SUSTAINABLE USE OF WASTE FROM THE OLIVE INDUSTRY IN NORTHWEST ARGENTINA: CHARACTERIZATION AND BIOLOGICAL ACTIVITIES

TAPIA, P.E.; SILVA, A.M.; DELERUE-MATOS, C.; MOREIRA, M.; RODRIGUEZ, F.; VIOLA, C.M.; TORRES CARRO, R.; CARTAGENA, E.; ARENA, M.E.; ALBERTO, M.R.

San Juan

Congreso; XLI Reunión Anual de la Sociedad de Biología de Cuyo; 2023

Sociedad de Biología de Cuyo

The olive oil industry generates a residue known as "alperujo," which is considered phytotoxic due to its high phenol content. However, these compounds have a wide range of applications, including potential health benefits. Thus, we conducted an extensive study on the hydroalcoholic extract of alperujo, investigating its chemical composition, antioxidant properties, antipathogenic and inhibitory enzyme activities, ecotoxicity, and acute toxicity. In the quantitative analysis, we found that the total phenolic content was 30.4 ± 2.8 mg GAE/g DW (Galic acid equivalent). Through HPLC-DAD analysis, we identified 29 phenolic compounds, with the most prominent ones including: kaempferol-3-O-glucoside>4,5-di-O-caffeoylquinic acid>caftaric acid>rutin>gallic acid>isorhamnetin-3-O-glucoside> myricetin>ellagic acid>catechin>quercetin-3-O-galactoside. Furthermore, the alperujo extract exhibited significant total antioxidant capacity, with a value of 62.1 ± 1.1 mg AAE/g DW (Ascorbic acid equivalent). It demonstrated the ability to scavenge ABTS•+ (IC50=64.7 ± 0.6 µg/ml), superoxide anion (IC50=551.8 ± 64.7 µg/ml), nitric oxide (IC50=482.6 ± 8.9 µg/ml), hypochlorite (IC50=18.7 ± 1.4 µg/ml), also efficiently reduced Fe3+ ions (RC50= 88.0 ± 1.7 µg/ml) and Cu2+ ions (29.8 ± 2.0 mg GAE/g DW). Additionally, it displayed iron-chelating abilities (CC50= 574.7 ± 2.5 µg/ml) and inhibited the proinflammatory enzyme lipoxygenase (IC50= 419.4 ± 3.5 µg/ml). In toxicity tests, the alperujo extract demonstrated no toxicity at the maximum tested concentration (1000 µg/ml) in the acute toxicity test using the crustacean Artemia salina and the ecotoxicity test involving Lemna minor and Armadidilium vulgare. However, in the Bacillus subtilis test (another ecotoxicity model organism), a concentration of 1000 µg/ml inhibited bacterial growth by 60%, indicating toxicicity toward bacteria. Additionally, the extract significantly reduced biofilm formation by Staphylococcus aureus y Pseudomonas aeruginosa strains and disrupted a previously formed biofilm by reducing biomass and cellular metabolism. Furthermore, it exhibited Quorum sensing (QS) inhibitory activity against Chromobacterium violaceum, limited the spread of P. aeruginosa by restricting swarming and swimming movements, and interfered with other QS-controlled phenotypes such as elastase and pyocyanin. The diverse array of phenolic metabolites found in the alperujo extract, coupled with its beneficial biological activities, suggests its potential to promote human health.