Bioactive Wound Healing 3D Structure Based on Chitosan Hydrogel Loaded with Naringin/Cyclodextrin Inclusion Nanocomplex

The current assay aimed to fabricate and analyze a potent wound healing structure based on a naringin (Nar)/β-cyclodextrin (β-CD)-loaded chitosan hydrogel. Using the simulation studies, we assessed the interactions among the Nar, β-CD, and the formation of the inclusion complex. Then, the formation of the hydrogel nanocomplex was simulated and evaluated using the in silico methods. The results showed that after optimization of the structures by DMol3 based on DFT-D, the total energies of Nar, GP, CD, and β-CD were calculated at -2100.159, -912.192, -3778.370, and -4273.078 Ha, respectively. The encapsulation energy of Nar on β-CD in the solvent phase was calculated at -93.626 kcal/mol, and the Nar structure was located inside β-CD in solution. The negative interaction energy value for the encapsulation of Nar on β-CD suggests the exothermic adsorption process and a stable structure between Nar and β-CD. Monte Carlo method was applied to obtain adsorption of CS/GP on Nar/β-CD. Its value of the obtained interaction energy was calculated at -1.423 × 103 kcal/mol. The characterization confirmed the formation of a Nar/β-CD inclusion complex. The Zeta potential of the pristine β-CD changed from -4.60 ± 1.1 to -17.60 ± 2.34 mV after interaction with Nar, and the heightened surface negativity can be attributed to the existence of electron-rich naringin molecules, as well as the orientation of the hydroxyl (OH) group of the β-CD toward the surface in an aqueous solution. The porosity of the fabricated hydrogels was in the range of 70-90% and during 14 days around 47.0 ± 3.1% of the pure hydrogel and around 56.4 ± 5.1 of hydrogel nanocomposite was degraded. The MTT assay showed that the hydrogels were biocompatible, and the wound contraction measurement (in an animal model) showed that the closure of the induced wound in the hydrogel nanocomposite treatment was faster than that of the control group (wound without treatment). The results of this study indicate that the developed bioactive wound healing 3D structure, which is composed of a chitosan hydrogel containing a Nar/β-CD inclusion nanocomplex, has potential as an effective material for wound dressing applications.

Interaction of luteolin, naringenin, and their sulfate and glucuronide conjugates with human serum albumin, cytochrome P450 (CYP2C9, CYP2C19, and CYP3A4) enzymes and organic anion transporting polypeptide (OATP1B1 and OATP2B1) transporters

Luteolin and naringenin are flavonoids found in various foods/beverages and present in certain dietary supplements. After a high intake of these flavonoids, their sulfate and glucuronide conjugates reach micromolar concentrations in the bloodstream. Some pharmacokinetic interactions of luteolin and naringenin have been investigated in previous studies; however, only limited data are available in regard to their metabolites. In this study, we aimed to investigate the interactions of the sulfate and glucuronic acid conjugates of luteolin and naringenin with human serum albumin, cytochrome P450 (CYP2C9, 2C19, and 3A4) enzymes, and organic anion transporting polypeptide (OATP1B1 and OATP2B1) transporters. Our main findings are as follows: (1) Sulfate conjugates formed more stable complexes with albumin than the parent flavonoids. (2) Luteolin and naringenin conjugates showed no or only weak inhibitory action on the CYP enzymes examined. (3) Certain conjugates of luteolin and naringenin are potent inhibitors of OATP1B1 and/or OATP2B1 enzymes. (4) Conjugated metabolites of luteolin and naringenin may play an important role in the pharmacokinetic interactions of these flavonoids.

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.

Variability in the Beneficial Effects of Phenolic Compounds: A Review

When analysing the beneficial effects of phenolic compounds, several factors that exert a clear influence should be taken into account. The content of phenolic compounds in foods is highly variable, directly affecting individual dietary intake. Once ingested, these compounds have a greater or lesser bioaccessibility, defined as the amount available for absorption in the intestine after digestion, and a certain bioavailability, defined as the proportion of the molecule that is available after digestion, absorption and metabolism. Among the external factors that modify the content of phenolic compounds in food are the variety, the cultivation technique and the climate. Regarding functional foods, it is important to take into account the role of the selected food matrix, such as dairy matrices, liquid or solid matrices. It is also essential to consider the interactions between phenolic compounds as well as the interplay that occurs between these and several other components of the diet (macro- and micronutrients) at absorption, metabolism and mechanism of action levels. Furthermore, there is a great inter-individual variability in terms of phase II metabolism of these compounds, composition of the microbiota, and metabolic state or metabotype to which the subject belongs. All these factors introduce variability in the responses observed after ingestion of foods or nutraceuticals containing phenolic compounds.

