Palmitoylethanolamide (PEA) is an endogenous lipid mediator with powerful anti-inflammatory and analgesic functions. PEA can be hydrolyzed by a lysosomal enzyme N-acylethanolamine acid amidase (NAAA), which is highly expressed in macrophages and other immune cells. The pharmacological inhibition of NAAA activity is a potential therapeutic strategy for inflammation-related diseases. Fucoxanthinol (FXOH) is a marine carotenoid from brown seaweeds with various beneficial effects. However, the anti-inflammatory effects and mechanism of action of FXOH in lipopolysaccharide (LPS)-stimulated macrophages remain unclear. This study aimed to explore the role of FXOH in the NAAA–PEA pathway and the anti-inflammatory effects based on this mechanism. In vitro results showed that FXOH can directly bind to the active site of NAAA protein and specifically inhibit the activity of NAAA enzyme. In an LPS-induced inflammatory model in macrophages, FXOH pretreatment significantly reversed the LPS-induced downregulation of PEA levels. FXOH also substantially attenuated the mRNA expression of inflammatory factors, including inducible nitric oxide synthase (iNOS), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α), and markedly reduced the production of TNF-α, IL-6, IL-1β, and nitric oxide (NO). Moreover, the inhibitory effect of FXOH on NO induction was significantly abolished by the peroxisome proliferator-activated receptor α (PPAR-α) inhibitor GW6471. All these findings demonstrated that FXOH can prevent LPS-induced inflammation in macrophages, and its mechanisms may be associated with the regulation of the NAAA-PEA-PPAR-α pathway.

Objective: Hydroxypropyl-β-cyclodextrin (HP-β-CD)/menthyl acetate (MA) microcapsules were developed to overcome the volatile and unstable defects of MA and improve the ease of use and storage. Methods: MA microcapsules were prepared via spray drying using HP-β-CD as the wall material. The embedding rate of MA microcapsules was determined through gas chromatography. The embedding characteristics were studied using phase solubility and nuclear magnetic resonance (NMR). The stability was characterized via differential scanning calorimetry (DSC) and the release and retention rates of MA microcapsules at different temperatures. Results: The embedding rate of HP-β-CD /MA microcapsules was 96.3%. The Gibbs free energy change, enthalpy change and entropy change of the embedding reaction between HP-β-CD and MA were all less than zero, indicating that the embedding process was a spontaneous exothermic reaction. NMR spectra showed that MA entered the cavity of HP-β-CD through the large opening end and interacted with the inner wall of the small opening end. DSC and the release and retention rates of MA microcapsules at different temperatures showed that the stability of MA was significantly enhanced after being embedded in HP-β-CD. Conclusion: The HP-β-CD/MA microcapsules are able to significantly improve the stability of MA and reduce the volatilization of MA.

A new certified reference material (CRM) of D-mannitol (GBW(E) 100681) has been developed in this study. We describe the preparation, structure determination, characterization, homogeneity study, stability study, as well as uncertainty estimation. The main component was 99.91% ± 0.01%. The moisture content of the candidate CRM was 0.036% ± 0.002%, as measured by Karl Fischer titration. The nonvolatile and volatile impurities in the candidate CRM were all much less than 0.01%, which was determined by the ICP–MS and headspace GC–FID methods, respectively. The purity of the D-mannitol CRM was 99.9% ± 1.1% (k = 2), as measured by the two independent approaches involving the mass balance method (MB) and quantitative nuclear magnetic resonance technique (qNMR). The D-mannitol CRM was stable during the monitoring period for each temperature. It is stable for up to 48 months at room temperature and 28 days at 50 °C. The uncertainty was evaluated by combining the contributions from characterization, homogeneity, and stability. The developed D-mannitol CRM would effectively support method validation and proficiency testing, as well as effectively guarantee the accuracy, reliability, and comparability of results.

A novel approach to producing high-purity fucoxanthinol (FXOH) was exploited as a sustainable method to maximize fucoxanthin (FX) utilization. Through fusing the genes of cholesterol esterase and SpyTag and then expressing them in Escherichia coli, the fusion chimera was self-assembled into insoluble active aggregates by SpyTag, which could be regarded as carrier-free immobilization. The immobilization yield of the active cholesterol esterase aggregates could reach 60%. They have expressed good activity retention at 92.48% and 60.13% after 3 and 12 cycles, respectively, which is an exciting finding. The conversion ratio of FX to FXOH is 95.02%, which is remarkably higher than those realized via the conventional chemical reduction method (55.86%) and the enzymatic hydrolysis method by free cholesterol esterases (84.51%). The purity of FXOH obtained by this method is as high as 98%, which is much higher than those obtained by other methods. Thus, a promising method for simultaneously purifying and immobilizing active cholesterol esterase aggregates is demonstrated in this study by SpyTag tailoring. In addition, this study provides an eco-friendly method for producing high-purity FXOH from FX in a highly efficient manner.