Essential Oil Composition of Bupleurum praealtum and Bupleurum affine: New Natural Constituents.

This study explores the chemical composition of essential oils from two Serbian Bupleurum species (Apiaceae), Bupleurum praealtum L. and Bupleurum affine L., traditionally recognized in Chinese medicine for their therapeutic potential but less studied for their essential oils. Through GC-MS analysis, we identified 230 constituents, revealing distinct profiles between the species. Perillyl 2-methylbutanoate was identified in B. affine oil for the first time, confirmed using synthetic approaches and characterized by advanced spectroscopic techniques, including two-dimensional NMR and spin-simulation of 1H NMR spectra. Additionally, new natural compounds, including tentatively identified 4-decyl acetate and 4-undecyl acetate, were discovered. The study also reports five stereoisomeric esters of tetradeca-5,7,9,11-tetraen-1-ol. These findings significantly contribute to the understanding of the phytochemical diversity within the genus Bupleurum and underscore potential differences in ecological adaptations or biosynthetic pathways among species.

Morphometric and functional changes in the kidney of rats induced by inorganic selenium.

Selenium (Se) is an essential trace element. Depending on concentration, Se can manifest both beneficial and harmful effects on the cell and can have both oxidative and antioxidant effects. Because the therapeutic index for Se is very narrow and it can depend on the form of Se used, we aimed to investigate the potential safety and side effects of inorganic Se on kidney function and structure in rats. After 8 days of treatment, no detectable signs of microscopic changes or oxidative stress in kidney tissue were observed. We detected a moderate increase in urea and creatinine levels in the blood as a sign of a slight decrease in kidney function. The most notable changes in our study were morphometric alterations in proximal tubules and glomeruli, both of which were considerably enlarged. The short-term application of inorganic Se to rats in a supratherapeutic dose induced mild functional and ultrastructural changes in the kidneys. The dose of inorganic Se used could be considered relatively safe for short-term application in situations where Se could be beneficial to the organism, such as the usage of known nephrotoxicants or high levels of oxidative stress in the body.

Amazon Rainforest Hidden Volatiles-Part I: Unveiling New Compounds from Acmella oleracea (L.) R.K. Jansen Essential Oil.

Motivated by the culinary and ethnopharmacological use of Acmella oleracea (L.) R.K. Jansen, this study aimed to unveil new chemical compounds from its essential oil (EO). Acmella oleracea, known for its anesthetic and spicy properties, has been used in traditional medicine and cuisine, particularly in Northern Brazil. Through a detailed GC-MS analysis, 180 constituents were identified, including 12 tentatively identified long-chain α-keto esters of various acids. Additionally, 18 new esters were synthesized for structural verification. This research expands the known chemical diversity of A. oleracea EO, providing a basis for potential pharmacological applications. The identification of new natural products, including homologs and analogs of acmellonate, underscores the EO's rich chemical profile and its potential for novel bioproduct development.

Conformation Analysis and Stereodynamics of Symmetrically ortho-Disubstituted Carvacrol Derivatives.

The design and synthesis of analogs of natural products can be a valuable source of medicinal preparations for the pharmaceutical industry. In the present study, the structural elucidation of eleven derivatives of 2,4-dihalogeno substituted synthetic analogues of the natural compound carvacrol was carried out by means of NMR experiments, and of another thirteen by DFT calculations. By selective NOE experiments and the irradiation of CH signals of the isopropyl group, individual conformers were assigned as syn and anti. By comparing GIAO/B3LYP/6-311++G(d,p)-calculated and experimentally measured vicinal 3JCH spin-spin constants, this assignment was confirmed. An unusual relationship is reported for proton-carbon vicinal couplings: 3JCH (180°) < 3JCH (0°). The conformational mobility of carvacrols was studied by 2D EXSY spectra. The application of homonuclear decoupling technique (HOBS) to these spectra simplifies the spectra, improves resolution without reducing the sensitivity, and allows a systematic examination of the rotational barrier of all compounds via their CH signals of the isopropyl group in a wider temperature interval. The rate constants of the isopropyl rotation between syn and anti conformers were determined and the corresponding energy barriers (14-17 kcal/mol) were calculated. DFT calculations of the energy barriers in carvacrol derivatives allowed the determination of the steric origin of the restricted isopropyl rotation. The barrier height depends on the size of the 2- and 4-position substituents, and is independent of the derivatization of the OH group.

