*4.1. Antioxidant Effect*

Investigations highlight the antioxidant potential of Maqui, which is more potent compared to other berries; the antioxidant capacity expressed as Trolox equivalents is higher in Maqui berries compared to *Vaccinium floribundum* [61]. Other authors also point out that this berry has a better potential for radical scavenging and antioxidant reactivity using in vitro antioxidant capacity tests [66]. Some works refer to the antioxidant activity of the methanolic extract of the Maqui fruit, and the cardioprotective effects on acute ischemia/reperfusion induced in an in vivo rat model. In this study, the methanolic extract protected the animals from cardiac damage due to the incidence of reperfusion dysrhythmias and non-recovery of

sinus rhythm. The antioxidant effect of this extract was also evaluated with ORAC, FRAP, and DPPH assays presenting an IC50 of 1.62 ppm against DPPH [20].

It has been shown that the antioxidant activity of the Maqui berry is directly related to cognitive protection and a decrease in oxidative stress markers. Methanol/water extracts and their partitions (acetone and ethyl acetate) of three Maqui varieties were studied for antitumor effects in HT-29, Caco-2, and NF-κ colon cancer cells. The inhibition of cell growth and nitric oxide (NO) production by the most active extracts was dose-dependent and significant effects were observed at concentrations of 25.0 and 10.0 ppm, respectively [67].

Maqui berries have shown better results against different in vitro tests of antioxidant activity [68]. A new drink based on lemon juice and Maqui has been compared against other mixtures with açai and blackthorn. The Maqui mixture was the most interesting in terms of antioxidant capacity. An ABTS assay showed that Maqui-containing mixtures presented better results (8.35 ± 0.55 mM Trolox), supporting the strong antioxidant activity of this berry. Açai blends showed lower capacity compared to Maqui blends (3.88 ± 0.58 mM Trolox). This study also showed the most potent reducing capacity of Maqui compared to açai against the DPPH radical (3.07 mM ± 0.09 mM Trolox and 0.12 ± 0.19 mM Trolox, respectively) [69].

### *4.2. Effect on Inflammation and Endothelial Dysfunction*

Maqui has received attention due to its broad biological potential, including reducing inflammation. In vitro studies have mainly shown that Maqui limits adipogenesis and inflammatory pathways [61] in addition to affecting the production of NO [70]. A hydroalcoholic extract of this species, as well as rutin, improved endothelium-dependent relaxation and reduced plasma levels of cholesterol, LDL, and triglycerides. Additionally, Maqui and rutin improve the bioavailability of NO [71]. Another study evidenced the protective effect of a hydroethanolic extract of Maqui and its flavonoids (rutin and quercetin) on endothelial dysfunction induced by high glucose and pyrogallol, through a greater generation and bioavailability of NO [72]. An aqueous extract of Maqui berries modulated NO production in a hyperglycemic and/or hyperinsulinemic microenvironment, in addition to improving endothelial function, through the possible vasorelaxant properties of NO [70]. Maqui methanolic extracts under inflammatory conditions suppress NO production, through the regulation of inducible nitric oxide synthases (iNOSs). These results correlate with the inhibition of the expressions of NF-κB and COX-2 proteins [67]. On the other hand, the methanolic extract of the Maqui fruit decreases lipid oxidation and reduces the concentration of thiobarbituric acid reactive species (lipid peroxidation index) [20]. In human endothelial cell cultures, Maqui juice dose-dependently protects intracellular oxidative stress induced by hydrogen peroxide, suggesting that it might have antiatherogenic properties [66].