Beneficial Effects of Citrus Flavanones Naringin and Naringenin and Their Food Sources on Lipid Metabolism: An Update on Bioavailability, Pharmacokinetics, and Mechanisms

Naringin and naringin's aglycone naringenin belong to a subclass of flavonoids called flavanones. While many studies of pure naringenin and naringin and their food sources have shown beneficial health effects, including improved lipid metabolism, in animals and humans, the mechanisms underlying the lipid-lowering effects have not been completely understood. In recent years, multiple studies using various in vitro and rodent models have revealed new mechanisms underlying the hypolipidemic effects of naringin and naringenin, including regulation of lipid digestion, reverse cholesterol transport, and LDL receptor expression. In addition, naringin and naringenin show diverse effects in populations with different health conditions, such as obesity and diabetes. Furthermore, a novel naringin and naringenin enriched food source citrus bergamia (bergamot) and other citrus fruits have recently been studied for lipid-lowering effects in animal models and human clinical trials. In this review, we provide an update on recent advances on naringin and naringenin and their enriched food sources on lipid metabolism and underlying mechanisms. Because absorption, distribution, metabolism, and excretion, particularly in the presence of food matrix, impact the bioavailability, which in turn affects the bioactivities of these flavonoids in vivo, we also summarize new findings from the pharmacokinetics studies and on interplays between naringin and naringenin and gut microbiota.

Double-responsive hyaluronic acid-based prodrugs for efficient tumour targeting

Hyaluronic acid (HA)-based prodrugs bearing double-responsive (acid pH or oxidation) boronates of catechol-containing drugs were used to treat xenografted human prostate tumours (LNCaP) in SCID mice. The HA prodrugs accumulated significantly only in tumours (impressively, up to 40% of the injected dose after 24 h) and in liver, with negligible - actually anti-inflammatory - consequences in the latter. A quercetin-HA prodrug significantly slowed down tumour growth, in a dose-dependent fashion and with a much higher efficacy (up to 4 times) than equivalent doses of free quercetin. In short, boronated HA appears to be a very promising platform for targeted chemotherapy.

Smart Responsive Quercetin-Conjugated Glycol Chitosan Prodrug Micelles for Treatment of Inflammatory Bowel Diseases

The incidence and progression of inflammatory bowel disease are closely related to oxidative stress caused by excessive production of reactive oxygen species (ROS). To develop an efficacious and safe nanotherapy against inflammatory bowel diseases (IBD), we designed a novel pH/ROS dual-responsive prodrug micelle GC-B-Que as an inflammatory-targeted drug, which was comprised by active quercetin (Que) covalently linked to biocompatible glycol chitosan (GC) by aryl boronic ester as a responsive linker. The optimized micelles exhibited well-controlled physiochemical properties and stability in a physiological environment. Time-dependent NMR spectra traced the changes in the polymer structure in the presence of H₂O₂, confirming the release of the drug. The in vitro drug release studies indicated a low release rate (<20 wt %) in physiological conditions, but nearly complete release (>95 wt % after 72 h incubation) in a pH 5.8 medium containing 10 μM H₂O₂, exhibiting a pH/ROS dual-responsive property and sustained release behavior. Importantly, the negligible drug release in a simulated gastric environment in 1 h allowed us to perform intragastric administration, which has potential to achieve the oral delivery by mature enteric-coating modification in future. Further in vivo activities and biodistribution experiments found that the GC-B-Que micelles tended to accumulate in intestinal inflammation sites and showed better therapeutic efficacy than the free drugs (quercetin and mesalazine) in a colitis mice model. Typical inflammatory cytokines including TNF-α, IL-6, and iNOS were significantly suppressed by GC-B-Que micelle treatment. Our work promoted inflammatory-targeted delivery and intestinal drug accumulation for active single drug quercetin and improved the therapeutic effect of IBD. The current study also provided an alternative strategy for designing a smart responsive nanocarrier for a catechol-based drug to better achieve the target drug delivery.

The pharmacokinetics of flavanones

The intake of flavanones, the predominant flavonoid in the Citrus genus in human diets is variable but considerable. It is thus unsurprising that they have attracted interest for their claimed positive effects on health. However, to substantiate any purported impact on health and decipher the underlying mechanism(s), knowledge of pharmacokinetics is crucial. The aim of this article is to review currently known aspects of the fate of flavanones in the organism including absorption, metabolism, distribution, and excretion as well as possible kinetic interactions with clinically used drugs. There are three principal keynotes: (1) The level of parent flavanones in plasma is negligible. The major reason for this is that although flavanones are absorbed into enterocytes after oral intake, they are rapidly metabolized, in particular, into conjugates, sulfates and glucuronides, which are the major forms circulating in plasma. (2) A large fraction reaches the colon where it is efficiently metabolized into small absorbable phenolics. (3) The form (aglycone vs. glycoside) and species (e.g. human vs. rat) have important impact. In conclusion, knowledge of the pharmacokinetics of flavanones, in particular of metabolites, their achievable plasma concentration and half-lives, should be borne in mind when their biological effects are investigated.

