Identification and antioxidant activity of flavonoid metabolites in plasma and urine of eriocitrin-treated rats

Anti-Neurodegenerating Activity: Structure-Activity Relationship Analysis of Flavonoids

An anti-neurodegeneration activity study was carried out for 80 flavonoid compounds. The structure-activity analysis of the structures was carried out by performing three different anti-neurodegeneration screening tests, showing that in these structures, the presence of a hydroxy substituent group at position C3' as well as C5' of ring B and a methoxy substituent group at the C7 position of ring A play a vital role in neuroprotective and antioxidant as well as anti-inflammatory activity. Further, we found structure (5) was the top-performing active structure out of 80 structures. Subsequently, a molecular docking study was carried out for the 3 lead flavonoid compounds (4), (5), and (23) and 21 similar hypothetical proposed structures to estimate the binding strength between the tested compounds and proteins potentially involved in disease causation. Ligand-based pharmacophores were generated to guide future drug design studies.

A Comprehensive Review on the Biological, Agricultural and Pharmaceutical Properties of Secondary Metabolites Based-Plant Origin

Natural products are compounds produced by living organisms and can be divided into two main categories: primary (PMs) and secondary metabolites (SMs). Plant PMs are crucial for plant growth and reproduction since they are directly involved in living cell processes, whereas plant SMs are organic substances directly involved in plant defense and resistance. SMs are divided into three main groups: terpenoids, phenolics and nitrogen-containing compounds. The SMs contain a variety of biological capabilities that can be used as flavoring agents, food additives, plant-disease control, strengthen plant defenses against herbivores and, additionally, it can help plant cells to be better adapted to the physiological stress response. The current review is mainly focusing on certain key elements related to the significance, biosynthesis, classification, biochemical characterization and medical/pharmaceutical uses of the major categories of plant SMs. In addition, the usefulness of SMs in controlling plant diseases, boosting plant resistance and as potential natural, safe, eco-friendly substitutes for chemosynthetic pesticides were also reported in this review.

Metabolism of eriocitrin in the gut and its regulation on gut microbiota in mice

Introduction

Eriocitrin, found in lemon fruit, has shown a wide range of biological properties. Herein, we investigated the intestinal metabolic profile of eriocitrin in colon, and the regulation of dietary intervention of eriocitrin on gut microbiota.

Methods

We performed ultra performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS), 16S rDNA gene sequencing and gas chromatography-mass (GC-MS) on colon contents from the eriocitrin group (n=6), and compared them with control participants (n=6).

Results

A total of 136 flavonoids were found in colon contents, including eriocitrin and its six metabolites (eriodictyol, homoeriodictyol, hesperetin, eriodictyol-3'-O-glucoside, hesperetin-7-O-glucoside and eriodictyol-7-O-(6″-O-galloyl) glucoside). Moreover, dietary intervention of eriocitrin significantly alters the beta diversity of the gut microbiota, the probiotics such as Lachnospiraceae_UCG_006 were significantly enriched, and the production of butyrate, valerate and hexanoate in the colon pool of short-chain fatty acids were significant increased. The spearman's association analysis performed some intestinal bacteria may be involved in the metabolism of eriocitrin.

Discussion

Collectively, our results preliminarily suggest the metabolism of eriocitrin in the gut, demonstrating alterations of eriocitrin in gut microbiota, which warrants further investigation to determine its potential use in food and biomedical applications.

Fine characterization and microbiota assessment as keys to understanding the positive effect of standardized natural citrus extract on broiler chickens

The objective of this study was to investigate the effect and composition of a standardized natural citrus extract (SNCE) on both broiler chickens' growth performances and intestinal microbiota. A total of 930 one-day-old males were randomly assigned to three dietary treatments: a control treatment (CTL) in which broiler chickens were fed with a standard diet and two citrus treatments in which broiler chickens were fed with the same standard diet supplemented with 250 ppm and 2,500 ppm of SNCE, respectively. Each dietary treatment was composed of 10 experimental units (pen) of 31 broiler chickens each. Growth performances such as feed consumption, body weight, and feed conversion ratio (FCR) were recorded weekly until day 42. Litter quality was also weekly recorded while mortality was daily recorded. One broiler chicken was randomly selected from each pen (10 chickens/group) and ceca samples were collected for microbiota analysis at day 7 and 42. Chromatographic methods were used to determine molecules that enter into the composition of the SNCE. Results from the characterization of SNCE allowed to identify pectic oligosaccharides (POS) as a major component of the SNCE. In addition, 35 secondary metabolites, including eriocitrin, hesperidin, and naringin, were identified. The experiment performed on broiler chickens showed that the final body weight of broiler chickens fed diets supplemented with SNCE was higher than those fed the CTL diets (P < 0.01). Broiler cecal microbiota was impacted by age (P < 0.01) but not by the dietary supplementation of SNCE. Results indicate that SNCE allowed enhancing chickens' performances without any modulation of the cecal microbiota of broiler chickens. The characterization of SNCE allowed to identify compounds such as eriocitrin, naringin, hesperidin, and POS. Thus, opening new horizons for a better understanding of the observed effect on broiler chickens' growth performances.

Review of factors affecting citrus polyphenol bioavailability and their importance in designing in vitro, animal, and intervention studies

Evidence from in vitro, animal, and human studies links citrus fruit consumption with several health-promoting effects. However, many in vitro studies disregard bioavailability data, a key factor determining responses in humans. Citrus (poly)phenol metabolism and bioavailability follow specific pathways that vary widely among individuals and are affected by several intrinsic (age, sex, gut microbiota, metabolic state, genetic polymorphisms) and extrinsic (food matrix, co-consumed food, (poly)phenol solubility, dose, food processing, lifestyle) factors. The gut microbiota is crucial to both absorption of citrus (poly)phenols and the production of catabolites, and absorption of both takes place mostly in the colon. Citrus (poly)phenol absorption can reach up to 100% in some individuals when the sum of the gut microbiota products are taken into account. This review emphasizes the importance of understanding citrus (poly)phenol absorption, metabolism, and bioavailability using evidence primarily derived from human studies in designing in vitro, animal, and further human clinical studies.

