Evaluation of phytochemical and allelopathic properties of Artemisia dubia Wall. extracts and investigation of heating value and elemental composition of the solid residue

Abstract

In recent years, there has been increasing interest in the use of agricultural biomass for energy purpose in many northern countries. This has created demand for novel, high biomass yielding, specific quality crops for sustainable use [1]. The aim of the research is to investigate Artemisia dubia Wall. multistep solvent extraction fractions phytochemical, allelopathic capabilities and the solid phase leftovers biofuel characteristics before and after the extraction. Phytochmical analysis was done using the modified spectrophotometric analysis methods [2] to evaluate the total amount of phenolic compounds using Folin-Ciocalteu reagent, the total amount of flavonoids using AlCl3 reagent and the antioxidant activity using the DPPH reagent. The results are as follows: largest phenolic content and antioxidant activity was in the third increasing polarity fraction of 50% methanol extract – 66.5 mg RE/g and 48.0 RE mg/g respectively; largest amount of flavonoids were in the decreasing polarity water and methyl tert-butyl ether fractions – 10.4 mg RE/g and 11.4 RE mg/g. In the research, using a modified allelopathic capabilities evaluation method [3], it was determined that small concentrations of both polar and nonpolar fractions are required to trigger noticeable allopathic activates on Garden cress (lat. Lepidium sativum) seeds germination and growth. The most noticeable fraction – decreasing polarity secondary 50% methanol fraction – showed 15% germination and 0.7 mm seedling length, compared to the control group of 85% germination and 20.4 mm seedling length. As for the solid phase biomass, left from solvent-solvent extraction, thermal equipment research and testing laboratory standards [4] and equipment were used to determine thermal capabilities, organogenic composition, moisture and ash content. Ash content before the extraction was 11.6%, afterwards – 6.8-6.5%. Same proportional decrease was shown in the Sulphur content – from 0.241% to 0.138-0.