Elemental characterization and determination of 226Ra, 228Ra and 210Pb in common herbal medicines

Abstract

Since the early days of human kind, plants has been used as food and medicinal source. Observing animals feeding themselves, men stated to taste plants and realized that some kind of plants were able to relieve headaches, stomachaches and a variety of other diseases as muscular aches that were relieved by external use of the plants. Generally the main goal in fitoterapic researches is to characterize the active ingredient of the plant for scientific evidence of its therapeutical properties. Therefore, few information exist in literature about the activity concentration of radionuclides that belong to natural radioactive series of U-238 and Th-232. The knowledge of the elemental concentrations of these elements can be useful to verify possible interferences in therapeutic activity or if its amount represents some threat for human being. As for radionuclides, few papers are found in literature about the stable elements concentration in plants used with this objective in Brazil. Instrumental neutron activation analysis is one of the most used methods for elemental characterization. The major amount of Ra and Pb that enter the human body occurs via ingestion. Approximately 20% of Ra and 10 to 15% of the Pb ingested reaches the blood stream and is distributed for the whole body and follows the same metabolism of Ca. The objective of this work it to determine the activity concentration of Ra-226, Ra-228 and Pb-210 as well as chemically characterize samples of common medicinal plants in its elemental concentration.