Bioactive properties of Acacia dealbata flowers extracts

Floral waste has been considered one of the major concerns, even for those that may have industrial applications, such as dyes or perfumes. In the present study, the possibility of using Acacia dealbata flowers’ extracts and respective fractions as bioactive agents was explored in vitro systems. A. dealbata flowers were extracted with ethanol and the solid residue was further processed with (i) a sequence of organic solvents and (ii) a sequence of greener stages (aqueous, acid and microwave hydrogravity extraction). Total extraction yield and phenolic content were analysed. Ethanolic extracts presented more than 25% phenolic content. Their antiradical activity was evidenced by 85% of the ABTS radical scavenging potency of Trolox. For selected extracts different biological properties, including antibrowning, antilipogenic, anti-inflammatory and cytotoxicity against tumoral cells, were also evaluated. Different extracts were protective against neutrophils oxidative burst and moderately cytotoxic against colon carcinoma HCT-116 and lung adenocarcinoma A549 cells. A multistage extraction process with green solvents was suitable for the production of extracts and fractions from A. dealbata flowers with interesting biological properties. Extracts with higher activities were selected for further assessment as solvents in bioactive hydrogels, observing a positive correlation between gels softening and extracts bioactivity features.