Stable vesicle self-assembled from phospholipid and mannosylerythritol lipid and its application in encapsulating anthocyanins

Enhancement of mono-acylated MEL-D production in an acyltransferase gene-deleted strain of Pseudozyma tsukubaensis by supplementation with di-acylated MEL-B in culture medium

Mannosylerythritol lipids (MELs) are glycolipid biosurfactants produced by various yeasts. MEL producers produce mainly di-acylated MELs (consisting of two fatty acid chains). Among them, Pseudozyma tsukubaensis is a di-acylated MEL-B (d-MEL-B) producer. In a previous study, we generated an acyltransferase-deleted strain of P. tsukubaensis (ΔPtMAC2), which selectively produced mono-acylated MEL-D (m-MEL-D, consisting of one fatty acid chain), but not d-MEL-B. However, m-MEL-D productivity in ΔPtMAC2 was low, and oil consumption was significantly reduced compared to the parent strain. Based on these findings, we hypothesized that the d-MEL-B produced by the parent strain may act as an emulsifier in the culture medium, leading to easier utilization of the oil. By contrast, the m-MEL-D produced by ΔPtMAC2 may not have the ability to emulsify oil, thus the oil is used inefficiently and productivity of m-MEL-D is low. Therefore, we expected that adding d-MEL-B to the culture medium during ΔPtMAC2 cultivation would increase m-MEL-D production. To enhance the oil consumption and m-MEL-D production of ΔPtMAC2, d-MEL-B and chemical surfactants were added to the culture medium as emulsifiers during ΔPtMAC2 cultivation. Adding d-MEL-B enhanced both the oil consumption and m-MEL-D production of ΔPtMAC2; Tween 20 and Triton X-100 also showed enhancement effects. As expected, d-MEL-B, Tween20 and TritonX-100, showed marked olive oil emulsification activity, whereas m-MEL-D did not. These results strongly support our hypothesis and significantly improve m-MEL-D productivity.

Characterization of a KU70-disrupted strain of the mannosylerythritol lipid-producing yeast Pseudozyma tsukubaensis constructed by a marker recycling system

The basidiomycetous yeast Pseudozyma tsukubaensis is known as an industrial mannosylerythritol lipid producer. In this study, the PtURA5 marker gene was deleted by homologous recombination. Using the PtURA5-deleted mutant as a host strain, we obtained a derivative disrupted for the PtKU70 gene, a putative ortholog of the KU70 gene encoding a protein involved in the nonhomologous end-joining pathway of DNA repair. Subsequently, the introduced PtURA5 gene was re-deleted by marker recycling. These results demonstrated that the PtURA5 gene can be used as a recyclable marker gene. Although the frequency of homologous recombination has been shown to be increased by KU70 disruption in other fungi, the PtKU70-disrupted strain of P. tsukubaensis did not demonstrate an elevated frequency of homologous recombination. Furthermore, the PtKU70-disrupted strain did not show increased susceptibility to bleomycin. These results suggested that the function of this KU70 ortholog in P. tsukubaensis is distinct from that in other fungi.

Unravelling the interactions between small molecules and liposomal bilayers via molecular dynamics and thermodynamic modelling

