculata L. Walp Pod

Vigna unguiculata (L. Walp) or Cowpea pod methanolic extracts phytochemical analysis, total phenolic content (TPC), and secondary metabolite profiling were determined using gas chromatography-mass spectrometry (GC/MS) and liquid chromatography-mass spectrometry (LC/MS) analysis. GC/MS analysis revealed twenty compounds in the extract, while LC/MS analysis identified twenty-four compounds. GC/MS chromatogram analysis suggested the presence of opioid α-N-Normethadol a major constituent found in methanolic extract and fatty acid esters carotenoid is found second major constituent. LC/MS chromatogram and the mass spectral analysis demonstrated the presence of flavonoids, carotenoids, and alkaloids as major phytochemicals. We investigated the antibacterial, anti-fungal, and anti-oxidant activity of pod methanolic extract. The extract was found equally effective against E. coli, S. pyogenes, and P. aeruginosa with MIC 100 μg/mL similar to the standard Ampicillin (MIC 100 μg/mL). C. albicans were found to be most susceptible to Vign unguiculata pods methanolic extract with a MIC of 250 μg/mL. The pod extract showed significant DPPH scavenging activity (IC₅₀=78.38±0.15) which suggests its antioxidant potential.     

Antibacterial Flavonoids and Other Compounds from the Aerial Parts of Vernonia guineensis Benth. (Asteraceae)

An extensive phytochemical study of the aerial parts of Vernonia guineensis Benth. (Asteraceae) led to the isolation of a new flavone, vernoguinoflavone and a naturally isolated glycerol ester, eicosanoic acid 2‐hydroxy‐1,3‐propanediyl ester, together with eighteen known secondary metabolites including quercetin, luteolin, vernopicrin, vernomelitensin, β‐amyrin, oleanolic acid, ursolic acid, lupeol, betulinic acid, β‐carotene, a mixture of stigmasterol and β‐sitosterol, β‐sitosterol‐3‐O‐β‐D‐glucoside, 2,3‐dihydroxypropyl heptacosanoate, pentacosanoic acid, docosan‐1‐ol, tritriacontan‐1‐ol, and heptatriacontan‐1‐ol. Eleven compounds are reported herein for the first time from this species. The structures of these compounds were elucidated on the basis of extensive spectroscopic analyses, particularly 1D and 2D NMR, and HR‐ESI‐MS and by comparison of their data with those reported in the literature. The crude extract, fractions and some isolated compounds were evaluated for their antibacterial activity against Gram‐negative bacteria: Escherichia coli (ATCC 25922), Shigella flexineri (NR 518), Salmonella muenchen, Salmonella typhimurium and Salmonella typhi (ATCC 19430). All the tested compounds demonstrated inhibitory activities against the tested enteric bacteria with MIC values ranging from 3.12 to 100 μg/ml. Three flavonoids isolated from the most active fraction demonstrated the best bioactivities against Escherichia coli, Salmonella muenchen and Salmonella typhimurium with MIC values ranging from 3.12 to 25 μg/mL.     

Convolutamines I and J, antitrypanosomal alkaloids from the bryozoan Amathia tortusa

Mass-directed isolation of the CH(2)Cl(2)/CH(3)OH extract from the marine bryozoan Amathia tortusa resulted in the purification of two new brominated alkaloids, convolutamines I (1) and J (2). The structures of 1 and 2 were determined following spectroscopic data analysis. Both compounds were isolated during a drug discovery program aimed at identifying new antitrypanosomal leads from a prefractionated natural product library. Compounds 1 and 2 were shown to be active toward the parasite Trypanosoma brucei brucei with IC(50) values of 1.1 and 13.7 μM, respectively. Preliminary toxicity profiling was also performed on both 1 and 2 using the human embryonic kidney cell line, HEK293. Compound 1 was shown to exhibit cytotoxicity against HEK293 with an IC(50) of 22.0 μM whilst 2 was inactive at 41.0 μM.     

