Attenuation of Polycyclic Aromatic Hydrocarbon (PAH)-Induced Carcinogenesis and Tumorigenesis by Omega-3 Fatty Acids in Mice In Vivo.

Lung cancer is the leading cause of cancer death worldwide. Polycyclic aromatic hydrocarbons (PAHs) are metabolized by the cytochrome P450 (CYP)1A and 1B1 to DNA-reactive metabolites, which could lead to mutations in critical genes, eventually resulting in cancer. Omega-3 fatty acids, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are beneficial against cancers. In this investigation, we elucidated the mechanisms by which omega-3 fatty acids EPA and DHA will attenuate PAH-DNA adducts and lung carcinogenesis and tumorigenesis mediated by the PAHs BP and MC. Adult wild-type (WT) (A/J) mice, Cyp1a1-null, Cyp1a2-null, or Cyp1b1-null mice were exposed to PAHs benzo[a]pyrene (BP) or 3-methylcholanthrene (MC), and the effects of omega-3 fatty acid on PAH-mediated lung carcinogenesis and tumorigenesis were studied. The major findings were as follows: (i) omega-3 fatty acids significantly decreased PAH-DNA adducts in the lungs of each of the genotypes studied; (ii) decreases in PAH-DNA adduct levels by EPA/DHA was in part due to inhibition of CYP1B1; (iii) inhibition of soluble epoxide hydrolase (sEH) enhanced the EPA/DHA-mediated prevention of pulmonary carcinogenesis; and (iv) EPA/DHA attenuated PAH-mediated carcinogenesis in part by epigenetic mechanisms. Taken together, our results suggest that omega-3 fatty acids have the potential to be developed as cancer chemo-preventive agents in people.

Reciprocal control of obesity and anxiety-depressive disorder via a GABA and serotonin neural circuit.

The high comorbidity between obesity and mental disorders, such as depression and anxiety, often exacerbates metabolic and neurological symptoms significantly. However, neural mechanisms that underlie reciprocal control of feeding and mental states are largely elusive. Here we report that melanocortin 4 receptor (MC4R) neurons located in the dorsal bed nucleus of the stria terminus (dBNST) engage in the regulation of mentally associated weight gain by receiving GABAergic projections from hypothalamic AgRP neurons onto α5-containing GABAA receptors and serotonergic afferents onto 5-HT3 receptors. Chronic treatment with a high-fat diet (HFD) significantly blunts the hyperexcitability of AgRP neurons in response to not only hunger but also anxiety and depression-like stimuli. Such HFD-mediated desensitization reduces GABAergic outputs from AgRP neurons to downstream MC4RdBNST neurons, resulting in severe mental dysregulation. Genetic enhancement of the GABAAR-α5 or suppression of the 5-HT3R within the MC4RdBNST neurons not only abolishes HFD-induced anxiety and depression but also robustly reduces body weight by suppression of food intake. To gain further translational insights, we revealed that combined treatment of zonisamide (enhancing the GABAAR-α5 signaling) and granisetron (a selective 5-HT3R antagonist) alleviates mental dysfunction and yields a robust reversal of diet-induced obesity by reducing total calorie intake and altering food preference towards a healthy low-fat diet. Our results unveil a neural mechanism for reciprocal control of appetite and mental states, which culminates in a novel zonisamide-granisetron cocktail therapy for potential tackling the psychosis-obesity comorbidity.

Alterations to cardiac morphology and function among high-altitude workers: a retrospective cohort study.

OBJECTIVES: Exposure to high altitude can affect human health, including the development of adverse cardiovascular effects. This study aimed to investigate alterations in cardiac morphology and function in high-altitude workers and to identify risk factors associated with cardiac abnormalities. METHODS: A retrospective cohort study was conducted with 286 Qinghai-Tibetan Railroad maintenance workers. Participant data were collected from company personnel records. Data on echocardiography and diagnosis of cardiac abnormalities were extracted from participants' medical records. Time-to-event analysis was used to investigate the risk of cardiac abnormalities among participants with different baseline characteristics and identify risk factors associated with cardiac abnormalities that developed as a result of working at high altitude. RESULTS: A total of 173 participants had developed cardiac abnormalities during the follow-up period. The most common cardiac abnormality was right atrial enlargement, followed by left ventricular diastolic dysfunction and tricuspid regurgitation. Among participants with cardiac abnormalities, the median follow-up time was 17 months. Compared with participants who were younger than 20 years and working at altitude <4000 m, participants older at employment and working at extremely high altitude were more likely to develop cardiac abnormalities. Nearly 40% of the participants who worked at altitude <4000 m remained without cardiac abnormalities during the follow-up period. CONCLUSIONS: Over 60% of participants developed cardiac abnormalities after working at high altitude, predominantly right heart enlargement and left ventricular diastolic dysfunction. Age at employment and workplace altitude were significant risk factors for cardiac abnormalities. Enhanced regular physical examinations are recommended for high-altitude workers.

