Polyphenols are the biggest group of phytochemicals, and many of them have been found in plant-based foods. Polyphenol-rich diets have been linked to many health benefits. This paper is intended to ...review the chemistry and biochemistry of polyphenols as related to classification, extraction, separation and analytical methods, their occurrence and biosynthesis in plants, and the biological activities and implications in human health. The discussions are focused on important and most recent advances in the above aspects, and challenges are identified for future research.
Light-emitting diode (LED) lights have recently been applied in controlled environment agriculture toward growing vegetables of various assortments, including microgreens. Spectral qualities of LED ...light on photosynthesis in microgreens are currently being studied for their ease of spectral optimization and high photosynthetic efficiency. This review aims to summarize the most recent discoveries and advances in specific phytochemical biosyntheses modulated by LED and other conventional lighting, to identify research gaps, and to provide future perspectives in this emerging multidisciplinary field of research and development. Specific emphasis was made on the effect of light spectral qualities on the biosynthesis of phenolics, carotenoids, and glucosinolates, as these phytochemicals are known for their antioxidant, anti-inflammatory effects, and many health benefits. Future perspectives on enhancing biosynthesis of these bioactives using the rapidly progressing LED light technology are further discussed.
•The bioavailability of resveratrol encapsulated in nanoemulsions was investigated.•Mechanisms of cell uptake of encapsulated resveratrol was studied during digestion.•Developed nanoemulsion carriers ...are not cytotoxic and can be safely used.•Nanoemulsions deliver resveratrol through cell monolayers avoiding its degradation.•The engineered delivery systems ensure a sustained release of resveratrol.
Different O/W nanoemulsion-based delivery systems were developed in order to optimize the bioavailability of encapsulated resveratrol for potential oral administration. Blank formulations without resveratrol had no negative effect on cell viability or the cytoskeleton structure of Caco-2 cells (XTT viability assay and confocal microscopy). All nanoemulsions were then evaluated based on permeability tests on Caco-2 cells. As a result, the most efficient formulations were lecithin-based nanoemulsions which were able to transport resveratrol through cell monolayers in characteristically shorter times (1–6h) than those required for their metabolization (3–12h), allowing for better preservation of the integrity of the emulsion droplets, thus better protecting the resveratrol molecule. Fluorescence spectroscopy studies confirmed that resveratrol was encapsulated in the inner core of the nanoemulsions, which provides protection against chemical degradation. Furthermore, the developed systems also demonstrated the capability of nanoemulsions in sustained release of resveratrol from dialysis bags compared to the unencapsulated compound.
The anti-inflammatory effects and cellular transport mechanisms of all-E-astaxanthin and its 9Z- and 13Z-isomers were investigated in a Caco-2 cell monolayer model. All three astaxanthin isomers at ...1.2 μM significantly reduced the TNF-α-induced secretion of IL-8 by 22–27%. Z-Astaxanthins, especially 9Z-astaxanthin exhibited greater anti-inflammatory effect than all-E-astaxanthin by down-regulating pro-inflammatory cytokines COX-2 and TNF-α gene expression to 0.88 ± 0.01-fold and 0.83 ± 0.17-fold that of the negative control (NC), respectively. The anti-inflammatory effects of astaxanthin isomers were achieved via modulating the NF-κB signaling pathway as they down-regulated TNF-α-induced phosphorylation of IκBα from 5.3 ± 0.19-fold to 3.8 ± 0.33–4.5 ± 0.27-fold of NC. The scavenger receptor class B type I protein (SR-BI) was found to facilitate the cellular uptake of astaxanthin isomers. Its inhibitor (BLT-1) and antibody (Anti-SRBI) significantly reduced cellular uptake efficiency of all-E-astaxanthin (18.9% and 16.7%, respectively) and 13Z-astaxanthin (28.8% and 30.2%, respectively), but not of 9Z-astaxanthin. The molecular docking experiment showed that 13Z-astaxanthin had significantly higher affinity with SR-BI (atomic contact energy: −420.31) than all-E-astaxanthin and 9Z-astaxanthin, which at least partially supports the higher bioavailability of 13Z-astaxanthin observed in vivo by others.