Metabolism of phenolics in coffee and plant-based foods by canonical pathways: an assessment of the role of fatty acid β-oxidation to generate biologically-active and -inactive intermediates

ω-Phenyl-alkenoic acids are abundant in coffee, fruits, and vegetables. Along with ω-phenyl-alkanoic acids, they are produced from numerous dietary (poly)phenols and aromatic amino acids in vivo. This review addresses how phenyl-ring substitution and flux modulates their gut microbiota and endogenous β-oxidation. 3',5'-Dihydroxy-derivatives (from alkyl-resorcinols, flavanols, proanthocyanidins), and 4'-hydroxy-phenolic acids (from tyrosine, p-coumaric acid, naringenin) are β-oxidation substrates yielding benzoic acids. In contrast, 3',4',5'-tri-substituted-derivatives, 3',4'-dihydroxy-derivatives and 3'-methoxy-4'-hydroxy-derivatives (from coffee, tea, cereals, many fruits and vegetables) are poor β-oxidation substrates with metabolism diverted via gut microbiota dehydroxylation, phenylvalerolactone formation and phase-2 conjugation, possibly a strategy to conserve limited pools of coenzyme A. 4'-Methoxy-derivatives (citrus fruits) or 3',4'-dimethoxy-derivatives (coffee) are susceptible to hepatic "reverse" hydrogenation suggesting incompatibility with enoyl-CoA-hydratase. Gut microbiota-produced 3'-hydroxy-4'-methoxy-derivatives (citrus fruits) and 3'-hydroxy-derivatives (numerous (poly)phenols) are excreted as the phenyl-hydracrylic acid β-oxidation intermediate suggesting incompatibility with hydroxy-acyl-CoA dehydrogenase, albeit with considerable inter-individual variation. Further investigation is required to explain inter-individual variation, factors determining the amino acid to which C6-C3 and C6-C1 metabolites are conjugated, the precise role(s) of l-carnitine, whether glycine might be limiting, and whether phenolic acid-modulation of β-oxidation explains how phenolic acids affect key metabolic conditions, such as fatty liver, carbohydrate metabolism and insulin resistance.

Eriocitrin: A review of pharmacological effects

The present study aimed to recognize the recent literature to highlight the pharmacological impacts and highlight the therapeutic potential of the active molecule eriocitrin. Citrus limon are a good resource of the flavanone eriocitrin (eriodictyol 7-O-β-D-rutinoside). Eriocitrin has potent biological actions due to its strong antioxidant, antitumor, anti-allergic, antidiabetic and anti-inflammatory activities. Eriocitrin is more potent in suppressing oxidative stress in diabetes mellitus (DM) and other chronic diseases incurred by excessive oxidative stress. During metabolism, eriocitrin is metabolized by gut microbiota, and a chain of molecules such as eriodictyol, methy-eriodictyol, 3,4-dihydroxyhydrocinnamic acid (DHCA), and much more conjugated molecules. More in-depth studies are recommended to explore this drug for clinical trials.

Flavonoids a Bioactive Compound from Medicinal Plants and Its Therapeutic Applications

Plants generally secrete secondary metabolites in response to stress. These secondary metabolites are very useful for humankind as they possess a wide range of therapeutic activities. Secondary metabolites produced by plants include alkaloids, flavonoids, terpenoids, and steroids. Flavonoids are one of the classes of secondary metabolites of plants found mainly in edible plant parts such as fruits, vegetables, stems, grains, and bark. They are synthesized by the phenylpropanoid pathway. Flavonoids possess antibacterial, antiviral, antioxidant, anti-inflammatory, antimutagenic, and anticarcinogenic properties. Due to their various therapeutic applications, various pharmaceutical companies have exploited different plants for the production of flavonoids. To overcome this situation, various biotechnological strategies have been incorporated to improve the production of different types of flavonoids. In this review, we have highlighted the various types of flavonoids, their biosynthesis, properties, and different strategies to enhance the production of flavonoids.

Influences of Solubility and Vehicle Carriers on Eriodictyol Pharmacokinetics in Rats

In this study, the pharmacokinetics of oral doses of eriodictyol in 1% sodium carboxymethylcellulose and in saline/PEG400/Tween80 (75/20/5, v/v/v) in rats were compared. The pharmacokinetics of eriocitrin administered as a dissolved solution in water were also characterized. Metabolites of eriodictyol and eriocitrin in whole blood consisted mainly of eriodictyol, homoeriodictyol, and hesperetin glucuronides and ring-fission metabolites. In whole blood, no free nonconjugated flavanone aglycones were detected. Significant differences were observed in the pharmacokinetics of eriodictyol administered as a suspension in 1% sodium carboxymethylcellulose versus administration as a dissolved solution in saline/PEG400/Tween80 (75/20/5, v/v/v). At a dose of 25 mg kg^-1 eriodictyol administered with 1% sodium carboxymethylcellulose, a biphasic pharmacokinetic curve was observed, while only a single concentration peak was observed following an administration of 25 mg kg^-1 eriodictyol dissolved in saline/PEG400/Tween80 (75/20/5, v/v/v). For all trials, the pharmacokinetics of eriodictyol differed from those of eriocitrin dissolved in water.

Safety and efficacy of a feed additive consisting of an aqueous extract of Citrus limon (L.) Osbeck (lemon extract) for use in all animal species (Nor-Feed SAS)

Following a request from the European Commission, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of an aqueous extract of Citrus limon (L.) Osbeck (lemon extract) when used as a sensory additive in feed for all animal species. The FEEDAP Panel concluded that the additive under assessment is safe for all animal species up to the maximum proposed use levels of 1,000 mg/kg complete feed and 250 mg/kg water for drinking. No concerns for consumers were identified following the use of lemon extract up to the highest safe level in feed. The additive should be considered a skin and eye irritant, and a potential corrosive. The use of the extract in animal feed under the proposed conditions was not expected to pose a risk for the environment. Lemon extract was recognised to flavour food. Since its function in feed would be essentially the same as that in food, no further demonstration of efficacy was considered necessary.

