Citrus flavonoids suppress IL-5 and ROS through distinct pathways in PMA/ionomycin-induced EL-4 cells

Natural flavonoid hesperetin blocks amyloid β-protein fibrillogenesis, depolymerizes preformed fibrils and alleviates cytotoxicity caused by amyloids

The aggregation of β-amyloid (Aβ) peptides to form amyloid plaques is one of the primary hallmarks for Alzheimer's disease (AD). Dietary flavonoid supplements containing hesperetin have an ability to decline the risk of developing AD, but the molecular mechanism is still unclear. In this work, hesperetin, a flavanone abundant in citrus fruits, has been proven to prevent the formation of Aβ aggregates and depolymerized preformed fibrils in a concentration-dependent fashion. Hesperetin inhibited the conformational conversion from the natural structure to a β-sheet-rich conformation. It was found that hesperetin significantly reduced the cytotoxicity and relieved oxidative stress eventuated by Aβ aggregates in a concentration-dependent manner. Additionally, the beneficial effects of hesperetin were confirmed in Caenorhabditis elegans, including the inhibition of the formation and deposition of Aβ aggregates and extension of their lifespan. Finally, the results of molecular dynamics simulations showed that hesperetin directly interacted with an Aβ42 pentamer mainly through strong non-polar and electrostatic interactions, which destroyed the structural stability of the preformed pentamer. To summarize, hesperetin exhibits great potential as a prospective dietary supplement for preventing and improving AD.

Evaluation of the Multifunctionality of Soybean Proteins and Peptides in Immune Cell Models

Inflammatory and oxidative processes are tightly regulated by innate and adaptive immune systems, which are involved in the pathology of a diversity of chronic diseases. Soybean peptides, such as lunasin, have emerged as one of the most hopeful food-derived peptides with a positive impact on health. The aim was to study the potential antioxidant and immunomodulatory activity of a lunasin-enriched soybean extract (LES). The protein profile of LES was characterized, and its behavior under simulated gastrointestinal digestion was evaluated. Besides its in vitro radical scavenging capacity, LES and lunasin's effects on cell viability, phagocytic capacity, oxidative stress, and inflammation-associated biomarkers were investigated in both RAW264.7 macrophages and lymphocytes EL4. Lunasin and other soluble peptides enriched after aqueous solvent extraction partially resisted the action of digestive enzymes, being potentially responsible for the beneficial effects of LES. This extract scavenged radicals, reduced reactive oxygen species (ROS) and exerted immunostimulatory effects, increasing nitric oxide (NO) production, phagocytic activity, and cytokine release in macrophages. Lunasin and LES also exerted dose-dependent immunomodulatory effects on EL4 cell proliferation and cytokine production. The modulatory effects of soybean peptides on both immune cell models suggest their potential protective role against oxidative stress, inflammation, and immune response-associated disorders.

Recent developments in citrus bioflavonoid encapsulation to reinforce controlled antioxidant delivery and generate therapeutic uses: Review

Citrus fruits contain numerous antioxidative biomolecules including phenolic acids, flavonols, flavanones, polymethoxyflavones (PMFs), and their derivatives. Previous in vitro and in vivo studies thoroughly investigated the antioxidant and therapeutic potential of bioflavonoids extracted from different citrus varieties and fruit fractions. Major bioflavonoids such as hesperidin, naringin, naringenin, and PMFs, had restricted their incorporation into food and health products due to their poor solubility, chemical stability and bioavailability. Considering these limitations, modern encapsulation methodologies such as hydrogelation, liposomal interactions, emulsifications, and nanoparticles have been designed to shield bioflavonoids with improved target distribution for therapeutic enhancements. The size, durability, and binding efficiency of bioflavonoid-loaded encapsulates were acquired by the optimized chemical and instrumental parameters such as solubility, gelation, dispersion, extrusion, and drying. Bioflavonoid-enriched encapsulates have been also proven to be effective against cancer, inflammation, neurodegeneration, and various other illnesses. However, in the future, newer natural binding agents with higher binding capacity might accelerate the encapsulating potential, controlled release, and enhanced bioavailability of citrus bioflavonoids. Overall, these modern encapsulation systems are currently leading to a new era of diet-based medicine, as demand for citrus fruit-based nutritional supplements and edibles grows.

