Trans-ε-Viniferin Encapsulation in Multi-Lamellar Liposomes: Consequences on Pharmacokinetic Parameters, Biodistribution and Glucuronide Formation in Rats

Enhancing Solubility and Bioefficacy of Stilbenes by Liposomal Encapsulation-The Case of Macasiamenene F

Stilbenes in food and medicinal plants have been described as potent antiphlogistic and antioxidant compounds, and therefore, they present an interesting potential for the development of dietary supplements. Among them, macasiamenene F (MF) has recently been shown to be an effective anti-inflammatory and cytoprotective agent that dampens peripheral and CNS inflammation in vitro. Nevertheless, this promising molecule, like other stilbenes and a large percentage of drugs under development, faces poor water solubility, which results in trickier in vivo administration and low bioavailability. With the aim of improving MF solubility and developing a form optimized for in vivo administration, eight types of conventional liposomal nanocarriers and one type of PEGylated liposomes were formulated and characterized. In order to select the appropriate form of MF encapsulation, the safety of MF liposomal formulations was evaluated on THP-1 and THP-1-XBlue-MD2-CD14 monocytes, BV-2 microglia, and primary cortical neurons in culture. Furthermore, the cellular uptake of liposomes and the effect of encapsulation on MF anti-inflammatory effectiveness were evaluated on THP-1-XBlue-MD2-CD14 monocytes and BV-2 microglia. MF (5 mol %) encapsulated in PEGylated liposomes with an average size of 160 nm and polydispersity index of 0.122 was stable, safe, and the most promising form of MF encapsulation keeping its cytoprotective and anti-inflammatory properties.

Beneficial Effects of ε-Viniferin on Obesity and Related Health Alterations

Viniferin is a phenolic compound belonging to the group of stilbenoids. In particular, ε-viniferin is a dimer of resveratrol, found in many plant genders, among which grapes (Vitis vinifera) are a primary source. Due to the fact that ε-viniferin is mainly present in the woody parts of plants, their use as a source of this bioactive compound is a very interesting issue in a circular economy. Both, in vitro studies carried out in pre-adipocytes and mature adipocytes and in vivo studies addressed in mice show that ε-viniferin is able to reduce fat accumulation. Moreover, it prevents the development of some obesity co-morbidities, such as type 2 diabetes, dyslipidemias, hypertension and fatty liver. ε-viniferin can be absorbed orally, but it shows a very low bioavailability. In this scenario, further research on animal models is needed to confirm the effects reported in a great number of studies; to determine which metabolites are involved, including the main one responsible for the biological effects observed and the mechanisms that justify these effects. In a further phase, human studies should be addressed in order to use ε-viniferin as a new tool for obesity management, as a nutraceutical or to be included in functional foods.

Oxyresveratrol and Gnetol Glucuronide Metabolites: Chemical Production, Structural Identification, Metabolism by Human and Rat Liver Fractions, and In Vitro Anti-inflammatory Properties

Stilbene metabolites are attracting great interest because many of them exhibit similar or even stronger biological effects than their parent compounds. Furthermore, the metabolized forms are predominant in biological fluids; therefore, their study is highly relevant. After hemisynthesis production, isolation, and structural elucidation, three glucuronide metabolites for oxyresveratrol (ORV) were formed: trans-ORV-4'-O-glucuronide, trans-ORV-3-O-glucuronide, and trans-ORV-2'-O-glucuronide. In addition, two glucuronide metabolites were obtained for gnetol (GN): trans-GN-2'-O-glucuronide and trans-GN-3-O-glucuronide. When the metabolism of ORV and GN is studied in vitro by human and rat hepatic enzymes, four of the five hemisynthesized compounds were identified and quantified. Human enzymes glucuronidated preferably at the C-2' position, whereas rat enzymes do so at the C-3 position. In view of these kinetic findings, rat enzymes have a stronger metabolic capacity than human enzymes. Finally, ORV, GN, and their glucuronide metabolites (mainly at the C-3 position) decreased nitric oxide, reactive oxygen species, interleukin 1β, and tumor necrosis factor α production in lipopolysaccharide-stimulated macrophages.