Effect of season and processing steps in nutritional components and bioactivities of blue mussels (Mytilus edulis)

Blue mussels (Mytilus edulis) from Tongyeong, South Korea were evaluated for seasonal variation in terms of proximate composition, fatty acid (FA) profile, antioxidant activities (DPPH radical scavenging, superoxide anion radical scavenging, and reducing power), and alcohol dehydrogenase (ADH) activity. The effect of different processing steps on blue mussels (from harvest to market) was also assessed. Samples were taken from late autumn to early spring (November 2015 - April 2016). Moisture (79.4 - 82.9%), lipid (1.3 - 2.2%), and protein (8.9 - 10.5%) components varied significantly according to season and processing stage; while ash content remained relative (2.1 - 2.4%). The lowest glycogen (34.2 - 36.7 mg/g) content was found in mussels sampled in January, signifying its usage to generate energy and combat cold stress in winter. Meanwhile, an inverse relationship was observed in mussel lipid (highest, 2.0 - 2.1%) and protein (lowest, 8.9 - 9.3%) contents in April, signifying the conversion of protein to lipid in preparation for spawning in summer. The main FA from lipid class profiling were n-3 polyunsaturated FAs (PUFA, 39.0 - 45.1%), and primarily DHA (14.8 - 16.9%). Atherogenic (AI), thrombogenic (TI), and hypocholesterolaemic/hypercholesterolaemic (h/H) indices, as well as PUFA/SFA and DHA/EPA ratios remained relative throughout the duration of the study. Freshly-harvested mussels exhibited significantly greater radical scavenging and ADH activities than the marketed mussels which emphasise the importance of keeping the bivalve’s freshness. April was determined as the most suitable time for utilising blue mussels as food, food ingredient, and/or for pharmaceutical development. This is because it is during its harvest season where the proximate composition is neither too high nor too low, and omega-3 PUFA content (28.7 - 30.9%) and omega-3/omega-6 PUFA ratio (6.5 - 7.2) are at their peak which support better antioxidant benefits.

Safety and efficacy of a feed additive consisting of a flavonoid-rich dried extract of Citrus × aurantium L. fruit (bitter orange extract) for use in all animal species (FEFANA asbl)

Following a request from the European Commission, the EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of a dried flavonoid-rich extract of Citrus × aurantium L. fruit (bitter orange extract), when used as a sensory additive for all animal species. The use of the additive in feed was not expected to increase the exposure to furocoumarins of those target species that are already fed citrus by-products to a relevant extent (< 5%). For dog, cat and ornamental fish, not normally exposed to citrus by-products, no conclusion could be drawn. The FEEDAP Panel concluded that the additive under assessment is safe up to the maximum proposed use level of 400 mg/kg for veal calf (milk replacer), sheep, goat, horse and salmon. For the other species, the calculated maximum safe concentration in complete feed is 102 mg/kg for chicken for fattening, 151 mg/kg for laying hen, 136 mg/kg for turkey for fattening, 182 mg/kg for piglet, 217 mg/kg for pig for fattening, 268 mg/kg for sow, 259 mg/kg for dairy cow and 161 mg/kg for rabbit. The FEEDAP Panel considered that the use in water for drinking is safe provided that the total daily intake of the additive does not exceed the daily amount that is considered safe when consumed via feed, except dog, cat and ornamental fish. No concerns for consumer safety were identified following the use of the additive up to highest safe level in feed for the target animals. The extract under assessment should be considered as irritant to skin, eyes and the respiratory tract, and as a skin sensitiser. Since the additive contains 5-methoxypsoralen, it may cause phototoxicity. The use of the extract in animal feed under the proposed conditions was not expected to pose a risk for the environment. Bitter orange extract was recognised to flavour food. Since its function in feed would be essentially the same as that in food, no further demonstration of efficacy was considered necessary.

LC-ESI-QTOF-MS/MS Characterisation of Phenolics in Herbal Tea Infusion and Their Antioxidant Potential

Ginger (Zingiber officinale R.), lemon (Citrus limon L.) and mint (Mentha sp.) are commonly consumed medicinal plants that have been of interest due to their health benefits and purported antioxidant capacities. This study was conducted on the premise that no previous study has been performed to elucidate the antioxidant and phenolic profile of the ginger, lemon and mint herbal tea infusion (GLMT). The aim of the study was to investigate and characterise the phenolic contents of ginger, lemon, mint and GLMT, as well as determine their antioxidant potential. Mint recorded the highest total phenolic content, TPC (14.35 ± 0.19 mg gallic acid equivalent/g) and 2,2′-azino-bis(3-e-thylbenzothiazoline-6-sulfonic acid), ABTS (24.25 ± 2.18 mg ascorbic acid equivalent/g) antioxidant activity. GLMT recorded the highest antioxidant activity in the reducing power assay, RPA (1.01 ± 0.04 mg ascorbic acid equivalent/g) and hydroxyl radical scavenging assay, •OH-RSA (0.77 ± 0.08 mg ascorbic acid equivalent/g). Correlation analysis showed that phenolic content positively correlated with the antioxidant activity. Venn diagram analysis revealed that mint contained a high proportion of exclusive phenolic compounds. Liquid chromatography coupled with electrospray ionisation and quadrupole time of flight tandem mass spectrometry (LC-ESI-QTOF-MS/MS) characterised a total of 73 phenolic compounds, out of which 11, 31 and 49 were found in ginger, lemon and mint respectively. These characterised phenolic compounds include phenolic acids (24), flavonoids (35), other phenolic compounds (9), lignans (4) and stilbene (1). High-performance liquid chromatography photometric diode array (HPLC-PDA) quantification showed that GLMT does contain a relatively high concentration of phenolic compounds. This study presented the phenolic profile and antioxidant potential of GLMT and its ingredients, which may increase the confidence in developing GLMT into functional food products or nutraceuticals.

