Growing and Processing Conditions Lead to Changes in the Carotenoid Profile of Spinach

This study aimed to evaluate the influence of different light regimens during spinach cultivation on the isomeric composition of β-carotene. Irradiation with a halogen lamp, which has a wavelength spectrum close to that of daylight, was used to mimic field-grown conditions. The additional use of optical filters was established as a model system for greenhouse cultivation. Field-grown model systems led to a preferential increase of 9-<i>cis</i>-β-carotene, whereas 13-<i>cis</i>-β-carotene was just formed at the beginning of irradiation. Additionally 9,13-di-<i>cis</i>-β-carotene decreased significantly in the presence of energy-rich light. Isomerization of β-carotene was strongly suppressed during irradiation in greenhouse-grown model systems and led to significant differences. These results were verified in biological samples. Authentic field-grown spinach (Spinacia oleracea L.) showed among changes of other isomers a significantly higher level of 9-<i>cis</i>-isomers (7.52 ± 0.14%) and a significantly lower level of 9,13-di-<i>cis</i>-isomers (0.25 ± 0.03%) compared to authentic greenhouse-grown spinach (6.49 ± 0.11 and 0.76 ± 0.05%). Almost all analyzed commercial spinach samples (fresh and frozen) were identified as common field-grown cultivation. Further investigations resulted in a clear differentiation of frozen commercial samples from fresh spinach, caused by significantly higher levels of 13-<i>cis</i>- and 15-<i>cis</i>-β-carotene as a result of industrial blanching processes

Structure and Absolute Configuration of Pseudohygrophorones A¹² and B¹², Alkyl Cyclohexenone Derivatives from <i>Hygrophorus abieticola </i>(Basidiomycetes)

Pseudohygrophorones A¹² (<b>1</b>) and B¹² (<b>2</b>), the first naturally occurring alkyl cyclohexenones from a fungal source, and the recently reported hygrophorone B¹² (<b>3</b>) have been isolated from fruiting bodies of the basidiomycete <i>Hygrophorus abieticola</i> Krieglst. ex Gröger & Bresinsky. Their structures were assigned on the basis of extensive one- and two-dimensional NMR spectroscopic analysis as well as ESI-HRMS measurements. The absolute configuration of the three stereogenic centers in the diastereomeric compounds <b>1</b> and <b>2</b> was established with the aid of ³<i>J</i>_H,H and ⁴<i>J</i>_H,H coupling constants, NOE interactions, and conformational analysis in conjunction with quantum chemical CD calculations. It was concluded that pseudohygrophorone A¹² (<b>1</b>) is 4<i>S</i>,5<i>S</i>,6<i>S</i> configured, while pseudohygrophorone B¹² (<b>2</b>) was identified as the C-6 epimer of <b>1</b>, corresponding to the absolute configuration 4<i>S</i>,5<i>S</i>,6<i>R</i>. In addition, the mass spectrometric fragmentation behavior of <b>1</b>–<b>3</b> obtained by the higher energy collisional dissociation method allows a clear distinction between the pseudohygrophorones (<b>1</b> and <b>2</b>) and hygrophorone B¹² (<b>3</b>). The isolated compounds <b>1</b>–<b>3</b> exhibited pronounced activity against phytopathogenic organisms

Hierarchical cluster analysis and chemical characterisation of <i>Myrtus communis</i> L. essential oil from Yemen region and its antimicrobial, antioxidant and anti-colorectal adenocarcinoma properties