•The in vitro antioxidant and in vivo anti-inflammatory activities of a unique purple tomato V118.•The bioaccessibility of the phytochemicals in V118 before and after gastrointestinal ...digestion.•Correlation between the phytochemicals and cellular antioxidant activity.•Changes of biomarkers and enzyme activities in the carrageenan-induced paw oedema rat.
The bioaccessibility, antioxidant activities and anti-inflammatory activities of phytochemicals in a purple tomato (Solanum lycopersicum L.) V118 was studied using a simulated gastrointestinal digestion model, chemical and cell based antioxidant assays. The total phenolic and carotenoid contents and the antioxidant activities were significantly lowered (37–72%) and degradation seemed to have occurred during the in vitro digestion. Results indicated that these phytochemicals were bioavailable to the cells as demonstrated by the cell based antioxidant assay. Extracts from the purple tomato showed significant and dose dependent anti-inflammatory effect in the in vivo carrageenan-induced paw oedema rat study (oedematous inhibition: 7.48% and 13.8%), suggesting that anthocyanins may play a role in the anti-inflammatory effect. Direct antioxidant actions as indicated by reduced MDA and NO production and indirect actions as shown in increased GPx and SOD activities in oedematous tissue support the conclusion that tomatoes containing anthocyanins can potentially provide better protection against oxidative stress related chronic diseases of humans.
•Commercially available pulses were cooked and evaluated for antioxidant activity.•Total phenolics, tocopherol, carotenoid, and fatty acid composition were measured.•Bioactive concentration varied ...widely, correlating with antioxidant activity.•Pulses are a candidate ingredient for developing functional food products.
To quantitate bioactive compounds in cooked cultivars of commercially available Canadian pulses, 14 peas, lentils, beans, and chickpeas were analyzed for total polyphenol content (TPC), antioxidant activity (DPPH, FRAP and ORAC) and fatty acid, carotenoid and tocopherol content. On a dry weight (DW) basis, cooked pulses contained (mean±SD) 1.65±0.10–8.39±0.03% lipids; 22.5±0.6–170.5±2.0μg/g total tocopherols, primarily γ-tocopherols (80–96%); 4.21±0.40–20.26±2.43μg/g total carotenoids with lutein being the primary carotenoid (78–87%) then zeaxanthin (6–17%). TPC ranged from 1.16±0.07 to 7.45±0.69mg gallic acid equivalents/g DW. TPC was significantly correlated with DPPH (r=0.688, p=0.006), FRAP (r=0.881, p<0.001) and ORAC (r=0.859, p<0.001). Antioxidant activity was related to tocopherol (r=0.665, p=0.009) but not carotenoid content (r=0.541, p=0.132). These results support the continued use of Canadian pulses for functional foods with health benefits.
Different foods possess different bioactive compounds with varied antioxidant capacities. When foods are consumed together, the total antioxidant capacity of food mixtures may be modified via ...synergistic, additive, or antagonistic interactions among these components, which may in turn alter their physiological impacts. The main objective of this study was to investigate these interactions and identify any synergistic combinations. Eleven foods from three categories, including fruits (raspberry, blackberry, and apple), vegetables (broccoli, tomato, mushroom, and purple cauliflower), and legumes (soybean, adzuki bean, red kidney bean, and black bean) were combined in pairs. Four assays (total phenolic content, ferric reducing antioxidant power, 2,2-diphenyl-1-picrylhydrazyl, radical scavenging capacity, and oxygen radical absorbance capacity) were used to evaluate the antioxidant capacities of individual foods and their combinations. The results indicated that within the same food category, 13, 68, and 21% of the combinations produced synergistic, additive, and antagonistic interactions, respectively, while the combinations produced 21, 54, and 25% synergistic, additive, and antagonistic effects, respectively, across food categories. Combining specific foods across categories (e.g., fruit and legume) was more likely to result in synergistic antioxidant capacity than combinations within a food group. Combining raspberry and adzuki bean extracts demonstrated synergistic interactions in all four chemical-based assays. Compositional changes did not seem to have occurred in the mixture. Results in this study suggest the importance of strategically selecting foods or diets to maximum synergisms as well as to minimum antagonisms in antioxidant activity.
