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The expression of the adhesion molecule vascular cell adhesion molecule-1 (VCAM-1) on endothelial cells enables the attachment of leukocytes to the endothelium, which may lead to inflammation and the development of atherosclerosis. Magnolol is a major bioactive compound derived from the plant species Magnolia officinalis. In this study, we synthesized a novel nanoparticle formulation of magnolol to improve its water solubility and physicochemical properties, evaluated its effects on TNF-α-induced VCAM-1 expression in endothelial cells, and determined the signal transduction pathways involved. Our findings demonstrated that the magnolol nanoparticle system showed great improvements in physicochemical properties and water solubility owing to a reduction in particle size, transformation from a crystalline to amorphous structure, and the formation of hydrogen bonds with the nanoparticle carriers. In terms of its biological actions, magnolol nanoparticles attenuated TNF-α-induced VCAM-1 protein expression, promoter activity, and mRNA expression in endothelial cells in vitro. This was found to be mediated by the ERK, AKT, and NF-κB signaling pathways. In addition, magnolol nanoparticles inhibited TNF-α-induced leukocyte adhesion to endothelial cells, and suppressed TNF-α-induced VCAM-1 expression in the aortic endothelium of mice. In summary, since magnolol nanoparticles inhibit endothelial VCAM-1 expression and leukocyte adhesion to endothelial cells, this novel drug formulation may be a potentially useful therapeutic formulation to prevent the development of atherosclerosis and inflammatory diseases.

Silymarin, a well known hepatoprotective drug, has been routinely used in treating liver disorders. However, its bioavailability and therapeutic efficiency are limited by the poor aqueous solubility. In this study, we used the nanoprecipitation technique to develop a nanoparticles system to improve the solubility of silymarin. The newly developed silymarin nanoparticles were characterized for mean particle size, morphology, intermolecular interaction, crystalline features and dissolution property, as well as assessing for antioxidant activities. Results indicated that a drastic change in the physiochemical properties of silymarin was noted in the form of nanoparticles, as displayed by the extremely small particle size (46.1 +/- 1.73 nm), the formation of intermolecular hydrogen bonding between silymarin and matrix of nanoparticles, and the rendering of amorphous state. These phenomena have contributed to the enhanced dissolution property of silymarin nanoparticles, as well as a greater potency in DPPH radical scavenging, anti-superoxide anion formation, and superoxide anion scavenging activities than the crude silymarin. The present study concludes that silymarin nanoparticles have an improved physicochemical property as demonstrated by an increased solubility and enhanced antioxidant activities.