Marrubiin Inhibits Peritoneal Inflammatory Response Induced by Carrageenan Application in C57 Mice.

Marrubiin is a diterpene with a long history of a wide range of biological activities. In this study, the anti-inflammatory effects of marrubiin were investigated using several in vitro and in vivo assays. Marrubiin inhibited carrageenan-induced peritoneal inflammation by preventing inflammatory cell infiltration and peritoneal mast cell degranulation. The anti-inflammatory activity was further demonstrated by monitoring a set of biochemical parameters, showing that the peritoneal fluid of animals treated with marrubiin had lower levels of proteins and lower myeloperoxidase activity compared with the fluid of animals that were not treated. Marrubiin exerted the most pronounced cytotoxic activity towards peripheral mononuclear cells, being the main contributors to peritoneal inflammation. Additionally, a moderate lipoxygenase inhibition activity of marrubiin was observed.

Oregano (Origanum vulgare) Essential Oil and Its Constituents Prevent Rat Kidney Tissue Injury and Inflammation Induced by a High Dose of L-Arginine.

This study aimed to evaluate the protective action of oregano (Origanum vulgare) essential oil and its monoterpene constituents (thymol and carvacrol) in L-arginine-induced kidney damage by studying inflammatory and tissue damage parameters. The determination of biochemical markers that reflect kidney function, i.e., serum levels of urea and creatinine, tissue levels of neutrophil-gelatinase-associated lipocalin (NGAL), and kidney injury molecule-1 (KIM-1), as well as a panel of oxidative-stress-related and inflammatory biomarkers, was performed. Furthermore, histopathological and immunohistochemical analyses of kidneys obtained from different experimental groups were conducted. Pre-treatment with the investigated compounds prevented an L-arginine-induced increase in serum and tissue kidney damage markers and, additionally, decreased the levels of inflammation-related parameters (TNF-α and nitric oxide concentrations and myeloperoxidase activity). Micromorphological kidney tissue changes correlate with the alterations observed in the biochemical parameters, as well as the expression of CD95 in tubule cells and CD68 in inflammatory infiltrate cells. The present results revealed that oregano essential oil, thymol, and carvacrol exert nephroprotective activity, which could be, to a great extent, associated with their anti-inflammatory, antiradical scavenging, and antiapoptotic action and, above all, due to their ability to lessen the disturbances arising from acute pancreatic damage. Further in-depth studies are needed in order to provide more detailed explanations of the observed activities.

New esters from the essential oil of dry flowers of elder (Sambucus nigra L.).

BACKGROUND: Elder (Sambucus nigra L.) has relevance for the food, fragrance and pharmaceutical industries. Flowers of this species emit a very pleasant scent; for processing purposes, inflorescences are either collected from the wild or harvested from a cultivated crop. The study of elderflower-derived volatiles bears both phytochemical and commercial importance. RESULTS: Three samples of dry elderflower essential oil obtained from laboratory-scale hydrodistillations were analyzed. By use of gas chromatography-mass spectrometry, synthesis and NMR studies of chromatographic fractions of a distillation water extract prepared in a semi-industrial scale steam distillation, 252 constituents of the oil were identified; 115 compounds were not previously reported as elderflower volatiles, seven of which were new natural esters. Particularly interesting were those of isosenecioic (3-methylbut-3-enoic) acid because these were never before found in the plant kingdom. CONCLUSION: With these identifications, the known essential oil constituents accounted for 89.0-93.0% of the analyzed samples. Although the number of known S. nigra flower-derived volatiles is now quite high, further research (both analytical and olfactory) is needed to unveil all of the relevant contributions to the unique odor of elderflowers. © 2023 Society of Chemical Industry.