Functional Interrogation of the AgRP Neural Circuits in Control of Appetite, Body Weight, and Behaviors.

Neurons expressing agouti-related protein (AgRP), the so-called hunger neurons, protect mammals from starvation by promoting food-seeking behaviors (Trends Neurosci 36:504-512, 2013). Now an increasing amount of evidence show that these hunger-sensing neurons not only motivate animals to forage and ingest food but also help conserve energy by inhibiting innate processes that demand large amounts of energy such as growth, reproduction, and stress response. It has further been perceived that AgRP neurons transmit signals with negative valence to reward and cognitive centers so as to engage the motivational behavior toward seeking and obtaining foods (Physiol Behav 190:34-42, 2017). Recent advancement in genome editing and neurotechniques unleashed an escalated research of uniquely defined neuronal populations and neural circuits underlying the behavioral regulation of body weight and food responses (Nat Biotechnol 32:347-355, 2014; Proc Natl Acad Sci 113, 2016). In this chapter we will review literatures describing the functional organization of the AgRP circuit and its correlative signaling components that influence ingestive, foraging, motivational, and cognitive responses, a framework that reshaped our thinking toward the new hope and challenges in treatment of obesity and eating disorders.

Reversal of Obesity by Enhancing Slow-wave Sleep via a Prokineticin Receptor Neural Circuit.

Obese subjects often exhibit hypersomnia accompanied by severe sleep fragmentation, while emerging evidence suggests that poor sleep quality promotes overeating and exacerbates diet-induced obesity (DIO). However, the neural circuit and signaling mechanism underlying the reciprocal control of appetite and sleep is yet not elucidated. Here, we report a neural circuit where prokineticin receptor 2 (PROKR2)-expressing neurons within the parabrachial nucleus (PBN) of the brainstem received direct projections from neuropeptide Y receptor Y2 (NPY2R)-expressing neurons within the lateral preoptic area (LPO) of the hypothalamus. The RNA-Seq results revealed Prokr2 in the PBN is the most regulated GPCR signaling gene that is responsible for comorbidity of obesity and sleep dysfunction. Furthermore, those NPY2R LPO neurons are minimally active during NREM sleep and maximally active during wakefulness and REM sleep. Activation of the NPY2R LPO →PBN circuit or the postsynaptic PROKR2 PBN neurons suppressed feeding of a high-fat diet and abrogated morbid sleep patterns in DIO mice. Further studies showed that genetic ablation of the PROKR2 signaling within PROKR2 PBN neurons alleviated the hyperphagia and weight gain, and restored sleep dysfunction in DIO mice. We further discovered pterostilbene, a plant-derived stilbenoid, is a powerful anti-obesity and sleep-improving agent, robustly suppressed hyperphagia and promoted reconstruction of a healthier sleep architecture, thereby leading to significant weight loss. Collectively, our results unveil a neural mechanism for the reciprocal control of appetite and sleep, through which pterostilbene, along with a class of similarly structured compounds, may be developed as effective therapeutics for tackling obesity and sleep disorders.

Prenatal exposure to polycyclic aromatic hydrocarbons (PAHs) augments neonatal hyperoxic lung injury: Role of cytochrome P450 (CYP)1A1, 1A2, and 1B1.

