Determination of the water-extractable fraction of iron in selected medicinal plant raw materials: Folium Menthae, Folium Urticae and Folium Salviae

摘要

The aim of the investigation was to study the water-extractable iron species at different pH values from selected medicinal plant materials, therefore total and water-extractable iron species were determined in 30 samples of the medicinal plants Folium Menthae, Folium Urticae and Folium Salviae. The extractions were infusions popularly used by patients. Microwave digestion of the plant samples, and flame atomic absorption spectrometry (FAAS) was used for the determination of iron. Total iron ranged from 132.93 to 149.26 mg kg(-1) of dry plant weight (d.w.) in Folium Menthae, from 47.62 to 58.09 mg kg(-1) (d.w.) in Folium Urticae, and from 189.81 to 233.58 mg kg(-1) (d.w.) in Folium Salviae. The ranges of concentrations of water-extractable iron species were found to be lower than those of the total iron concentrations, viz. 9.45, 5.38 and 9.04 mg kg(-1) of d.w. in Folium Menthae, Folium Urticae and Folium Salviae, respectively. Taking into consideration the potential bioavailability of iron species in solutions of different pH values representing the acidity of particular segments of the digestive system of humans, these fractions of iron are very low in comparison with the total iron contents, especially the species detected at pH = 1.2. Based on the comparison with the values of Recommended Daily Allowances (RDA) for women and men, the water-extractable fractions of iron found in the studied plant materials, cannot be significant sources of that microelement for patients.