An Up-to-Date Review on Citrus Flavonoids: Chemistry and Benefits in Health and Diseases

Flavonoids, the main class of polyphenols, are characterized by the presence of 2-phenyl-benzo-pyrane nucleus. They are found in rich quantities in citrus fruits. Citrus flavonoids are classified into flavanones, flavones, flavonols, polymethoxyflavones and anthocyanins (found only in blood oranges). Flavanones are the most abundant flavonoids in citrus fruits. In many situations, there are structure-function relationships. Due to their especial structures and presence of many hydroxyls, polymethoxies and glycoside moiety, the flavonoids have an array of multiple biological and pharmacological activities. This article provides an updated overview of the differences in chemical structures of the classes and members of citrus flavonoids and their benefits in health and diseases. The review article also sheds light on the mechanisms of actions of citrus flavonoids in the treatment of different diseases, including arthritis, diabetes mellitus, cancer and neurodegenerative disorders as well as liver, kidney and heart diseases. The accumulated and updated knowledge in this review may provide useful information and ideas in the discovery of new strategies for the use of citrus flavonoids in the protection, prevention and therapy of diseases.

Pharmacokinetics and Biodistribution of Eriocitrin in Rats

Eriocitrin plays a role in the reduction of oxidative stress and inflammation linked to the development of diabetes mellitus and atherosclerosis. We investigated the pharmacokinetics and distribution of eriocitrin metabolites in rats orally administered with eriocitrin. Plasma, urine, and organs were collected at 12 different time points from 0 to 24 h and analyzed by HPLC-PDA-MS. For the first time, the metabolism and distribution of orally administered eriocitrin were shown. Nine metabolites of eriocitrin were identified in rat urine, and seven in various tissues (eriodictyol, homoeriodictyol, hesperetin, and glucuronidated metabolites), and preliminary identifications of these metabolites are suggested. Overall, eriocitrin metabolites were widely distributed in the rat tissues, where homoeriodictyol and homoeriodictyol-7-O-glucuronide were the major metabolites. The half-lives of the metabolites in plasma were between 3 and 3.2 h, and the total bioavailability of eriocitrin was less than 1%.

Low doses of eriocitrin attenuate metabolic impairment of glucose and lipids in ongoing obesogenic diet in mice

Eriocitrin is a citrus flavonoid with a high capacity to reduce the oxidative stress related to metabolic disorders and obesity. We assessed the effects of low doses of eriocitrin on the oxidative stress, inflammation, and metabolism of glucose and lipids of high-fat diet (HFD)-fed obese mice. Fifty male C57BL/6J mice were randomly assigned into five groups (n 10). The mice were fed an HFD (45 % kcal from fat, i.e. lard) for 4 weeks for obesity induction. After this period, the mice continued receiving the same HFD, but supplemented with eriocitrin at 10, 25 or 100 mg/kg body weight (bw) for an additional 4 weeks. Control groups were fed with standard diet (10 % kcal of fat, i.e. soy oil) or with HFD without eriocitrin, for eight consecutive weeks. At the end of the study, mice supplemented with eriocitrin showed lower levels of blood serum glucose and blood and liver triacylglycerols (P < 0⋅05). There was also improved levels of insulin, HOMA-IR, total-cholesterol, resistin and lipid peroxidation in the supplemented mice. It was concluded that the 25 mg dose of eriocitrin improved all the parameters studied and had positive effects on oxidative stress, systemic inflammation and metabolism of lipids and glucose in general.

Citrus flavonoids and the intestinal barrier: Interactions and effects

The intestinal barrier plays a central role in sustaining gut homeostasis and, when dysfunctional, may contribute to diseases. Dietary flavonoids derived from Citrus genus represent one of the main naturally occurring phytochemicals with multiple potential benefits for the intestinal barrier function. In the intestine, citrus flavonoids (CFs) undergo ingestion from the lumen, biotransformation in the epithelial cells and/or crosstalk with luminal microbiota to afford various metabolites that may in turn exert protective actions on gut barrier along with their parental compounds. Specifically, the health-promoting properties of CFs and their metabolic bioactives for the intestinal barrier include their capacity to (a) modulate barrier permeability; (b) protect mucus layer; (c) regulate intestinal immune system; (d) fight against oxidative stress; and (e) positively shape microbiome and metabolome. Notably, local effects of CFs can also generate systemic benefits, for instance, improvement of gut microbial dysbiosis helpful to orchestrate gut homeostasis and leading to alleviation of systemic dysmetabolism. Given the important role of the intestinal barrier in overall health, further understanding of underlying action mechanisms and ultimate health effects of CFs as well as their metabolites on the intestine is of great significance to future application of citrus plants and their bioactives as dietary supplements and/or functional ingredients in medical foods.

Selectivity of Current Extraction Techniques for Flavonoids from Plant Materials

Flavonoids have a broad spectrum of established positive effects on human and animal health. They find an application in medicine for disease therapy and chemoprevention, whence the interest in flavonoids increases. In addition, they are used in food and cosmetic industries as pigments and biopreservatives. Plants are an inexhaustible source of flavonoids. The most important step of plant raw material processing is extraction and isolation of target compounds. The quality of an extract and efficiency of a procedure are influenced by several factors: Plant material and pre-extracting sample preparation, type of solvent, extraction technique, physicochemical conditions, etc. The present overview discusses the common problems and key challenges of the extraction procedures and the different mechanisms for selective extraction of flavonoids from different plant sources. In summary, there is no universal extraction method and each optimized procedure is individual for the respective plants. For an extraction technique to be selective, it must combine an optimal solvent or mixture of solvents with an appropriate technique. Last but not least, its optimization is important for a variety of applications. Moreover, when the selected method needs to be standardized, it must achieve acceptable degree of repeatability and reproducibility.

