Gut Microbiota Modulation by Bioactive Compounds from Ilex paraguariensis: an In Vivo Study.

Yerba-mate (Ilex paraguariensis) is recognized for its biocompounds and bioactive properties. This study aimed to assess the potential of yerba-mate extract to modulate the intestinal microbiota in rats. After the ethical committee approval (CEUA - UPF, number 025/2018), the Wistar rats were given a daily dose of 3.29 mg of phenolic compounds per animal for 45 days. The antioxidant activity of the extract was assessed by ABTS and FRAP assays and the total phenolic compounds was measured at different pH levels. Identification and quantification of chlorogenic acid isomers were carried out using high-performance liquid chromatography (HPLC). Intestinal microbiota modulation was evaluated by administering the yerba-mate extract or water (control) to Wistar rats via intragastric gavage and its efficiency was measured through PCR. The antioxidant capacity of the yerba-mate extract was 64.53 ± 0.26 µmol Trolox/mL (ABTS) and 52.96 ± 0.86 µmol Trolox/mL (FRAP). The total phenolic compounds showed higher levels at pH 7.5 compared to pH 2.0. Chlorogenic acid isomers were found in greater abundance, with a concentration of 14.22 g/100 g. The administration of the extract resulted in positive modulation of the intestinal microbiota, specifically for the genera Lactobacillus sp. and Prevotella sp. The increase of these genera is related to the promotion of homeostasis of the gut microbiota. Therefore, these findings indicate that yerba-mate extract possesses significant antioxidant activity and can effectively modulate the intestinal microbiota in rats. These results support the potential use of yerba-mate as an alternative for controlling and preventing diseases associated with intestinal dysbiosis.

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

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.

What is the role of phenolic compounds of yerba mate (Ilex paraguariensis) in gut microbiota?

Diet actively influences gut microbiota and body homeostasis. The predominance of beneficial species results in symbiosis, while dysbiosis is characterized by an imbalance between microbial communities. Food plays a key role in this dynamic and in promoting the health of individuals. Ilex paraguariensis, also known as yerba mate, is a traditional plant from Latin America that has a complex matrix of bioactive substances, including methylxanthines, triterpenes, saponins, and phenolics. The consumption of yerba mate is associated with antioxidant, cardioprotective, anti-inflammatory, and anti-obesity effects. However, to the best of our knowledge, there have been no studies on yerba mate as a modulating agent of intestinal microbiota. Phenolics are the major compounds in yerba mate and have been reported to act in modulating the microbiome. In this review, we explore the activity of yerba mate as a possible stimulant of gut microbiota and present its main phenolics and their biological effects. We also propose different mechanisms of action of these phenolics and possible doses for their effectiveness.