Lipid-based drug delivery systems hold immense promise in addressing critical medical needs, from cancer and neurodegenerative diseases to infectious diseases. By encapsulating active pharmaceutical ingredients - ranging from small molecule drugs to proteins and nucleic acids - these nanocarriers enhance treatment efficacy and safety. However, their commercial success faces hurdles, such as the lack of a systematic design approach and the issues related to scalability and reproducibility. This work aims to provide insights into the drug-phospholipid interaction by combining molecular dynamic simulations and thermodynamic modelling techniques. In particular, we have made a connection between the structural properties of the drug-phospholipid system and the physicochemical performance of the drug-loaded liposomal nanoformulations. We have considered two prototypical drugs, felodipine (FEL) and naproxen (NPX), and one model hydrogenated soy phosphatidylcholine (HSPC) bilayer membrane. Molecular dynamic simulations revealed which regions within the phospholipid bilayers are most and least favoured by the drug molecules. NPX tends to reside at the water-phospholipid interface and is characterized by a lower free energy barrier for bilayer membrane permeation. Meanwhile, FEL prefers to sit within the hydrophobic tails of the phospholipids and is characterized by a higher free energy barrier for membrane permeation. Flory-Huggins thermodynamic modelling, small angle X-ray scattering, dynamic light scattering, TEM, and drug release studies of these liposomal nanoformulations confirmed this drug-phospholipid structural difference. The naproxen-phospholipid system has a lower free energy barrier for permeation, higher drug miscibility with the bilayer, larger liposomal nanoparticle size, and faster drug release in the aqueous medium than felodipine. We suggest that this combination of molecular dynamics and thermodynamics approach may offer a new tool for designing and developing lipid-based nanocarriers for unmet medical applications.

Promising Application, Efficient Production, and Genetic Basis of Mannosylerythritol Lipids

Mannosylerythritol lipids (MELs) are a class of glycolipids that have been receiving increasing attention in recent years due to their diverse biological activities. MELs are produced by certain fungi and display a range of bioactivities, making them attractive candidates for various applications in medicine, agriculture, and biotechnology. Despite their remarkable qualities, industrial-scale production of MELs remains a challenge for fungal strains. Excellent fungal strains and fermentation processes are essential for the efficient production of MELs, so efforts have been made to improve the fermentation yield by screening high-yielding strains, optimizing fermentation conditions, and improving product purification processes. The availability of the genome sequence is pivotal for elucidating the genetic basis of fungal MEL biosynthesis. This review aims to shed light on the applications of MELs and provide insights into the genetic basis for efficient MEL production. Additionally, this review offers new perspectives on optimizing MEL production, contributing to the advancement of sustainable biosurfactant technologies.

Recent development of carrier materials in anthocyanins encapsulation applications: A comprehensive literature review

Anthocyanins are natural polyphenols belonging to the flavonoid family that possess a variety of putative health benefits when consumed in a balanced diet. However, applications of anthocyanins in, for example, functional foods are limited due to poor stability, degradation, and low transmembrane efficiency. To maintain bioactivities of anthocyanins and optimize their use, various carrier materials have been developed. Here, we reviewed the uses of the different carrier materials (organic/inorganic, micro/nano) for anthocyanin encapsulation and delivery over the past five years. The performance of different materials and interactions between anthocyanins and these materials are described. Lastly, we give our perspective on the future development trend of anthocyanin encapsulation strategies.

Sucrose Osmotic Self-Oscillation Drives Membrane Permeability

Molecular permeation through phospholipid membranes is a fundamental biological process for small molecules. Sucrose is one of the most widely used sweeteners and a key factor in the pathogenesis of obesity and diabetes, yet a detailed understanding of its mechanism involved in permeability into phospholipid membranes is still lacking. Here, using giant unimolecular vesicles (GUVs) reconstituting membrane properties, we compared the osmotic behavior of sucrose in GUVs and HepG2 cells to explore the effect of sucrose on membrane stability in the absence of protein enhancers. The results suggested that the particle size and potential of GUVs and the cellular membrane potential changed significantly with increasing the sucrose concentration (p < 0.05). In microscopic images of cells containing GUVs and sucrose, the fluorescence intensity of vesicles was 537 ± 17.69 after 15 min, and the value was significantly higher than that of microscopic images of cells without sucrose addition (p < 0.05). These changes suggested that the permeability of the phospholipid membrane became larger under a sucrose environment. This study provides a theoretical basis for better insight on the role of sucrose in the physiological environment.