Bioisosteric ferrocenyl 1,3-thiazolidine-4-carboxylic acid derivatives: In vitro antiproliferative and antimicrobial evaluations.

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.

Synthesis of Small Libraries of Natural Products: Part II: Identification of a New Natural Product from the Essential Oil of Pleurospermum austriacum (L.) Hoffm. (Apiaceae).

Herein, comprehensive data of NMR, MS, IR, and gas chromatography (RI) obtained by GC-MS on commonly used capillary columns of different polarity (non-polar DB-5MS and polar HP-Innowax) of a series of esters of all constitutional isomers of hexanoic acid with a homologous series of ω-phenylalkan-1-ols (phenylmethanol, 2-phenylethanol, 3-phenylpropan-1-ol, 4-phenylbutan-1-ol, and 5-phenylpentan-1-ol) and phenol, in total 48 chemical entities, were collected. The created synthetic library allowed the identification of a new constituent of the P. austriacum essential oil (3-phenylpropyl 2-methylpentanoate). The accumulated spectral and chromatographical data, as well as the established correlation between RI values and structures of regioisomeric hexanoates, provide (phyto)chemists with a tool that will make future identification of related natural compounds a straightforward task.

Wax Composition of Serbian Dianthus spp. (Caryophyllaceae): Identification of New Metabolites and Chemotaxonomic Implications.

Although ethnopharmacologically renowned, wax constituents of Dianthus species were sporadically studied. A combination of GC-MS analysis, synthesis, and chemical transformations enabled the identification of 275 constituents of diethyl-ether washings of aerial parts and/or flowers of six Dianthus taxa (Dianthus carthusianorum, D. deltoides, D. giganteus subsp. banaticus, D. integer subsp. minutiflorus, D. petraeus, and D. superbus) and one Petrorhagia taxon (P. prolifera) from Serbia. Seventeen of these constituents (nonacosyl benzoate, additional 12 benzoates with anteiso-branched 1-alkanols, eicosyl tiglate, triacontane-14,16-dione, dotriacontane-14,16-dione, and tetratriacontane-16,18-dione) and two additional synthesized eicosyl esters (angelate and senecioate) represent completely new compounds. The structures of the tentatively identified ß-ketones were confirmed by analysis of the mass fragmentation of the corresponding pyrazoles and silyl enol ethers obtained by transformations of crude extracts and extract fractions. Silylation allowed the identification of 114 additional constituents, including a completely new natural product (30-methylhentriacontan-1-ol). The results obtained by multivariate statistical analyses showed that the chemical profile of Dianthus taxa's surface waxes is subject to both genetic and ecological factors, whereas the latter seemingly takes a more important role for the studied Dianthus samples.

The potential of lemon balm (Melissa officinalis L.) essential oil as an anti-anxiety agent - is the citronellal the activity carrier?

ETHNOPHARMACOLOGICAL RELEVANCE: Among the fewest drugs discovered are those belonging to the class of anxiolytics. Although some drug targets for anxiety disorders are established, it is hard to modify and selectively choose the active principle for those targets. Thus, the ethnomedical approach to treating anxiety disorders remains one of the most prevalent ways for (self)managing the symptoms. Melissa officinalis L. (lemon balm) has been extensively used as an ethnomedicinal remedy for the treatment of different psyche-related symptoms, especially dose related to restlessness. AIM OF THE STUDY: This work aimed to evaluate the anxiolytic activity, in several in vivo models, of the essential oil extracted from Melissa officinalis (MO) and its main constituent citronellal, a widespread plant utilized for managing anxiety. MATERIALS AND METHODS: In the present study several animal models were used to assess MO anxiolytic potential in mice. The effect of the MO essential oil applied in doses ranging from 12.5 to 100 mg/kg was estimated in light/dark, hole board, and marble burying tests. In parallel doses of citronellal corresponding to the ones in the MO essential oil were applied to animals to determine if this is the activity carrier. RESULTS: The results indicate that the MO essential oil exerts anxiolytic potential in all three experimental settings by significantly altering the traced parameters. The effects of citronellal are somewhat inconclusive and should not be interpreted only as anxiolytic but rather as a combination of anti-anxiety and motor-inhibiting effects. CONCLUSIONS: In conclusion, we could say that the results of the present study provide a base for future mechanistic studies that would evaluate the activity of M. officinalis essential oil on various neurotransmitter systems involved in the generation, propagation, and maintenance of anxiety.

