Chemical Composition and Antimicrobial Activity of the Essential Oil from the Edible Aromatic Plant Aristolochia delavayi

The essential oil obtained by hydrodistillation from the aerial parts of Aristolochia delavayi Franch. (Aristolochiaceae), a unique edible aromatic plant consumed by the Nakhi (Naxi) people in Yunnan, China, was investigated using GC/MS analysis. In total, 95 components, representing more than 95% of the oil composition, were identified, and the main constituents found were (E)‐dec‐2‐enal (52.0%), (E)‐dodec‐2‐enal (6.8%), dodecanal (3.35%), heptanal (2.88%), and decanal (2.63%). The essential oil showed strong inhibitory activity (96% reduction) of the production of bacterial volatile sulfide compounds (VSC) by Klebsiella pneumoniae, an effect that was comparable with that of the reference compound citral (91% reduction). Moreover, the antimicrobial activity of the essential oil and the isolated major compound against eight bacterial and six fungal strains were evaluated. The essential oil showed significant antibacterial activity against Providencia stuartii and Escherichia coli, with minimal inhibitory concentrations (MIC) ranging from 3.9 to 62.5 μg/ml. The oil also showed strong inhibitory activity against the fungal strains Trichophyton ajelloi, Trichophyton terrestre, Candida glabrata, Candida guilliermondii, and Cryptococcus neoformans, with MIC values ranging from 3.9 to 31.25 μg/ml, while (E)‐dec‐2‐enal presented a lower antifungal activity than the essential oil.     

Variability of the Needle Essential Oils of Juniperus deltoides R.P.Adams from Different Populations in Serbia and Croatia

The essential‐oil compositions of one Croatian and three Serbian populations of Juniperus deltoides R.P.Adams have been determined by GC/MS analysis. In total, 147 compounds were identified, representing 97.3–98.3% of the oil composition. The oils were dominated by monoterpenes, which are characteristic components for the species of the section Juniperus. Two monoterpenes, α‐pinene and limonene, were the dominant constituents, with a summed‐up average content of 49.45%. Statistical methods were used to determine the diversity of the terpene classes and the common terpenes between the newly described J. deltoides populations from Serbia and Croatia. Only reports on several specimens from this species have been reported so far, and there are no studies that treat population diversity. Cluster analysis of the oil contents of 21 terpenes showed high correlation with the geographical distribution of the populations, separating the Croatian from the Serbian populations. The comparison of the essential‐oil compositions obtained in the present study with literature data, showed the separation of J. deltoides and J. oxycedrus ssp. oxycedrus from the western Mediterranean region.     

Synthesis,Characterization, and Anti‐Amoebic Activity of N‐(Pyrimidin‐2‐yl)benzenesulfonamide Derivatives

A new series of N‐(pyrimidin‐2‐yl)benzenesulfonamide derivatives, 3a – 3i and 4a – 4i , was synthesized from pyrimidin‐2‐amines, 2a – 2i , with the aim to explore their effects on in vitro growth of Entamoeba histolytica. The chemical structures of the compounds were elucidated by elemental analysis, FT‐IR, ¹H‐ and ¹³C‐NMR, and ESI mass‐spectral data. In vitro anti‐amoebic activity was evaluated against HM1 : IMSS strain of Entamoeba histolytica. The IC₅₀ values were calculated by using the double dilution method. The results were compared with the IC₅₀ value of the standard drug ‘metronidazole’. The selected compounds were tested for their cytotoxic activities by cell‐viability assay using H9C2 cardiac myoblasts cell line, and the results indicated that all the compounds displayed remarkable >80% viabilities to a concentration of 100 μg/ml.     

Identification and Quantitation of New Glutamic Acid Derivatives in Soy Sauce by UPLC/MS/MS

Glutamic acid is an abundant amino acid that lends a characteristic umami taste to foods. In fermented foods, glutamic acid can be found as a free amino acid formed by proteolysis or as a non‐proteolytic derivative formed by microorganisms. The aim of the present study was to identify different structures of glutamic acid derivatives in a typical fermented protein‐based food product, soy sauce. An acidic fraction was prepared with anion‐exchange solid‐phase extraction (SPE) and analyzed by UPLC/MS/MS and UPLC/TOF‐MS. α‐Glutamyl, γ‐glutamyl, and pyroglutamyl dipeptides, as well as lactoyl amino acids, were identified in the acidic fraction of soy sauce. They were chemically synthesized for confirmation of their occurrence and quantified in the selected reaction monitoring (SRM) mode. Pyroglutamyl dipeptides accounted for 770 mg/kg of soy sauce, followed by lactoyl amino acids (135 mg/kg) and γ‐glutamyl dipeptides (70 mg/kg). In addition, N‐succinoylglutamic acid was identified for the first time in food as a minor compound in soy sauce (5 mg/kg).     

Naphtho‐γ‐pyrones from Endophyte Aspergillus niger Occurring in the Liverwort Heteroscyphus tener (Steph.) Schiffn.

Bioactivity‐guided fractionation of the cytotoxic extract of Aspergillus niger, an endophytic fungus from the Chinese liverwort Heteroscyphus tener (Steph .) Schiffn ., afforded five new naphtho‐γ‐pyrones, rubrofusarin‐6‐O‐α‐D ‐ribofuranoside ( 1 ), (R)‐10‐(3‐succinimidyl)‐TMC‐256A1 ( 2 ), asperpyrone E ( 3 ), isoaurasperone A ( 4 ), and isoaurasperone F ( 5 ), as well as four known ones, dianhydroaurasperone C ( 6 ), aurasperone D ( 7 ), asperpyrone D ( 8 ), and asperpyrone A ( 9 ), together with a cytotoxic cyclic pentapeptide, malformin A₁ ( 10 ). Their structures were determined by extensive spectroscopic analysis. The absolute configurations of dimeric naphtho‐γ‐pyrones 3 – 9 were also determined by analysis of their respective CD spectra.     

Chemopreventive and Antioxidant Activity of the Chamazulene‐Rich Essential Oil Obtained from Artemisia arborescens L. Growing on the Isle of La Maddalena,Sardinia, Italy

The essential oils of Artemisia arborescens growing in Sardinia (Italy), collected during three plant growth stages, i.e., from the vegetative stage to post‐blooming time, were characterized. Moreover, the in vitro antiproliferative and antioxidant activities of the oil isolated from aerial parts collected in February were evaluated. The essential oils belonged to the β‐thujone/chamazulene chemotype, notably with the highest amount of chamazulene (ca. 52%) ever detected up to now in the genus Artemisia and, in general, in essential oils. Quantitative variations in the oil composition were observed as the plant passes from the vegetative to the blooming stage. The oil was tested for its potential tumor cell growth‐inhibitory effect on T98G, MDA‐MB 435S, A375, and HCT116 human cell lines, using the MTT (=3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl‐2H‐tetrazolium bromide) assay. The highest activity was observed on A375 and HCT116 cell lines, with IC₅₀ values of 14 μg/ml. Moreover, the in vitro antioxidant and free radical‐scavenging assays revealed the oil to be an effective scavenger of the ABTS radical cation, with an activity comparable to that of Trolox^®. These results support the use of A. arborescens oil for the treatment of inflamed skin conditions. Finally, the composition of the polar fraction of the A. arborescens aerial parts was also examined, and the main component detected was 5‐O‐caffeoylquinic acid, which was identified for the first time in this plant.