The pharmacological and biological roles of eriodictyol

Eriodictyol is a flavonoid in the flavanones subclass. It is abundantly present in a wide range of medicinal plants, citrus fruits, and vegetables that are considered to have potential health importance. Having the considerable medicinal properties, eriodictyol has been predicted to clarify the mode of action in various cellular and molecular pathways. Evidence for the existing therapeutic roles of eriodictyol includes antioxidant, anti-inflammatory, anti-cancer, neuroprotective, cardioprotective, anti-diabetic, anti-obesity, hepatoprotective, and miscellaneous. Therefore, this review aims to present the recent evidence regarding the mechanisms of action of eriodictyol in different signaling pathways in a specific disease condition. In view of the immense therapeutic effects, eriodictyol may serve as a potential drug source to enhance community health standards.

Dispersion stability and biocompatibility of four ligand-exchanged NaYF4: Yb, Er upconversion nanoparticles

Surface modification to obtain high dispersion stability and biocompatibility is a key factor for bio-application of upconversion nanoparticles (UCNPs). A systematic study of UCNPs modified with four hydrophilic molecules separately, comparing their dispersion stability in biological buffers and cellular biocompatibility is reported here. The results show that carboxyl-functionalized UCNPs (modified by 3,4-dihydrocinnamic acid (DHCA) or poly(monoacryloxyethyl phosphate (MAEP)) with negative surface charge have superior even-distribution in biological buffers compared to amino-functionalized UCNPs (modified by (aminomethyl)phosphonic (AMPA) or (3-Aminopropyl)triethoxysilane (APTES)) with positive surface charge. Subsequent investigation of cellular interactions revealed high levels of non-targeted cellular uptake of the particles modified with either of the three small molecules (AMPA, APTES, DHCA) and high levels of cytotoxicity when used at high concentrations. The particles were seen to be trapped as particle-aggregates within the cellular cytoplasm, leading to reduced cell viability and cell proliferation, along with dysregulation of the cell cycle as assessed by DNA content measurements. The dramatically reduced proportion of cells in G₁ phase and the slightly increased proportion in G₂ phase indicates inhibition of M phase, and the appearance of sub-G₁ phase reflects cell necrosis. In contrast, MAEP-modified UCNPs are bio-friendly with increased dispersion stability in biological buffers, are non-cytotoxic, with negligible levels of non-specific cellular uptake and no effect on the cell cycle at both low and high concentrations. MAEP-modified UCNPs were further functionalized with streptavidin for intracellular microtubule imaging, and showed clear cytoskeletal structures via their upconversion luminescence. STATEMENT OF SIGNIFICANCE: Upconversion nanoparticles (UCNP) are an exciting potential nanomaterial for bio-applications. Their anti-Stokes luminescence makes them especially attractive to be used as imaging probes and thermal therapeutic reagents. Surface modification is the key to achieving stable and compatible hydrophilic-UCNPs. However, the lack of criteria to assess molecular ligands used for ligand exchange of nanoparticles has hampered the development of surface modification, and further limits UCNP's bio-application. Herein, we report a systematic comparative study of modified-UCNPs with four distinct hydrophilic molecules, assessing each particles' colloidal stability in biological buffers and their cellular biocompatibility. The protocol established here can serve as a potential guide for the surface modification of UCNPs in bio-applications.

Absorption and Metabolic Behavior of Hesperidin (Rutinosylated Hesperetin) after Single Oral Administration to Sprague-Dawley Rats

We investigated the absorption and metabolic behavior of hesperidin (hesperetin-7-O-rutinoside) in the blood system of Sprague-Dawley rats by liquid chromatography- and matrix-assisted laser desorption ionization mass spectrometries (LC-MS and MALDI-MS). After a single oral administration of hesperidin (10 mg/kg), which was expected to be absorbed in its degraded hesperetin form, we detected intact hesperidin in the portal vein blood (t_max, 2 h) for the first time. We successfully detected glucuronized hesperidin in the circulating bloodstream, while intact hesperidin had disappeared. Further MS analyses revealed that homoeriodictyol and eriodictyol conjugates were detected in both portal and circulating blood systems. This indicated that hesperidin and/or hesperetin are susceptible to methylation and demethylation during the intestinal membrane transport process. Sulfated and glucuronized metabolites were also detected in both blood systems. In conclusion, hesperidin can enter into the circulating bloodstream in its conjugated forms, together with the conjugated forms of hesperetin, homoeriodictyol, and/or eriodictyol.

Natural flavonoids for the prevention of colon cancer: A comprehensive review of preclinical and clinical studies

Flavonoids comprise a group of natural polyphenols consisting of more than 5,000 subtypes mostly existing in fruits and vegetables. Flavonoids consumption could potentially attenuate the incidence and recurrence risk of colorectal cancers through their antiperoxidative, antioxidant, and anti-inflammatory effects. In addition, these compounds regulate the mitochondrial function, balance the bacterial flora and promote the apoptosis process in cancerous cells. However, some previous data failed to show the effectiveness of flavonoids in reducing the risk of colorectal cancer. In this study, we have reviewed the efficacy of different flavonoids subtypes on the risk of colon cancer and molecular mechanisms involved in this process in both clinical and animal studies. In addition, we tried to elucidate the potential synergy between these compounds and current colorectal cancer treatments.