New Iron Twist to Chloroquine─Upgrading Antimalarials with Immunomodulatory and Antimicrobial Features.

Herein, upgraded chloroquine (CQ) derivatives capable of overcoming Plasmodium resistance and, at the same time, suppressing excessive immune response and risk of concurrent bacteremia were developed. Twelve new ferrocene-CQ hybrids tethered with a small azathia heterocycle (1,3-thiazolidin-4-one, 1,3-thiazinan-4-one, or 5-methyl-1,3-thiazolidin-4-one) were synthesized and fully characterized. All hybrids were evaluated for their in vitro antiplasmodial, antimicrobial, and immunomodulatory activities. Additional assays were performed on selected hybrids to gain insights into their mode of action. Although only hybrid 4a was more potent than the parent drug toward CQ-resistant Dd2 Plasmodium falciparum strain, several other hybrids (such as 6b, 6c, and 6d) manifested substantially improved antimicrobial and immunomodulatory properties. Interesting structure-activity relationship data were obtained, hinting at future research for the development of new multitarget chemotherapies for malaria and other infectious diseases complicated by drug resistance, bacterial co-infection, and immune-driven pathology issues.

On the configuration and occurrence of 2,6-cyclocuparan-3-ols: Resolving a lasting discrepancy.

2,6-Cyclocuparan-3-ols are chemical markers and major volatiles of several liverwort species. Conflicting reports on the structures of these cyclocuparanols can be found in the literature-different research groups assigned the same spectral data to different structures, yet these inconsistencies were never addressed, let alone satisfactorily explained. Following the isolation of all four diastereoisomeric cyclocuparanols from Marchantia polymorpha, their relative and absolute configurations were extensively studied by chemical and spectroscopic methods and definite stereostructures were proposed.

Pulicaria dysenterica (L.) Bernh.-Rightfully Earned Name? Identification and Biological Activity of New 3-Methoxycuminyl Esters from P. dysenterica Essential Oil.

Motivated by the ethnopharmacological use of Pulicaria dysenterica, in the present study, the antimicrobial potential of the extracted essential oil was investigated against a panel of eighteen microorganism strains. Additionally, anti-acetylcholinesterase and antispasmodic (isolated rat distal colon) activities, general acute toxicity (Artemia salina model), and immunomodulatory properties (cytotoxicity on isolated mouse macrophages) were studied. Detailed analyses of the essential oil led to the identification of 3-methoxycuminyl 2-methylbutanoate (a new natural product) and 3-methoxycuminyl 3-methylbutanoate (a rare natural product). The obtained esters and intermediates in the synthesis of the starting alcohol (3-methoxycuminol) were subjected to a battery of 1D- and 2D-NMR experiments. The synthesized esters were additionally characterized by GC-MS, IR, and UV-Vis. The synthesized compounds (ten in total) were biologically tested in the same way as the extracted P. dysenterica essential oil. The obtained low acute toxicity and promising antimicrobial potential suggest that the P. dysenterica essential oil might partially explain the ethnopharmacological application of P. dysenterica plant material for the treatment of gastrointestinal infections.

Volatiles of Capparis cartilaginea Decne. from Saudi Arabia.

