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.

Species of the genus Doronicum are known for their pharmacological properties and essential oils, the chemical composition of which remains inadequately studied. In this work, GC-MS analysis, synthesis, and spectral techniques (UV, IR, MS, and NMR) were employed to identify 83 constituents in the essential oil from D. columnae roots, which accounted for 98.1% of the total GC-peak area. The major components were thymyl isobutyrate (32.8%) and thymyl 2-methylbutyrate (22.8%), while the minor constituents were methoxy-p-cymene derivatives. Six new natural products were identified through synthesis, GC co-injection experiments and spectral characterization, including esters (isobutyrate, 2-methylbutyrate, and/or isovalerate) of 2-methoxycuminol, 6-methoxythymol, and 6-hydroxythymyl methyl ether, as well as methyl 3-methoxycuminate. Their identification was made possible by synthesis efforts, as isolating pure compounds was impracticable because of their low abundance and the overall structural similarity within the highly complex mixture that was the essential oil.

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.

Bupleurum falcatum (Apiaceae) sensu lato includes multiple infraspecific taxa with longstanding taxonomic ambiguities, often resulting from incomplete morphological and chemical characterizations. Herein, diethyl ether extracts were analyzed from four Balkan populations that were tentatively identified as B. falcatum subsp. falcatum (syn. B. falcatum) and B. falcatum subsp. cernuum (syn. B. sibthorpianum). Comprehensive chromatography and spectroscopic techniques (GC-MS and 1D/2D NMR) enabled the isolation of several newly identified aliphatic polyunsaturated esters, including compounds bearing uncommon conjugated tetraene and triyne backbones. These novel structures differ from canonical falcarinol derivatives by lacking the usual 3-hydroxylation, suggesting a divergent branch in the crepenynate pathway. The chemical profiles of each sample correlated closely with leaf morphology and infraspecific designations: for example, the Galičica Mt. population of B. falcatum featured a unique newly detected heptadecadientriyne, while the populations from Šar Planina and Suva Planina displayed distinct polyunsaturated repertoires. Extracts from B. sibthorpianum likewise contained stereoisomeric compounds that highlight metabolic divergence. Collectively, these findings demonstrate significant chemotypic variation within the Bupleurum falcatum complex and provide the first account of less-polar secondary metabolites, including newly discovered polyunsaturated metabolites. Future research integrating molecular markers and bioactivity assays may elucidate how these specialized metabolites contribute to both the taxonomy and pharmacological potential of these understudied taxa.

In this study, an NMR spectral analysis of the mixture of diastereomeric acetals, synthesized from 2,3-dihydrofurane and a racemic mixture of citronellol, was performed. 1H-NMR full spin analysis was achieved by manually adjusting ?H and J values (previously calculated using the Spartan software) to fit the experimentally available values, followed by further optimization using MestreNova software. The simulated 1H- and 13C-NMR spectra of individual diastereomers, as well as their superimposed and summed spectra, were compared with the obtained experimental spectra. Spin simulation of proton signals was particularly useful for the assignment of the diastereotopic protons of tetrahydrofuranyl moiety and diastereomer discrimination. The NMR spectral data of individual diastereomers ? chemical shifts, coupling constants, HMBC and NOESY interactions were systematized in appropriate tables and schemes. To the best of our knowledge, this is for the first time that the complete assignment of tetrahydrofuranyl moiety was performed, and the data obtained herein may be of great importance for the utilization of this protecting group in the future.