Highly efficient preparation of sphingoid bases from glucosylceramides by chemoenzymatic method

Lipidomic Profiling of Rice Bran after Green Solid-Liquid Extractions for the Development of Circular Economy Approaches

Rice bran is a rather underutilized by-product of the rice industry that nowadays is far from being valorized. In this study, the lipidomic profile of bran of the Italian rice variety, Roma, has been evaluated through ultra performance liquid chromatography-tandem mass spectrometry. Crude lipid extracts were obtained from rice bran treated with different green solvents (1-butanol, ethanol and methyl tert-butyl ether/methanol mixture) in combination with an ultrasonic pre-treatment, and then compared with extracts obtained with standard solvents (chloroform/methanol mixture). Lipid yield, number and type of lipids and composition of prevalent lipid classes extracted were evaluated in order to provide an exhaustive lipid profile of the rice bran and to identify the most efficient green solvent for solid-liquid extractions. Twelve different lipid classes and a maximum of 276 lipids were identified. Ethanol and methyl tert-butyl ether/methanol solvents provided higher lipid extraction yields, the former being the most effective solvent for the extraction of triglycerides and N-acylethanolamines and the latter the most effective for the extraction of diglycerides, phospholipids and ceramides at 4 °C. Moreover, extraction with ethanol at 20 °C gave similar results as at 4 °C in terms of lipid yield and for most of the classes of lipids extracted. Taken together, our results indicate ethanol and methyl tert-butyl ether/methanol as excellent solvents for lipid extraction from rice bran, with the aim to further valorize this food by-product in the perspective of a circular economy.

Sphingoid base in pineapple glucosylceramide suppresses experimental allergy by binding leukocyte mono-immunoglobulin-like receptor 3

BACKGROUND

The increase in patients suffering from type I hypersensitivity, including hay fever and food allergy, is a serious public health issue around the world. Recent studies have focused on allergy prevention by food factors with fewer side effects. The purpose of this study was to evaluate the effect of dietary glucosylceramide from pineapples (P-GlcCer) on type I hypersensitivity and elucidate mechanisms.

RESULTS

Oral administration of P-GlcCer inhibited ear edema in passive cutaneous anaphylaxis reaction. In a Caco-2/RBL-2H3 co-culture system, P-GlcCer inhibited β-hexosaminidase release from RBL-2H3 cells. The direct treatment of P-GlcCer on RBL-2H3 did not affect β-hexosaminidase release, but sphingoid base moiety of P-GlcCer did. These results predicted that sphingoid base, a metabolite of P-GlcCer, through the intestine inhibited type I hypersensitivity by inhibiting mast cell degranulation. In addition, the inhibitory effects of P-GlcCer on ear edema and degranulation of RBL-2H3 cells were canceled by pretreatment of leukocyte mono-immunoglobulin-like receptor 3 (LMIR3)-Fc, which can block LMIR3-mediated inhibitory signals.

CONCLUSION

It was demonstrated that a sphingoid base, one of the metabolites of P-GlcCer, may inhibit mast cell degranulation by binding to LMIR3. The oral administration of P-GlcCer is a novel and attractive food factor that acts directly on mast cells to suppress allergy. © 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Structure-dependent absorption of atypical sphingoid long-chain bases from digestive tract into lymph

BACKGROUND

Dietary sphingolipids have various biofunctions, including skin barrier improvement and anti-inflammatory and anti-carcinoma properties. Long-chain bases (LCBs), the essential backbones of sphingolipids, are expected to be important for these bioactivities, and they vary structurally between species. Given these findings, however, the absorption dynamics of each LCB remain unclear.

