Onion (Allium cepa L.)-Derived Nanoparticles Inhibited LPS-Induced Nitrate Production, However, Their Intracellular Incorporation by Endocytosis Was Not Involved in This Effect on RAW264 Cells.

The aim of this study was to evaluate the involvement of nanoparticles prepared from Allium cepa L. as anti-inflammatory agents. In the present study, we identified nanoparticles from Allium cepa L. using the ultracentrifugation exosome purification method. The nanoparticles were referred to as 17,000× g and 200,000× g precipitates, and they contained quercetins, proteins, lipids, and small-sized RNA. The nanoparticles inhibited nitric oxide production from lipopolysaccharide (LPS)-stimulated RAW264 cells without cytotoxic properties. Cellular incorporation was confirmed by laser microscopic observation after PKH26 staining. The inhibition of caveolae-dependent endocytosis and macropinocytosis significantly prevented the incorporation of the nanoparticles but had no effect on the inhibition of nitric oxide in RAW264 cells. Collectively, the identified nanoparticles were capable of inhibiting the LPS response via extracellular mechanisms. Taken together, the way of consuming Allium cepa L. without collapsing the nanoparticles is expected to provide an efficient anti-inflammatory effect.

Enhanced water dispersibility and permeability through a Caco-2 cell monolayer of ß-cryptoxanthin extracted from kumquats by complexation with casein.

ß-Cryptoxanthin (BCX) possesses potential therapeutic and health benefits. However, BCX absorption is low because of its poor aqueous solubility. In this study, a complex between BCX and casein (Cas) was prepared to improve the water dispersibility and bioavailability of BCX. BCX was recovered quantitatively from freeze-dried kumquat powder through solid-liquid extraction and saponification. The complexation significantly improved the apparent solubility of BCX under acidic and neutral conditions. A cell membrane permeation test using a Caco-2 cell monolayer was performed to evaluate the bioavailability of the BCX-Cas complex. This complex and a blank sample were digested in vitro and added to the apical side of the Caco-2 cell membrane. The quantity of BCX that permeated using the BCX-Cas complex after 24 h was 22.7 times greater than that of the blank. Thus, complexation of BCX with Cas improved dramatically the bioavailability of BCX from a kumquat extract.

Enhanced water dispersibility of coenzyme Q10 by complexation with albumin hydrolysate.

The biologically important coenzyme Q10 (CoQ10) is widely used as a drug for chronic heart failure, as a nutritional supplement, and in cosmetics. However, the oral bioavailability of CoQ10 is poor due to its extremely low solubility in aqueous media. In this study, complexation of CoQ10 with albumin hydrolysate as a peptide mixture (Pep) was shown to enhance the water dispersibility of CoQ10. An aqueous solution of Pep and an acetone solution of CoQ10 were mixed and lyophilized to obtain a white-yellow powder containing peptides and CoQ10 complex (Q10-Pep). The water dispersibility of Q10-Pep was much higher than that of CoQ10 alone and increased with the quantity of Pep. The particle size of Q10-Pep in aqueous media was 170-280 nm, suggesting that Q10-Pep was present as a hydrocolloidal material. Characterization of Q10-Pep using differential scanning calorimetry showed that CoQ10 was incorporated in the hydrocolloid in an amorphous state.