Formation and structural features of micelles formed by surfactin homologues.

Surfactin, a group of cyclic lipopeptides produced by Bacillus subtilis, possesses surfactant properties and is a promising natural and biologically active compound. In this study, we present a comprehensive characterization of surfactin, including its production, chromatographic separation into pure homologues (C12, C13, C14, C15), and investigation of their physicochemical properties. We determined adsorption isotherms and interpreted them using the Gibbs adsorption equation, revealing that the C15 homologue exhibited the strongest surface tension reduction (27.5 mN/m), while surface activity decreased with decreasing carbon chain length (32.2 mN/m for C12). Critical micelle concentration (CMC) were also determined, showing a decrease in CMC values from 0.35 mM for C12 to 0.08 mM for C15. We employed dynamic light scattering (DLS), transmission electron microscopy (TEM), and density functional theory (DFT) calculations to estimate the size of micellar aggregates, which increased with longer carbon chains, ranging from 4.7 nm for C12 to 5.7 nm for C15. Furthermore, aggregation numbers were determined, revealing the number of molecules in a micelle. Contact angles and emulsification indexes (E24) were measured to assess the functional properties of the homologues, showing that wettability increased with chain length up to C14, which is intriguing as C14 is the most abundant homologue. Our findings highlight the relationship between the structure and properties of surfactin, providing valuable insights for understanding its biological significance and potential applications in various industries. Moreover, the methodology developed in this study can be readily applied to other cyclic lipopeptides, facilitating a better understanding of their structure-properties relationship.

A Novel Strategy for the Separation of Functional Oils from Chamomile Seeds.

The main aim of this study was to evaluate the oils from chamomile seeds as a new source of bioactive compounds suitable for human consumption. A green extraction technique with supercritical carbon dioxide (sc-CO2) at pressures up to 450 bar and temperatures up to 60 °C was employed for the production of a high amount of biologically active oil. Additionally, exhausted waste material was re-extracted using sc-CO2 with the addition of ethanol. By optimization in operating pressure, temperature, production cost, fraction of milled seeds, and co-solvent addition, the amount of separated chamomile oil increased from 2.4 to 18.6% and the content of unsaturated fatty acids up to 88.7%. Oils contained α-bisabolol oxide A and B in amounts up to 1.4%. Linoleic acid was detected in an amount up to 711.1 mg/g and α-linolenic acid up to 27.5 mg/g. The total phenolic content in separated oil reached 80.4 mg GAE/g while the total flavonoid content reached 11.6 mg QE/g. The obtained chamomile oils showed antioxidant activity with an IC50 of up to 3.9 mg/mL. Among the 23 tested microorganisms, the antimicrobial activity of oils was the most pronounced against Gram-positive bacteria. The cytotoxic activity of oils was tested on normal and cancer-derived cell lines. Results indicated a significant potential for oil from chamomile seeds, produced in an eco-friendly manner, as a functional food. Supplementary Information: The online version contains supplementary material available at 10.1007/s11947-023-03038-9.

Molecular Distillation of Lavender Supercritical Extracts: Physicochemical and Antimicrobial Characterization of Feedstocks and Assessment of Distillates Enriched with Oxygenated Fragrance Components.

Lavandula angustifolia is one of the most widely cultivated non-food crops used in the production of essential oil; it is used in perfumery, aromatherapy, pharmaceutical preparations, and food ingredients. In this study, supercritical fluid extraction (SFE) and molecular distillation (MD) were combined, primarily to enrich scCO2 extracts with lavender oxygenated monoterpenes, avoiding thermal degradation, hydrolysis, and solvent contamination, and maintaining the natural characteristics of the obtained oils. Molecular distillation was developed for the first time for the extraction of crucial lavender fragrance ingredients, i.e., from two scCO2 extracts obtained from dry flower stems of lavender cultivated in Poland and Bulgaria. The best results for high-quality distillates were obtained at 85 °C (EVT) and confirmed that linalyl acetate content increased from 51.54 mg/g (initial Bulgarian lavender extract, L-Bg-E) and 89.53 mg/g (initial Polish lavender extract, L-Pl-E) to 118.41 and 185.42 mg/g, respectively, corresponding to increases of 2.3 and 2.1 times in both distillate streams, respectively. The distillates, light oils, and extracts from lavender were also evaluated for their antimicrobial properties by determining the minimum inhibitory concentration (MIC) by the broth microdilution method. Generally, Gram-positive bacteria and Candida spp. were more sensitive to all distilled fractions and extracts than Escherichia coli (Gram-negative bacteria).

Bioactive Compounds Obtained from Polish "Marynka" Hop Variety Using Efficient Two-Step Supercritical Fluid Extraction and Comparison of Their Antibacterial, Cytotoxic, and Anti-Proliferative Activities In Vitro.

Given the health-beneficial properties of compounds from hop, there is still a growing trend towards developing successful extraction methods with the highest yield and also receiving the products with high added value. The aim of this study was to develop efficient extraction method for isolation of bioactive compounds from the Polish "Marynka" hop variety. The modified two-step supercritical fluid extraction allowed to obtain two hop samples, namely crude extract (E1), composed of α-acids, ß-acids, and terpene derivatives, as well as pure xanthohumol with higher yield than that of other available methods. The post-extraction residues (R1) were re-extracted in order to obtain extract E2 enriched in xanthohumol. Then, both samples were subjected to investigation of their antibacterial (anti-acne, anti-caries), cytotoxic, and anti-proliferative activities in vitro. It was demonstrated that extract (E1) possessed more beneficial biological properties than xanthohumol. It exhibited not only better antibacterial activity against Gram-positive bacteria strains (MIC, MBC) but also possessed a higher synergistic effect with commercial antibiotics when compared to xanthohumol. Moreover, cell culture experiments revealed that crude extract neither inhibited viability nor divisions of normal skin fibroblasts as strongly as xanthohumol. In turn, calculated selectivity indexes showed that the crude extract had from slightly to significantly better selective anti-proliferative activity towards cancer cells in comparison with xanthohumol.

Determination of fat- and water-soluble vitamins by supercritical fluid chromatography: A review.

Vitamins are compounds that take part in all basic functions of an organism but also are subject of number of studies performed by different researchers. Two groups of vitamins are distinguished taking into consideration their solubility. Chromatography with supercritical CO2 has found application in the determination, separation, and quantitative analyses of both fat- and water-soluble vitamins. The methods of vitamins separation have developed and improved throughout the years. Both groups of compounds were separated using supercritical fluid chromatography with different detection on different stationary phases. The main aim of this review is to provide an overview of the studies of vitamins separation that have been determined so far.