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Abstract Different oregano species have been traditionally used as infusions in folk medicine. Oregano medicinal properties, such as antioxidant and anti-inflammatory, have been partially attributed to its polyphenolic content. However, information regarding bioaccessibility of oregano polyphenols is limited. Cell-based antioxidant activity, and in vitro hypoglycemic, and hypolipidemic properties of polyphenolic extracts from three species of oregano species, namely, Hedeoma patens (HP), Lippia graveolens (LG) and Lippia palmeri (LP), subjected to simulated gastrointestinal digestion were evaluated. LC-TOF-MS analysis of HP, LG and LP allowed the identification of 9 flavonoids and 6 hydroxycinnamic acid derivatives with nutraceutical significance. Oregano polyphenolic extracts and digests from HP, LG, and LP exhibited cellular antioxidant capacity, hypoglycemic and hypolipidemic properties. Altogether, our results suggest that HP, LG and LP polyphenols exhibit potential for use as hypoglycemic, hypolipidemic, and antioxidant agents. Graphical abstract Unlabelled Image Highlights • Cellular antioxidant activity of oregano polyphenols is enhanced after digestion. • Oregano polyphenols show higher α-glucosidase inhibition than acarbose. • Oregano polyphenols showed lower inhibition of α-amylase than acarbose. • Lipase inhibition of polyphenols from oregano is enhanced after digestion. [ABSTRACT FROM AUTHOR]

Oregano phenolic compounds have been studied for their anti-inflammatory properties. Nonetheless, after ingestion, the gastrointestinal environment can affect their antioxidant stability and thus their bioactive properties. To evaluate the effect of in vitro gastrointestinal (GI) digestion on the phenolic compounds of 3 species of oregano ( Hedeoma patens, Lippia graveolens, and Lippia palmeri), the total reducing capacity, total flavonoid content, and antioxidant capacity were evaluated before and after in vitro GI digestion. In addition, the phenolic compounds of the 3 oregano species were identified and quantified by UPLC-PDA before and after in vitro GI digestion. It was shown that the reducing capacity, flavonoid content and antioxidant capacity were affected by the GI digestion process. Moreover, the phenolic compounds identified were apigenin-7-glucoside, scutellarein, luteolin, luteolin-7-glucoside, phloridzin and chlorogenic acid, and their levels were affected by the in vitro GI process. Our results showed that the phenolic compounds from these 3 species of oregano are affected by the in vitro digestion process, and this effect is largely attributable to pH changes. These changes can modify the bioavailability and further anti-inflammatory activity of oregano phenolics, and thus, further research is needed. Practical Application Oregano is a rich source of polyphenols that have shown bioactive properties like anti-inflammatory potential. However, little is known of the gastrointestinal fate of oregano polyphenols which is imperative to fully understand its bioaccessibility. Our results are important to develop new administration strategies which could help protect the antioxidant and anti-inflammatory potential and bioaccessibility of such compounds. [ABSTRACT FROM AUTHOR]

Ethnopharmacological relevance Mexican oregano infusions have been traditionally used in México for the treatment of inflammation-related diseases, such as respiratory and digestive disorders, headaches and rheumatism, among others. Nevertheless, there is limited information regarding the phenolic compounds, terpenes and composition as well as biological activity of Mexican oregano. Aim of the study To determine the phenolic and terpene composition and to evaluate the anti-inflammatory potential of three species of Mexican oregano ( Lippia graveolens (LG), Lippia palmeri (LP) and Hedeoma patens (HP)) in order to provide a scientific basis for their use. Materials and methods We obtained methanol and chloroform extracts from dried oregano leaves of each species. We used LC-DAD-ESI-MS/MS and GC-MS to determine the phenolic and terpene profiles of the leaves, respectively. We evaluated anti-inflammatory potential by measuring the effect of Mexican oregano extracts on some pro-inflammatory mediators, such as nitric oxide (NO) and reactive oxygen species (ROS) using lipopolysaccharide(LPS)-stimulated RAW 264.7 macrophage cells and evaluating cyclooxygenase activity (COX-1, COX-2). Results Nine phenolic compounds (phenolic acids and flavonoids) and 22 terpenes (monoterpenes and sesquiterpenes) were detected in LG, LP and HP. We studied extracts from LG, LP and HP, and fractions from LG and LP in order to know their effect on some pro-inflammatory mediators. The phenolic and terpene extracts from LG, LP and HP exhibited significant inhibitory effect on ROS and NO production and mitochondrial activity in LPS-induced inflammation in RAW 264.7 macrophage cells. Nitric oxide production was also diminished by the terpene LG fraction LGF2 and the LP fractions LPF1, LPF2 and LPF3, confirming that both monoterpenes and sesquiterpenes are active compounds of oregano. Furthermore, the total extracts of LG, LP and HP exhibited non-selective inhibitions against the activity of the cyclooxygenases COX-1 and COX-2. Conclusions Our results suggest that Lippia graveolens, Lippia palmeri and Hedeoma patens extracts have the potential to treat inflammatory diseases; their activity is mediated by polyphenols and terpenes. These findings support the claim for their traditional use in the treatment of inflammation-related diseases. [ABSTRACT FROM AUTHOR]