Chemical characterization and biological effects of Sicilian Opuntia ficus indica (L.) Mill. fruit juice: antioxidant and antiulcerogenic activity - Galati, E M; Mondello, M R; Giuffrida, D; Dugo, G; Miceli, N; Pergolizzi, S; Taviano, M F (J Agric Food Chem, 2003)