Phenolic composition, volatile profile, and in vitro antioxidative potential of hydroethanolic flower extracts of Sambucus nigra L. as a valuable food ingredient

Abstract

Elderberry (Sambucus nigra L.) flowers contain a variety of nutrients and bioactive compounds, and are appreciated in traditional medicine for the treatment of infections. This study aimed to investigate the proper ethanol concentration (20–80 %) in hydroethanolic solvent to obtain Sambucus nigra L. flower extracts rich in bioactive compounds (phenolic and volatiles) and their corresponding antioxidative potential. Extraction yield ranged from 4.8 % to 24.5 % in water and 70 % ethanol extracts, respectively. A higher number of phenolic compounds (41) were identified in hydroethanolic extracts than in water one (31). Hydroethanolic extracts distinguished from water extract with a variety and content of flavonoids (15–19, and 9 compounds, respectively) and a lower number of phenolic acids (10–15 and 20, respectively). The contents of kaempferol dihexoside 1, rutin, and caffeoylquinic acid dominated in the phenolic profile of hydroethanolic extracts. The concentration of ethanol, 20 % and 40 % resulted in efficient extraction of volatiles, 28 and 20 compounds. The l-isoleucine, methyl ester, β-ocimene, citronellol, and citronellyl acetate were assayed as the most important aroma contributors identified in all variant extracts. The enhancement of ethanol in solvent (from 20 % to 80 %) resulted in a 2.5-fold increase in the scavenging activity of DPPH^•, a 2-fold increase in the scavenging ABTS^•+ radicals, and about a 2-fold increase in reducing power activity measured by FRAP. Results of the study indicate that using a hydroethanolic solvent with 80 % ethanol concentration is the most suitable to obtain Sambucus nigra L. flowers extract rich in phenolic compounds and high antioxidative potential.