Publications

Quercetin, a natural polyphenol with strong antioxidant activity, was loaded in Eudragit-coated liposomes conceived for intestinal delivery. Eudragit was used to form a protective shell on the surface of liposomes to resist gastric environment and allow the delivery of quercetin to the intestine. The physico-chemical properties of the liposomes were assessed by light scattering and cryogenic transmission electron microscopy. Small, spherical, uni- and bilamellar liposomes were produced, with the presence of multilamellar structures in Eudragit-coated liposomes. The Eudragit coating increased the physical stability of the vesicular system in fluids mimicking the gastrointestinal environment. Further, the incorporation of quercetin in the vesicular system did not affect its intrinsic antioxidant activity, as DPPH radical was almost completely inhibited, and the vesicles were also capable of ensuring optimal protection against oxidative stress in human intestinal cells by reducing reactive oxygen species (ROS)production. The proposed approach based on quercetin vesicular formulations may be of value in the treatment of pathological conditions associated with intestinal oxidative stress.

JTD Keywords: Antioxidant, Eudragit, HT-29 cells, Intestinal delivery, Liposomes, Quercetin

In the present work, quercetin and resveratrol, natural polyphenols with strong antioxidant and anti-inflammatory properties, were co-loaded in polymer-associated liposomes conceived for oral delivery, by exploiting the potential of pH-sensitive succinyl-chitosan. Chitosan was succinylated, characterized by Nuclear Magnetic Resonance spectroscopy and Gel Permeation Chromatography, and used to form a protective shell on the surface of liposomes. The physico-chemical properties of the succinyl-chitosan liposomes were assessed by light scattering, zeta potential, cryogenic transmission electron microscopy, and small angle X-ray scattering. Small, spherical, uni- and bilamellar vesicles were produced. The succinyl-chitosan shell increased not only the physical stability of the vesicular system, as demonstrated by accelerated stability tests, but also the release of the polyphenols to a greater extent at pH 7.0, mimicking the intestinal environment. The proposed approach based on polyphenol vesicular formulations may be of value in the treatment of pre-cancerous/cancerous intestinal conditions associated with inflammation and oxidative stress.

JTD Keywords: Antioxidant, Liposome, Oral delivery, Quercetin, Resveratrol, Succinyl-chitosan

The present investigation reports the development of liposomes for the co-delivery of naturally occurring polyphenols, namely quercetin and resveratrol. Small, spherical, uni/bilamellar vesicles were produced, as demonstrated by light scattering, cryo-TEM, SAXS. The incorporation of quercetin and resveratrol in liposomes did not affect their intrinsic antioxidant activity, as DPPH radical was almost completely inhibited. The cellular uptake of the polyphenols was higher when they were formulated in liposomes, and especially when co-loaded rather than as single agents, which resulted in a superior ability to scavenge ROS in fibroblasts. The in vivo efficacy of the polyphenols in liposomes was assessed in a mouse model of skin lesion. The topical administration of liposomes led to a remarkable amelioration of the tissue damage, with a significant reduction of oedema and leukocyte infiltration. Therefore, the proposed approach based on polyphenol vesicular formulation may be of value in the treatment of inflammation/oxidative stress associated with pre-cancerous/cancerous skin lesions.

JTD Keywords: Antioxidant, Fibroblast, Liposome, Quercetin, Resveratrol, Skin lesion

Biocompatible quercetin nanovesicles were developed by coating polyethylene glycol-containing vesicles with chitosan and nutriose, aimed at targeting the colon. Uncoated and coated vesicles were prepared using hydrogenated soy phosphatidylcholine and quercetin, a potent natural anti-inflammatory and antioxidant drug. Physicochemical characterization was carried out by light scattering, cryogenic microscopy and X-ray scattering, the results showing that vesicles were predominantly multilamellar and around 130 nm in size. The in vitro release of quercetin was investigated under different pH conditions simulating the environment of the gastrointestinal tract, and confirmed that the chitosan/nutriose coating improved the gastric resistance of vesicles, making them a potential carrier system for colon delivery. The preferential localization of fluorescent vesicles in the intestine was demonstrated using the In Vivo FX PRO Imaging System. Above all, a marked amelioration of symptoms of 2,4,6-trinitrobenzenesulfonic acid-induced colitis was observed in animals treated with quercetin-loaded coated vesicles, favoring the restoration of physiological conditions. Therefore, quercetin-loaded chitosan/nutriose-coated vesicles can represent a valuable therapeutic tool for the treatment of chronic intestinal inflammatory diseases, and presumably a preventive system, due to the synergic action of antioxidant quercetin and beneficial prebiotic effects of the chitosan/nutriose complex.

JTD Keywords: Chitosan/nutriose complex, Colon targeting, Phospholipid vesicles, Quercetin, Rat colitis