Advantages of contemporary extraction techniques for the extraction of bioactive constituents from black elderberry (Sambucus nigra L.) flowers

Since ancient times, elderberry (Sambucus nigra L.) has been used in traditional medicine, but also as a supplement in various beverages and dishes. Although elderberry is a widespread species in the Balkan Peninsula, it is not sufficiently exploited and it is barely chemically and biologically characterized. The present study was focused on the phytochemical composition and biological effects of S. nigra flowers' extracts, obtained by different techniques (microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE) and maceration (MAC)) in the presence of different solvents (50% ethanol (EtOH) or water (H2O)). The phytochemical profiles of the obtained extracts were determined by LC-MS/MS and spectrophotometric techniques: rutin and 5-O-caf-feoylquinic acid were found to be the major compounds in all extracts. To evaluate its biological potential, antioxidant, neuroprotective (acetyl - and butyrylcholinesterase inhibition (AChE and BChE)), antityrosinase and antilipase abilities were tested. MAE with 50% EtOH exhibited the strongest antioxidant activity, which was in good correlation with the high content of phenolics. The best AChE inhibitory effect was observed by MAC with H2O extract. However, the strongest tyrosinase inhibitors were 50% EtOH extracts. The presented results prove the high biological and industrial potential of S. nigra flowers and open new directions towards novel product design.