Cooperation of NAD(P)H:quinone oxidoreductase 1 and UDP-glucuronosyltransferases reduces menadione cytotoxicity in HEK293 cells

Previous studies have shown that NAD(P)H:quinone oxidoreductase 1 (NQO1) plays an important role in the detoxification of menadione (2-methyl-1,4-naphthoquinone, also known as vitamin K3). However, menadiol (2-methyl-1,4-naphthalenediol) formed from menadione by NQO1-mediated reduction continues to be an unstable substance, which undergoes the reformation of menadione with concomitant formation of reactive oxygen species (ROS). Hence, we focused on the roles of phase II enzymes, with particular attention to UDP-glucuronosyltransferases (UGTs), in the detoxification process of menadione. In this study, we established an HEK293 cell line stably expressing NQO1 (HEK293/NQO1) and HEK293/NQO1 cell lines with doxycycline (DOX)-regulated expression of UGT1A6 (HEK293/NQO1/UGT1A6) and UGT1A10 (HEK293/NQO1/UGT1A10), and evaluated the role of NQO1 and UGTs against menadione-induced cytotoxicity. Our results differed from those of previous studies. HEK293/NQO1 was the most sensitive cell line to menadione cytotoxicity among cell lines established in this study. These phenomena were also observed in HEK293/NQO1/UGT1A6 and HEK293/NQO1/UGT1A10 cells in which the expression of UGT was suppressed by DOX treatment. On the contrary, HEK293/NQO1/UGT1A6 and HEK293/NQO1/UGT1A10 cells without DOX treatment were resistant to menadione-induced cytotoxicity. These results demonstrated that NQO1 is not a detoxification enzyme for menadione and that UGT-mediated glucuronidation of menadiol is the most important detoxification process.     

Phenolic profile,antioxidant and cytotoxic properties of polar extracts from leaves and flowers of Isatis tinctoria L. (Brassicaceae) growing in Sicily

This study was designed to define and compare the antioxidant and cytotoxic properties of polar extracts obtained from basal leaves (It-BL), cauline leaves (It-CL) and flowers (It-F) of Isatis tinctoria L. growing wild around Acireale (Sicily, Italy). The phenolic profile was characterized by HPLC-PDA-ESI-MS analysis and the correlation between phenolic content and the observed biological effects was established. Further, LC/MS analysis showed that the extracts contain glucosinolates at very low concentrations. The antioxidant activity of the extracts was tested in vitro; It-F was the most effective in the DPPH test (IC₅₀ = 0.437 ± 0.003 mg/mL), whilst It-CL showed the best reducing power (1.546 ± 0.006 ASE/mL) and ferrous ions chelating activity (IC₅₀ = 0.564 ± 0.011 mg/mL). The extracts exhibited anti-proliferative effects against three different human thyroid carcinoma cell lines, and It-BL displayed the strongest activity; particularly, it markedly inhibited the growth of CAL-62 cells, causing nearly 85% reduction of viability at the highest tested dose. No cytotoxicity against Artemia salina was observed. The results of our investigations indicate that the polar extracts obtained from I. tinctoria are a potential source of antioxidant and anticancer compounds, which could be suitable for nutraceutical and therapeutic applications.     

Triterpenoids of Colletia spinosissima

The neutral components from the stems of Colletia spinosissima Gmel. include lupenone, sitosterol lupeol, daucosterine. Acid hydrolysis of the glycoside fraction afforded ethyl sinapate and two homologous degradation products from the corresponding sapogenins. Mild hydrolysis of the glycoside fraction afforded the intact sapogenins, which have been tentatively assigned the structures (VIIb) and (VIIIb). The chemistry of the latter compounds has been explored.     

A novel microtubule depolymerizing colchicine analogue triggers apoptosis and autophagy in HCT‐116 colon cancer cells

Colchicine is a tubulin‐binding natural product isolated from Colchicum autumnale. Here we report the in vitro anticancer activity of C‐ring modified semi‐synthetic derivative of colchicine; N‐[(7S)‐1,2,3‐trimethoxy‐9‐oxo‐10‐(4‐phenyl‐piperidin‐1‐yl)‐5,6,7,9 tetrahydrobenzo[a]heptalen‐7‐yl]acetamide ( 4h ) on colon cancer HCT‐116 cell line. The compound 4h was screened for anti‐proliferative activity against different human cancer cell lines and was found to exhibit higher cytotoxicity against colon cancer cell lines HCT‐116 and Colo‐205 with IC₅₀ of 1 and 0.8 μM respectively. Cytotoxicity of the compound to the normal fR2 breast epithelial cells and normal HEK293 human embryonic kidney cells was evaluated in concentration and time‐dependent manner to estimate its selectivity for cancer cells which showed much better selectivity than that of colchicine. Compound 4h induced cell death in HCT‐116 cells by activating apoptosis and autophagy pathways. Autophagy inhibitor 3‐MA blocked the production of LC3‐II and reduced the cytotoxicity in response to 4h , but did not affect apoptosis, suggesting thereby that these two were independent events. Reactive oxygen species scavenger ascorbic acid pretreatment not only decreased the reactive oxygen species level but also reversed 4h induced cytotoxicity. Treatment with compound 4h depolymerized microtubules and the majority of cells arrested at the G2/M transition. Together, these data suggest that 4h has better selectivity and is a microtubule depolymerizer, which activates dual cell‐death machineries, and thus, it could be a potential novel therapeutic agent in cancer therapy. Copyright © 2016 John Wiley & Sons, Ltd.     