Pregnant women exposed to polycyclic aromatic hydrocarbons (PAHs) are at increased risk for premature delivery. Premature infants often require supplemental oxygen, a known risk factor for bronchopulmonary dysplasia (BPD). Cytochrome P450 (CYP) enzymes have been implicated in hyperoxic lung injury. We hypothesize that prenatal PAH exposure exacerbates oxygen-mediated lung injury in neonatal mice, and that this effect is differentially altered in mice lacking the gene for (Cyp)1a1, 1a2, or 1b1. Timed pregnant wild type (WT) (C57BL/6J) mice were orally administered a PAH mixture of benzo[a]pyrene (BP) and benzo[b]fluoranthene (BbF) or the vehicle corn oil (CO) once daily on gestational days 16-19, and the dose response on postnatal lung injury was examined. In addition, timed pregnant mice with one of four genotypes, WT, Cyp1a1-null, Cyp1a2-null, and Cyp1b1-null, were treated orally with CO or PAH on gestational days 16-19 and exposed to hyperoxia or room air for 14 days. Lung injury was assessed on PND15 by radial alveolar count (RAC) and mean linear intercept (MLI) Gene expression of DNA repair genes in lung and liver were measured. Results showed that neonatal hyperoxic lung injury is augmented by prenatal PAH exposure in a dose-dependent manner. This effect was differentially altered in the Cyp-null mice, with Cyp1a2-null showing the greatest extent of lung injury. We concluded that newborn mice exposed to PAH in utero had more significant lung injury in response to hyperoxia than non-PAH exposed pups, and that CYP1A1 and CYP1A2 are protective against lung injury while CYP1B1 augments lung injury.

Impact of dietary plant flavonoids on 7,8-dihydroxyflavone transepithelial transport in human intestinal Caco-2 cells.

7,8-dihydroxyflavone (7,8-DHF) is a biologically active flavone with various physiological activities, including neuroprotection, anti-inflammation, and weight loss. Previous studies have found that the efflux protein P-glycoprotein (P-gp) significantly affects the transepithelial transport of 7,8-DHF in the intestine, resulting in its low oral bioavailability. Based on this, in this study, a Caco-2 monolayer cell model was used to investigate 14 dietary plant flavonoids as potential P-gp inhibitors, and their effects on the transepithelial transport and in vitro digestion of 7,8-DHF were explored. The results showed that among the 14 plant flavonoids, hesperetin, epigallocatechin gallate, fisetin, kaempferol, quercetin, and isoorientin increased and the apparent permeability coefficients (P app) of 7,8-DHF at AP → BL direction and lowered P app value at BL → AP direction to varying degrees, reducing the efflux ratio of 7,8-DHF less than 1.5. In particular, kaempferol and quercetin exhibited the best effect on promoting the transepithelial transport of 7,8-DHF, especially when used at molar concentration ratios of 1:1 and 1:2 with 7,8-DHF. This is beneficial for improving the oral bioavailability of 7,8-DHF. Meanwhile, 7,8-DHF was found to maintain structural stability in simulated saliva, gastric juice, and intestinal juice, and its stability was not affected by the coexistence of quercetin and kaempferol. Overall, this study provided a theoretical basis for seeking natural and safe P-gp inhibitors to improve the oral absorption of natural products.

Loss of cytochrome P450 (CYP)1B1 mitigates hyperoxia response in adult mouse lung by reprogramming metabolism and translation.

Oxygen supplementation is life saving for premature infants and for COVID-19 patients but can induce long-term pulmonary injury by triggering inflammation, with xenobiotic-metabolizing CYP enzymes playing a critical role. Murine studies showed that CYP1B1 enhances, while CYP1A1 and CYP1A2 protect from, hyperoxic lung injury. In this study we tested the hypothesis that Cyp1b1-null mice would revert hyperoxia-induced transcriptomic changes observed in WT mice at the transcript and pathway level. Wild type (WT) C57BL/6J and Cyp1b1-null mice aged 8-10 weeks were maintained in room air (21% O2) or exposed to hyperoxia (>95% O2) for 48h. Transcriptomic profiling was conducted using the Illumina microarray platform. Hyperoxia exposure led to robust changes in gene expression and in the same direction in WT, Cyp1a1-, Cyp1a2-, and Cyp1b1-null mice, but to different extents for each mouse genotype. At the transcriptome level, all Cyp1-null murine models reversed hyperoxia effects. Gene Set Enrichment Analysis identified 118 hyperoxia-affected pathways mitigated only in Cyp1b1-null mice, including lipid, glutamate, and amino acid metabolism. Cell cycle genes Cdkn1a and Ccnd1 were induced by hyperoxia in both WT and Cyp1b1-null mice but mitigated in Cyp1b1-null O2 compared to WT O2 mice. Hyperoxia gene signatures associated positively with bronchopulmonary dysplasia (BPD), which occurs in premature infants (with supplemental oxygen being one of the risk factors), but only in the Cyp1b1-null mice did the gene profile after hyperoxia exposure show a partial rescue of BPD-associated transcriptome. Our study suggests that CYP1B1 plays a pro-oxidant role in hyperoxia-induced lung injury.

