Chemical constituents from Eupatorium fortunei and their anti-inflammatory evaluation by in silico and experimental approaches

The well-known aromatic and medicinal plant Eupatorium fortunei Turcz. is widely cultivated in China, and previous studies on its bioactive constituents mainly focus on the essential oil ingredients especially thymol derivatives. However, reports on other type of constituents and the potential application are lacking. In the present project, an intensive chemical fractionation on the aerial part extract of E. fortunei led to the isolation and identification of a series of fatty acid derivatives (lipids, 1a/1b-19) including seven pairs of previously undescribed enantiomers (1a/1b-7a/7b), as well as a lignan (brachangobinan A (BBA), 20) and two monoterpenes (8S/8R-9-hydroxythymol, 21a/21b). A preliminary biological evaluation of these compounds in a NO production inhibitory assay model demonstrated compound BBA as the most active one. Network pharmacology analysis was used to predict and explore the possible anti-inflammatory targets and mechanism of BBA, which revealed some potential inflammation-related proteins and signaling pathways. Further experimental investigations validated that the anti-inflammatory effect of BBA could be achieved by suppressing pro-inflammatory factors and blocking the activation of NF-κB signaling pathway. Taken together, our work shows that E. fortunei can serve as a potential resource of lipids and anti-inflammatory agents.

Enzymatic esterification of lauric acid to give monolaurin in a microreactor

Monolaurin is a naturally occurring compound widely utilized in food and cosmetics. In this paper, we present a new method for the synthesis of monolaurin by esterification between lauric acid and glycerol catalyzed by Novozym® 435 using a microreactor. The conversion of lauric acid is 87.04% in 20 min, compared with 70.54% via the batch approach in 5 h. Using an optimized solvent system consisting of t-BuOH/ tert-amyl alcohol (1:1, v/v), the selectivity using the microreactor method is enhanced to 90.63% and the space–time yield of the process is 380.91 g/h/L. This newly devised method has the potential for application to other multiphase and enzymatic reactions.

Racemic Phospholipids for Origin of Life Studies

Although prebiotic condensations of glycerol, phosphate and fatty acids produce phospholipid esters with a racemic backbone, most experimental studies on vesicles intended as protocell models have been carried out by employing commercial enantiopure phospholipids. Current experimental research on realistic protocell models urgently requires racemic phospholipids and efficient synthetic routes for their production. Here we propose three synthetic pathways starting from glycerol or from racemic solketal (α,β-isopropylidene-dl-glycerol) for the gram-scale production (up to 4 g) of racemic phospholipid ester precursors. We describe and compare these synthetic pathways with literature data. Racemic phosphatidylcholines and phosphatidylethanolamines were obtained in good yields and high purity from 1,2-diacylglycerols. Racemic POPC (rac-POPC, (R,S)-1-palmitoyl-2-oleoyl-3-phosphocholine), was used as a model compound for the preparation of giant vesicles (GVs). Confocal laser scanning fluorescence microscopy was used to compare GVs prepared from enantiopure (R)-POPC), racemic POPC (rac-POPC) and a scalemic mixture (scal-POPC) of (R)-POPC enriched with rac-POPC. Vesicle morphology and size distribution were similar among the different (R)-POPC, rac-POPC and scal-POPC, while calcein entrapments in (R)-POPC and in scal-POPC were significantly distinct by about 10%.

Microbiota and metabolome responses in the cecum and serum of broiler chickens fed with plant essential oils or virginiamycin

This study investigated the cecal microbiota and serum metabolite profile of chickens fed with plant essential oils (PEO) or virginiamycin (VIRG) using high-throughput 16S rRNA gene sequencing and untargeted metabolomics approach. The main aim of this work was to explore the biochemical mechanisms involved in the improved growth performance of antibiotics and their alternatives in animal production. The results showed that both PEO and VIRG treatment significantly increased the relative abundance of phyla Bacteroidetes and decreased the abundance of phyla Firmicutes and genus of Lactobacillus in cecal microbiota of chickens. Compared to the control group (CT group), the relative abundance of genus of Alistipes, unclassified Rikenellaceae, Roseburia, and Anaeroplasma was enriched in the PEO group; that of genus Bacteroides, Lachnospiraceae, and unclassified Enterobacteriaceae was enriched in the cecal microbiota of the VIRG group. Untargeted metabolomics analyses revealed that the PEO treatment modified 102 metabolites and 3 KEGG pathways (primary bile acid biosynthesis and phenylalanine metabolism) in the cecal microbiota, and 81 metabolites and relevant KEGG pathways (fructose and mannose metabolism, biosynthesis of unsaturated fatty acids, and linoleic acid.) in the serum of the chicken. Compared to the CT group, VIRG treatment group differed 217 metabolites and 10 KEGG pathways in cecal contents and 142 metabolites and 7 KEGG pathways in serum of chickens. Pearson’s correlation analysis showed that phyla Bacteroidetes and genus of Bacteroides, Alistipes, and unclassified Rikenellaceae (in the VIRG and PE group) were positively correlated with many lipid metabolites. However, phyla Firmicutes and genera Lactobacillus (higher in the CT group) were negatively correlated with the lipid and thymine metabolism, and positively correlated with hydroxyisocaproic acid, cytosine, and taurine. This study shows that dietary supplementation with PEO and VIRG altered the composition and metabolism profile of the cecal microbiota, modified the serum metabolism profile.