Anthocyanins: Modified New Technologies and Challenges

Anthocyanins are bioactive compounds belonging to the flavonoid class which are commonly applied in foods due to their attractive color and health-promoting benefits. However, the instability of anthocyanins leads to their easy degradation, reduction in bioactivity, and color fading in food processing, which limits their application and causes economic losses. Therefore, the objective of this review is to provide a systematic evaluation of the published research on modified methods of anthocyanin use. Modification technology of anthocyanins mainly includes chemical modification (chemical acylation, enzymatic acylation, and formation of pyran anthocyanidin), co-pigmentation, and physical modification (microencapsulation and preparation of pickering emulsion). Modification technology of anthocyanins can not only increase bioavailability and stability of anthocyanin but also can improve effects of anthocyanin on disease prevention and treatment. We also propose potential challenges and perspectives for diversification of anthocyanin-rich products for food application. Overall, integrated strategies are warranted for improving anthocyanin stabilization and promoting their further application in the food industry, medicine, and other fields.

Effects of encapsulation methods on bioaccessibility of anthocyanins: a systematic review and meta-analysis

Anthocyanins have multiple health benefits. However, they are prone to degradation during gastrointestinal digestion, impeding their utilization. Various encapsulation systems have been proposed to improve their bioaccessibility and bioavailability. This review aims to provide a systematic evaluation and meta-analysis of published studies examining the effect of microencapsulation on the bioaccessibility of anthocyanins. A comprehensive and systematic literature search of three databases (Scopus, PubMed, and Web of Science) was conducted. Studies were selected according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria and were reviewed independently by two investigators. Overall, 34 articles were included in the systematic review and 24 were included in the meta-analysis. The fold changes in bioaccessibility between encapsulated and non-encapsulated anthocyanins from eligible studies were calculated. The median and 95% confidence intervals (CI) of the fold changes for spray-drying (median 1.23, 95% CI 0.91-1.92), freeze-drying (median 1.19, 95% CI 0.61-1.28), simple coacervation (median 1.80, 95% CI 1.41-3.20), and complex coacervation (median 1.61, 95% CI 0.21-25.00) were calculated. Simple coacervation showed a promising protection against degradation during in vitro digestion. However, when a large number of anthocyanins cannot be released from the microparticles during digestion, encapsulation impedes the bioaccessibility of anthocyanins.

Improvement of Oil Degradation and MEL Production in a Yeast Strain, Pseudozyma tsukubaensis, by Translation Elongation Factor 1 Promoter-driven Expression of a Lipase

The basidiomycetous yeast Pseudozyma tsukubaensis produces a mannosylerythritol lipid (MEL) homologue, a diastereomer type of MEL-B, from olive oil. In a previous study, MEL-B production was increased by the overexpression of lipase PaLIPAp in P. tsukubaensis 1E5, through the enhancement of oil consumption. In the present study, RNA sequence analysis was used to identify a promoter able to induce high-level PaLIPA expression. The recombinant strain, expressing PaLIPA via the translation elongation factor 1 alpha/Tu promoter, showed higher lipase activity, rates of oil degradation, and MEL-B production than the strain which generated in our previous study.

Cosmetic-Derived Mannosylerythritol Lipid-B-Phospholipid Nanoliposome: An Acid-Stabilized Carrier for Efficient Gastromucosal Delivery of Amoxicillin for In Vivo Treatment of Helicobacter pylori

Helicobacter pylori infection is a leading cause of gastritis and peptic ulcer. Current treatments for H. pylori are limited by the increase in antibiotic-resistant strains and low drug delivery to the infection site, indicating the need for effective delivery systems of antibiotics. Although liposomes are the most successful drug delivery carriers that have already been applied commercially, their acidic stability still stands as a problem. Herein, we developed a novel nanoliposome using cosmetic raw materials of mannosylerythritol lipid-B (MEL-B), soy bean lecithin, and cholesterol, namely, LipoSC-MELB. LipoSC-MELB exhibited enhanced stability under the simulated gastric-acid condition, owing to its strong intermolecular hydrogen-bond interactions caused by the incorporation of MEL-B. Moreover, amoxicillin-loaded LipoSC-MELB (LipoSC-MELB/AMX) had a particle size of approximately 100 nm and exhibited sustained drug release under varying pH conditions (pH 3-7). Besides, LipoSC-MELB/AMX exhibited significantly higher anti-H. pylori and anti-H. pylori biofilm activity as compared with free AMX. Furthermore, LipoSC-MELB was able to carry AMX across the barriers of gastric mucus and H. pylori biofilms. Remarkably, in vivo assays indicated that LipoSC-MELB/AMX was effective in treating H. pylori infection and its associated gastritis and gastric ulcers. Overall, the findings of this study showed that LipoSC-MELB was effective for gastromucosal delivery of amoxicillin to improve its bioavailability for the treatment of H. pylori infection.