In this study, GC and GC-MS analysis of the essential oil obtained from the leaves of Saudi Arabian Capparis cartilaginea Decne. (CC) allowed for the identification of 41 constituents, comprising 99.99% of the total oil composition. The major compounds identified were isopropyl isothiocyanate (31.0%), 2-methylbutanenitrile (21.4%), 2-butyl isothiocyanate (18.1%), isobutyronitrile (15.4%), and 3-methylbutanenitrile (8.2%). The chemical composition of the derived oil and 12 additional oils obtained from selected Capparis taxa were compared using multivariate analyses including principal component analysis (PCA) and agglomerative hierarchical cluster analysis (AHC). The results of the statistical analyses of this particular data set pointed out that isopropyl isothiocyanate could be potentially used as a valuable infrageneric chemotaxonomical marker for CC. Moreover, the results distinctly separate CC from other members of its genus on the basis of its components. In addition, environmental and geographical stressors may be implicated in the essential oil profile of plants found within the genus Capparis.

An HPLC-based assay for improved measurement of glutamate decarboxylase inhibition/activation.

L-Glutamic acid decarboxylase (GAD) is an enzyme that ensures the balance between the levels of two neurotransmitters, γ-aminobutyric acid (GABA) and L-glutamic acid (L-Glu), necessary for proper brain functioning. A reduction in the concentrations of GABA and/or GAD activity has been implicated in the symptoms associated with epilepsy, which could be plausibly alleviated by the application of GAD activators. As any unnecessary interference in GAD catalytic activity could be detrimental, it is important to study whether CNS (or other) drug candidates act on GAD or not. The ability to identify and reduce this risk early could significantly improve the process of drug development. Although many methods for measuring GAD activity in various biological samples have been described, only few (such as manometric and radiometric) were adopted as in vitro assays for the screening of potential GAD inhibitors/activators. However, these methods require specialized equipment and/or an expensive radiolabeled substrate, and may have sensitivity and/or reliability issues. Therefore, this study aimed to develop an HPLC-DAD-based assay that would allow a simple and more accurate measurement of GAD inhibition or activation using unpurified mice or rat brain homogenates. This assay is based on the quantification of GABA, formed during the enzymatic reaction, after its derivatization with dansyl chloride. Various parameters were evaluated to optimize the assay procedure (e.g. homogenate volume, incubation time, DMSO content, GAD, GABA, and dansyl-GABA stabilities). This assay was validated for pharmacological screenings using 3-mercaptopropionic acid and gallic acid and GAD obtained from different experimental animals.

New neryl esters from Helichrysum italicum (Roth) G. Don (Asteraceae) essential oil.

Helichrysum italicum (immortelle) is a dwarf aromatic shrub native to the Mediterranean region. The typical subspecies (italicum) produces an essential oil rich in neryl acetate and characteristic ß-diketones, italidiones, highly valued in the perfume industry. As esters are an important group of aroma-active volatiles, herein the composition of the ester fraction of this immortelle chemotype essential oil was studied in detail. Chromatographic separation of Corsican immortelle essential oil enabled the discovery of numerous potentially olfactory-interesting esters of nerol and/or angelic acid, undetectable by direct GC-MS analyses of the unfractioned oil. Four esters of nerol and medium-chain branched fatty acids represent new natural products, while several other esters have a rather restricted occurrence in the Plant Kingdom.

The essential oil of the condiment species Clinopodium thymifolium (Scop.) Kuntze: new natural products and seasonal variation.

BACKGROUND: Clinopodium thymifolium is an aromatic plant species that is widespread in the Mediterranean region. It has been considered as a condiment and is used in cooking. As a promising spice plant, some efforts are being made to introduce this plant as a new crop species and it has been successfully cultivated in northern Italy. RESULTS: Essential oils isolated from the aerial parts of a flavoring species C. thymifolium were analyzed by gas chromatography and gas chromatography/mass spectrometry. The results of a detailed analysis of the chemical composition of the oils showed the domination of pulegone, piperitone, piperitenone and isomenthone, as well as a significant alteration of the pulegone/isomenthone ratio with the developmental stage of the plant. Additionally, a comprehensive chemical analysis of the oils in combination with detailed spectral analyses and chemical synthesis of selected compounds has led to the identification of two new natural products: isomenthyl formate and neomenthyl 2-methylbutanoate. CONCLUSION: The observed chemical variability at the intrapopulation level appeared to be a phenological variation. In an evolutionary sense, the alteration of the pulegone/isomenthone ratio suggests their possible role in the ecological adaptation of the species to pollinators. Significant quantitative changes in the chemical composition of the oil at different phenological stages may be relevant in the case of plant material intended for edible purposes. © 2021 Society of Chemical Industry.

