Neutron activation analysis of phytotherapics of Maytenus ilicifolia and Solanum melongena plants

Abstract

In Brazil, the consumption of phytotherapics has become very popular due to the vast biodiversity of the immense flora, to the belief that plants that are of natural origin are safe and without side effects. Besides phytotherapics, in general, are cheaper than synthetic products. The objective of this study is to evaluate the elemental concentrations in phytotherapics of the plants Maytenus ilicifolia, also known as Holly or "Espinheira Santa", and Solanum melongena, known as Eggplant. The analysis of the elemental composition of phitotherapics is of great importance since these products may contain toxic or essential elements above of the safe limits for human consumption. The determinations also may be used to study the correlation the presence of some elements with their therapeutic effects. The phytotherapics samples were acquired in drug stores in São Paulo city and they were in powder form placed in capsules. Their elemental concentrations were determined by Neutron Activation Analysis (NAA) method. Aliquots of the samples and synthetic elemental standards were irradiated at the IEA-R1 nuclear reactor with thermal neutron flux of about 4.24 1012 n cm􀀀2 s􀀀1 during 16h. After adequate decay times, the irradiated samples and standards were measured using a HGe detector coupled to a gamma ray spectrometer. The radionuclides were identified by the gamma rays energies and the half- lives. Concentrations of the elements were calculated by comparative method. For quality control of the results, the certified reference material INCT-MPH-2 Mixed Polish Herbs was analyzed. Elements Br, Ca, Cr, Cs, Co, Fe, K, La, Rb, Sb, Sc, Se and Zn were determined in this study. Results obtained in the certified reference material showed a good agreement with the certified values. The variation (Relative Standard Deviation) of the contents of each capsule was of 6.1% for "Espinheira Santa" sample, and of 5.6% for Eggplant. This result indicates that the sample of "Espinheira Santa" phytotherapic presented more homogeneous in terms of mass of the contents in each capsule than that of Eggplant. In the phytotherapics, the elements Ca and K were found at the percentage levels, the elements Br, Fe, Rb and Zn at the g/g and the Co, Cr, Cs, La, Sb and Sc at the ng/g level. In the Eggplant phytotherapic, the element As was found but at very low concentration of ng/g.