Effects of lifelong intake of lemon polyphenols on aging and intestinal microbiome in the senescence-accelerated mouse prone 1 (SAMP1)

Polyphenols have been examined for their beneficial effects on health, particularly in rodents, but their lifelong effects are unclear. Lemons (Citrus limon), containing lemon polyphenols (LPP), are widely consumed but the effects of LPP on aging are unknown. Therefore, we examined the effects of LPP on aging such as aging-related scores, locomotor activity, cognitive functions, and intestinal microbiome using senescence-accelerated mouse prone 1 (SAMP1) and senescence-accelerated resistant mouse 1 (SAMR1). All mice had ad libitum access to water (P1_water group, SAMR1) or 0.1% LPP (P1_LPP group). In the P1_LPP group, LPP intake prolonged the lifespan by approximately 3 weeks and delayed increases in aging-related scores (e.g., periophthalmic lesions) and locomotor atrophy. The P1_water group showed large changes in the intestinal microbiome structure, while the R1 and P1_LPP groups did not. The phylum Bacteroidetes/Firmicutes, which is associated with obesity, in the P1_water group was significantly lower and higher than that in the P1_LPP and R1 groups, respectively. Although the relative abundance of Lactobacillus significantly increased in both P1 groups with aging, the P1_LPP group showed a significantly lower increase than the P1_water group. Thus, lifelong intake of LPP may have anti-aging effects on both phenotypes and the intestinal environment.

Antioxidant constituents of chrysanthemum 'jinsidaju' cultivated in Kaifeng

Dendranthema morifolium cv. 'jinsidaju', cultivated only in Kaifeng, has been eaten for more than 1000 years. During the antioxidant-activity-guided studies on its chemistry and health care function, two new bisabolane-type sesquiterpenes, (6R,7R)-7-hydroxybisabol-2,9E,11-triene-4-one (jinsidajuol A, 1) and (6R,7R)-7-hydroxy-11-methoxybisabol-2,9E-diene-4-one (jinsidajuol B, 2), and thirteen known compounds (3-15) were isolated from the flowers. Their structures were elucidated by 1D and 2D NMR spectroscopy and HRMS. 1 and 2 are the first example of bisabolane-type sesquiterpenes isolated from the genus Dendranthema. Compounds 6-8, 12 and 13 exhibited strong scavenging activities on the ABTS radical cation with IC₅₀ 3.33, 5.67, 2.00, 2.50, 5.33 μg/mL, respectively. The IC₅₀ values of all compounds on HepG2 human hepatoma tumor cell line were higher than 50 μM.

A comprehensive study of eriocitrin metabolism in vivo and in vitro based on an efficient UHPLC-Q-TOF-MS/MS strategy

Eriocitrin, a main flavonoid in lemons, possesses strong antioxidant, lipid-lowering and anticancer activities and has long been used in food, beverages and wine. However, its metabolism in vivo and in vitro is still unclear. In this study, an efficient strategy was developed to detect and identify metabolites of eriocitrin by using ultra-high-performance liquid chromatography coupled with hybrid triple quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS) based on online data acquisition and multiple data processing techniques. A total of 32 metabolites in vivo and 27 metabolites in vitro were obtained based on the above method. Furthermore, the main metabolic pathways of eriocitrin included reduction, hydrogenation, N-acetylation, ketone formation, oxidation, methylation, sulfate conjugation, glutamine conjugation, glycine conjugation, desaturation and demethylation to carboxylic acid. This study will lay a foundation for further studies on the metabolic mechanisms of eriocitrin.

41 metabolites of eriocitrin in vivo and in vitro was identified based on the efficient UHPLC-Q-TOF-MS/MS strategy.

Integrated analysis of transcriptomic and metabolomic data reveals critical metabolic pathways involved in polyphenol biosynthesis in Nicotiana tabacum under chilling stress

Chilling stress increases the amount of polyphenols, especially lignin, which protects tobacco (Nicotiana tabacum L. cv. k326) from chilling stress. To clarify the molecular biosynthesis mechanism of the key representative compounds, specifically lignin, RNA sequencing and ultra-high pressure liquid chromatography coupled to quadrupole-time of flight mass spectrometry technologies were used to construct transcriptomic and metabolomic libraries from the leaves of tobacco plants subjected to normal (25°C) and chilling (4°C) temperature treatments. Transcriptomic libraries from the different samples were sequenced, generating more than 40million raw reads. Among nine samples, metabolomic analysis identified a total of 97 encoding enzymes that function in the key steps of pathways related to polyphenol biosynthesis, where 42 metabolites were also located. An integrated analysis of metabolic and transcriptomic data revealed that most of the intermediate metabolites and enzymes related to lignin biosynthesis were synthesised in the leaves under chilling stress, which suggests that the biosynthesis of lignin plays an important role in the response of tobacco leaves to cold temperatures. In addition, the cold insensitivity of chalcone synthase genes might be considered to be an important rate-limiting factor in the process of precursor substance flow to flavonoid biosynthesis under chilling stress. Furthermore, the upregulated expression of phenylalanine ammonia lyase (PAL), hydroxycinnamoyl transferase (HCT) and cinnamyl-alcohol dehydrogenase (CAD) under chilling stress is the key to an increase in lignin synthesis. This study provides a hypothetical basis for the screening of new active metabolites and the metabolic engineering of polyphenols in tobacco.

Appetite-Inducing Effects of Homoeriodictyol: Two Randomized, Cross-Over Interventions

SCOPE

Anorexia of aging, characterized by a decrease in appetite and/or food intake, is a major risk factor of under-nutrition and adverse health outcomes in elderly people. Recent in vitro evidence suggests homoeriodictyol (HED), a naturally occurring, bitter-masking flavanone, as a promising agent to increase appetite and food intake.

METHODS AND RESULTS

In two cross-over intervention trials, 30 mg NaHED, either solely (n = 10, Study I) or in combination with a 75 g glucose load (n = 17, study II) were administered to healthy adult subjects. Ratings of hunger were assessed at fasting and either 30 min (Study I) or 120 min (Study II) post intervention. Ad libitum energy intake from a standardized breakfast and plasma changes in hunger-/satiety-associated hormones PYY, GLP-1, ghrelin and serotonin were determined after blood drawings. Effects were more pronounced when NaHED was administered in combination with 75 g glucose since ad libitum energy (+ 9.52 ± 4.60%) and protein (+ 7.08 ± 7.97%) intake as well as plasma ΔAUC ghrelin values increased in study II solely, whereas plasma serotonin concentrations decreased after both interventions.

