Siraitia grosvenorii residual extract attenuates ovalbumin-induced lung inflammation by down-regulating IL-4, IL-5, IL-13, IL-17, and MUC5AC expression in mice

BACKGROUND

Siraitia grosvenorii fruits are used in traditional medicine to treat cough, sore throat, bronchitis, and asthma.

PURPOSE

This study aimed to investigate the anti-inflammatory and anti-asthmatic effects of S. grosvenorii residual extract (SGRE) on ovalbumin (OVA)-induced asthma in mice.

METHODS

Asthma was induced in BALB/c mice by systemic sensitization to OVA, followed by intratracheal, intraperitoneal, and aerosol allergen challenges. SGRE was orally administered for four weeks. We investigated the effects of SGRE on airway hyper-responsiveness, OVA-specific IgE production, histological analysis of lung and trachea, immune cell phenotyping, Th1/Th2 cytokine production in bronchoalveolar lavage fluid (BAL) fluid and splenocytes, and gene expression in the lung.

RESULTS

SGRE ameliorated OVA-driven airway hyper-responsiveness, serum IgE production, and histopathological changes in the lung and trachea. SGRE reduced the total number of cells in the lung and BAL, the total number of lymphocytes, neutrophils, monocytes, and eosinophils in the lung and BAL, the absolute number of CD4+/CD69+ T cells in the lung, and the absolute number of CD4+/CD8+ T cells and CD11b+/Gr-1+ granulocytes in the lung and BAL. SGRE also reduced Th2 cytokines (IL-4, IL-5, and IL-13) and increased the Th1 cytokine IFN-γ in the BAL fluid and supernatant of splenocyte cultures. SGRE decreased the OVA-induced increase of IL-13, TARC, MUC5AC, TNF-α, and IL-17 expression in the lung.

CONCLUSION

SGRE exerts anti-asthmatic effects via the inhibition of Th2 and Th17 cytokines and the increase of Th1 cytokines, suggesting that SGRE may be a potential therapeutic agent for allergic lung inflammation, such as asthma.

Hyperproduction of β-Glucanase Exg1 Promotes the Bioconversion of Mogrosides in Saccharomyces cerevisiae Mutants Defective in Mannoprotein Deposition

Bacteria and fungi can secrete extracellular enzymes to convert macromolecules into smaller units. Hyperproduction of extracellular enzymes is often associated with alterations in cell wall structure in fungi. Recently, we identified that Saccharomyces cerevisiae kre6Δ mutants can efficiently convert mogroside V into mogroside III E, which has antidiabetic properties. However, the underlying efficient bioconversion mechanism is unclear. In the present study, the mogroside (MG) bioconversion properties of several cell wall structure defective mutants were analyzed. We also compared the cell walls of these mutants by transmission electron microscopy, a zymolyase sensitivity test, and a mannoprotein release assay. We found zymolyase-sensitive mutants (including kre1Δ, las21Δ, gas1Δ, and kre6Δ), with defects in mannoprotein deposition, exhibit efficient MG conversion and excessive leakage of Exg1; such defects were not observed in wild-type cells, or mutants with abnormal levels of glucans in the cell wall. Thus, yeast mutants defective in mannoprotein deposition may be employed to convert glycosylated bioactive compounds.

Spontaneous vesicle formation from sodium salt of acidic sophorolipid and its application as a skin penetration enhancer

In this study, spontaneous vesicle formation from the sodium salt of acidic sophorolipid (SLNa) was observed, and its potential application as a skin penetration enhancer for triterpene glycosides extracted from the fruits of Siraitia grosvenorii Swingle was then investigated. Dynamic light scattering (DLS) measurements of the SLNa assemblies prepared by the gentle mixing of SLNa with water (1%) showed their hydrodynamic radius (Rh) to be 96.2 nm, and their structure was assigned to be vesicles by freeze-fracture electron microscopy (FF-TEM). DLS and FF-TEM also revealed that the size of the vesicles increased with an increase in the concentration of the triterpene glycosides, indicating that the triterpene glycosides were incorporated into the SLNa vesicles. The results of an in vitro skin permeation assay, after loading the SLNa vesicles on a 3D cultured skin model, showed that the amount of SLNa that penetrated though the skin model increased with time. It was also found that the amount of permeated mogroside, which is the main active component of triterpene glycosides, was significantly enhanced by the SLNa vesicle formulation. These results clearly demonstrated that spontaneously formed vesicles composed of the bolaamphiphile SLNa are useful for application as penetration enhancers for active ingredients such as mogroside V.

Digestion and absorption of Siraitia grosvenori triterpenoids in the rat

When administered to rats, mogroside V (a pentaglucose-conjugated mogroside), the main sweetening component of Siraitia grosvenori, was mostly degraded by digestive enzymes and intestinal microflora, and was excreted in the feces as mogrol (aglycone) and its mono- and diglucosides. However, trace amounts of mogrol and its monoglucoside were found in the portal blood as sulfates and/or glucuronide conjugates.

Induction of GST-P-positive proliferative lesions facilitating lipid peroxidation with possible involvement of transferrin receptor up-regulation and ceruloplasmin down-regulation from the early stage of liver tumor promotion in rats

To elucidate the role of metal-related molecules in hepatocarcinogenesis, we examined immunolocalization of transferrin receptor (Tfrc), ceruloplasmin (Cp) and metallothionein (MT)-1/2 in relation to liver cell foci positive for glutathione-S-transferase placental form (GST-P) in the early stage of tumor promotion by fenbendazole (FB), phenobarbital, piperonyl butoxide or thioacetamide in a rat two-stage hepatocarcinogenesis model. To estimate the involvement of oxidative stress responses to the promotion, immunolocalization of 4-hydroxy-2-nonenal, malondialdehyde and acrolein was similarly examined. Our findings showed that MT-1/2 immunoreactivity was not associated with the cellular distribution of GST-P and proliferating cell nuclear antigen, suggesting no role of MT-1/2 in hepatocarcinogenesis. We also found enhanced expression of Tfrc after treatment with strong tumor-promoting chemicals. With regard to Cp, the population showing down-regulation was increased in the GST-P-positive foci in relation to tumor promotion. Up-regulation of Tfrc and down-regulation of Cp was maintained in GST-P-positive neoplastic lesions induced after long-term promotion with FB, suggesting the expression changes occurring downstream of the signaling pathway involved in the formation of GST-P-positive lesions. Furthermore, enhanced accumulation of lipid peroxidation end products was observed in the GST-P-positive foci by promotion. Post-initiation treatment with peroxisome proliferator-activated receptor alpha agonists did not enhance any such distribution changes in GST-P-negative foci. The results thus suggest that facilitation of lipid peroxidation is involved in the induction of GST-P-positive lesions by tumor promotion from an early stage, and up-regulation of Tfrc and down-regulation of Cp may be a signature of enhanced oxidative cellular stress in these lesions.