Speciation of metals in medicinal plants under different stress condition by HPLC-ICP-MS

NASCIMIENTO JÄHNKE, SAMARA; SOLDATI, ANALIA L.; SOUND, IRIS; VICENTE VILAS, VÍCTOR; BAUMANN, WOLFRAM

Río de Janeiro, Brasil

Conferencia; Nuclear Analytical Methods in Life Sciences (NAMLS08); 2005

Much is known about the occurrence of metals in plants but little about their species, binding forms and oxidation state, as well [1]. This holds particularly for medicinal plants and even more specific for Brazilian medicinal plants. Three species very common in Brazil have been selected: Jambti {Spilanthes oleracea) - Asteraceae; Beldroega {Portu/aca oleracea) - Portulacaceae; Alfavaca {Ocimum gratissimum) - Labiatae. The present speciation study focuses on the complexation of manganese in these plants under normal and under manganese stress conditions. Methods involved are various types of chromatography, such as high performance liquid chromatography (HPLC) online coupled to mass-spectrometry (MS). Since a common preparation for such plants in popular medicine is tea, standardized aqueous extracts have been prepared. By size exclusion chromatography on a PROTONSIL 60-10-DIOL column (Bischoff, Germany) coupled on line to an inductive coupled plasma mass spectrometry instrument (ICP-MS) (ELEMENT 2 thermo electron) and tuned to manganese the range of molecular weight has been defined in which manganese is present. Accordingly, manganese is predominantly bound to small compounds but in some cases like Jambü also to higher molecular weight compounds. Further characterisation of the low molecular weight fraction is now done by reversed phase HPLC and ion-chromatography. [1] G. Weber, P. Konieczynski, Speciation of Mg, Mn and Zn in extracts of medicinal plants; Anal. Bioanal. Chem, 375, 1067 - 1073, 2003.