Acute Effect of a Single Dose of Tomato Sofrito on Plasmatic Inflammatory Biomarkers in Healthy Men

Sofrito is a Mediterranean tomato-based sauce that typically also contains olive oil, onion, and garlic. The preparation of sofrito modifies the bioactive compounds (carotenoids and polyphenols) in the ingredients to more bioavailable forms, promoting cis-lycopene formation and polyphenol bioaccessibility. To evaluate the health benefits of this cooking technique, the effect of consuming an acute dose of sofrito on the inflammatory status was studied. In a clinical trial, 22 healthy male subjects consumed a single dose of sofrito (240 g/70 kg) after three days without ingesting any tomato products and following a low-antioxidant diet the day before the intervention. Plasma carotenoids and total polyphenol excretion (TPE) were evaluated, as well as the inflammatory biomarkers C-reactive protein (CRP), interleukin-6 (IL-6), interleukin 1β (IL-1β) and tumor necrosis factor-α (TNF-α). After the sofrito intake, a significant decrease in CRP (p = 0.010) and TNF-α (p = 0.011) was observed, but only TNF-α was inversely correlated with an increase in TPE and plasma β-carotene (not the major carotenoid, lycopene). The positive health effects of this tomato-based product may be attributed not only to lycopene, but to the bioactive compounds of all the ingredients.

Naringenin, a dietary flavanone, enhances insulin-like growth factor 1 receptor-mediated antioxidant defense and attenuates methylglyoxal-induced neurite damage and apoptotic death

Objectives: Recent studies revealed the neuroprotective effects of naringenin (NGEN), a common dietary bioflavonoid contained in citrus fruits. However, there are limited data on its protection against methylglyoxal (MG), the most potent precursor of advanced glycation end-products. The present study was to investigate the protection of NGEN on MG-induced neurotoxicity and the involvement of insulin-like growth factor 1 receptor (IGF-1R) signaling. Methods: NSC34 motor neuron-like cells was used. Cell viability was measured by MTT assay. Protein expressions were analyzed by western blots. Morphological changes of neurites were observed by an inverted microscope. Reactive oxygen species (ROS) production and apoptotic cell numbers were measured by flow cytometer. Glutathione (GSH) level and superoxide dismutase (SOD) activity were measured by ELISA. Results: >NGEN attenuated ROS production and increased GSH level, SOD activity and nuclear factor erythroid 2-related factor 2 (Nrf2) nuclear expression in MG-treated NSC34 cells. NGEN also increased neurite length and enhanced IGF-1R and p-Akt in MG-treated NSC34 cells. Furthermore, NGEN attenuated MG-induced apoptotic death accompanied with down-regulation of cleaved-poly (ADP-ribose) polymerase (PARP) and up-regulation of B-cell lymphoma-2 (Bcl-2). However, AG1024, an IGF-1R antagonist, attenuated the anti-oxidative and anti-apoptotic effects of NGEN in MG-treated cells. Discussion: The present results demonstrated that NGEN decreased neuronal apoptosis and improved antioxidant defense in MG-treated NSC34 cells. Moreover, IGF-1R-mediated antioxidant defense plays an important role in this protective mechanism. These findings suggest the potential benefits of NGEN on the prevention of MG-induced or diabetes/hyperglycemia-related neurotoxicity. In vivo studies are needed for further confirmation on NGEN-mediated neuroprotection.

Intestinal disposition of quercetin and its phase-II metabolites after oral administration in healthy volunteers

OBJECTIVES

Quercetin is one of the main dietary flavonoids and undergoes a substantial intestinal phase-II metabolism. Quercetin conjugates have been detected in plasma and in urine, but their presence in the small intestine has not been assessed. This study aimed to investigate the intestinal metabolism and metabolite excretion of quercetin by the human small intestinal wall after oral dosing.

METHODS

Six healthy volunteers were given a capsule of 500 mg of quercetin with 240 ml of water. Duodenal fluids were collected using the intraluminal sampling technique for 4 h and analysed by LC-MS/MS.

KEY FINDINGS

Phase-II metabolites of quercetin were detected and quantified in aspirated intestinal fluids. Metabolites appeared almost immediately after administration, indicating an intestinal metabolism and apical excretion into the lumen. Quercetin-3'-O-glucuronide was found to be the main intestinal metabolite. Our results could not conclude on the enterohepatic recycling of quercetin or its metabolites, although several individual profiles showed distinctive peaks.

CONCLUSIONS

This study highlights the intestinal metabolism and excretion of quercetin and its conjugates in humans and gives insights into the relevant concentrations which should be used to investigate potential food-drug interactions in vitro.