1. Div. of Analytical Chemistry, Inst. of Chemistry, Biological Chemistry and Chemometrics; Federal University of Rio Grande do Norte; Natal RN 59072-970 Brazil
2. Dept. of Biophysics and Pharmacology; Post-graduation programme in Public Health/Post graduation programme in Pharmaceutical Science, Federal University of Rio Grande do Norte; Natal RN 59072-970 Brazil
3. Dept. of Morphology, Post-graduation programme in Health Science/Post graduation programme in Structural and Functional Biology; Federal University of Rio Grande do Norte; Natal RN 59072-970 Brazil