Preparation, characterization, and coating effect of bio-active nano-emulsion based on combined plant essential oils on quality of grass carp fillets.

This study aimed to develop a satisfactory essential oil (EO) nano-emulsion through high pressure microjet technology and explore its physiochemical properties and synergistic coating effects on grass carp fillets. The optimal conditions for oregano/litsea cubeba (6:4, wt%/wt%) nano-emulsion were shown to be 80 s high pressure microjet pretreatment time, 9000 lb per square inch pretreatment pressure, 6 % oil phase, and 3:2 Km (mass ratio of surfactant to co-surfactant). The obtained nano-emulsion exhibited 100.42 ± 0.96 nm oil diameter at 4 °C after 15-day storage, coupled with high stability after centrifugation, freeze-thaw and heating treatment. Compared with untreated samples at day 6 storage, the nano-emulsion-treated grass carp fillets exhibited improved textural properties, higher water-holding capacity (74.23 % ± 0.80 %), lower total volatile basic nitrogen (TVB-N, 13.46 ± 0.30 mg/100g)/thiobaric acid (TBA,0.43 ± 0.02 mgMDA/100g), and lower total viable spoilage bacteria count (4.98 ± 0.21 lgCFU/g). This study facilitates understanding the combined EOs nano-emulsion on improving the shelf life of grass carp fillets.

Synthesis and application of gelatin-based controlled-release antibacterial films containing oregano essential oil/ß-cyclodextrin microcapsules for chilling preservation of grass carp fillets.

This work aimed to synthesize oregano essential oil/ß-cyclodextrin microcapsules (OEO/ß-CDs) and then prepare gelatin-based controlled-release antibacterial films with different OEO/ß-CDs contents (0%-2%) for chilling preservation of grass carp fillets. The results of FTIR, XRD, DSC and accelerated release ratio showed that OEO was successfully encapsulated in OEO/ß-CDs and its thermal stability was effectively improved. Moreover, at 2% of addition amount of OEO/ß-CDs, the tensile strength of the films increased from 14.43 MPa to 18.72 MPa. In addition, the films showed significant antibacterial activity against Pseudomonas (61.52%), Aeromonas (62.87%), and Shewanella putrefaciens (66.67%). Preservation experiments showed that the films effectively prevented the increase of TVB-N, and TBA value of the refrigerated fillets and significantly suppressed the growth of spoilage organisms, thus extending the shelf life by 2-3 days. Therefore, the synthesized film has promising potential as an active packaging material for the preservation of grass carp.

Effects of Phenolics on the Physicochemical and Structural Properties of Collagen Hydrogel.

In the current era, the treatment of collagen hydrogels with natural phenolics for the improvement in physicochemical properties has been the subject of considerable attention. The present research aimed to fabricate collagen hydrogels cross-linked with gallic acid (GA) and ellagic acid (EA) at different concentrations depending on the collagen dry weight. The structural, enzymatic, thermal, morphological, and physical properties of the native collagen hydrogels were compared with those of the GA/EA cross-linked hydrogels. XRD and FTIR spectroscopic analyses confirmed the structural stability and reliability of the collagen after treatment with either GA or EA. The cross-linking also significantly contributed to the improvement in the storage modulus, of 435 Pa for 100% GA cross-linked hydrogels. The thermal stability was improved, as the highest residual weight of 43.8% was obtained for the hydrogels cross-linked with 50% GA in comparison with all the other hydrogels. The hydrogels immersed in 30%, 50%, and 100% concentrations of GA also showed improved swelling behavior and porosity, and the highest resistance to type 1 collagenase (76.56%), was obtained for 50% GA cross-linked collagen hydrogels. Moreover, GA 100% and EA 100% obtained the highest denaturation temperatures (Td) of 74.96 °C and 75.78 °C, respectively. In addition, SEM analysis was also carried out to check the surface morphology of the pristine collagen hydrogels and the cross-linked collagen hydrogels. The result showed that the hydrogels cross-linked with GA/EA were denser and more compact. However, the improved physicochemical properties were probably due to the formation of hydrogen bonds between the phenolic hydroxyl groups of GA and EA and the nitrogen atoms of the collagen backbone. The presence of inter- and intramolecular cross-links between collagen and GA or EA components and an increased density of intermolecular bonds suggest potential hydrogen bonding or hydrophobic interactions. Overall, the present study paves the way for further investigations in the field by providing valuable insights into the GA/EA interaction with collagen molecules.

M1/M2 re-polarization of kaempferol biomimetic NPs in anti-inflammatory therapy of atherosclerosis.

