The present study has focused on an investigation of the antibacterial effects of Juncus inflexus and the isolation and identification of its active compounds. Eleven phenanthrenes were isolated from a methanolic extract of the roots. Four compounds (jinflexins A-D, 1-4) are new natural products, while seven phenanthrenes [juncuenins A (5), B (6), and D (8), juncusol (7), dehydrojuncuenins A (9) and B (11), and dehydrojuncusol (10)] were isolated for the first time from the plant. Jinflexin D (4) is a dimer with an unprecedented heptacyclic ring system. The absolute configurations of the new compounds were determined by TDDFT-ECD calculations, and their enantiomeric purity was checked by chiral HPLC analysis. Extracts of different polarity (n-hexane, dichloromethane, and ethyl acetate) were evaluated for their antimicrobial effects against methicillin-resistant Staphylococcus aureus, extended-spectrum β-lactamase (ESBL)-producing Citrobacter freundii, Escherichia coli, Enterobacter cloacae, Klebsiella pneumoniae, multiresistant Acinetobacter baumannii, and Pseudomonas aeruginosa. The MIC values of the isolated compounds were determined by a microdilution method. Jinflexin B (2), juncusol (7), juncuenin D (8), and dehydrojuncuenin B (11) showed significant activity (MIC value range 12.5-100 μg/mL) against MRSA strains.

From an extract of red mamey (Pouteria sapota) β-cryptoxanthin-5,6-epoxide, β-cryptoxanthin-5',6'-epoxide, 3'-deoxycapsanthin, and cryptocapsin were isolated and characterized by UV-vis spectroscopy, electronic circular dichroism (ECD), nuclear magnetic resonance (NMR) spectroscopy, and mass spectrometry (MS). Epoxidation of β-cryptoxanthin delivered the β-(5'R,6'S)- and (5'S,6'R)-cryptoxanthin-5',6'-epoxides, which were identified by HPLC-ECD analysis. These carotenoids among others are quite common in the fruits of Central America, and as they are natural provitamins A, they should play an important role in the diet of the mostly vitamin A deficient population of this region.

The present study focused on the anti-inflammatory screening of Luzula species native to the Carpathian Basin and bioactivity-guided isolation of compounds of Luzula luzuloides (Lam.) Dandy & Wilmott. The anti-inflammatory properties of extracts with different polarity prepared from Luzula species were determined. Among them, the CHCl-soluble fraction of L. luzuloides possessed strong inhibitory effects on superoxide anion generation (99.39±0.37%) and elastase release (114.22±3.13%) in fMLP/CB-induced human neutrophils at concentration of 10μg/mL. From this fraction, six compounds (1-6) were isolated by the combination of different chromatographic methods. The structures of the compounds were determined by means of MS, 1D and 2D NMR spectroscopy. The results allowed the identification of the new 1,6-dihydroxy-2-keto-1,7-dimethyl-8-vinyl-1,2-dihydrophenanthrene (1) from the plant, named luzulin A. Chiral HPLC and HPLC-ECD analysis revealed that 1 possesses low enantiomeric excess and TDDFT-ECD calculations afforded the configurational assignment of the separated enantiomers. Three known phenanthrenes [juncuenin B (2), dehydrojuncuenin B (3) and juncusol (4)] and two flavonoids [apigenin (5) and luteolin (6)] were also isolated. The anti-inflammatory activity of the isolated compounds was tested and IC values were determined. This was the first time that phenanthrenes were detected in a Luzula species. The oxidative transformation of juncuenin B (3) led to the isolation of its possible biometabolites, namely luzulin A (1), dehydrojuncuenin B (4), and juncuenin D (7). The isolated compounds (1-4) confirm that besides flavonoids, phenanthrenes could also serve as chemotaxonomic markers for Luzula species and prove the close relationship of Juncus and Luzula genus.

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The Heck-oxyarylation of 2H-chromenes afforded (6S*,6aR*,11aR*)-6-naphthylpterocarpans with potent antiproliferative activity. Absolute configurations and conformations of the separated enantiomers were determined by TDDFT-ECD calculations.

Starting from racemic naringenin ((±)-1), a mixture of dracocephin A stereoisomers 6-(2”-pyrrolidinone-5”-yl)naringenin (±)-2a–d and its regioisomer, dracocephin B 8-(2”-pyrrolidinone-5”-yl)naringenin (±)-3a–d originally isolated from Dracocephalum rupestre, have been synthesized in a one-pot reaction. The separation of 2a–d and 3a–d was achieved by preparative HPLC. The four stereoisomers of each natural product were separated by analytical chiral HPLC and their absolute configuration was studied by the combination of HPLC–ECD measurements and TDDFT–ECD calculations. The synthesized flavonoid alkaloids were further characterized by physicochemical and in vitro pharmacological studies.

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Racemic chiral O,N-heterocycles containing 2-arylchroman or 2-aryl-2H-chromene subunit condensed with morpholine, thiazole, or pyrrole moieties at the C-3-C-4 bond were synthesized with various substitution patterns of the aryl group by the cyclization of cis- or trans-3-aminoflavanone analogues. The 3-aminoflavanone precursors were obtained in a Neber rearrangement of oxime tosylates of flavanones, which provided the trans diastereomer as the major product and enabled the isolation of both the cis- and trans-diastereomers. The cis- and trans-aminoflavanones were utilized to prepare three diastereomers of 5-aryl-chromeno[4,3-b][1,4]oxazines. Antiproliferative activity of the condensed heterocycles and precursors was evaluated against A2780 and WM35 cancer cell lines. For a 3-(N-chloroacetylamino)-flavan-4-ol derivative, showing structural analogy with acyclic acid ceramidase inhibitors, 0.15 μM, 3.50 μM, and 6.06 μM IC50 values were measured against A2780, WM35, and HaCat cell lines, and apoptotic mechanism was confirmed. Low micromolar IC50 values down to 2.14 μM were identified for the thiazole- and pyrrole-condensed 2H-chromene derivatives. Enantiomers of the condensed heterocycles were separated by HPLC using chiral stationary phase, HPLC-ECD spectra were recorded and TDDFT-ECD calculations were performed to determine the absolute configuration and solution conformation. Characteristic ECD transitions of the separated enantiomers were correlated with the absolute configuration and effect of substitution pattern on the HPLC elution order was determined.