Design and optimization of cranberry extract loaded bile salt augmented liposomes for targeting of MCP-1/STAT3/VEGF signaling pathway in DMN-intoxicated liver in rats

Cranberry extract (CBE) is a major source of the antioxidant polyphenolics but suffers from limited bioavailability. The goal of this research was to encapsulate the nutraceutical (CBE), into bile salt augmented liposomes (BSALs) as a promising oral delivery system to potentiate its hepatoprotective impact against dimethylnitrosamine (DMN) induced liver injury in rats. The inclusion of bile salt in the liposomal structure can enhance their stability within the gastrointestinal tract and promote CBE permeability. CBE loaded BSALs formulations were fabricated utilizing a (2³) factorial design to explore the impact of phospholipid type (X₁), phospholipid amount (X₂), and sodium glycocholate (SGC) amount (X₃) on BSALs properties, namely; entrapment efficiency percent, (EE%); vesicle size, (VS); polydispersity index; (PDI); zeta potential, (ZP); and release efficiency percent, (RE%). The optimum formulation (F1) exhibited spherical vesicles with EE% of 71.27 ± 0.32%, VS; 148.60 ± 6.46 nm, PDI; 0.38 ± 0.02, ZP; −18.27 ± 0.67 mV and RE%; 61.96 ± 1.07%. Compared to CBE solution, F1 had attenuated DMN-induced hepatic injury, as evidenced by the significant decrease in serum level of ALT, AST, ALP, MDA, and elevation of GSH level, as well as SOD and GPX activities. Furthermore, F1 exhibited an anti-inflammatory character by suppressing TNF-α, MCP-1, and IL-6, as well as downregulation of VEGF-C, STAT-3, and IFN-γ mRNA levels. This study verified that when CBE was integrated into BSALs, F1, its hepatoprotective effect was significantly potentiated to protect the liver against DMN-induced damage. Therefore, F1 could be deliberated as an antioxidant, antiproliferative, and antifibrotic therapy to slow down the progression of hepatic damage.

Production of mannosylerythritol lipids: biosynthesis, multi-omics approaches, and commercial exploitation

Compilation of resources regarding MEL biosynthesis, key production parameters; available omics resources and current commercial applications, for smut fungi known to produce MELs.

Advanced approaches for improving bioavailability and controlled release of anthocyanins

Anthocyanins are a group of phytochemicals responsible for the purple or red color of plants. Additionally, they are recognized to have health promoting functions including anti-cardiovascular, anti-thrombotic, anti-diabetic, antimicrobial, neuroprotective, and visual protective effect as well as anti-cancer activities. Thus, consumption of anthocyanin supplement or anthocyanin-rich foods has been recommended to prevent the risk of development of chronic diseases. However, the low stability and bioavailability of anthocyanins limit the efficacy and distribution of anthocyanins in human body. Thus, strategies to achieve target site-local delivery with good bioavailability and controlled release rate are necessary. This review introduced and discussed the latest advanced techniques of designing lipid-based, polysaccharide-based and protein-based complexes, nano-encapsulation and exosome to overcome the limitation of anthocyanins. The improved bioavailability and controlled release of anthocyanins have great significance for gastrointestinal tract absorption, transepithelial transportation and cellular uptake. The techniques of applying different biocompatible materials and modifying the solubility of anthocyanins complex could achieve target site-local delivery with negligible degradation and good bioavailability in human body.