Atherosclerosis (AS), a leading cause of death worldwide, involves chronic macrophage inflammation from its initiation to the emergence of complications. Targeting plaque inflammation by re-polarizing pro-inflammatory M1 to anti-inflammatory M2 could therefore provide a promising strategy to treat AS, but currently available anti-inflammatory drugs limit clinical outcomes. In this study, we found that kaempferol (KPF) is capable of potential anti-inflammation as a novel drug candidate, which has been scarcely reported. Building upon these findings, we fabricated a macrophage-biomimetic KPF delivery platform, abbreviated as KPF@MM-NPs to potentiate therapeutic payloads, wherein the designed ROS-responsive Dextran-g-PBMEO NPs with π-π stacking were coated with macrophage membrane (MM) for effective target and accumulation in atherosclerotic lesions. Therapy of KPF@MM-NPs afforded significant decrease in proliferating macrophage inflammation while went with the reduction of key pro-inflammatory cytokines and re-polarization M1 to M2 phenotype, inducing excellent anti-AS responses in ApoE-/- mice after i.p. delivery. The mechanism of KPF@MM-NPs was further investigated and found it related to block the ROS/NF-κB signaling pathways. Together with as well demonstrated biosafety profiles, this proof-of-concept opens an instructive door for the study of KPF-mediated nanodrugs in treatment of AS based on biomimetic NPs.

Discovery of fusidic acid derivatives as novel STING inhibitors for treatment of sepsis.

Sepsis is often caused by systemic inflammatory responses. Stimulator of interferon genes (STING) could be a promising treatment target for sepsis. In this study, we report the design and synthesis of a new series of fusidic acid derivatives. Among the synthesized derivatives, the promising compound 30 inhibited lipopolysaccharide (LPS)-induced nitric oxide production in macrophages with an IC50 of 1.15 µM. Compound 30 was then identified as a STING inhibitor that suppressed LPS-induced inflammatory responses and inhibited the abnormal activation of the TBK1, IRF3, and NF-κB signaling pathways by targeting STING. In vivo treatment with compound 30 significantly inhibited the inflammatory response and ameliorated the histopathological changes of the liver, and the mechanism of its anti-inflammatory effect in vivo was the same as that in vitro. Our studies identified compound 30 as a potent STING inhibitor, laying the groundwork for future drug development of anti-inflammatory agents for the treatment of sepsis.

Kaempferol alleviates the inflammatory response and stabilizes the pulmonary vascular endothelial barrier in LPS-induced sepsis through regulating the SphK1/S1P signaling pathway.

Sepsis, a clinical syndrome causing multi-organ failure, is one of the leading causes of morbidity and mortality. The effective treatment strategies for sepsis are limited. Some studies have demonstrated the benefits of kaempferol in countering sepsis, but its specific mechanism of action is unclear. The study aimed to investigate the anti-sepsis effects and mechanisms of kaempferol via sphingosine kinase 1/sphingosine-1-phosphate (SphK1/S1P) signaling pathway in a lipopolysaccharide (LPS)-induced sepsis model. We elucidated the effect of kaempferol on sepsis in LPS-induced RAW264.7 cells, HUVECs and septic mice. In RAW264.7 cells. We found that kaempferol decreased the levels of inflammatory mediators NO and PGE2. Western blot showed that kaempferol inhibited the expression of SphK1, p-p65 and p-IκB-α. LC-MS/MS analyze showed that kaempferol decreased S1P content in RAW264.7 cells. In HUVECs, we found that kaempferol promoted the expression of SphK1 and S1P, while kaempferol increased the expression levels of VE-Cadherin and ß-catenin. In vivo, consistent with the in vitro results, kaempferol alleviated LPS-induced inflammatory responses and endothelial barrier damage. In addition, by immunofluorescence localization of F4/80, CD31 and SphK1, we found that kaempferol inhibited the expression of SphK1 in macrophages and increased the expression of SphK1 in endothelial cells. In summary, our present results not only suggested that kaempferol alleviated the inflammatory response and stabilizes the endothelial barrier in LPS-induced sepsis by regulating the SphK1/S1P signaling pathway, but also showed that kaempferol exhibited cell-specific effects on the regulation of SphK1 expression.

The Use of Herbal Medicines for the Prevention of Glucocorticoid-Induced Osteoporosis.

Glucocorticoids are drugs that are widely used to suppress inflammation and the activation of the immune system. However, the prolonged use or at high doses of glucocorticoid can result in adverse side effects including osteoporosis, bone loss, and an increased risk of fracture. A number of compounds derived from natural plant sources have been reported to exert anti-inflammatory activity by interacting with the glucocorticoid receptor (GR), likely owing to their chemical similarity to glucocorticoids, or by regulating GR, without a concomitant risk of treatment-related side effects such as osteoporosis. Other herbal compounds can counteract the pathogenic processes underlying glucocorticoid-induced osteoporosis (GIOP) by regulating homeostatic bone metabolic processes. Herein, we systematically searched the PubMed, Embase, and Cochrane library databases to identify articles discussing such compounds published as of May 01, 2021. Compounds reported to exert anti-inflammatory glucocorticoid-like activity without inducing GIOP include escin, ginsenosides, and glycyrrhizic acid, while compounds reported to alleviate GIOP by improving osteoblast function or modulating steroid hormone synthesis include tanshinol and icariin.