BAG3 regulates total MAP1LC3B protein levels through a translational but not transcriptional mechanism

Autophagy is mainly regulated by post-translational and lipid modifications of ATG proteins. In some scenarios, the induction of autophagy is accompanied by increased levels of certain ATG mRNAs such as MAP1LC3B/LC3B, ATG5 or ATG12. However, little is known about the regulation of ATG protein synthesis at the translational level. The cochaperone of the HSP70 system BAG3 (BCL2-associated athanogene 3) has been associated to LC3B lipidation through an unknown mechanism. In the present work, we studied how BAG3 controls autophagy in HeLa and HEK293 cells. Our results showed that BAG3 regulates the basal amount of total cellular LC3B protein by controlling its mRNA translation. This effect was apparently specific to LC3B because other ATG protein levels were not affected. BAG3 knockdown did not affect LC3B lipidation induced by nutrient deprivation or proteasome inhibition. We concluded that BAG3 maintains the basal amount of LC3B protein by controlling the translation of its mRNA in HeLa and HEK293 cells.     

Comparative analysis of the cytotoxic activity of extracts from different parts of A. absinthium L. on breast cancer cell lines and correlation with active compounds concentration

The aim of the present study was to compare the cytotoxicity of different extracts of the plant Artemisia absinthium on breast cancer cell lines and to establish the correlation between the cytotoxicity and the active constituent’s level in these extracts. The cytotoxicity of the extracts was evaluated on the breast cancer cell lines, MCF-7 and MDA MB-231 by MTT assay and LDH release assay. An HPTLC method was developed for the simultaneous estimation of active constituents, that is, artemisinin, artemisinic acid, and alpha-thujone in different parts of A. absinthium. The whole extract was best among all the extracts tested with least IC₅₀ value and high LDH release that is, 491.19?µg/µL with 27.92% for MCF-7 and 459.97?µg/µL with 29.43% for MDA MB-231 cell lines respectively. Although, the concentration of all three quantified active compounds was higher in the extract from aerial part; however, the whole extract showed the best cytotoxicity among all extracts evaluated on the breast cancer cell lines. Surprisingly, our results demonstrate that the quantified active compounds were not solely responsible for the cytotoxic activity of the plant parts and further studies may be conducted to identify the compounds with synergistic, allosteric or antagonistic effects.     

Lemairones A and B: Two new antibacterial tetraflavonoids from the leaves of Zanthoxylum lemairei (Rutaceae)

Zanthoxylum lemairei is widely used in African folk medicine for its pharmacological relevance. Chemical investigation of the ethanol extract from the leaves of this plant lead to the isolation of two new tetraflavonoids, lemairones A (1) and B (2), along with three known compounds, lupeol, sitosterol, and sitosterol 3-O-β-d-glucopyranoside. The antibacterial screening of the leaves of this plant, characterization of compounds 1 and 2, and their antibacterial activity are reported for the first time. The isolation of the compounds was performed using different chromatographic methods while their structures were elucidated by spectroscopic techniques including MS and NMR, and by comparison of data with those of similar flavonoids reported in the literature. The isolated compounds and the crude extract were tested against ten Gram negative multi-resistance bacterial strains including clinical isolates using a broth dilution method. The crude ethanol extract showed weak activity against the tested bacteria strains with a minimal inhibitory concentration (MIC) ranging from 512 to 1024 μg/mL. Among the isolated metabolites, only the new tetraflavonoids were tested. Lemairone A displayed weak activity while lemairone B had moderate activity against the resistant Escherichia coli AG100 with MIC values of 128 μg/mL and 64 μg/mL respectively. In addition, both molecules displayed weak activity against Klebsiella pneumoniae KP55 (MIC 128 μg/mL).     

Alkylbenzoquinones with antiproliferative effect against human cancer cell lines from stem of Ardisia kivuensis

Two new alkylbenzoquinone derivatives, named as ardisiaquinone J (1) and K (2) were isolated from the MeOH extract of the stem of Ardisia kivuensis Taton (Myrsinaceae), together with the known lupeol and β-sitosterol. Their structures were elucidated on the basis of spectroscopic analysis and comparison with authentic samples. The new compounds exhibited considerable antiproliferative activity against Ishikawa, HeLa, MCF7 and A431 cell lines with IC₅₀ values between 6.64 and 15.40 μM. In addition, compound 2 exerted a moderate free radical scavenging effect on DPPH-assay.