Phytochemicals in fruits, vegetables, spices and traditional herbal medicinal plants have been found to play protective roles against many human chronic diseases including cancer and cardiovascular ...diseases (CVD). These diseases are associated with oxidative stresses caused by excess free radicals and other reactive oxygen species. Antioxidant phytochemicals exert their effect by neutralizing these highly reactive radicals. Among the tens of thousands of phytochemicals found in our diets or traditional medicines, polyphenols and carotenoids stand out as the two most important groups of natural antioxidants. However, although collectively these phytochemicals are good antioxidants, the roles and effect of individual compounds are often not well known. Hundreds of carotenoids and thousands of polyphenols have been identified so far from various plants. A single plant could contain highly complex profiles of these compounds, which sometimes are labile to heat, air and light, and they may exist at very low concentrations in the plants. This makes the separation and detection of these antioxidant phytochemicals a challenging task. The present review focuses on the antioxidant activity, chemical types, sampling and sample processing procedures, and separation using various chromatographic and electrophoretic techniques. Detection and quantification using ultraviolet–visible–diode array and mass spectrometry will be discussed.
•Phenolics and anthocyanins of purple carrots and potatoes were characterized.•The anthocyanin-rich extracts significantly inhibit H2O2-induced IL-8 in Caco-2 cells.•These extracts modulated H2O2 ...mediated pro-inflammatory cytokines expression.•These extracts enhanced cellular antioxidant enzyme activities and glutathione level.
Highly pigmented root vegetables are ideal sources of phytochemical antioxidants particularly anthocyanins. The objective of this study was to characterise the phenolic composition in a purple variety of carrot and potato by examining the aglycone profiles and their antioxidative stress activity. Cyanidin and petunidin were the dominant phenolics among 11 identified aglycones in carrot and potato, respectively. The anthocyanin-rich phenolic extracts not only showed strong antioxidant activities by direct radical scavenging, but more importantly they significantly reduced H2O2-induced interleukins (IL)-1β, IL-6, IL-8 and tumour necrosis factor (TNF)-α in Caco-2 cells. In addition, the extracts were able to restore the intrinsic antioxidant defences as seen in significantly elevated antioxidant enzyme activities and glutathione concentration. These results suggest that purple varieties of carrots and potatoes rich in anthocyanins can ameliorate oxidative stress mediated intestinal inflammatory responses, leading to restoration of the impaired redox balance, ultimately improved health.
•Total and individual phenolics differed among parts of three Amaranthus species.•Total individual betacyanins differed among parts of three Amaranthus species.•Amaranthus hypochondriacus leaf showed ...the highest antioxidant activities.•The antioxidant activities positively correlated with the phytochemical content.
Hydrophilic extracts from different parts including leaves, stalks, seeds, flowers and sprouts of 3 Amaranthus species (Amaranthus hypochondriacus, Amaranthus caudatus and Amaranthus cruentus) were characterized for their phytochemical profiles including the phenolics and betacyanins by UHPLC and LC–ESI–MS, and their antioxidant activities by FRAP and ORAC assays. The main betacyanins in Amaranthus samples were identified to be amaranthine and isoamaranthine. Eleven phenolic compounds (gallic acid, protocatechuic acid, chlorogenic acid, gentistic acid, 2,4-dihydroxybenzoic acid, ferulic acid, salicylic acid, rutin, ellagic acid, kaempferol-3-rutinoside and quercetin) were identified in the extracts of different parts of Amaranthus. The total phenolic content (TPC) ranged from 1.04 to 14.94mg GAE/g DW; the total flavonoid content (TFC) ranged from 0.27 to 11.40mg CAE/g DW; while the total betalain content (TBC) ranged from 0.07 to 20.93mg/100g DW. FRAP values ranged from 0.63 to 62.21μmol AAE/g DW and ORAC ranged from 30.67 to 451.37μmol TE/g DW. The leaves of Amaranthus showed the highest TPC, TFC, TBC, FRAP and ORAC values; while the seeds and stalks the lowest. There was a strong correlation between TPC, TBC, TFC and the antioxidant activity. The result suggests that all parts of the Amaranthus plant can be a good source of antioxidants.
PDF
