Herein, a novel soil bacterium Streptomyces sp. NP10 able to grow outside usual streptomycetes optimum conditions (e.g., at 4 °C, pH 9 and high NaCl concentration), exhibiting atypical hemolytic, ...DNAse, and cellulolytic activities, is described. This strain produces and excretes into the growth medium large amounts of free long-chain fatty acids (FAs). A concurrent lipidomics study revealed a large structural diversity of FAs with over 50 different n- and branched-chain, (un)saturated, and cyclopropane FAs (C₇–C₃₀) produced by this strain. Two of these, i-17:0cy9-10 and a-18:0cy9-10, represent new natural products and the first ever identified branched cyclopropane FAs. Both free and bound lipid profiles of Streptomyces sp. NP10 were dominated by saturated branched chain FAs (i-14:0, a-15:0, and i-16:0). Although these free FAs showed only a moderate antimicrobial activity, our results suggest that they could have an ecophysiological role in interspecies signaling with another soil microorganism Pseudomonas aeruginosa. This work represents the first comprehensive report on the structural diversity and complexity of the free FA pool in Streptomyces. A naturally occurring streptomycete, such as Streptomyces sp. NP10, which secretes significant amounts of free long-chain FAs (non-cytotoxic) into the medium, could be useful in microbial biodiesel production.
Two volatile alkaloids, methyl (MMA) and isopropyl N-methylanthranilates (IMA), identified in the essential oil of Choisya ternata Kunth (Rutaceae), have been proven to possess polypharmacological ...properties (antinociceptive, anti-inflammatory, gastro-, hepato-, nephroprotective activities, anxiolytic and antidepressant properties, and likewise an effect on diazepam-induced sleep). In the continuation of our investigation of their urinary-metabolite profiles, we performed GC-MS analyses of the diethyl-ether extracts of selected tissues (liver, kidneys, heart, brain, lungs, quadriceps femoris muscle, and spleen) of rats intraperitoneally treated with MMA or IMA (2 g kg−1). Organ-metabolite profiles of MMA and IMA were qualitatively mutually analogous (varying only in the alcohol moiety of the metabolites), and generally analogous to their urinary-metabolite profiles. The greatest diversity and the highest overall amount of anthranilate metabolites was found in the hepatic tissue. The principal anthranilate-related compounds in the organs of rats treated with MMA, among 12 detected, were the products of ester hydrolysis, N-methylanthranilic and anthranilic acids. In the tissues of IMA-treated rats, among 16 compounds, the most abundant ones were the unmetabolized IMA and N-methylanthranilic acid. A collection of the compositional data regarding the anthranilate-related metabolites was statistically treated by multivariate statistical analysis that provided a better insight into the possible biotransformation pathways.
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•Metabolism of methyl (MMA) and isopropyl N-methylanthranilates (IMA) was investigated.•GC-MS analyses of the Et2O extracts of the homogenates of the chosen tissues of MMA/IMA-treated rats were performed.•Organ-metabolite profiles of MMA and IMA were qualitatively analogous and analogous to their urinary-metabolite profiles.•Products of ester group hydrolysis and the unmetabolized compounds were the major anthranilates detected in the organs.•Multivariate statistical analysis pinpointed to specific connections between the analyzed xenobiotic metabolites.
A recent identification of eugenyl (allylmethoxyphenyl) esters as Anthemis segetalis Ten. (Asteraceae) essential oil constituents, accomplished by means of organic synthesis, motivated us to expand ...the existing synthetic library with an aim to examine the generality of structure‐chromatographic property relationships within this series of volatiles. Herein, the design, synthesis, gas–chromatographic and spectral characterization of members of a library of 85 allylmethoxyphenyl esters (64 are completely new) were described. Analysis of experimentally obtained RI data showed that esters of the same acid and different allylmethoxyphenols always elute in the same order from an apolar gas chromatography (DB‐5MS) column: 2‐allyl‐6‐methoxyphenyl < 2‐allyl‐3‐methoxyphenyl < 2‐allyl‐5‐methoxyphenyl < 2‐allyl‐4‐methoxyphenyl < 4‐allyl‐2‐methoxyphenyl esters. Based on the obtained RI values, several quantitative structure–property relationship models were built up that correlated several easily available parameters (e.g. Wiener WI, Balaban BI, and molecular topological MTI indices) of the mentioned esters and their RI data. The generated various quantitative structure–property relationships models (equations that predict RIs of esters of different regioisomers of allylmethoxyphenols with the same acids and the ones that predict RIs of esters of different acids with the same allylmethoxyphenols) were tested on data of previously known related esters. RI data of esters of allylmethoxyphenol regioisomers could be successfully predicted based on 1D topological indices, such as the Balaban, Wiener, and molecular topological indices. Together with RI and MS data accumulated in this work, these models represent a new and simple tool for the identification of allylmethoxyphenyl esters that might potentially represent new or rare natural products.
