In the present study, we assessed the antioxidant activity of the phenolic extracts and major phenolic compounds of alfalfa, buckwheat, clover and orange honeys collected in North America using chemical-based and cell-based antioxidant assays (CAA). Cell culture models using Caco-2 BBe1 were established to evaluate the effect of honey phenolics on antioxidant enzyme activities and secretion of interleukin 8 (IL-8). Moreover, bioaccessibility, transmembrane transport and cellular uptake of honey phenolics were also studied. Based on the same quantity of the honey studied, phenolic extract of buckwheat honey showed the highest FRAP, DPPH, ORAC and CAA values, and strongest activity in restoring activities of antioxidant enzymes (GR, SOD and CAT) and in reducing TNF-α-induced IL-8 secretion. Our results showed that compared to the major phenolic component of honey of plant origin, minor phenolics or combination of different phenolic compounds, particularly those derived from propolis, and their phase Ⅱ metabolites may play contribute more to the overall antioxidant and anti-inflammatory effects. Future research will focus on bioavailability of honey phenolics and their metabolites, and the molecular mechanism of the antioxidant, anti-inflammatory activities.

Phenolic and amino acid profiles along with organic acid, vitamin and mineral contents, major and minor sugars and enzyme activities of selected honey samples collected in North America were analyzed using different methods and potential markers of their botanical origin were identified. A total of 29 phenolic compounds were detected, of which some were found to be a good chemical markers to distinguish a genuine honey given its propolis origin. Quantitative data and principal component analysis showed that hesperidin, caffeic acid/isoferulic acid, and p-hydroxybenzoic acid/p-coumaric acid have the most positive relationship to the orange, alfalfa, and buckwheat honey, respectively, indicating their potential roles as chemical markers of these floral honeys. Free amino acid profiles were similar in all honeys except buckwheat which not only had significantly higher branched-chain amino acids but was the only floral honey that contained L-norvaline that was identified for the first time. The enzyme activities and the major and rare sugar composition helped explain the presence of the various organic acids in the honeys. Compositional data of these bioactives and other nutrients will not only serve as database information for honey derived from North America but also provide insightful knowledge for the underlining potential health benefits.

Dietary polyphenols including anthocyanins possess strong antioxidant and anti-inflammatory properties, and are known to help reduce risks of oxidative stress-induced chronic diseases. However, their effects on various aspects of the gut microenvironment towards preventing the unhealthy diet-induced metabolic disorders are still not well understood. The present study aims to verify the in vitro antioxidant and anti-inflammatory effects of the anthocyanin-rich extracts of purple potato (PPE), using a lipopolysaccharide (LPS) and high-fat diet (HFD)-induced obesity C57/BL6J mouse model, and to examine the effects of PPE on LPS+HFD-impaired metabolic homeostasis and the underlying mechanisms. We found that PPE, especially at higher dose significantly improved the glucose and lipid metabolism, and reduced inflammation in the plasma and various tissues. It significantly improved intestinal barrier integrity, altered fecal metabolite profile and gut microbiota composition. Our findings provide new insights into the roles of highly-pigmented vegetable-derived anthocyanins in maintaining gut health and ameliorating metabolic syndrome.

Mustard bran is enriched with bioactive phenolic compounds and glucosinolates, yet it is underutilized as a low-value processing by-product. Here, we investigate the effects of solid-state fermentation (SSF) using various food-grade microorganisms (Aspergillus spp., Rhizopus spp., Bacillus subtilis, Saccharomyces cerevisiae) on the phytochemical composition and antioxidant activities of oriental mustard and yellow mustard brans. The total phenolic contents (TPC) and antioxidant activities (FRAP, DPPH assays) of oriental and yellow mustard brans were significantly improved (p < 0.05) after fermentation, especially by R. oligosporus and R. oryzae. Moreover, SSF by R. oligosporus and R. oryzae significantly increased (p < 0.05) the levels of p-hydroxybenzoic acid, syringic acid, protocatechuic acid, sinapic acid and kaempferol-3-O-glucoside in both mustard brans. Conversely, a significant reduction (p < 0.05) of major glucosinolates in oriental and yellow mustard brans were observed after SSF by R. oligosporus. Findings from this study show that SSF by filamentous fungi is a promising strategy to enhance the phenolic contents, antioxidant properties and overall value of oriental and yellow mustard brans.

Lentils contain a plethora of bioactive phytochemicals such as extractable and insoluble-bound phenolics, carotenoids, tocopherols, saponins, phytic acid, and phytosterols, which have been increasingly attributed to the health benefits of lentil consumption in the diet. The concentration and stability of these phytochemicals in lentils may be affected by several processing parameters including different thermal processing, exogenous enzyme treatment and germination. Consumption of lentils has been associated with the risk reduction of many diseases due to the potential antioxidant activity and anti-inflammatory potential of phytochemicals in lentils. This mini review is intended to provide most current information on the phytochemical composition of lentils, and the potential antioxidant and anti-inflammatory properties of these compounds.