The bark of trees contains an interesting mixture of bioactive compounds, or so-called extractives. The use of supercritical carbon dioxide (sc-CO2) eliminates both the need for organic solvents as extractants and the danger that solvent traces might compromise the purity of the extracts. Unfortunately, the complexity and natural variability of extracts’ composition render any utilization attempts rather challenging. Thus, in order to implement exploitation concepts in a meaningful way, appropriate analytical techniques for characterizing extracts must be available beforehand. In our work, we explored gas chromatography coupled to both mass spectrometry and a flame ionization detector (GC-MS/FID), in combination with ultraperformance convergence chromatography and quadrupole time-of-flight mass spectrometry (UPC2-QTof-MS), for the characterization of bark extracts from pine (Pinus sylvestris L.) in both qualitative and quantitative terms. Although the conventional GC-MS/FID approach is a robust method for overall quantification of extractives, it fails to provide ample information about native sterol esters and triglycerides. These data are provided by a new, complementary analytical technique based on supercritical carbon dioxide, as the chromatographic eluant, coupled to a high-resolution mass spectrometer. The combination of both techniques and the use of sc-CO2 as both an extraction solvent and eluant made this combined tool especially powerful. The most prominent triglycerides in the extract were identified qualitatively and quantitatively, and the dominating sterol esters were identified qualitatively, by UPC2-QTof-MS.

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Acid-sensitive ion channels (ASICs) are sodium channels partially permeable to Ca 2+ ions, listed among putative targets in central nervous system (CNS) diseases in which a pH modification occurs. We targeted novel compounds able to modulate ASIC1 and to reduce the progression of ischemic brain injury. We rationally designed and synthesized several diminazeneinspired diaryl mono-and bis-guanyl hydrazones. A correlation between their predicted docking affinities for the acidic pocket (AcP site) in chicken ASIC1 and their inhibition of homo-and heteromeric hASIC1 channels in HEK-293 cells was found. Their activity on murine ASIC1a currents and their selectivity vs mASIC2a were assessed in engineered CHO-K1 cells, highlighting a limited isoform selectivity. Neuroprotective effects were confirmed in vitro, on primary rat cortical neurons exposed to oxygen-glucose deprivation followed by reoxygenation, and in vivo, in ischemic mice. Early lead 3b, showing a good selectivity for hASIC1 in human neurons, was neuroprotective against focal ischemia induced in mice.

The impact of totally chlorine-free (TCF) bleaching chemicals on the composition and behavior of detrimental lipophilic wood extractives in a mixed hardwood sulfite pulp was studied to determine their potential for pitch control without the need for additional reagents. Toward this end, the acetone extracts of pulp were analyzed with commonly used gas chromatography (GC) and more sophisticated ultraperformance convergence chromatography (UPC2). During EO­(P)–Z–P bleaching, the highest decrease in the lipophilic extractive content was achieved after ozone bleaching (Z), with a 38% reduction of GC-FID/MS-detectable resins. Oxygen-reinforced alkaline extraction EO­(P) and peroxide bleaching (P) were less effective in terms of resin quality and quantity (−30 and −27%, respectively). Analyzing the acetone extracts after alkaline hydrolysis revealed a different pattern: EO­(P) with −44%, P with −20%, and Z with only −8% less lipophilic extractives. A series of oxidized compounds, such as acyl chain-oxidized sterol esters and acylglycerols, and acidic secosterol analogues, were detected for the first time with UPC2-ESI-QToF-MS after ozone bleaching. These compounds lead to an underestimation of the GC-detectable resin content and may be involved in the formation of deposits during lignocellulosic processing. Reaction pathways for lipophilic extractives during ozone bleaching were established.

Wood extractives are known to cause problems during the production of pulp and paper and to impact their mechanical properties. In the present work, we systematically explored whether minute residual amounts of extractives that reprecipitate on the fiber surface in the final stages of the pulping process would lower the thermal resilience of softwood Kraft pulp. Pulp samples subjected to different extraction methods were characterized by means of thermogravimetric analysis. The compound classes constituting the respective extracts were identified and quantified via gas chromatography-mass spectrometry/flame ionization detector (GC-MS/FID) and the influence of the individual compound classes on the thermal stability of the samples was investigated separately. Soxhlet extraction with an ethanol/toluene solvent system clearly led to increased thermal stability. Besides fatty acids and resin acids also sterols and sterol esters that do not carry carboxylic acid functionalities contributed to the deterioration of the thermal pulp properties. Lateral order indices derived from Fourier transformed infrared spectra and crystallinity indices derived from solid-state 13C nuclear magnetic resonance spectra indicate that upon thermal degradation, the presence of even minute amounts of extractives leads to an increased degree of supramolecular disorder. Moreover, the characterization of the samples’ carbohydrate composition by means of acidic hydrolysis showed a tendency towards facilitated pyrolysis of the hemicelluloses if extractives were present in the pulp.

Background Spermacoce princeae (K. Schum) has been used in the treatment of bacterial skin infections in Uganda. Pharmacological studies revealed that extracts of S. princeae exhibited antibacterial, antioxidant, and sun protection potential. This study aimed at isolating and identifying pure compounds from the extracts based on comprehensive analytical characterization by multiple analytical techniques. Methods The plant samples were extracted by sequential maceration using n-hexane, ethyl acetate, methanol, and distilled water. The compounds were isolated using a combination of chromatographic techniques and their structures were elucidated by multiple spectroscopic techniques. The antibacterial and antifungal activity determination of the isolated compounds was carried out using an agar well diffusion and potato dextrose assay against Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Candida albicans, and Aspergillus flavus while the antioxidant activity was screened with the 2,2-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging assay. The sun protection factor was determined using a Shimadzu Ultra Violet-visible (UV–VIS) double beam spectrophotometer between 290 to 320 nm. Results Eleven compounds; quercetin (1), kaempferol-3-O-rutinoside (2), rutin (3, 12), myo-inositol (4), asperulosidic acid (5), hexadecanoic acid (6), β-sitosterol (7), stigmasterol (8), campesterol (9), ursolic acid (10), and β-sitosterol glucoside (11) were identified in the S. princeae extracts. Compound 2 had good antifungal activity against C. albicans (zone of inhibition, 23.0 ± 0.1 mm). Compound 10 showed antibacterial and antifungal activity against S. aureus, P. aeruginosa, C. albicans, and A. flavus. Compound 2 had a good percentage radical scavenging effect (IC50 = 64.81 µg/ml) and a good sun protection factor (SPF = 26.83). Conclusion This study reports the first-time isolation and identification of compounds 1 to 11 from S. princeae, which contribute to its antimicrobial, antioxidant, and sun protection potential.