Attenuation of Polycyclic Aromatic Hydrocarbon (PAH)-Mediated Pulmonary DNA Adducts and Cytochrome P450 (CYP)1B1 by Dietary Antioxidants, Omega-3 Fatty Acids, in Mice.

Numerous human and animal studies have reported positive correlation between carcinogen-DNA adduct levels and cancer occurrence. Therefore, attenuation of DNA adduct levels would be expected to suppress tumorigenesis. In this investigation, we report that the antioxidants omega 3-fatty acids, which are constituents of fish oil (FO), significantly decreased DNA adduct formation by polycyclic aromatic hydrocarbons (PAHs). B6C3F1 male mice were fed an FO or corn oil (CO) diet, or A/J male mice were pre-fed with omega-3 fatty acids eicosapentaenoic acid (EPA) and/or docosahexaenoic acid (DHA). While the B6C3F1 mice were administered two doses of a mixture of seven carcinogenic PAHs including benzo(a)pyrene (BP), the A/J mice were treated i.p. with pure benzo[a]pyrene (BP). Animals were euthanized after 1, 3, or 7 d after PAH treatment. DNA adduct levels were measured by the 32P-postlabeling assay. Our results showed that DNA adduct levels in the lungs of mice 7 d after treatment were significantly decreased in the FO or EPA/DHA groups compared with the CO group. Interestingly, both qPCR and Western blot analyses revealed that FO, DHA and EPA/DHA significantly decreased the expression of cytochrome P450 (CYP) 1B1. CYP1B1 plays a critical role in the metabolic activation of BP to DNA-reactive metabolites. qPCR also showed that the expression of some metabolic and DNA repair genes was induced by BP and inhibited by FO or omega-3 fatty acids in liver, but not lung. Our results suggest that a combination of mechanism entailing CYP1B1 inhibition and the modulation of DNA repair genes contribute to the attenuation of PAH-mediated carcinogenesis by omega 3 fatty acids.

A hindbrain dopaminergic neural circuit prevents weight gain by reinforcing food satiation.

The neural circuitry mechanism that underlies dopaminergic (DA) control of innate feeding behavior is largely uncharacterized. Here, we identified a subpopulation of DA neurons situated in the caudal ventral tegmental area (cVTA) directly innervating DRD1-expressing neurons within the lateral parabrachial nucleus (LPBN). This neural circuit potently suppresses food intake via enhanced satiation response. Notably, this cohort of DAcVTA neurons is activated immediately before the cessation of each feeding bout. Acute inhibition of these DA neurons before bout termination substantially suppresses satiety and prolongs the consummatory feeding. Activation of postsynaptic DRD1LPBN neurons inhibits feeding, whereas genetic deletion of Drd1 within the LPBN causes robust increase in food intake and subsequent weight gain. Furthermore, the DRD1LPBN signaling manifests the central mechanism in methylphenidate-induced hypophagia. In conclusion, our study illuminates a hindbrain DAergic circuit that controls feeding through dynamic regulation in satiety response and meal structure.

A Comparative Study of Colour Effects on Cognitive Performance in Real-World and VR Environments.

This research explores the influence of colour on cognitive performance and intellectual abilities (i.e., logical and lateral thinking abilities and people's attention to detail) in a conventional laboratory setting and an approximately identical virtual reality (VR) environment. Comparative experiments using psychological methods were carried out in both settings to explore the impact of immersive colour experience. This work builds on earlier studies that suggest that the VR environment enhances user experiences, with results evidencing that a considered approach to colour design can trigger a positive impact on user engagement. The experiments further evaluated the positive effects of immersive colour stimuli in VR by evaluating participants' logical and lateral thinking abilities, as well as their attention to detail. Their response time and error rate when completing each psychometric test were recorded with different hue backgrounds in both environments. The data collected from participants reveal the differential impacts of colour between the reality setting using standard colour imaging displays and in an approximately identical VR environment. Analysis of the psychometric tests shows the differential influence of colours on logical and lateral thinking abilities and people's attention to detail between the physical environment and the VR environment. Our findings add to the data demonstrating that a well-designed immersive colour experience in VR can trigger positive user engagement and, as explored in this study, improve cognitive performance. This again positions immersive colour experience as an important design tool to be fully considered in the creation of effective VR research and applications.

