Energy and environmental analysis of flavonoids extraction from bark using alternative solvents

Abstract

[EN] Tree barks are rich in extractive compounds, among which the flavonoids are considered as products of interest. Due to the increase in the demand for these natural products, the development of efficient and sustainable extraction processes is needed. This work aimed to study the selective extraction of flavonoids from Larix decidua bark using an environmentally friendly process. For this purpose, different extraction techniques as well as different solvents were used in order to achieve the highest flavonoid content. The characterisation results revealed improvements in extraction yield not only with the use of intensification processes, but also with the use of ionic liquids as solvents with a proven selectivity for flavonoids. [C4C1im]Br and [C4C1im][BF4] considerably improved the total flavonoid content in comparison with the other extraction methods. The antioxidant capacities of all the extracts obtained were very high, confirming their potential for different applications. The [C4C1im]Br (25 wt%) was selected as the best solvent not only because of its good flavonoid extraction ability, but also because of the good antioxidant properties of the extract, and simultaneous microwave-ultrasound assisted extraction was the most energy saving process.