Natural deep eutectic solvents (NADES) have emerged as an eco-friendly alternative for extracting bioactives, avoiding the use of flammable organic solvents and extreme temperatures and pH conditions. NADES rely on intermolecular interactions between hydrogen bonding donors (HBD) and hydrogen bonding acceptors (HBA) to form eutectic mixtures with significantly lower melting points than their individual components. These matrices are influenced by factors like water content, temperature, and component ratios. NADES high viscosity can hinder extractive efficiency, which can be mitigated by adding water or working at higher temperatures. However, excessive dilution with water may disrupt the supramolecular structure of NADES, reducing extraction efficiency. A notable feature of NADES is their fine-tunability for specific purposes. Adjusting physicochemical properties such as polarity, pH, and viscosity optimizes extraction efficiency by promoting the solubility of target molecules and interactions between the NADES and target molecules. NADES, unlike organic solvents, can partially disrupt plant and microalgae cell walls, enhancing permeability and extraction efficiency. Moreover, NADES can have a stabilising effect on bioactives and can enhance their biological activity and bioavailability. These attributes, coupled with their low environmental impact in terms of low toxicity and high biodegradability, make NADES attractive for biorefinery applications.

Background Deep eutectic solvents (DESs) have garnered significant interest in natural products research, owing to their green and natural attributes in comparison to conventional solvents. However, the approach of demonstrating that DESs are superior extractants has led to an underestimation of their full potential in this field. This perspective disregards crucial challenges related to their practical application and potential scalability, mainly the difficulty of target component separation from intermolecular network forming by DESs. Conversely, the DESs unique features can enhance aspects such as solubilization, stabilization, and storage of natural products, as well as improve their biological activities. By addressing key challenges and limitations, we aim to provide valuable insights into the potential of DESs in this domain. Methodology In this review, we conducted an exhaustive literature search to gather relevant articles about DESs and their applications in bioactive natural product research. The gathered literature was analyzed, and a systematic thematic categorization was performed, emphasizing studies where the use of DESs yielded relevant outcomes that could potentially present an advantage in the exploration of bioactive natural products. The approach in structuring this review aimed to provide an overview of the potential and challenges associated with DESs in the domain of bioactive natural product research, transcending their conventional role as mere extraction solvents. Results Through this critical analysis of the literature, this review delves into the potential of DESs as effective solvents for the solubilization, stabilization, and storage of bioactive natural products. In addition, it highlights the ability of DESs to improve the biological activities of natural products, as well as to be used as formulation media for the transport of pharmaceutical active ingredients. By revealing these advances, the review contributes to a more complete understanding of DESs and its applicability in the field of bioactive natural products research. Conclusions The studies compiled in this review underscore the expanded potential of DESs, beyond extraction, finding relevance in the realm of natural products research. Notably, they contribute to enhancing the desired attributes of the final product, signifying a promising avenue for future advancements in this field.

Background The main process limitation of microalgae biofuel technology is lack of cost-effective and efficient lipid extraction methods. Thus, the aim of this study was to investigate the effectiveness and efficiency of six caprolactam-based ionic liquids (CPILs) namely, Caprolactamium chloride, Caprolactamium methyl sulphonate, Caprolactamium trifluoromethane sulfonate, Caprolactamium acetate, Caprolactamium hydrogen sulphate and Caprolactamium trifluoromethane-acetate—for extraction of lipids from wet and dry Spirulina platensis microalgae biomass. Of these, the first three are novel CPILs. Methods The caprolactam-based ionic liquids (CPILs) were formed by a combination of caprolactam with different organic and inorganic Brønsted acids, and used for lipid extraction from wet and dry S. platensis microalgae biomass. Extraction of microalgae was performed in a reflux at 95 °C for 2 h using pure CPILs and mixtures of CPIL with methanol (as co-solvent) in a ratio of 1:1 (w/w). The microalgae biomass was mixed with the ILs/ methanol in a ratio of 1:19 (w/w) under magnetic stirring. Results The yield by control experiment from dry and wet biomass was found to be 9.5% and 4.1%, respectively. A lipid recovery of 10% from dry biomass was recorded with both caprolactamium acetate (CPAA) and caprolactamium trifluoroacetate (CPTFA), followed by caprolactamium chloride (CPHA, 9.3 ± 0.1%). When the CPILs were mixed with methanol, observable lipids’ yield enhancement of 14% and 8% (CPAA), 13% and 5% (CPTFA), and 11% and 6% (CPHA) were recorded from dry and wet biomass, respectively. The fatty acid composition showed that C16 and C18 were dominant, and this is comparable to results obtained from the traditional solvent (methanol-hexane) extraction method. The lower level of pigments in the lipids extracted with CPHA and CPTFA is one of the advantages of using CPILs because they lower the cost of biodiesel production by reducing the purification steps. Conclusion In conclusion, the three CPILs, CPAA, CPHA and CPTFA can be considered as promising green solvents in terms of energy and cost saving in the lipid extraction and thus biodiesel production process.

Background Extracellular vesicles (EVs) are released by most cell types and are involved in multiple basic biological processes. Medium/large EVs (m/lEVs), which are of a different size from exosomes, play an important role in the coagulation in blood, and are secreted from cancer cells, etc., suggesting functions related to malignant transformation. The m/lEVs levels in blood or urine may help unravel pathophysiological findings in many diseases. However, it remains unclear how many naturally-occurring m/lEV subtypes exist as well as how their characteristics and functions differ from one another. Methods We used the blood and urinal sample from each 10 healthy donors for analysis. Using a flow cytometer, we focus on characterization of EVs with large sizes (>200 nm) that are different from exosomes. We also searched for a membrane protein for characterization with a flow cytometer using shotgun proteomics. We then identified m/lEVs pelleted from plasma and urine samples by differential centrifugation and characterized by flow cytometry. Results Using proteomic profiling, we identified several proteins involved in m/lEV biogenesis including adhesion molecules, peptidases and exocytosis regulatory proteins. In healthy human plasma, we could distinguish m/lEVs derived from platelets, erythrocytes, monocytes/macrophages, T and B cells, and vascular endothelial cells with more than two positive surface antigens. The ratio of phosphatidylserine appearing on the membrane surface differed depending on the cell-derived m/lEVs. In urine, 50% of m/lEVs were Annexin V negative but contained various membrane peptidases derived from renal tubular villi. Urinary m/lEVs, but not plasma m/lEVs, showed peptidase activity. The knowledge of the new characteristics is considered to be useful as a diagnostic material and the newly developed method suggests the possibility of clinical application.