Field-Grown and In Vitro Propagated Round-Leaved Sundew (Drosera rotundifolia L.) Show Differences in Metabolic Profiles and Biological Activities

Drosera rotundifolia L. is a carnivorous plant used in traditional medicine for its therapeutic properties. Because of its small size, its collection in nature is laborious and different cultivation methods have been studied to ensure availability. However, only a few studies exist where the lab-grown sundew tissue and field-grown sundew would have been compared in their functionality or metabolic profiles. In this study, the antioxidant and antiviral activities of lab-grown and field-grown sundew extracts and their metabolic profiles are examined. The effect of drying methods on the chromatographic profile of the extracts is also shown. Antioxidant activity was significantly higher (5–6 times) in field-grown sundew but antiviral activity against enterovirus strains coxsackievirus A9 and B3 was similar in higher extract concentrations (cell viability ca. 90%). Metabolic profiles showed that the majority of the identified compounds were the same but field-grown sundew contained higher numbers and amounts of secondary metabolites. Freeze-drying, herbal dryer, and oven or room temperature drying of the extract significantly decreased the metabolite content from −72% up to −100%. Freezing was the best option to preserve the metabolic composition of the sundew extract. In conclusion, when accurately handled, the lab-grown sundew possesses promising antiviral properties, but the secondary metabolite content needs to be higher for it to be considered as a good alternative for the field-grown sundew.     

Harnack's inequality for quasiminimizers with nonstandard growth conditions

We prove Harnack inequalities for quasiminimizers of the variable exponent Dirichlet energy integral by employing the De Giorgi method.     

Additional insights into luminescence process of polycyclic aromatic hydrocarbons with carbonyl groups: photophysical properties of secondary N-alkyl and tertiary n,n-dialkyl carboxamides of naphthalene, anthracene, and pyrene

Here we report the substitution effects of N-alkyl and N,N-dialkyl carboxamide groups on the fluorescence properties of polycyclic aromatic hydrocarbon chromophores, so as to control their fluorescence properties. The fluorescence properties of compounds obtained using solvents with different polarities showed very little change, indicating that the modified compounds do not form charge transfer states. TD-DFT calculations and measurements performed at low temperature (78 K) and in viscous solvents revealed that the N-alkyl and N,N-dialkyl carboxamide groups tend to reduce the contributions from intersystem crossing and increase those from internal conversion. Considering that the fluorescence mechanism of low-fluorescence carbonyl compounds such as aldehyde and ketone is dominated by intersystem crossing and that of high-luminescence carbonyl compounds such as carboxylic acid and ester is dominated by a radiative process, it can be said that the photophysical process of N-alkyl and N,N-dialkyl carboxamides is novel. In addition, the calculation results for excited states indicated that such contributions can be controlled by selecting the appropriate polycyclic aromatic hydrocarbon or amide structure, in addition to solvent viscosity and temperature.     

Chemotaxonomically Important Volatiles of the Genus Anthemis L. – a Detailed GC and GC/MS Analyses of Anthemis Segetalis Ten. from Montenegro

Although there are more than two hundred taxa in the pharmacologically important genus Anthemis, essential oil composition is known only for a small number of them. This is the first report on the volatiles of A. segetalis Ten. GC and GC/MS analyses of the essential oil hydrodistilled from A. segetalis aerial parts enabled the identification of 155 constituents, representing 92.4% of the total oil. Major constituents of the oil were sabinene (19.5%), germacrene D (12.6%), terpinen‐4‐ol (6.2%) and 1,8‐cineole (6.1%). Monoterpenoids (49.9%, especially those of thujane and p‐menthane skeletons) and sesquiterpenoids (39.4%, predominantly those of germacrane‐, cadinane‐ and caryophyllane‐types) were found to be the most abundant compound classes. The comparison of the essential oil composition of other Anthemis species with the present one was used as an additional tool for the clarification of infrageneric relationships. The results support the treatment of Anthemis subg. Cota as a separate genus.     

Singularities of ball quotients

We prove a result on the singularities of ball quotients ${\Gamma\backslash\mathbb{C}{H^n}}$ by an arithmetic group. More precisely, we show that a ball quotient has at most canonical singularities under certain restrictions on the dimension n and the underlying lattice. We also extend this result to the toroidal compactification.     

Nitrogen-rich 5,5'-bistetrazolates and their potential use in propellant systems: a comprehensive study

A large variety of twice-deprotonated nitrogen-rich 5,5'-bistetrazolates, that is, the ammonium (1), hydrazinium (2), hydroxylammonium (3), guanidinium (4), aminoguanidinium (5), diaminoguanidinium (6), triaminoguanidinium (7), and diaminouronium (8) salts, have been synthesized. Energetic compounds 1-8 were fully characterized by single-crystal X-ray diffraction (except 8), NMR spectroscopy, IR and Raman spectroscopy, and differential scanning calorimetry (DSC) measurements. With respect to their potential use in propellant applications, the sensitivity towards impact, friction, and electrical discharge were determined. Several propulsion and detonation parameters (e.g., heat of explosion, detonation velocity) were computed by using the EXPLO5 computer code based on calculated (CBS-4M) heats of formation and X-ray densities. Additionally, the performance of 1-8 in various formulations was investigated by calculating the specific energy and specific impulse of the compounds under isochoric conditions.     

New 3,4-Annelated Coumarin Derivatives: Synthesis, Antimicrobial Activity, Antioxidant Capacity, and Molecular Modeling

Summary.  The one pot reaction preparation, spectral analysis, and molecular modeling experiments on the new 3,4-annelated coumarin systems with bioactivity associated structural features are described. These provided the insight into the equilibrium of the respective tautomeric forms making possible the reconciliation of previously published spectral data with the structure assignments as well as the correction of erroneously established structures. The synthesized compounds were tested in a standard disk diffusion assay and displayed strong to moderate antimicrobial activity, with a promising new lead prototype compound (7-amino-9-hydroxy-5-oxa-7a,8,11-triazacyclopenta[b]phenanthren-6-one (5)) possessing greater activity that the antibiotics Ampicillin and Nystatin. Antioxidant capacities of the compounds, determined spectrophotometrically using a phosphomolybdenum method, were greater, and in the case of compound 5 four times the activity of α-tocopherol acetate.