CONCLUSIONS

NaHED demonstrated appetizing effects in healthy adults when administered with a glucose load. Long-term intervention studies are warranted to verify these effects in compromised subjects.

Urinary metabolite profiling of flavonoids in Chinese volunteers after consumption of orange juice by UFLC-Q-TOF-MS/MS

The metabolism of flavonoids derived from orange juice in Chinese volunteers has not been well investigated. With the ultra-fast liquid chromatography-quadrupole-time-of-flight tandem mass spectrometry (UFLC-Q-TOF-MS/MS) system, orange juice-derived flavonoids, as well as metabolites contained in urine collected from healthy Chinese volunteers after consumption of 250mL orange juice, were systematically identified and quantified. Finally, a total of 9 flavonoids and 30 metabolites were detected. Obtained results revealed that flavonoids derived from orange juice underwent extensive phase II metabolism in human, mainly comprising glucuronidation and sulfation. The overall recovery of the primary flavonoid aglycones, i.e., naringenin and hesperetin, were both approximately equivalent 22% of intake, primarily occurred in 4-12h post consumption. Meanwhile, additional 35 phenolic catabolites were identified in urine collected post consumption. However, it is difficult to determine the exact amounts of phenolic catabolites derived from specific flavonoid due to the interference of diets and other flavonoids. This work would be valuable for the clarification of metabolic profiles for flavonoids in Chinese population.

Development and In Vitro Evaluation of an Innovative "Dietary Flavonoid Supplement" on Osteoarthritis Process

The aim of this study was to evaluate the antidegenerative effect in osteoarthritis damage of eriocitrin alone and eriocitrin formulated as innovative "dietary flavonoid supplement." A complexation between eriocitrin and hydroxypropyl β-cyclodextrin by solubilization/freeze-drying method was performed. The complex in solution was evaluated by phase solubility studies and the optimal 1 : 2 flavanone/cyclodextrin molar ratio was selected. Hydroxypropyl β-cyclodextrin was able to complex eriocitrin as confirmed by UV-Vis absorption, DSC, and FTIR studies. The complex formed increased the eriocitrin water solubility (from 4.1 ± 0.2 g·L-1 to 11.0 ± 0.1 g·L-1) and dissolution rate (from 37.0% to 100%) in 30 min. The in vitro studies exhibit the notion that eriocitrin and its complex inhibit AGEs in a similar manner because hydroxypropyl β-cyclodextrin does not interfere with the flavanone intrinsic property. Instead, the presence of cyclodextrin improves eriocitrin antioxidant stability maintaining a high fluorescence value until 8 hours with respect to the pure materials. Moreover, hydroxypropyl β-cyclodextrin showed moderate GAGs restoration acting synergistically with the complexed compound to maintain the structural chondrocytes integrity. The results point out that ERT/HP-betaCD complex possesses technological and biological characteristics able to obtain an easily soluble nutraceutical product, which reduces the degenerative and oxidative damage which occurs in osteoarthritis, and improve the patient compliance.

Inhibitory Effects of Viscum coloratum Extract on IgE/Antigen-Activated Mast Cells and Mast Cell-Derived Inflammatory Mediator-Activated Chondrocytes

The accumulation and infiltration of mast cells are found in osteoarthritic lesions in humans and rodents. Nonetheless, the roles of mast cells in osteoarthritis are almost unknown. Although Viscum coloratum has various beneficial actions, its effect on allergic and osteoarthritic responses is unknown. In this study, we established an in vitro model of mast cell-mediated osteoarthritis and investigated the effect of the ethanol extract of Viscum coloratum (VEE) on IgE/antigen (IgE/Ag)-activated mast cells and mast cell-derived inflammatory mediator (MDIM)-stimulated chondrocytes. The anti-allergic effect of VEE was evaluated by degranulation, inflammatory mediators, and the FcεRI signaling cascade in IgE/Ag-activated RBL-2H3 cells. The anti-osteoarthritic action of VEE was evaluated by cell migration, and the expression, secretion, and activity of MMPs in MDIM-stimulated SW1353 cells. VEE significantly inhibited degranulation (IC₅₀: 93.04 μg/mL), the production of IL-4 (IC₅₀: 73.28 μg/mL), TNF-α (IC₅₀: 50.59 μg/mL), PGD₂ and LTC₄, and activation of the FcεRI signaling cascade in IgE/Ag-activated RBL-2H3 cells. Moreover, VEE not only reduced cell migration but also inhibited the expression, secretion, and/or activity of MMP-1, MMP-3, or MMP-13 in MDIM-stimulated SW1353 cells. In conclusion, VEE possesses both anti-allergic and anti-osteoarthritic properties. Therefore, VEE could possibly be considered a new herbal drug for anti-allergic and anti-osteoarthritic therapy. Moreover, the in vitro model may be useful for the development of anti-osteoarthritic drugs.

Citrus flavanones prevent systemic inflammation and ameliorate oxidative stress in C57BL/6J mice fed high-fat diet

The flavanones hesperidin, eriocitrin and eriodictyol were investigated for their prevention of the oxidative stress and systemic inflammation caused by high-fat diet in C57BL/6J mice. The mice received a standard diet (9.5% kcal from fat), high-fat diet (45% kcal from fat) or high-fat diet supplemented with hesperidin, eriocitrin or eriodictyol for a period of four weeks. Hesperidin, eriocitrin and eriodictyol increased the serum total antioxidant capacity, and restrained the elevation of interleukin-6 (IL-6), macrophage chemoattractant protein-1 (MCP-1), and C-reactive protein (hs-CRP). In addition, the liver TBARS levels and spleen mass (g per kg body weight) were lower for the flavanone-treated mice than in the unsupplemented mice. Eriocitrin and eriodictyol reduced TBARS levels in the blood serum, and hesperidin and eriodictyol also reduced fat accumulation and liver damage. The results showed that hesperidin, eriocitrin and eriodictyol had protective effects against inflammation and oxidative stress caused by high-fat diet in mice, and may therefore prevent metabolic alterations associated with the development of cardiovascular diseases in other animals.

