[1] Univ Salerno, Dipartimento Sci Farmaceut, I-84084 Salerno, Italy
[2] Univ Siena, Dipartimento Farmacochim Technol, I-53100 Siena, Italy
[3] Univ Naples Federico II, Dipartimento Chim Sostanze Nat, I-80131 Naples, Italy
[4] Univ Naples Federico II, Dipartimento Chim Farmaceut & Tossicol, I-80131 Naples, Italy
[5] Max Planck Inst Biophys, D-6000 Frankfurt, Germany
[6] Univ Munster, Inst Biochem, D-48149 Munster, Germany
[7] Univ St Andrews, St Andrews KY16 9ST, Fife, Scotland
[8] Ist Ric Farmacol Mario Negri, I-20157 Milan, Italy