Author(s):
1. Sasa Djurovic, Univerzitet u Novom Sadu, Tehnološki fakultet, Novi Sad, Serbia
2. Marija Radojković, Univerzitet u Novom Sadu, Tehnološki fakultet, Novi Sad, Serbia
3. Zoran Zeković, Univerzitet u Novom Sadu, Tehnološki fakultet, Novi Sad, Serbia

Abstract:
Ultrasound-assisted extractions of stinging nettle (Urtica dioica L.) leaves were conducted using the following solvents: water, ethanol, methylene chloride, ethyl acetate, acetone and n-hexane during 45 minutes and sample-to-solvent ratio of 1:30. Obtained extracts were used for total phenolics (TPC) and total flavonoids contents (TFC) estimation by spectrophotometric tests, as well as determination of antioxidant activities using DPPH and Reducing power assays. Results were expressed as follows: TPC as mg of chlorogenic acid equivalents pre g of dry weight (mg CAE/g DW), TFC as mg of catechin equivalents per g of dry weight (mg CE/g DW), while results for antioxidant activity were expressed as IC50 values (mg/mL). Conducted spectrophotometric tests and antioxidant activity assays showed that water extract contained the highest amounts of polyphenolic and flavonoid compounds and was the most potent antioxidant. The obtained results for water extract were as following: total phenolics content of 183.41 mg CAE/g DW, total flavonoids content of 5.7 mg CE/g DW, while IC50 values were 0.028 mg/mL and 0.067 mg/mL for DPPH and reducing power assays, respectively. Conducted HPLC analysis of water extract showed that Ferulic acid was the most abundant compound in extract with the content of 88.59 µg/g of dry extract.

Key words:
Stinging nettle,antioxidant activity,total phenolics content,total flavonoids content

Thematic field:
Food Technology

Date of abstract submission:
28.07.2016.

Conference:
XI Savjetovanje hemičara, tehnologa i ekologa Republike Srpske

Abstract