Natural polyphenols are valuable compounds possessing scavenging properties towards radical oxygen species, and complexing properties towards proteins. These abilities make polyphenols interesting for the treatment of various diseases like inflammation or cancer, but also for anti-ageing purposes in cosmetic formulations, or for nutraceutical applications. Unfortunately, these properties are also responsible for a lack in long-term stability, making these natural compounds very sensitive to light and heat. Moreover, polyphenols often present a poor biodisponibility mainly due to low water solubility. Lastly, many of these molecules possess a very astringent and bitter taste, which limits their use in food or in oral medications. To circumvent these drawbacks, delivery systems have been developed, and among them, encapsulation would appear to be a promising approach. Many encapsulation methods are described in the literature, among which some have been successfully applied to plant polyphenols. In this review, after a general presentation of the large chemical family of plant polyphenols and of their main chemical and biological properties, encapsulation processes applied to polyphenols are classified into physical, physico-chemical, chemical methods, and other connected stabilization methods. After a brief description of each encapsulation process, their applications to polyphenol encapsulation for pharmaceutical, food or cosmetological purposes are presented.

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Encapsulation of Natural Polyphenolic Compounds; a Review

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Administration of resveratrol: What formulation solutions to bioavailability limitations?

Lipid nanoparticles as vehicles for topical psoralen delivery: solid lipid nanoparticles (SLN) versus nanostructured lipid carriers (NLC).

Crystals and crystallization in oil-in-water emulsions: implications for emulsion-based delivery systems.

Resveratrol is a polyphenol that among other sources occurs in grapes and for this reason, red wines also contain considerable amounts of this compound. Resveratrol is thought to be responsible for the "French Paradox" which associates red wine consumption to the low incidence of cardiovascular diseases. The interest in resveratrol has increased due to its pharmacological effects that include cardio and neuroprotection and several other benefic actions (e.g. antioxidant, anti-inflammatory, anti-carcinogenic and anti-aging). Despite the therapeutic effects of resveratrol, its pharmacokinetic properties are not favorable since this compound has poor bioavailability being rapidly and extensively metabolized and excreted. To overcome this problem, drug delivery systems have been developed to protect and stabilize resveratrol and to enhance its bioavailability. Herein is presented an up-to-date revision covering the literature reported for nano and microformulations for resveratrol encapsulation that include liposomes, polymeric nanoparticles, solid lipid nanoparticles, lipospheres, cyclodextrins, polymeric microspheres, yeast cells carriers and calcium or zinc pectinate beads. Regarding the interaction of resveratrol with cell membranes, only few studies have been published so far. However, it is believed that this interaction can be implied in the biological activities of resveratrol since transmembranar proteins are one of its cellular targets. Indeed, resveratrol presents the capacity to modulate the membrane organization which may consequently affect the protein functionality. Therefore, the intracellular effects of resveratrol and the effects of this compound at the membrane level were also revised since their knowledge is essential for understanding the pharmacological and therapeutic activities of this bioactive compound.

Resveratrol in Medicinal Chemistry: A Critical Review of its Pharmacokinetics, Drug-Delivery, and Membrane Interactions

Nano- and submicron-sized vesicles are beneficial for the controlled delivery of drugs Resveratrol, the main active polyphenol in red wine, was incorporated into various combinations of emulsions and liposomes to examine its physicochemical characteristics and cardiovascular protection The blends of emulsion-liposome were composed of coconut oil, soybean lecithin, glycerol formal, and non-ionic surfactants Multiple systems were assessed by evaluating the droplet size, surface charge, drug encapsulation, release rate, and stability The vesicle diameter of the systems ranged from 114 to 195 nm The liposomal vesicles in the systems had smaller diameters (of 43 approximately 56 nm) (F6 and F7) Drug encapsulation of approximately 70% were achieved by the vesicles The inclusion of resveratrol in these systems retarded the drug release in both the presence and absence of plasma in vitro The emulsion-liposome blends which incorporated Brij 98 (F5) exhibited the slowest release at zero-order for resveratrol delivery Treatment using resveratrol in the blended formulations dramatically inhibited vascular intimal thickening, which was tested in an experimental model in which endothelial injury was produced in normal rat carotid arteries Intraperitoneal injection of the multiple systems was associated with no or negligible liver and kidney toxicity We concluded that encapsulation by the emulsion-liposome blends is a potent way to enhance the preventative and therapeutic benefits of resveratrol

Jia-You Fang

Papers

Development and evaluation of emulsion-liposome blends for resveratrol delivery.