Bioavailable Phenolic Compounds from Olive Pomace Present Anti-Neuroinflammatory Potential on Microglia Cells

Luana Schmidt; Bruna Krieger Vargas; Camila Sant'Anna Monteiro; Lauren Pappis; Renius de Oliveira Mello; Alencar Kolinski Machado; Tatiana Emanuelli; Marco Antônio Zachia Ayub; José Cláudio Fonseca Moreira; Paula Rossini Augusti

doi:10.3390/foods12224048

Bioavailable Phenolic Compounds from Olive Pomace Present Anti-Neuroinflammatory Potential on Microglia Cells

Foods. 2023 Nov 7;12(22):4048. doi: 10.3390/foods12224048.

Affiliations

¹ Institute of Basic Health Sciences, Postgraduate Program in Biological Sciences: Biochemistry, Federal University of Rio Grande do Sul (UFRGS), Ramiro Barcelos Street, 2600-Annex, Porto Alegre CEP 90035-003, RS, Brazil.
² Institute of Food Science and Technology, Federal University of Rio Grande do Sul (UFRGS), Av. Bento Gonçalves, 9500, Campus do Vale, Porto Alegre CEP 91501-970, RS, Brazil.
³ Department of Food Technology and Science, Center of Rural Sciences, Federal University of Santa Maria, Camobi, Santa Maria CEP 97105-900, RS, Brazil.
⁴ Graduate Program in Nanoscience, Franciscan University, Santa Maria CEP 97105-900, RS, Brazil.
⁵ Laboratory of Cell Culture and Genetics, Franciscan University, Santa Maria CEP 97105-900, RS, Brazil.

Abstract

The neuroinflammatory process is considered one of the main characteristics of central nervous system diseases, where a pro-inflammatory response results in oxidative stress through the generation of reactive oxygen and nitrogen species (ROS and RNS). Olive (Olea europaea L.) pomace is a by-product of olive oil production that is rich in phenolic compounds (PCs), known for their antioxidant and anti-inflammatory properties. This work looked at the antioxidant and anti-neuroinflammatory effects of the bioavailable PC from olive pomace in cell-free models and microglia cells. The bioavailable PC of olive pomace was obtained through the process of in vitro gastrointestinal digestion of fractionated olive pomace (OPF, particles size < 2 mm) and micronized olive pomace (OPM, particles size < 20 µm). The profile of the PC that is present in the bioavailable fraction as well as its in vitro antioxidant capacity were determined. The anti-neuroinflammatory capacity of the bioavailable PC from olive pomace (0.03-3 mg L^-1) was evaluated in BV-2 cells activated by lipopolysaccharide (LPS) for 24 h. The total bioavailable PC concentration and antioxidant activity against peroxyl radical were higher in the OPM than those observed in the OPF sample. The activation of BV-2 cells by LPS resulted in increased levels of ROS and nitric oxide (NO). The bioavailable PCs from both OPF and OPM, at their lowest concentrations, were able to reduce the ROS generation in activated BV-2 cells. In contrast, the highest PC concentration of OPF and OPM was able to reduce the NO levels in activated microglial cells. Our results demonstrate that bioavailable PCs from olive pomace can act as anti-neuroinflammatory agents in vitro, independent of particle size. Moreover, studies approaching ways to increase the bioavailability of PCs from olive pomace, as well as any possible toxic effects, are needed before a final statement on its nutritional use is made.

Keywords: BV-2 cells; gastrointestinal digestion; neuroinflammation; nitric oxide; oxygen reactive species.

Grants and funding

This study was supported by a PhD fellowship of the “Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)”. Process number 88882.345543/2010-01.