Lemon balm (Melissa officinalis L.) essential oil and citronellal modulate anxiety-related symptoms - In vitro and in vivo studies.

ETHNOPHARMACOLOGICAL RELEVANCE: Besides psyche-related symptoms, patients with anxiety disorders can have a large number of somatic symptoms as well. Although the treatment of these disorders is mainly focused on resolving their mental component, one cannot neglect the need for the treatment of accompanying somatic symptoms. Melissa officinalis L. (lemon balm), in various formulations, has been extensively used as an ethnomedicinal remedy for the treatment of different psyche-related symptoms, and its use is considered relatively safe. AIM OF THE STUDY: In the present study, the activity of M. officinalis (MO) essential oil was evaluated in several in vitro and in vivo models mimicking or involving anxiety-related somatic symptoms. MATERIALS AND METHODS: To address the effect of MO essential oil on the gastrointestinal and heart-related symptoms accompanying anxiety disorders, in vitro models were utilized that follow the function of the isolated mouse ileum and atria tissues, respectively, after exposure to MO essential oil. Effects of MO essential oil on BALB/c mice motor activity was estimated using the open field, rota-rod, and horizontal wire tests. Additionally, the essential oil was assayed for its potential in inhibiting acetylcholinesterase activity. RESULTS: The performance of mice treated with 25 mg/kg of the oil showed a statistically significant decrease in the motor impairment arising from acute anxiety (open field test), while there was a prolonged latency and a reduction of the frequency of falling from a rotating rod and/or a horizontal wire (signs of muscle weakness/spasms). Concentrations of the essential oil higher than 1 µg/mL were found to inhibit both spontaneous and induced ileum contractions. Moreover, the essential oil and citronellal were found to decrease isolated mouse atria contraction frequency, as well as contraction force. However, the oil was found to be a very weak acetylcholinesterase inhibitor. CONCLUSION: The modulation of anxiety-related symptoms by the oil was found not to be mediated through the inhibition of the acetylcholinesterase, nonetheless, the mechanistic studies involving the ileum and cardiac tissues, revealed that the activity of MO and citronellal might be related to the modification of either voltage-gated Ca2+ channels or muscarinic receptors. Mice locomotion, balance, and muscle strength were not impacted by the essential oil; however, its main constituent, citronellal, was found to exert a certain degree of muscle function inhibition. All these results suggest that the activity of MO essential oil arises from synergistic and/or antagonistic interactions of its constituents, and is not completely dependent on the oil's main constituent.

Methyl and Isopropyl N-Methylanthranilates Affect Primary Macrophage Function - An Insight into the Possible Immunomodulatory Mode of Action.

To complement the knowledge on the anti-inflammatory activity of methyl and isopropyl N-methylanthranilates, two natural products with panacea-like properties, we investigated their effects on thioglycolate-elicited macrophages by evaluating macrophage ability to metabolize MTT, macrophage membrane function, and macrophage myeloperoxidase and phagocytic activities. Moreover, two additional aspects of the inflammatory response of these compounds, their inhibitory activity on xanthine oxidase and catalase, were studied. It was found that these two compounds regulate elicited macrophage functions, most probably by interfering with the function of cell membranes and changing the reducing cellular capacity or enzyme activity of macrophages. Nonetheless, no significant inhibitory action either towards xanthine oxidase or catalase was found, suggesting that the inhibition of these enzymes is not involved in the anti-inflammatory mode of action of these two esters.