Binding interactions of β-conglycinin and glycinin with vitamin B12

Denatured protein-coated docetaxel nanoparticles: Alterable drug state and cytosolic delivery

Many lead compounds have a low solubility in water, which substantially hinders their clinical application. Nanosuspensions have been considered a promising strategy for the delivery of water-insoluble drugs. Here, denatured soy protein isolate (SPI)-coated docetaxel nanosuspensions (DTX-NS) were developed using an anti-solvent precipitation-ultrasonication method to improve the water-solubility of DTX, thus improving its intracellular delivery. DTX-NS, with a diameter of 150-250nm and drug-loading up to 18.18%, were successfully prepared by coating drug particles with SPI. Interestingly, the drug state of DTX-NS was alterable. Amorphous drug nanoparticles were obtained at low drug-loading, whereas at a high drug-loading, the DTX-NS drug was mainly present in the crystalline state. Moreover, DTX-NS could be internalized at high levels by cancer cells and enter the cytosol by lysosomal escape, enhancing cell cytotoxicity and apoptosis compared with free DTX. Taken together, denatured SPI has a strong stabilization effect on nanosuspensions, and the drug state in SPI-coated nanosuspensions is alterable by changing the drug-loading. Moreover, DTX-NS could achieve cytosolic delivery, generating enhanced cell cytotoxicity against cancer cells.

Denatured protein stabilized drug nanoparticles: tunable drug state and penetration across the intestinal barrier

Nanosuspensions of drugs are nanosized colloidal dispersions of pure particles. In contrast to conventional nanoparticles, the particles in nanosuspensions feature 100% drug loading. Stiripentol (STP) is an effective drug for severe myoclonic epilepsy of infancy (SMEI); however, because of its low water solubility, high oral doses of STP, up to 50 mg per kg per day in two or three divided doses, must be administered to patients, compromising therapy outcomes. Here, we report STP nanosuspensions (STP-Ns) stabilized with denatured soybean protein isolate (SPI) as a stabilizer to promote the absorption of STP and thus improve therapeutic outcomes. STP-Ns with a drug loading of up to 50% (w/w) and a diameter of 150 nm were successfully prepared. Importantly, in the presence of denatured SPI as a stabilizer, the drug state in the nanosuspensions was tunable by drug loading: low drug loading resulted in the formation of amorphous drug nanoparticles while high drug loading greater than 3.22% (w/w) in formulation induced the formation of nanosuspensions with the coexistence of amorphous and crystalline drug. This new nanosuspension formulation was related to the fact that the protein-drug complex exhibited a much stronger affinity for the drug particles over the protein itself. Interestingly, via the transcytosis pathway, the STP-Ns penetrated across the intestinal barrier into the systemic circulation, with the duodenum as the predominant absorption site. The bioavailability of the STP-Ns was 4-fold as great as that of raw crystals. The discovery of this mechanism for the use of globular protein as a stabilizer for nanosuspensions provides a new route for the preparation of amorphous drug nanoparticles. This work offers a new strategy to widen the application of globular protein and nanosuspensions of insoluble active compounds in drug delivery.

Investigation of binding mechanism of novel 8-substituted coumarin derivatives with human serum albumin and α-1-glycoprotein

Coumarin molecules have biological activities possessing lipid-controlling activity, anti-hepatitis C activity, anti-diabetic, anti-Parkinson activity, and anti-cancer activity. Here, we have presented an inclusive study on the interaction of 8-substituted-7-hydroxy coumarin derivatives (Umb-1/Umb-2) with α-1-glycoprotein (AGP) and human serum albumin (HSA) which are the major carrier proteins in the human blood plasma. Binding constants obtained from fluorescence emission data were found to be KUmb-1=3.1 ± .01 × 10(4) M(-1), KUmb-2 = 7 ± .01 × 10(4) M(-1), which corresponds to -6.1 and -6.5 kcal/mol of free energy for Umb-1 and Umb-2, respectively, suggesting that these derivatives bind strongly to HSA. Also these molecules bind to AGP with binding constants of KUmb-1-AGP=3.1 ± .01 × 10(3) M(-1) and KUmb-2-AGP = 4.6 ± .01 × 10(3) M(-1). Further, the distance, r between the donor (HSA) and acceptor (Umb-1/Umb-2) was calculated based on the Forster's theory of non-radiation energy transfer and the values were observed to be 1.14 and 1.29 nm in Umb-1-HSA and Umb-2-HSA system, respectively. The protein secondary structure of HSA was partially unfolded upon binding of Umb-1 and Umb-2. Furthermore, site displacement experiments with lidocaine, phenylbutazone (IIA), and ibuprofen (IIIA) proves that Umb derivatives significantly bind to subdomain IIIA of HSA which is further supported by docking studies. Furthermore, Umb-1 binds to LYS402 with one hydrogen bond distance of 2.8 Å and Umb-2 binds to GLU354 with one hydrogen bond at a distance of 2.0 Å. Moreover, these molecules are stabilized by hydrophobic interactions and hydrogen bond between the hydroxyl groups of carbon-3 of coumarin derivatives.

Unraveling the binding interaction of Toluidine blue O with bovine hemoglobin – a multi spectroscopic and molecular modeling approach

Toluidine blue O (TBO) is a cationic photosensitizer that belongs to the class of phenothiazinium dyes.

Plant protein-based delivery systems for bioactive ingredients in foods

The application of food-grade delivery systems for the encapsulation, protection and controlled release of bioactive food ingredients have recently gained increasing interest in the research fields of functional foods and pharmaceutics. The preparation and application of bifunctional particles provide a novel perspective for the design of plant protein-based delivery system.

Novel fluorescence resonance energy transfer optical sensors for vitamin B12 detection using thermally reduced carbon dots

After thermal reduction, the quantum yield of thermally reduced carbon dots demonstrated a 5-fold increase over that of the original carbon dots.

Intestinal uptake and transport of vitamin B12-loaded soy protein nanoparticles

BACKGROUND

Intestinal absorption of vitamin B12 (VB12) is a major challenge in combating pernicious anemia due to intrinsic factor (IF) deficiency.

PURPOSE

The aim of this study was to explore the feasibility of using soy protein isolates (SPI) nanoparticles to improve the intestinal transport and absorption of VB12.

METHODS

Three different sized VB12-loaded SPI nanoparticles were produced by modulating preparation conditions using a cold-gelation method. The intestinal uptake and transport mechanisms of SPI nanoparticles for VB12 delivery were investigated and related to particle size.

RESULTS

SPI nanoparticles were not cytotoxic to Caco-2 cells and were effectively internalized into the cytoplasm via multiple endocytosis pathways including clathrin- and/or caveolae-mediated endocytosis and macropinocytosis routes. VB12 transport across the Caco-2 cell monolayers was increased to 2-3 times after nanoencapsulation, which was dependent on particle size, in the increasing order of 30 > 100 > 180 nm. Using inhibitor block method, the transport of 30 and 100 nm SPI nanoparticles appeared to be clathrin-mediated transcytosis and macropinocytosis routes. The intestinal transport of VB12, assessed using rodent jejunum in Ussing chambers, was improved up to 4-fold after being encapsulated into 30 nm SPI nanoparticles.

CONCLUSIONS

The findings suggest that SPI nanoparticles could be a promising carrier to facilitate the oral delivery of VB12.

In vitro investigation of domain specific interactions of phenothiazine dye with serum proteins by spectroscopic and molecular docking approaches

In the present study the interaction of the chemotherapeutic agent, Azure A (AZA) with Human Serum Albumin (HSA) and Bovine Serum Albumin (BSA) was investigated by multi spectroscopic and molecular docking methods.