Self-Assembling Properties and Recovery Effects on Damaged Skin Cells of Chemically Synthesized Mannosylerythritol Lipids

Mannosylerythritol lipids (MELs), which are one of the representative sugar-based biosurfactants (BSs) produced by microorganisms, have attracted much attention in various fields in the sustainable development goals (SDGs) era. However, they are inseparable mixtures with respect to the chain length of the fatty acids. In this study, self-assembling properties and structure-activity relationship (SAR) studies of recovery effects on damaged skin cells using chemically synthesized MELs were investigated. It was revealed, for the first time, that synthetic and homogeneous MELs exhibited significant self-assembling properties to form droplets or giant vesicles. In addition, a small difference in the length of the fatty acid chains of the MELs significantly affected their recovery effects on the damaged skin cells. MELs with medium or longer length alkyl chains exhibited much higher recovery effects than that of C18-ceramide NP.

Development and evaluation of a novel nanofibersolosome for enhancing the stability, in vitro bioaccessibility, and colonic delivery of cyanidin-3-O-glucoside

The development of colon-specific carrier systems using polysaccharides for oral delivery of nutraceuticals is of great importance for the treatment and/or prevention of inflammatory bowel diseases. In this study, self-assembly with the assistance of vortexing and pulsed-ultrasonication was employed to develop a Fibersol®-2 (a digestion-resistant polysaccharide) and lipoid S75 based novel nanocarrier (denoted as nanofibersolosome) for the colonic delivery of cyanidin-3-O-glucoside (C3G). A series of nanofibersolosome formulations (CFS-0.5-4, 0.5-4 represent the ratios of Fibersol®-2:lipoid S75) were developed and their performance was compared with Fibersol®-2-free reference lipid formulation (CFS-0). The nanofibersolosomes (<150 nm) were spherical and unilamellar with high negative surface charge (-38 to -51 mV) and good encapsulation efficiency (EE > 90%). They performed much better than CFS-0 in retaining their physical properties during freeze drying, preventing particle aggregation, and retaining C3G during storage (4 and 25 ℃) and thermal treatments (40, 60, and 80 ℃). They also exhibited significantly higher stability during simulated gastrointestinal digestion than CFS-0. These desirable features of the nanofibersolosomes (especially CFS-0.5 and CFS-1) led to the efficient delivery of higher concentrations of C3G to the colon than CFS-0. Moreover, gastrointestinal-digested and colonic-fermented nanofibersolosome samples exhibited significantly higher DPPH radical scavenging activity and stronger promoting effect on short-chain fatty acid generation than CFS-0. These in vitro findings indicate that the novel nanofibersolosome possesses great potential for the colonic delivery of C3G and likely other hydrophilic labile phytochemicals that merits further evaluation in in vivo models.

Contributions of Glycolipid Biosurfactants and Glycolipid-Modified Materials to Antimicrobial Strategy: A Review

Glycolipid biosurfactants are natural amphiphiles and have gained particular interest recently in their biodegradability, diversity, and bioactivity. Microbial infection has caused severe morbidity and mortality and threatened public health security worldwide. Glycolipids have played an important role in combating many diseases as therapeutic agents depending on the self-assembly property, the anticancer and anti-inflammatory properties, and the antimicrobial properties, including antibacterial, antifungal, and antiviral effects. Besides, their role has been highlighted as scavengers in impeding the biofilm formation and rupturing mature biofilm, indicating their utility as suitable anti-adhesive coating agents for medical insertional materials leading to a reduction in vast hospital infections. Notably, glycolipids have been widely applied to the synthesis of novel antimicrobial materials due to their excellent amphipathicity, such as nanoparticles and liposomes. Accordingly, this review will provide various antimicrobial applications of glycolipids as functional ingredients in medical therapy.