METHODS

In this study, five structurally different LCBs were prepared from glucosylceramides (GlcCers) with LCB 18:2(4E,8Z);2OH and LCB 18:2(4E,8E);2OH moieties derived from konjac tuber (Amorphophallus konjac), from GlcCers with an LCB 18(9Me):2(4E,8E);2OH moiety derived from Tamogi mushroom (Pleurotus cornucopiae var. citrinopileatus), and from ceramide 2-aminoethyphosphonate with LCB 18:3(4E,8E,10E);2OH moiety and LCB 18(9Me):3(4E,8E,10E);2OH moiety derived from giant scallop (Mizuhopecten yessoensis), and their absorption percentages and metabolite levels were analyzed using a lymph-duct-cannulated rat model via liquid chromatography tandem mass spectrometry (LC/MS/MS) with a multistage fragmentation method.

RESULTS

The five orally administered LCBs were absorbed and detected in chyle (lipid-containing lymph) as LCBs and several metabolites including ceramides, hexosylceramides, and sphingomyelins. The absorption percentages of LCBs were 0.10-1.17%, depending on their structure. The absorption percentage of LCB 18:2(4E,8Z);2OH was the highest (1.17%), whereas that of LCB 18:3(4E,8E,10E);2OH was the lowest (0.10%). The amount of sphingomyelin with an LCB 18:2(4E,8Z);2OH moiety in chyle was particularly higher than sphingomyelins with other LCB moieties.

CONCLUSIONS

Structural differences among LCBs, particularly geometric isomerism at the C8-C9 position, significantly affected the absorption percentages and ratio of metabolites. This is the first report to elucidate that the absorption and metabolism of sphingolipids are dependent on their LCB structure. These results could be used to develop functional foods that are more readily absorbed.

Facile determination of sphingolipids under alkali condition using metal-free column by LC-MS/MS

Extraction and analysis of sphingolipids from biological samples is a critical step in lipidomics, especially for minor species such as sphingoid bases and sphingosine-1-phosphate. Although several liquid chromatography-mass spectrometry methods enabling the determination of sphingolipid molecular species have been reported, they were limited in analytical sensitivity and reproducibility by causing significant peak tailing, especially by the presence of phosphate groups, and most of the extraction techniques are laborious and do not cover a broad range of sphingolipid metabolites. In this study, we developed a rapid single-phase extraction and highly sensitive analytical method for the detection and quantification of sphingolipids (including phosphates) comprehensively using liquid chromatography-triple quadruple mass spectrometry. After validating the reliability of the method, we analyzed the intestinal tissue sphingolipids of germ-free (GF) and specific pathogen-free (SPF) mice and found significantly higher levels of free sphingoid bases and sphingosine-1-phosphate in the GF condition as compared to the SPF condition. This method enables a rapid extraction and highly sensitive determination of sphingolipids comprehensively at low femtomolar ranges. Graphical abstract Diagrammatic comparision of sphingolipid (phosphates) analysis between conventional and this method.

Facile Chemoselective Strategy toward Capturing Sphingoid Bases by a Unique Glutaraldehyde-Functionalized Resin

Sphingoid bases, which have a 2-amino-1,3-diol common functional group, are the structural backbone units of all sphingolipids. Recently, much attention has been focused on sphingoid bases because of their potentially beneficial bioactivities toward various cancer cells as well as their dietary interest. However, low abundance and the handling complexity caused by their amphiphilic character led to very limited research on them. Glutaraldehyde has two aldehyde groups, and it reacts rapidly with the 2-amino-1,3-diol functional group of sphingosine to give a tricyclic product. Immobilization of glutaraldehyde on a resin was successfully performed by organic synthesis, starting from trans-p-coumaric acid via eight steps. This approach suppresses the self-polymerization of glutaraldehyde, and addition of water to the developed resin causes the formation of cyclic double hemiacetal function, which avoids oxidation like a reducing sugar in nature and makes it stable even for up to 1 year incubation. The resin was applied to the solid-phase extracting experiment of free sphingosine from human serum at a concentration of 280 nM. Another extraction study of edible golden oyster mushrooms showed that the sphingoid base was selectively captured from complex natural extracts. These results demonstrate that the developed glutaraldehyde resin method is a highly selective method, and hence, the combination of it with the o-phthaldialdehyde HPLC method was confirmed as an efficient and sensitive method for analysis of sphingoid bases in biological samples.