<p>The hydrodistilled essential oil obtained from the dried leaves of <i>Myrtus communis</i>, collected in Yemen, was analysed by GC–MS. Forty-one compounds were identified, representing 96.3% of the total oil. The major constituents of essential oil were oxygenated monoterpenoids (87.1%), linalool (29.1%), 1,8-cineole (18.4%), α-terpineol (10.8%), geraniol (7.3%) and linalyl acetate (7.4%). The essential oil was assessed for its antimicrobial activity using a disc diffusion assay and resulted in moderate to potent antibacterial and antifungal activities targeting mainly <i>Bacillus subtilis, Staphylococcus aureus</i> and <i>Candida albicans.</i> The oil moderately reduced the diphenylpicrylhydrazyl radical (IC₅₀ = 4.2 μL/mL or 4.1 mg/mL). <i>In vitro</i> cytotoxicity evaluation against HT29 (human colonic adenocarcinoma cells) showed that the essential oil exhibited a moderate antitumor effect with IC₅₀ of 110 ± 4 μg/mL. Hierarchical cluster analysis of <i>M. communis</i> has been carried out based on the chemical compositions of 99 samples reported in the literature, including Yemeni sample.</p

Identification of Enterodiol as a Masker for Caffeine Bitterness by Using a Pharmacophore Model Based on Structural Analogues of Homoeriodictyol

Starting from previous structure–activity relationship studies of taste modifiers based on homoeriodictyol, dihydrochalcones, deoxybenzoins, and <i>trans</i>-3-hydroxyflavones as obvious analogues were investigated for their masking effect against caffeine. The most active compounds of the newly investigated taste modifiers were phloretin, the related dihydrochalcones 3-methoxy-2′,4,4′-trihydroxydihydrochalcone and 2′,4-dihydroxy-3-methoxydihydrochalcone, and the deoxybenzoin 2-(4-hydroxy-3-methoxyphenyl)-1-(4-hydroxyphenyl)­ethanone. Starting with the whole set of compounds showing activity >22%, a (Q)­SAR pharmacophore model for maskers of caffeine bitterness was calculated to explain the structural requirements. After docking of the pharmacophore into a structural model of the broadly tuned bitter receptor hTAS2R10 and docking of enterolactone and enterodiol as only very weakly related structures, it was possible to predict qualitatively their modulating activity. Enterodiol (25 mg L^–1) reduced the bitterness of the 500 mg L^–1 caffeine solution by about 30%, whereas enterolactone showed no masking but a slight bitter-enhancing effect

Chilenopeptins A and B, Peptaibols from the Chilean <i>Sepedonium</i> aff. <i>chalcipori</i> KSH 883

The Chilean <i>Sepedonium</i> aff. <i>chalcipori</i> strain KSH 883, isolated from the endemic <i>Boletus loyo</i> Philippi, was studied in a polythetic approach based on chemical, molecular, and biological data. A taxonomic study of the strain using molecular data of the ITS, EF1-α, and RPB2 barcoding genes confirmed the position of the isolated strain within the <i>S. chalcipori</i> clade, but also suggested the separation of this clade into three different species. Two new linear 15-residue peptaibols, named chilenopeptins A (<b>1</b>) and B (<b>2</b>), together with the known peptaibols tylopeptins A (<b>3</b>) and B (<b>4</b>) were isolated from the semisolid culture of strain KSH 883. The structures of <b>1</b> and <b>2</b> were elucidated on the basis of HRESIMS^<i>n</i> experiments in conjunction with comprehensive 1D and 2D NMR analysis. Thus, the sequence of chilenopeptin A (<b>1</b>) was identified as Ac-Aib¹-Ser²-<b><u>Trp</u></b>^<b>3</b>-Aib⁴-Pro⁵-Leu⁶-Aib⁷-Aib⁸-Gln⁹-Aib¹⁰-Aib¹¹-Gln¹²-Aib¹³-Leu¹⁴-Pheol¹⁵, while chilenopeptin B (<b>2</b>) differs from <b>1</b> by the replacement of Trp³ by Phe³. Additionally, the total synthesis of <b>1</b> and <b>2</b> was accomplished by a solid-phase approach, confirming the absolute configuration of all chiral amino acids as l. Both the chilenopeptins (<b>1</b> and <b>2</b>) and tylopeptins (<b>3</b> and <b>4</b>) were evaluated for their potential to inhibit the growth of phytopathogenic organisms