The use of vegetables has become widely spread as nourishment, medicinal and cosmetic purposes in recent years. Due to the importance of the analytical study of this class of plants, and considering the growing interest about their inorganic composition that can be represented by the significant number of publications during the last years, the present work intended to analyze the occurrence of some minerals in ten herbs of popular therapeutic use that play important roles in the human metabolism. The studied samples were treated by two different methods: 1) dry ashing followed by acid treatment and 2) as tea by infusion of leaves in boiling water. Next, the metals were quantitatively determined by atomic absorption spectrophotometry (Ca, Mg, Mn and Zn), molecular absorption spectrophotometry (Al and Fe) or flame photometry (K and Na). By comparing the results found in this work with those of the daily recommended values by RDA and WHO, studies are suggested with respect to the use of Chenopodium ambrosioides L. as an alternative source of Na, K, Mg and Zn. Likewise, Ageratum conyzoides L. could be a complementary source of Ca, Mg and Fe in the human diet. Although Lippia alba (Mill.) N. E. Brown and Justicia gendarussa L. have presented high Ca levels, caution should be recommended to some extent concerning the use of this vegetable in view of its significant Al levels.
medicinal plants; minerals; spectrophotometry
