Chemical and biological analysis of the by-product obtained by processing Gentiana lutea L. and other herbs during production of bitter liqueurs

• Simultaneous determination of 18 bioactive by using UHPLC–MS/MS triple quadrupole.
• Plants by-products are promising sources of bioactive compounds.
• By-product extract showed synergistic effects with nerve growth factor (NGF).
• Bitter liqueur by-products can be used in food, pharmaceutics and cosmetics.

The exploitation of plant by products is particularly important for the industries that produce bitter liqueurs, being the subsequent disposal very expensive. In fact, these wastes can be considered a good source of bioactive compounds that can be recycled due to favourable nutritional or biological properties. A new, sensitive and reliable HPLC–MS/MS method was described for the first time for the simultaneous determination of 18 bioactive compounds in the by-product of a bitter liqueur, which is particularly rich in gentiopicroside. Moreover, the waste extracts showed no cytotoxic activities against human fibroblasts (A549). The scavenging activity of ethanol:ethyl acetate (1:1) extract of the waste (S2, IC50 = 3.47 μg/ml) was particularly high, together with its total phenolic content. Finally, this by-product extract showed synergistic effects with nerve growth factor (NGF) by inducing proliferation and differentiation of rat pheochromacytoma (PC12 Adh) cells. Results showed that by-products obtained during bitter liqueurs production represent a source of valuable bioactive compounds to be used in food, pharmaceutical and cosmetic industries.