Aroused and Impulsive Effects of Colour Stimuli on Lateral and Logical Abilities.

The purpose of this study was to explore the influence of environmental colour on people's lateral and logical abilities. This was done by evaluating study participants' response time and error rate when completing six types of psychometric tests that were performed in various hue backgrounds on a computer. To maximise the colour stimulation provided by the monitor, the experiment was carried out in a dark laboratory. Analysis of participants' response time and error rate showed that different colours could significantly influence arousal and impulsiveness, which suggests that colour has indirect impacts on cognitive abilities. Further analysis revealed that different colours had various effects depending on the type of psychometric test given. These findings suggest that future research on environmental design should consider how to effectively use colour to impact people's performance and behaviour.

Development, Characterization, Stability and Bioaccessibility Improvement of 7,8-Dihydroxyflavone Loaded Zein/Sophorolipid/Polysaccharide Ternary Nanoparticles: Comparison of Sodium Alginate and Sodium Carboxymethyl Cellulose.

In this study, two polysaccharides [sodium alginate (ALG) and sodium carboxymethyl cellulose (CMC)] were selected to establish zein/sophorolipid/ALG (ALG/S/Z) and zein/sophorolipid/ALG (CMC/S/Z) nanoparticles to encapsulate 7,8-dihydroxyflavone (7,8-DHF), respectively. The results showed that polysaccharide types significantly affected performance of ternary nanoparticles, including CMC/S/Z possessed lower polydispersity index, particle size and turbidity, but higher zeta potential, encapsulation efficiency and loading capacity compared to ALG/S/Z. Compared to zein/sophorolipid nanoparticles (S/Z), both ALG/S/Z and CMC/S/Z had better stability against low pH (pH 3~4) and high ionic strengths (150~200 mM NaCl). Hydrophobic effects, electrostatic interactions and hydrogen bonding were confirmed in ternary nanoparticles fabrication via Fourier-transform infrared spectroscopy. Circular dichroism revealed that CMC and ALG had no evident impact on secondary structure of zein in S/Z, but changed surface morphology of S/Z as observed by scanning electron microscope. Encapsulated 7,8-DHF exhibited an amorphous state in ternary nanoparticles as detected by X-ray diffraction and differential scanning calorimetry. Furthermore, compared to S/Z, ALG/S/Z, and CMC/S/Z remarkably improved the storage stability and bioaccessibility of 7,8-DHF. CMC/S/Z possessed a greater storage stability for 7,8-DHF, however, ALG/S/Z exhibited a better in vitro bioaccessibility of 7,8-DHF. This research provides a theoretical reference for zein-based delivery system application.

Establishment and Characterization of Stable Zein/Glycosylated Lactoferrin Nanoparticles to Enhance the Storage Stability and in vitro Bioaccessibility of 7,8-Dihydroxyflavone.

In this work, the lactoferrin (LF) was glycosylated by dextran (molecular weight 10, 40, and 70 kDa, LF 10K, LF 40K, and LF 70K) via Maillard reaction as a stabilizer to establish zein/glycosylated LF nanoparticles and encapsulate 7,8-dihydroxyflavone (7,8-DHF). Three zein/glycosylated LF nanoparticles (79.27-87.24 nm) with low turbidity (<0.220) and polydispersity index (PDI) (<0.230) were successfully established by hydrophobic interactions and hydrogen bonding. Compared with zein/LF nanoparticles, zein/glycosylated LF nanoparticles further increased stability to ionic strength (0-500 mM NaCl) at low pH conditions. Zein/glycosylated LF nanoparticles had nanoscale spherical shape and glycosylated LF changed surface morphology of zein nanoparticles. Besides, encapsulated 7,8-DHF exhibited an amorphous state inside zein/glycosylated LF nanoparticles. Most importantly, zein/glycosylated LF nanoparticles had good water redispersibility, high encapsulation efficiency (above 98.50%), favorable storage stability, and bioaccessibility for 7,8-DHF, particularly LF 40K. Collectively, the above research provides a theoretical reference for the application of zein-based delivery systems.

Deciphering an AgRP-serotoninergic neural circuit in distinct control of energy metabolism from feeding.

