A ‘Low-Level’ Chemotaxonomic Analysis of the Plant Family Apiaceae: The Case ofScandix balansaeReut. exBoiss. (Tribe Scandiceae)

Pulicaria dysenterica (L.) Bernh.-Rightfully Earned Name? Identification and Biological Activity of New 3-Methoxycuminyl Esters from P. dysenterica Essential Oil

Motivated by the ethnopharmacological use of Pulicaria dysenterica, in the present study, the antimicrobial potential of the extracted essential oil was investigated against a panel of eighteen microorganism strains. Additionally, anti-acetylcholinesterase and antispasmodic (isolated rat distal colon) activities, general acute toxicity (Artemia salina model), and immunomodulatory properties (cytotoxicity on isolated mouse macrophages) were studied. Detailed analyses of the essential oil led to the identification of 3-methoxycuminyl 2-methylbutanoate (a new natural product) and 3-methoxycuminyl 3-methylbutanoate (a rare natural product). The obtained esters and intermediates in the synthesis of the starting alcohol (3-methoxycuminol) were subjected to a battery of 1D- and 2D-NMR experiments. The synthesized esters were additionally characterized by GC-MS, IR, and UV-Vis. The synthesized compounds (ten in total) were biologically tested in the same way as the extracted P. dysenterica essential oil. The obtained low acute toxicity and promising antimicrobial potential suggest that the P. dysenterica essential oil might partially explain the ethnopharmacological application of P. dysenterica plant material for the treatment of gastrointestinal infections.

Trypsin Inhibitor Isolated From Glycine max (Soya Bean) Extraction, Purification, and Characterization

The current study aims to isolate, purify, and characterize the trypsin inhibitor protein from seeds of soya beans, scientifically known as Glycine max. Its seeds were ground, and the powder was soaked several times using n-hexane. It was added to phosphate buffer saline (PBS) followed by filtration and centrifugation of the PBS dissolved extract. The supernatant was subjected to ammonium sulfate precipitation and about six fractions, 30% to 80% were prepared. The centrifuged pellets obtained from each fraction were dialyzed and run on SDS-PAGE. The trypsin inhibitor protein was precipitated and characterized in 30% pellet and molecular weight was 21.5 kDa compared to protein ladder (ThermoFisher 10-170 kDa). GC-MS analysis revealed the steroid derivatives such as stigmasterol, campesterol, beta-sitosterol, and gamma-tocopherol. Glycine max trypsin inhibitor could be used as a plant-derived drug to overcome the over-activation of trypsin without its real substrate (proteins) becoming activated and start auto digestion leading to pancreatitis.

Essential-Oil Constituents and Alkanes of Cephalaria ambrosioides Roem. & Schult. (Family Caprifoliaceae, Subfamily Dipsacaceae) and (Chemo)taxonomic Discernment of the Subfamilies Dipsacaceae and Morinaceae

Herein, the results of the first study of the volatile and alkane profiles of Cephalaria ambrosioides Roem. & Schult. (Caprifoliaceae, subfamily Dipsacaceae) were reported. The GC-FID and GC/MS analyses of the essential oils hydrodistilled from leaves and stems (CA1) and flowers (CA2) of C. ambrosioides allowed the identification of 284 different components. The main compounds of the studied oil samples were palmitic acid (24.3 and 32.5% for CA1 and CA2, resp.), hexahydrofarnesyl acetone (1.4 and 10.8% for CA1 and CA2, resp.), (Z)-hex-3-en-1-ol (7.0 and <0.1% for CA1 and CA2, resp.), and linoleic acid (1.9 and 6.5% for CA1 and CA2, resp.). Essential-oil compositional data of selected plant species belonging to the Dipsacaceae (15) and Morinaceae (2) subfamilies were used to resolve taxonomical ambiguities regarding the genus Cephalaria and its infrageneric relations, especially concerning the subfamily Morinaceae (formerly a genus within Dipsacaceae). The results of multivariate statistical analyses (25 different essential-oil samples) supported the exclusion of Morina species from the Dipsacaceae subfamily. The relative abundances of alkanes from n-, iso-, and anteiso-series followed a (distorted) Gaussian-like distribution and suggested that the biosyntheses of n- and branched alkanes in C. ambrosioides are possibly not controlled by the same elongase. Also, the obtained results suggested that there was a difference in the biosynthesis/accumulation of alkanes in the vegetative and reproductive parts of C. ambrosioides.

(Un)targeted metabolomics in Asteraceae: probing the applicability of essential-oil profiles of senecio L. (Senecioneae) taxa in chemotaxonomy

The possible applicability of (un)targeted metabolomics (volatile metabolites) for revealing taxonomic/evolutionary relationships among Senecio L. species (Asteraceae; tribe Senecioneae) was explored. Essential-oil compositional data of selected Senecio/Senecioneae/Asteraceae taxa (93 samples in total) were mutually compared by means of multivariate statistical analysis (MVA), i.e., agglomerative hierarchical clustering and principal component analysis. The MVA input data set included the very first compositional data on the essential oil extracted from the aerial parts of S. viscosus L. as well as on four different Serbian populations of S. vernalis Waldst. & Kit. (oils from aerial parts and roots; eight samples in total). This metabolomic screening of Senecio/Senecioneae/Asteraceae species (herein presented results and data from the literature) pointed to short-chain alk-1-enes (e.g., oct-1-ene, non-1-ene, and undec-1-ene), with up to now restricted general occurrence in Plantae, as characteristic chemotaxonomic markers/targets for future metabolomic studies of Senecio/Senecioneae taxa. The MVA additionally showed that the evolution of the terpene metabolism (volatile mono- and sesquiterpenoids) within the Asteraceae tribe Senecioneae was not genera specific. However, the MVA did confirm plant-organ specific production/accumulation of volatiles within S. vernalis and suggested the existence of at least two volatile chemotypes for this species.

Further antibacterial Geranium macrorrhizum L. metabolites and synthesis of epoxygermacrones

4,5- and 1,10-Epoxygermacrones were isolated from the essential oil of aerial parts of Geranium macrorrhizum L. (Geraniaceae). The structures of the epoxy derivatives were deduced from their 1D- and 2D-NMR spectra, molecular modeling, and confirmed by synthesis starting from germacrone. The epoxy compounds were screened for their antimicrobial activities by a microdilution assay, which revealed high activities of both compounds against Bacillus subtilis (minimum inhibitory concentrations (M/Cs) determined were 4.3 and 43 nmol/ml for 1,10- and 4,5-epoxygermacrone, resp.) and Pseudomonas aeruginosa (0.043 and 0.855 μmol/ml for 1,10- and 4,5-epoxygermacrone, resp.). The discovery and observed activity of the two epoxides fills the gap in our knowledge of the active principles in this highly renowned ethnomedicinal plant species.