The Chemistry and the Anti-Inflammatory Activity of Polymethoxyflavonoids from Citrus Genus

Polymethoxyflavonoids (PMFs) are a large group of compounds belonging to the more general class of flavonoids that possess a flavan carbon framework decorated with a variable number of methoxy groups. Hydroxylated polymethoxyflavonoids (HPMFs), instead, are characterized by the presence of both hydroxyl and methoxy groups in their structural unities. Some of these compounds are the aglycone part in a glycoside structure in which the glycosidic linkage can involve the -OH at various positions. These compounds are particular to Citrus genus plants, especially in fruits, and they are present mainly in the peel. A considerable number of PMFs and HPMFs have shown promising biological activities and they are considered to be important nutraceuticals, responsible for some of the known beneficial effects on health associated with a regular consumption of Citrus fruits. Among their several actions on human health, it is notable that the relevant contribution in controlling the intracellular redox imbalance is associated with the inflammation processes. In this work, we aim to describe the status concerning the chemical identification and the anti-inflammatory activity of both PMFs and HPMFs. In particular, all of the chemical entities unambiguously identified by isolation and complete NMR analysis, and for which a biochemical evaluation on the pure compound was performed, are included in this paper.

Traditional Chinese medicine Tongxie Yaofang treating irritable bowel syndrome with diarrhea and type 2 diabetes mellitus in rats with liver-depression and spleen-deficiency: A preliminary study

Tongxie Yaofang (TXYF), a Traditional Chinese Medicine (TCM) with four components as follows: Rhizoma Atractylodis Macrocephalae (baizhu), Radix Paeoniae Alba (baishao), Pericarpium Citri Reticulatae (chenpi) and Radix Saposhnikovia Divaricata (fangfeng), benefits irritable bowel syndrome (IBS). Nonetheless, proofs of this formula ameliorating D-IBS and T2DM are required. This research aimed at investigating the efficacy of TXYF in treating inflammation in rats with D-IBS and T2DM using animal models. In this study, gavage with high-fat diet, fasciculation, and senna was given to develop rat models with target diseases. To determine intestinal inflammations, major inflammatory factors, and intestinal permeability proteins, H&E staining, ELISA, and immunohistochemistry methods were employed, respectively. This study also utilized Western blot to discover potential inflammatory targets. Results of this research illustrates that TXYF treatment reduced the level of TNF-α, IL-1β, and IL-6, and raised the IL-10 concentration in liver-depressed spleende ficient rats with D-IBS and T2DM, indicating controlled inflammatory reactions. Staining analysis also showed improved disease states of animal models. Furthermore, efficient rebounds of claudin-1, an intestinal permeability-associated protein, were detected. Moreover, TXYF may treat D-IBS and T2DM in rats via the rage pathway.

Bioactive Compounds of Citrus Fruits: A Review of Composition and Health Benefits of Carotenoids, Flavonoids, Limonoids, and Terpenes

The increased consumption of fruits, vegetables, and whole grains contributes to the reduced risk of many diseases related to metabolic syndrome, including neurodegenerative diseases, cardiovascular disease (CVD), diabetes, and cancer. Citrus, the genus Citrus L., is one of the most important fruit crops, rich in carotenoids, flavonoids, terpenes, limonoids, and many other bioactive compounds of nutritional and nutraceutical value. Moreover, polymethoxylated flavones (PMFs), a unique class of bioactive flavonoids, abundantly occur in citrus fruits. In addition, citrus essential oil, rich in limonoids and terpenes, is an economically important product due to its potent antioxidant, antimicrobial, and flavoring properties. Mechanistic, observational, and intervention studies have demonstrated the health benefits of citrus bioactives in minimizing the risk of metabolic syndrome. This review provides a comprehensive view of the composition of carotenoids, flavonoids, terpenes, and limonoids of citrus fruits and their associated health benefits.