Contrasting to the established role of the hypothalamic agouti-related protein (AgRP) neurons in feeding regulation, the neural circuit and signaling mechanisms by which they control energy expenditure remains unclear. Here, we report that energy expenditure is regulated by a subgroup of AgRP neurons that send non-collateral projections to neurons within the dorsal lateral part of dorsal raphe nucleus (dlDRN) expressing the melanocortin 4 receptor (MC4R), which in turn innervate nearby serotonergic (5-HT) neurons. Genetic manipulations reveal a bi-directional control of energy expenditure by this circuit without affecting food intake. Fiber photometry and electrophysiological results indicate that the thermo-sensing MC4RdlDRN neurons integrate pre-synaptic AgRP signaling, thereby modulating the post-synaptic serotonergic pathway. Specifically, the MC4RdlDRN signaling elicits profound, bi-directional, regulation of body weight mainly through sympathetic outflow that reprograms mitochondrial bioenergetics within brown and beige fat while feeding remains intact. Together, we suggest that this AgRP neural circuit plays a unique role in persistent control of energy expenditure and body weight, hinting next-generation therapeutic approaches for obesity and metabolic disorders.

Formation, structural characterization, stability and in vitro bioaccessibility of 7,8-dihydroxyflavone loaded zein-/sophorolipid composite nanoparticles: effect of sophorolipid under two blending sequences.

Anti-solvent co-precipitation (ASCP) is the most commonly used method of fabricating food-grade nanoparticles, while the impact of the blending sequence on the formation of nanoparticles lacks research. In this study, 7,8-dihydroxyflavone (7,8-DHF) loaded zein-/sophorolipid nanoparticles with two blending sequences (DHF-Z-S and DHF-Z/S) were successfully fabricated by the ASCP method and used to improve the storage stability and the in vitro bioaccessibility of 7,8-DHF. The results showed that blending sequences significantly affect the physicochemical properties of nanoparticles. DHF-Z-S nanoparticles had smaller particle size, lower polydispersity index and turbidity, and higher negative charge, entrapment efficiency and loading capacity compared to DHF-Z/S nanoparticles. Transmission electron microscopy and scanning electron microscopy revealed that DHF-Z-S and DHF-Z/S nanoparticles have core-shell spherical shape at the nanoscale and sophorolipid changed the surface morphology of zein nanoparticles. Fourier transform infrared spectroscopy and fluorescence spectrum analysis confirmed the presence of effective hydrogen bonding, electrostatic interactions and hydrophobic effects between 7,8-DHF, zein and sophorolipid and the presence of stronger hydrogen bonding and hydrophobic effects in DHF-Z-S nanoparticles. The encapsulated 7,8-DHF was in an amorphous state rather than a crystalline form as determined by X-ray diffraction analysis. Circular dichroism revealed that 7,8-DHF and sophorolipid were capable of changing the secondary structure of zein remarkably. More importantly, compared to DHF-Z/S nanoparticles, the DHF-Z-S nanoparticles possessed higher storage stability and in vitro bioaccessibility. Collectively, DHF-Z-S nanoparticles developed in this study might be a promising means of encapsulating, protecting and delivering hydrophobic nutraceuticals for applications in functional foods.

Fabrication and characterization of zein/lactoferrin composite nanoparticles for encapsulating 7,8-dihydroxyflavone: Enhancement of stability, water solubility and bioaccessibility.

7,8-dihydroxyflavone (7,8-DHF), a tyrosine kinase B (TrkB) receptor agonist, can mimick physiological actions of brain-derived neurotrophic factor (BDNF) to attenuate neurogenic disease. However, its use as a functional food, is limited by its low-water solubility, chemical instability, and poor bioavailability. The purpose of this work is to fabricate stable 7,8-DHF loaded zein/lactoferrin (LF) composite nanoparticles (zein/LF-DHF) to overcome these challenges. Results showed that mean particle size of zein/LF nanoparticles was about 74 nm with low polydispersity index (<0.200) and turbidity (<0.300) values. Zein/LF nanoparticles had good stability against pH (3.0-9.0), ionic strengths (0-500 mM NaCl at neutral pH) and long-term storage. Zein/LF nanoparticles showed spherical structures formed by hydrogen bonding and hydrophobic interactions, however, LF changed surface morphology of zein nanoparticles as observed by scanning electron microscope. X-ray diffraction indicated 7,8-DHF was presented in an amorphous state inside zein/LF nanoparticles. Most importantly, zein/LF-DHF had good redispersibility, and increased the encapsulation efficiency, chemical stability, water solubility and bioaccessibility of 7,8-DHF. Collectively, zein/LF nanoparticles are promising delivery systems for 7,8-DHF in functional foods.

