Title : Mineral composition and antioxidant activity of forest plants
Abstract:
Heather (Calluna vulgaris) and wild berries (Vaccinium myrtillus L., Vaccinium vitis-idaea L.) are dominant species of forest shrubs growing in Poland. They are rich source of bioactive compounds such as flavonoids, phenolic acids, anthocyanins, stilbenes, tannins, sugars, essential oils, carotenoids, vitamins and minerals. Due to their beneficial properties they are commonly used as medicinal plants. Heather and wild berries samples were collected in three different locations in central Poland (the Mazovia plain).
The concentrations of 13 elements (Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb and Zn) were determined in several samples of these forest plants. The total metal contents after mineralization in acids and hot water extraction were analysed by inductively coupled plasma optical emission spectrometry. Ethyl acetate, water, ethanol and its mixture were used for the extraction of bioactive compounds from heather flowers and berries. The extracts from each plant were evaluated for the determination of some antioxidant capacity: total flavonoid content, reducing power by CUPRAC method, scavenging ability on DPPH radicals.
Forest berries and heather flowers are good sources of Ca, Na, Mg as well as Mn and Zn. Moreover, only low contents of toxic elements such as Pb and Cd were detected, ensuring the absence of risk for human health.
Antioxidant activity of prepared extracts strongly depends on the nature of extracting solvent due to the presence of different antioxidant compounds of varied chemical characteristics and polarities. Ethyl acetate and ethanol-water mixture were proved to be the best solvents. The observed differences in the antioxidant activities and metal composition of the extracts may correlate with the different ecological conditions in which they grow. One of the key factor is probably the composition of soil. The extracts of forest berries and heather contain plenty of compounds with high antioxidant properties.