Isosinensetin alleviates the injury of human bronchial epithelial cells induced by PM2.5

Flavonoids which are extracted from citrus peel and pulp have been reported to have multiple beneficial effects on human health. Isosinensetin (ISO) is a type of flavonoid compound, which has several protective effects including anticancer, antioxidant, antiviral, anti-inflammatory and bacteriostatic. However, the molecular mechanism of its antioxidant and anti-inflammatory effects remain unclear. The present study aimed to investigate the intervention effect and possible mechanism of ISO on human bronchial epithelial cells injured by fine particular matter ≤2.5 µm in diameter (PM_2.5). In the present study, the cell viability was detected by Cell Counting Kit-8 method. The levels of pro-inflammatory cytokines were analyzed by ELISA. The level of reactive oxygen species (ROS) was detected by fluorescence probe. The expression levels of proliferating cell nuclear antigen (PCNA), nuclear factor erythroid 2-related factor 2 (Nrf2) and nuclear factor кΒ (NF-кB) proteins were detected by western blotting. The results revealed that ISO evidently increased the viability of 16-HBE cells and sharply decreased the levels of pro-inflammatory factors in cell culture supernatant. ISO significantly inhibited ROS release caused by PM_2.5. Moreover, the expression levels of PCNA, Nrf2 and NF-кB proteins were downregulated after ISO incubation. These results indicated that ISO alleviated 16-HBE-cell injury by PM_2.5 through the ROS-Nrf2/NF-кB signaling pathway.

The Role of Respiratory Flora in the Pathogenesis of Chronic Respiratory Diseases

Large quantities of bacteria, including Firmicutes, Actinobacteria, and Bacteroidetes, colonize the surface of the respiratory mucosa of healthy people. They interact and coexist with the local mucosal immune system of the human airway, maintaining the immune stability and balance of the respiratory system. While suffering from chronic respiratory diseases, the microbial population in the airway changes and the proportion of Proteobacteria is increased in patients with asthma. The abundance of the microbial population in patients with chronic obstructive pulmonary disease (COPD) is decreased, and conversely, the proportion of Firmicutes and Proteobacteria increased. The diversity of airway microorganisms in cystic fibrosis (CF) patients is decreased, while pathogenic bacteria and conditional pathogenic bacteria are proliferated in large numbers. The proportion of Firmicutes and Proteobacteria is increased in patients with upper airway cough syndrome (UACS), which replaces the dominance of Streptococcus and Neisseria in the pharynx of a normal population. Therefore, a clear understanding of the immune process of the airway flora and the immune dysfunction of the flora on the pathogenesis of chronic respiratory diseases can provide new ideas for the prevention and treatment of human respiratory diseases.

GardeninA confers neuroprotection against environmental toxin in a Drosophila model of Parkinson's disease

Parkinson’s disease is an age-associated neurodegenerative disorder characterized by the progressive loss of dopaminergic neurons from the midbrain. Epidemiological studies have implicated exposures to environmental toxins like the herbicide paraquat as major contributors to Parkinson’s disease etiology in both mammalian and invertebrate models. We have employed a paraquat-induced Parkinson’s disease model in Drosophila as an inexpensive in vivo platform to screen therapeutics from natural products. We have identified the polymethoxyflavonoid, GardeninA, with neuroprotective potential against paraquat-induced parkinsonian symptoms involving reduced survival, mobility defects, and loss of dopaminergic neurons. GardeninA-mediated neuroprotection is not solely dependent on its antioxidant activities but also involves modulation of the neuroinflammatory and cellular death responses. Furthermore, we have successfully shown GardeninA bioavailability in the fly heads after oral administration using ultra-performance liquid chromatography and mass spectrometry. Our findings reveal a molecular mechanistic insight into GardeninA-mediated neuroprotection against environmental toxin-induced Parkinson’s disease pathogenesis for novel therapeutic intervention.

Maitra and colleagues identify the neuroprotective properties of GardeninA against environmental toxin-induced neurodegeneration in Drosophila. This study has the potential to influence future research into toxin-induced Parkinson’s disease pathogenesis.

Citrus flavonoids and their antioxidant evaluation

The antioxidant ability is the link and bridge connecting a variety of biological activities. Citrus flavonoids play an essential role in regulating oxidative stress and are an important source of daily intake of antioxidant supplements. Many studies have shown that citrus flavonoids promote health through antioxidation. In this review, the biosynthesis, composition and distribution of citrus flavonoids were concluded. The detection methods of antioxidant capacity of citrus flavonoids were divided into four categories: chemical, cellular, animal and clinical antioxidant capacity evaluation systems. The modeling methods, applicable scenarios, and their relative merits were compared based on these four systems. The antioxidant functions of citrus flavonoids under different evaluation systems were also discussed, especially the regulation of the Nrf2-antioxidases pathway. Some shortcomings in the current research were pointed out, and some suggestions for progress were put forward.