title: Antioxidant profile of strawberry tree honey and its marker homogentisic acid in several models of oxidative stress.
abstract: The antioxidant activity of several honeys was evaluated considering the different contribution of entire samples. The strawberry tree honey emerged as the richest in total phenols and the most active honey in the DPPH and FRAP tests, and could protect cholesterol against oxidative degradation (140°C). Homogentisic acid (2,5-dihydroxyphenylacetic acid, HGA), the main phenolic compound from strawberry tree honey, showed interesting antioxidant and antiradical activities, and protective effect against thermal-cholesterol degradation, comparable to those of well known antioxidants. Moreover, the pre-treatment with HGA significantly preserved liposomes and LDL from Cu(2+)-induced oxidative damage at 37°C for 2h, inhibiting the reduction of polyunsaturated fatty acids and cholesterol and the increase of their oxidative products. This phenol had no toxic effect in human intestinal epithelial Caco-2 cells within the concentration range tested (5-1000μM). HGA was able to pass through the Caco-2 monolayers, the apparent permeability coefficients (Papp) in the apical-to-basolateral and basolateral-to-apical direction were 3.48±1.22×10(-6) and 2.18±0.34×10(-6)cm/s, respectively, suggesting a passive diffusion pathway as the dominating process. The results of the work qualify HGA as natural antioxidant, able to exert a significant in vitro protective effect and to contribute to the strawberry tree honey antioxidant activity.
authors.affiliation: Dipartimento di Biologia Sperimentale, Sez. Patologia Sperimentale, Università degli Studi di Cagliari, Cittadella Universitaria, SS 554, km 4.5, 09042 Monserrato, Cagliari, Italy. Electronic address: anrosa@unica.it.
authors.forename: Antonella
authors.initials: A
authors.lastname: Rosa
authors.affiliation: Department of Toxicology, University of Cagliari, via Ospedale 72, 09124 Cagliari, Italy.
authors.forename: Carlo Ignazio Giovanni
authors.initials: CI
authors.lastname: Tuberoso
authors.affiliation: Dipartimento di Biologia Sperimentale, Sez. Patologia Sperimentale, Università degli Studi di Cagliari, Cittadella Universitaria, SS 554, km 4.5, 09042 Monserrato, Cagliari, Italy.
authors.forename: Angela
authors.initials: A
authors.lastname: Atzeri
authors.affiliation: Dipartimento di Biologia Sperimentale, Sez. Patologia Sperimentale, Università degli Studi di Cagliari, Cittadella Universitaria, SS 554, km 4.5, 09042 Monserrato, Cagliari, Italy.
authors.forename: Maria Paola
authors.initials: MP
authors.lastname: Melis
authors.affiliation: Department of Toxicology, University of Cagliari, via Ospedale 72, 09124 Cagliari, Italy.
authors.forename: Ersilia
authors.initials: E
authors.lastname: Bifulco
authors.affiliation: Dipartimento di Biologia Sperimentale, Sez. Patologia Sperimentale, Università degli Studi di Cagliari, Cittadella Universitaria, SS 554, km 4.5, 09042 Monserrato, Cagliari, Italy.
authors.forename: Maria Assunta
authors.initials: MA
authors.lastname: Dessì
keywords: Antioxidant activity; Antiradical activity; Arbutus unedo L. honey; Caco-2; Homogentisic acid