The chemical synthesis and preliminary biological studies of phosphodiester and phosphorothioate analogues of 2-methoxy-lysophosphatidylethanolamine

The chemical synthesis of phosphorothioate/phosphodiester analogues of 2-methoxy-lysophosphatidylethanolamine has been described. For the preparation of phosphorothioate derivatives oxathiaphospholane approach has been employed. The phosphodiester compounds were prepared by OXONE® oxidation of corresponding phosphorothioates. Each lysophospholipid analogue was synthesized as a series of four compounds, bearing different fatty acid residues both saturated (14:0, 16:0, 18:0) and unsaturated (18:1). The methylation of glycerol 2-hydroxyl function was applied in order to increase the stability of prepared analogues by preventing 1→2 acyl migration. The cytotoxicity of newly synthesized 2-methoxy-lysophosphatidylethanolamine derivatives was evaluated with resazurin-based method in prostate cancer PC3 cell line. The highest reduction of cell viability was noted for LPE analogues containing myristoyl acyl chain.

Structural evidence of the species-dependent albumin binding of the modified cyclic phosphatidic acid with cytotoxic properties

Cytotoxic properties of a new phosphorodithioate myristoyl derivative of cyclic phosphatidic acid as well as detailed binding mode of this ligand by human and equine serum albumins based on two crystal structures are presented.

Cyclic phosphatidic acids (cPAs) are naturally occurring, very active signalling molecules, which are involved in several pathological states, such as cancer, diabetes or obesity. As molecules of highly lipidic character found in the circulatory system, cPAs are bound and transported by the main extracellular lipid binding protein–serum albumin. Here, we present the detailed interactions between human serum albumin (HSA) and equine serum albumin (ESA) with a derivative of cPA, 1-O-myristoyl-sn-glycerol-2,3-cyclic phosphorodithioate (Myr-2S-cPA). Initial selection of the ligand used for the structural study was made by the analysis of the therapeutically promising properties of the sulfur containing analogues of cPA in respect to the unmodified lysophospholipids (LPLs). Substitution of one or two non-bridging oxygen atoms in the phosphate group with one or two sulfur atoms increases the cytotoxic effect of cPAs up to 60% on the human prostate cancer (PC) cells. Myr-2S-cPA reduces cancer cell viability in a dose-dependent manner, with IC₅₀ value of 29.0 μM after 24 h incubation, which is almost 30% lower than IC₅₀ of single substituted phosphorothioate cPA. Although, the structural homology between HSA and ESA is big, their crystal complexes with Myr-2S-cPA demonstrate significantly different mode of binding of this LPL analogue. HSA binds three molecules of Myr-2S-cPA, whereas ESA only one. Moreover, none of the identified Myr-2S-cPA binding sites overlap in both albumins.

Preparation of glycerol monostearate from glycerol carbonate and stearic acid

A new two-step procedure prepares glycerol monostearate from glycerol carbonate and stearic acid.

The chemical synthesis and cytotoxicity of new sulfur analogues of 2-methoxy-lysophosphatidylcholine

The chemical synthesis of phosphorothioate/phosphorodithioate analogues of 2-methoxy-lysophosphatidylcholine has been described. For the preparation of new sulfur derivatives of lysophosphatidylcholine both oxathiaphospholane and dithiaphospholane approaches have been employed. Each lysophospholipid analogue was synthesized as a series of five compounds, bearing different fatty acid residues both saturated (12:0, 14:0, 16:0, 18:0) and unsaturated (18:1). The methylation of glycerol 2-hydroxyl function was applied in order to increase the stability of prepared analogues by preventing 1 → 2 acyl migration. The cellular toxicity of newly synthesized 2-methoxy-lysophosphatidylcholine derivatives was measured using MTT viability assay and lactate dehydrogenase release method.

Synthesis and tandem mass spectrometry of chlorinated triacylglycerols

The incorporation of 9,10-dichlorooctadecanoyl groups using enzyme-catalyzed acylation and protecting group strategies yielded specific regioisomers of di- and tetrachlorinated triacylglycerols. Hexachloro- and hexabromotriacylglycerols were synthesized by addition of chlorine or bromine to tri-(cis-9-octadecenoyl)glycerol. Upon electrospray ionization and tandem mass spectrometry, the sodium adduct ions of all compounds containing a 9,10-dichlorooctadecanoyl group readily lost two molecules of HCl when subjected to collision-induced dissociation. A mechanism describing sequential HCl losses and the formation of a conjugated diene is proposed for the loss of both vicinal chlorine atoms from an alkyl chain. This characteristic fragmentation behavior and the availability of characterized standards will facilitate the development of quantitative analytical methods for the determination of chlorinated triacylglycerols in lipid mixtures isolated from marine and other biological sources.

The chemical synthesis of metabolically stabilized 2-OMe-LPA analogues and preliminary studies of their inhibitory activity toward autotaxin

The chemical synthesis of five new metabolically stabilized 2-OMe-LPA analogues (1a-e) possessing different fatty acid residues has been performed by phosphorylation of corresponding 1-O-acyl-2-OMe-glycerols which were prepared by multistep process from racemic glycidol. The now analogues were subjected to biological characterization as autotaxin inhibitors using the FRET-based, synthetic ATX substrate FS-3. Among tested compounds 1-O-oleoyl-2-OMe-LPA (1e) appeared to be the most potent, showing ATX inhibitory activity similar to that of unmodified 1-O-oleoyl-LPA. Parallel testing showed, that similar trend was also observed for corresponding 1-O-acyl-2-OMe-phosphorothioates (2a-e, synthesized as described by us previously). 1-O-oleoyl-2-OMe-LPA (1e) was found to be resistant toward alkaline phosphatase as opposed to unmodified 1-O-oleoyl-LPA.