Fructans, Polyphenols and Antioxidant Activity in Edible Roots and Thistles from Seven Medicinal Plants

Abstract

Abstract The research purposed to evaluate the bioactive compounds and antioxidant content in water and 50 % ethanol extracts from different vegetal parts of seven herbs (black bryony, dandelion, leuzea, asparagus, St. Benedict's thistle, cotton thistle, and sarsaparilla). Sugars and total fructans (inulin ad fructooligosacchrides (FOS) were analysed by spectrophotometric and chromatographic methods. The total phenols, total flavonoids and derivatives of caffeic acid were also determined. The antioxidant activity was evaluated by DPPH and FRAP methods. Inulin and FOS were detected only in three plants (leuzea, dandelion and the cotton thistle). Dandelion roots were evaluated as the richest source of total fructans (18 g/100 g dw). The highest phenolic content was found in sarsaparilla roots 50 % ethanol extracts (21 mg GAE/g dw). Leuzea roots were evaluated as a rich source of dihydroxycinnamic acid derivatives and flavonoids. The high antioxidant activity demonstrated sarsaparilla water extracts, followed by water and 95 % ethanol of leuzea roots and cotton thistle flowеring heads (20-98 mM TE/g dw). The study demonstrated the use of some medicinal plants (especially leuzea, sarsaparilla and cotton thistle) as sources of antioxidants and inulin-type fructans in food and beverages. Keywords: Antioxidant Activity, Fructan, Medicinal Plants, Polyphenols