Secondary metabolites exert significant pharmacological and toxicological effects and their efficient antioxidant activity has lead these compounds being used as nutraceuticals [1]. Artemisia dubia Wall. exhibits many of these natural compounds, such as flavonoids, phenolics and alkaloids. Aside from the pharmacological aspect, the plant is also a prosperous energetic plant, obtaining significant heating value and large growth rate, yearly reaching up to 11,10 t/ha [2].
The aim of the research is to investigate A. dubia Wall. methanol/water extraction fractions phytochemical properties and the solid phase residue heating value before and after the extraction. In the research A. dubia Wall. was harvested from 3 different areas on 2018 July 27 and dried for lower enzymatic activity. The areas differed one from each other by different level of nitrogen fertilizers: no fertilization, N90 and N180. Extraction was performed using distilled water and 3 concentrations of methanol: 50%, 75 % and 100 %. Phytochemical capabilities were measured using spectrophotometric analysis methods according to Stankevičius et al. (2011) to evaluate the total amount of phenolic compounds using Folin-Ciocalteu reagent and the total amount of flavonoids using AlCl3 reagent. Antioxidant activity was evaluated using DPPH reagent. The lower calorific value (LHV) of the dry basis for the solutions was measured by an IKA C5000 calorimeter in accordance with the LST EN ISO 18125:2017 adiabatic method for automated bomb calorimetry. Extraction influence on A. dubia Wall. calorific value and comparison of increasing polarity solvent effect on total phenolic content, flavonoid content and antioxidant activity has yet not been published.