Transepithelial transport mechanisms of 7,8-dihydroxyflavone, a small molecular TrkB receptor agonist, in human intestinal Caco-2 cells.

7,8-Dihydroxyflavone (7,8-DHF), as a high-affinity TrkB receptor agonist, has been extensively explored in many human disorders involving brain-derived neurotrophic factor (BDNF) such as Alzheimer's disease, Parkinson's disease, depression, and obesity. However, to date, the transepithelial transport mechanisms of 7,8-DHF in the intestines remain unclear. The aim of our work was to quantify and to characterize in vitro transport of naturally occurring 7,8-DHF distinguished by its physicochemical and pharmacological properties. We discussed the transport mechanisms of 7,8-DHF using the Caco-2 cell model to determine the bi-directional permeability with different environmental factors (time, concentration, pH, metabolic inhibitors etc.). The influx and efflux characteristics of 7,8-DHF were also clarified. 7,8-DHF was poorly transported across Caco-2 cell monolayers by mainly passive diffusion via a transcellular pathway and not a paracellular pathway. The transport of 7,8-DHF was time and concentration-dependent in both the apical (AP) to basolateral (BL) side and the reverse direction. Interestingly, decreasing the pH from 7.4 to 6.0 markedly enhanced 7,8-DHF transport. It is noteworthy that 7,8-DHF transport was strongly inhibited by metabolic inhibitors and was highly dependent on temperature. The efflux ratio (ER) values at different concentrations were all above 1.5, indicating the existence of the efflux transporter. We found that breast cancer resistance protein (BCRP) was not involved in 7,8-DHF secretion and that the transport mechanism of 7,8-DHF was passive transport with an active efflux mediated by P-glycoprotein (P-gp) and multidrug resistance associated proteins (MRPs), particularly MRP 2. Moreover, the use of various influx transporter inhibitors in Caco-2 cells showed that organic cation transporters (OCTs) and organic anion-transporting polypeptides (OATPs) participated in 7,8-DHF transport. Taken together, the elucidated transport characteristics of 7,8-DHF provide useful information for designing novel and efficient delivery systems and avoiding food-food or food-drug interactions.

Tannase-mediated biotransformation assisted separation and purification of theaflavin and epigallocatechin by high speed counter current chromatography and preparative high performance liquid chromatography: A comparative study.

A large scale isolation and purification of theaflavin (TF) and epigallocatechin (EGC) has been successfully developed by tannase-mediated biotransformation combining high-speed countercurrent chromatography. After tannase hydrolysis of a commercially available theaflavins extract (TE), the content of TF and EGC in tannase-mediated biotransformation product (TBP) achieved approximately 3 times enrichment. SEM studies revealed smooth tannase biotransformation and the possibility of recovery of the tannase. A single 1.5 hours' HSCCC separation for TF and EGC employing a two-phase solvent system could simultaneously produce 180.8 mg of 97.3% purity TF and 87.5 mg of 97.3% purity EGC. However, a preparative HPLC separation of maximum injection volume containing 120 mg TBP prepared 11.2 mg TF of 94.9% purity and 7.7 mg EGC of 89.9% purity. HSCCC separation demonstrated significant advantages over Prep HPLC in terms of sample loading size, separation time, environmental friendly solvent systems, and the production.

Simultaneous preparation of naturally abundant and rare catechins by tannase-mediated biotransformation combining high speed counter current chromatography.

Simultaneous preparation of naturally rare catechins, EGC and EC, has been realized by tannase-mediated biotransformation combining high speed counter current chromatography. In addition, simultaneous preparation of the four catechins, EGCG, ECG, EGC, and EC in green tea extract has also been achieved by HSCCC under the normal phase and the reversed phase modes. The identity of the catechins was determined by HPLC-DAD-ESI-MS and quantification of the catechins was performed by HPLC-DAD. In a typical HSCCC separation, 27.2 mg 98.8% EGCG, 14.1 mg 94.7% EGC, and 9.3 mg 97.5% EC were obtained. This new method is efficient, time-saving and valuable for biological studies.