Herein, the design, synthesis, gas chromatographic, and spectral characterization of members of a library of allylmethoxyphenyl esters (85 compounds, the majority of which (64) are new compounds) were described. The obtained quantitative structure–property modeling models represent, together with RI and MS data summarized in this work, a new and simple tool for the identification of allylmethoxyphenyl esters that might potentially represent new or rare (often erroneously identified or missed out during standard analyses) natural products.
The toxicity of natural marine iodoarenes or their synthetic counterparts is widely unknown despite the fact that triiodothyronine and thyroxine are members of this class. In this work we aimed to ...expand such knowledge on iodinated marine natural products and tested an ascidian (Didemnum rubeum) metabolite, N-(3,5-diiodo-4-methoxyphenethyl)benzamide, together with closely related synthetic iodinated tyramides: N-(2,5-diiodo-4-methoxyphenethyl)benzamide, N-(3-iodo-4-methoxyphenethyl)benzamide, N-(4-methoxyphenethyl)benzamide, and N-(3-iodo-4-methoxyphenethyl)formamide, for their effect on the viability of rat macrophages, as well as acute toxicity on Artemia salina. The tested tyramides exerted a varying degree of toxicity towards brine shrimps, but in certain cases, the determined lethal concentrations were even lower than those of known toxicants (e.g. strychnine sulfate, SDS). The toxicity was highly dependent on the structure of these mutually related compounds, while the natural one was shown to be the most toxic. In the case of macrophage cultures, the tested tyramides exerted much less toxicity but were found to have an effect on the functioning of these normal immune cells. The samples of the tyramides were obtained by synthesis, and were fully structurally and spectrally characterized, which also provided corroboration of the proposed structure of the natural product originally isolated in minute amounts.
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•An iodinated marine natural product and four related tyramides were synthesized and fully spectrally characterized.•Their acute toxicity was determined in the brine shrimp model, and some of them turned out to be more toxic than strychnine.•Their effect on rat macrophage viability and functioning (MPO activity and adhesion ability) was tested.•Macrophage functional properties were affected (especially by the natural product) while the viability was mainly unaltered.•The toxicity was highly dependent on structural variations, but the presence of an I atom and benzamide moiety were crucial.
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► Yarrow volatiles are more toxic to mice (LD50 853mg/kg) than thujone containing oils. ► Achillea umbellata constituents showed anxiolytic, analgesic and paralyzing activity. ► The ...oil is comprised of a rare monoterpene alcohol fragranol and its esters. ► A. umbellata oil exerts a different effect on prokaryotic and eukaryotic cells. ► Fragranol is believed to be the main carrier of the observed activity/toxicity.
Many plant species are used for medicinal purposes without the knowledge of their possible toxic effect. The ethnopharmacologically renowned genus Achillea L. (Asteraceae) is even more troublesome in this respect since different taxa are believed to have the same beneficial properties as A. millefolium. According to the median lethal i.p. dose (LD50=853mg/kg, mice), the volatiles of Achillea umbellata Sibth. et Sm. are more toxic than the thujone-containing essential oils (LD50>960mg/kg). A GC–MS analysis of A. umbellata oil revealed the presence of a series of fragranyl esters (six new natural products). The major constituents of this oil, the rare monoterpene alcohol fragranol and fragranyl acetate, and one more ester (benzoate), as well as the oil itself, showed antianxiety, analgesic and, in some instances, paralyzing properties at 50–150mg/kg but these are very likely sign of intoxication and not of possible beneficial effects of the plant volatiles. Testing of antimicrobial activity demonstrated that the oil possesses moderate activity against pathogenic microorganisms, but the effect of the oil differs in pro- and eukaryotic cells. According to the results obtained, fragranol may be considered as the main active principle responsible for the observed activity/toxicity.
