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.

Chemical Characterization of Three Artemisia tridentata Essential Oils and Multivariate Analyses: A Preliminary Investigation

Background/Objective: Big sagebrush ( Artemisia tridentata Nutt., Asteraceae) is a conspicuous shrub growing in arid and semi-arid regions of intermountain western North America, from eastern Washington and Oregon, through Nevada, Idaho, and Utah, into northern Arizona and New Mexico, and east as far as the western Dakotas, and Colorado. At least three subspecies of A. tridentata have been recognized, including A. tridentata subsp. tridentata Nutt. (basin big sagebrush), A. tridentata subsp. wyomingensis Beetle & A.L.Young (Wyoming big sagebrush), and A. tridentata subsp. vaseyana (Rydb.) Beetle (mountain big sagebrush). Although big sagebrush is an important food source and cover for several animal species, the volatile phytochemistry has shown wide variation in composition. The purpose of this work was to compare and contrast the essential oil compositions of the three subspecies of A. tridentata growing in southwestern Idaho. Methods/Results: Several samples of A. tridentata subsp. wyomingensis and A. tridentata subsp. vaseyana were collected, the essential oils obtained by hydrodistillation using a Likens-Nickerson apparatus in yields of 2.33%-4.45% and 0.90%-1.73%, respectively, and the essential oils analyzed by gas chromatographic techniques. Although A. tridentata shows wide variation in essential oil compositions, multivariate analysis (hierarchical cluster analysis and principal component analysis) indicated A. tridentata subsp. tridentata to be characterized by high concentrations of yomogi alcohol (5.8%-30.8%) and camphor (5.2%-20.1%), while camphor was the defining component in A. tridentata subsp. wyomingensis (10.0%-30.1%) and subsp. vaseyana (16.1%-40.2%). One sample of A. tridentata subsp. vaseyana was dominated by α-thujone (76.1%), however. Conclusion: There is much variation in essential oil compositions of A. tridentata, both within subspecies and between geographical locations; much additional investigation is necessary to more fully characterize the volatile phytochemistry of this plant.

Balkans' Asteraceae Species as a Source of Biologically Active Compounds for the Pharmaceutical and Food Industry

Herbal drugs are a useful source of different bioactive compounds. Asteraceae species, as the most widespread vascular plants, can be used both as food and as medicine due to the great diversity of recorded chemical components - different phenolic compounds, terpenes, carotenoids, vitamins, alkaloids, etc. The Balkan Peninsula is characterized by great diversity of plants from Asteraceae family, including presence of rare and endemic species. In this review, results of the survey of chemical composition and biological activity, mainly focusing on antioxidant, antimicrobial and anticancer effects of selected Balkans' Asteraceae species were provided. In addition, information on edible plants from Asteraceae family is presented, due to growing interest for the so-called 'healthy diet' and possible application of Balkans' Asteraceae species as food of high nutritional value or as a source of functional food ingredients.

Two goitrogenic 1,3-oxazolidine-2-thione derivatives from Brassicales taxa: Challenging identification, occurrence and immunomodulatory effects

1,3-Oxazolidine-2-thione derivatives are glucosinolate-related food constituents known to impart (thyreo)toxic properties to some cruciferous vegetables. In this work, 5,5-dimethyl-1,3-oxazolidine-2-thione and (-)-(R)-5-phenyl-1,3-oxazolidine-2-thione, known goitrogens, were isolated from Draba lasiocarpa Rochel (Brassicaceae) and Reseda luteola L. (Resedaceae), respectively, and were fully spectrally characterized. Subsequently, the occurrence of the two 1,3-oxazolidine-2-thiones was verified in six additional taxa out of in total 78 screened Serbian Brassicales taxa. The stereochemistry of 5-phenyl-1,3-oxazolidine-2-thione was inferred from nuclear magnetic resonance experiments with a chiral lanthanide-shift reagent, employed in this work for the first time for this type of compounds. Unexpectedly, during gas chromatography, 5-phenyl-1,3-oxazolidine-2-thione underwent an unreported thermal core isomerization (1,3-oxazolidine-2-thione to 1,3-thiazolidine-2-one). These goitrogenic volatile glucosinolate products were tested for their effect on rat macrophage viability (three assays) and nitric oxide production. It was shown that the compounds displayed different levels of cytotoxicity. All tested compounds caused a significant lactate dehydrogenase leakage, but only (R)-5-phenyl-1,3-oxazolidine-2-thione statistically significantly reduced macrophage mitochondrial activity, whereas the racemic 5-phenyl-1,3-oxazolidine-2-thione and 5,5-dimethyl-1,3-oxazolidine-2-thione had little or no effect. Again only (R)-5-phenyl-1,3-oxazolidine-2-thione exerted nitric oxide production-inhibiting properties, suggesting the higher immunomodulatory potential of this enantiomer compared with its antipode and racemic mixture.