Flavonoids as Potent Scavengers of Hydroxyl Radicals

Oxidative stress is a fundamental principle in the pathophysiology of many diseases. It occurs when the production of reactive oxygen species exceeds the capacity of the cell defense system. The hydroxyl radical is a reactive oxygen species that is commonly formed in vivo and can cause serious damage to biomolecules, such as lipids, proteins, and nucleic acids. It plays a role in inflammation-related diseases, like chronic inflammation, neurodegeneration, and cancer. To overcome excessive oxidative stress and thus to prevent or stop the progression of diseases connected to it, scientists try to combat oxidative stress and to find antioxidant molecules, including those that scavenge hydroxyl radical or diminish its production in inflamed tissues. This article reviews various methods of hydroxyl radical production and scavenging. Further, flavonoids, as natural plant antioxidants and essential component of the human diet, are reviewed as compounds interacting with the production of hydroxyl radicals. The relationship between hydroxyl radical scavenging and the structure of the flavonoids is discussed. The structural elements of the flavonoid molecule most important for hydroxyl radical scavenging are hydroxylation of ring B and a C2-C3 double bond connected with a C-3 hydroxyl group and a C-4 carbonyl group. Hydroxylation of ring A also enhances the activity, as does the presence of gallate and galactouronate moieties as substituents on the flavonoid skeleton.

Modulation of glucose transporter protein by dietary flavonoids in type 2 diabetes mellitus

Diabetes mellitus (DM) is a metabolic diseases characterized by hyperglycemia due to insufficient or inefficient insulin secretory response. This chronic disease is a global problem and there is a need for greater emphasis on therapeutic strategies in the health system. Phytochemicals such as flavonoids have recently attracted attention as source materials for the development of new antidiabetic drugs or alternative therapy for the management of diabetes and its related complications. The antidiabetic potential of flavonoids are mainly through their modulatory effects on glucose transporter by enhancing GLUT-2 expression in pancreatic β cells and increasing expression and promoting translocation of GLUT-4 via PI3K/AKT, CAP/Cb1/TC10 and AMPK pathways. This review highlights the recent findings on beneficial effects of flavonoids in the management of diabetes with particular emphasis on the investigations that explore the role of these compounds in modulating glucose transporter proteins at cellular and molecular level.

Characterization of the herb-derived components in rats following oral administration of Carthamus tinctorius extract by extracting diagnostic fragment ions (DFIs) in the MSn chromatograms

An E(DFI)MSⁿCs-based strategy was proposed to rapidly detect and identify the in vivo components derived from the extract of Carthamus tinctorius using LC-IT-TOF-MSⁿ.

Hexanoyl-lysine as an oxidative-injured marker - application of development of functional food

We could proposed that N(ε)-(hexanoy)lysine, HEL, become a useful biomarker for detection of oxidative stress damage occurred by exhaustive exercise. We examined the preventive effect of flavonoid compound, eriocitrin, against exercise-induced oxidative damage in rat liver. Eriocitrin administration prior to exercise significantly suppressed the increases in thiobarbituric acid-reactive substance caused by lipid peroxidation during exhaustive exercise. The increase in the contents of HEL in rat liver was also abolished by eriocitrin administration. The concentration of oxidized glutathione was significantly increased by exercise, but the eriocitrin administration suppressed this increase. These results suggested that eriocitrin administration prior to exercise prevented oxidative damages caused by exhaustive exercise-induced oxidative stress. Therefore, it was suggested that HEL could be a good biomarker for oxidative stress, especially at earlier stage when oxidative damage was occurred by lipid peroxidation than a stage of harmful aldehyde formation. Moreover, it was suggested that eriocitrin metabolites, eriodictyol and 3, 4 - dihydroxyhydrocinnamic, might scavenge free radicals and reactive oxygen species, resulting in suppression of lipid peroxidation and reactive proteins with radicals to form HEL. These findings implied that eriocitrin might be useful as an anti-oxidative compound to protect oxidative stress damages.

Chemistry and biological activities of flavonoids: an overview

There has been increasing interest in the research on flavonoids from plant sources because of their versatile health benefits reported in various epidemiological studies. Since flavonoids are directly associated with human dietary ingredients and health, there is need to evaluate structure and function relationship. The bioavailability, metabolism, and biological activity of flavonoids depend upon the configuration, total number of hydroxyl groups, and substitution of functional groups about their nuclear structure. Fruits and vegetables are the main dietary sources of flavonoids for humans, along with tea and wine. Most recent researches have focused on the health aspects of flavonoids for humans. Many flavonoids are shown to have antioxidative activity, free radical scavenging capacity, coronary heart disease prevention, hepatoprotective, anti-inflammatory, and anticancer activities, while some flavonoids exhibit potential antiviral activities. In plant systems, flavonoids help in combating oxidative stress and act as growth regulators. For pharmaceutical purposes cost-effective bulk production of different types of flavonoids has been made possible with the help of microbial biotechnology. This review highlights the structural features of flavonoids, their beneficial roles in human health, and significance in plants as well as their microbial production.

Wine polyphenols: potential agents in neuroprotection

There are numerous studies indicating that a moderate consumption of red wine provides certain health benefits, such as the protection against neurodegenerative diseases. This protective effect is most likely due to the presence of phenolic compounds in wine. Wine polyphenolic compounds are well known for the antioxidant properties. Oxidative stress is involved in many forms of cellular and molecular deterioration. This damage can lead to cell death and various neurodegenerative disorders, such as Parkinson's or Alzheimer's diseases. Extensive investigations have been undertaken to determine the neuroprotective effects of wine-related polyphenols. In this review we present the neuroprotective abilities of the major classes of wine-related polyphenols.