Synthesis, spectral analysis and bioactivity of new coumarin derivatives are described in this paper. Eight new coumarin derivatives were synthesized in moderate to good yields by condensation of ...4-chloro-3-nitrocoumarin and the corresponding heteroarylamine. The synthesized compounds were tested for their in vitro antimicrobial activity, in a standard disk diffusion assay, against thirteen strains of bacteria and three fungal strains. They have shown a wide range of activity - from one completely inactive compound to medium active ones.
The use of lanthanide complexes for resolving intricate NMR signals and, in the case of chiral ligands, for determining enantiomeric excess has progressively decreased in the last 30 years. Recently, ...a sesquiterpene aldehyde from Inula helenium with a possible potent antistaphylococcal activity remained unidentified due to the impossibility of separating the compound from its complex matrix available in very low amounts ( ca. 5 mg). Detailed analyses of 1D and 2D NMR spectra of this original complex sample allowed access to a very limited amount of structural data for the unknown aldehyde. We decided to investigate the potential usefulness of lanthanide-induced shift reagents for the resolution and assigning of overlapped 1 H NMR signals originating from different components of this complex mixture ( i.e. for a qualitative analysis). The incremental addition of tris(6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionato)europium( iii ) (Eu(fod) 3 ) led to a simplification of the NMR spectra in terms of signal overlap and removal of chemical shift degeneracy, allowing the mining of crucial data from the shifted NMR spectra. 2D NMR spectra ( 1 H– 1 H–COSY, NOESY, HSQC and HMBC) of the sample mixed with Eu(fod) 3 proved to be particularly valuable in this respect. The obtained additional information revealed that the compound in question was a rare sesquiterpene – elemenal (elema-1,3,11(13)-trien-12-al). Therefore, herein we report on a new chromatography-free methodology that could be of value in structure elucidation of unknown compounds even if they are not available in a pure state.
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•ALC67 belongs to a recently discovered family of novel antiproliferative agents.•A synthetic library of optically pure ferrocenyl analogs of ALC67 was prepared.•Two compounds (6c-cis ...and 6-d) showed similar cytotoxicity to ALC67 and cisplatin.•The cytotoxicity depended on the electrophilicity of the N-acyl side chain group.•Derivative 6c-cis also manifested a selective anti-Bacillus cereus activity.
To improve the antiproliferative effect of ALC67 (diastereomeric mixture of ethyl 2-phenyl-3-propioloyl-1,3-thiazolidine-4-carboxylate), its structure was modified via (i) bioisosteric substitution of the phenyl ring by the ferrocene unit and (ii) replacing the propiolamide side-chain in ACL67 with other acyl groups having differing electrophilicities. In this way, a small library of methyl N-acyl-2-ferrocenyl-1,3-thiazolidine-4-carboxylates (13 compounds in total) was created and characterized by spectral and crystallographic means. The last N-acylation step was highly diastereoselective toward the cis-diastereomer. In solution, most of the obtained compounds existed as a mixture of two rotamers and displayed a preference for the syn-orientation around the CN bond. A twisted 5T4 envelope conformation was adopted by the derivative containing the N-phenoxyacetyl group in the crystalline state. Two derivatives with chloroacetyl and bromoacetyl groups in the N-3 side chain were cytotoxic to fibroblasts and hepatocellular cancer cells in the low micromolar range (IC50(MRC5) = 9.0 and 11.8 μM, respectively, and IC50(HepG2) = 10.6 and 18.4 μM, respectively) causing an effect similar to the lead compound (IC50(HepG2) = 10.0 μM) and cisplatin (IC50(MRC5) = 4.0 μM and IC50(HepG2) = 7.7 μM). Several derivatives also manifested modest antimicrobial effects against the studied microbial strains (MICs in the range from 0.44 to 4.0 μmol/mL). Our findings demonstrated that the introduction of a ferrocene core facilitated the preparation of optically pure analogs of ALC67 and that the cytotoxicity of compounds may be enhanced by adding proper electrophilic centers to the N-acyl side-chain.
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