Pharmacological Activity of Eriodictyol: The Major Natural Polyphenolic Flavanone

Artemisia argyi extracts overcome lapatinib resistance via enhancing TMPRSS2 activation in HER2-positive breast cancer

Breast cancer stands as the predominant malignancy and primary cause of cancer-related mortality among females globally. Approximately 25% of breast cancers exhibit HER2 overexpression, imparting a more aggressive tumor phenotype and correlating with poor prognoses. Patients with metastatic breast cancer receiving HER2 tyrosine kinase inhibitors (HER2 TKIs), such as Lapatinib, develop acquired resistance within a year, posing a critical challenge in managing this disease. Here, we explore the potential of Artemisia argyi, a Chinese herbal medicine known for its anti-cancer properties, in mitigating HER2 TKI resistance in breast cancer. Analysis of the Cancer Genome Atlas (TCGA) revealed diminished expression of transmembrane serine protease 2 (TMPRSS2), a subfamily of membrane proteolytic enzymes, in breast cancer patients, correlating with unfavorable outcomes. Intriguingly, lapatinib-responsive patients exhibited higher TMPRSS2 expression. Our study unveiled that the compounds from Artemisia argyi, eriodictyol, and umbelliferone could inhibit the growth of lapatinib-resistant HER2-positive breast cancer cells. Mechanistically, they suppressed HER2 kinase activation by enhancing TMPRSS2 activity. Our findings propose TMPRSS2 as a critical determinant in lapatinib sensitivity, and Artemisia argyi emerges as a potential agent to overcome lapatinib via activating TMPRSS2 in HER2-positive breast cancer. This study not only unravels the molecular mechanisms driving cell death in HER2-positive breast cancer cells induced by Artemisia argyi but also lays the groundwork for developing novel inhibitors to enhance therapy outcomes.

Bioactivity of 2-(3,4-Dihydroxyphenyl)-5,7-dihydroxy-2,3-dihydrochromen-4-one from pistacia chinensis on ENPP1 and aldose reductase

Pistacia chinensis is used as a decorative tree and currently studied as a source of biofuels. Besides, its parts and extracts are endowed with several therapeutic uses which have been widely explored in traditional medicine and that are related to its rich composition in phytochemicals. Molecular docking and enzymatic inhibition tests were used to study the activity of eriodictyol, a flavonoid extracted from the barks of P. chinensis, against ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) and aldose reductase (ALR2). The compound was highlighted as a micromolar inhibitor in vitro (IC50 = 263.76 ± 1.32 µM and 4.21 ± 0.94 µM, respectively) and docking showed that eriodictyol efficiently targets the binding sites of the enzymes. In conclusion, this study unveils the potential of eriodictyol on enzymes that are involved in immunostimulation and in complications of diabetes mellitus.

Dietary Polyphenols: Review on Chemistry/Sources, Bioavailability/Metabolism, Antioxidant Effects, and Their Role in Disease Management

Polyphenols, as secondary metabolites ubiquitous in plant sources, have emerged as pivotal bioactive compounds with far-reaching implications for human health. Plant polyphenols exhibit direct or indirect associations with biomolecules capable of modulating diverse physiological pathways. Due to their inherent abundance and structural diversity, polyphenols have garnered substantial attention from both the scientific and clinical communities. The review begins by providing an in-depth analysis of the chemical intricacies of polyphenols, shedding light on their structural diversity and the implications of such diversity on their biological activities. Subsequently, an exploration of the dietary origins of polyphenols elucidates the natural plant-based sources that contribute to their global availability. The discussion extends to the bioavailability and metabolism of polyphenols within the human body, unraveling the complex journey from ingestion to systemic effects. A central focus of the review is dedicated to unravelling the antioxidant effects of polyphenols, highlighting their role in combating oxidative stress and associated health conditions. The comprehensive analysis encompasses their impact on diverse health concerns such as hypertension, allergies, aging, and chronic diseases like heart stroke and diabetes. Insights into the global beneficial effects of polyphenols further underscore their potential as preventive and therapeutic agents. This review article critically examines the multifaceted aspects of dietary polyphenols, encompassing their chemistry, dietary origins, bioavailability/metabolism dynamics, and profound antioxidant effects. The synthesis of information presented herein aims to provide a valuable resource for researchers, clinicians, and health enthusiasts, fostering a deeper understanding of the intricate relationship between polyphenols and human health.

Flavonoids derived from medicinal plants as a COVID-19 treatment

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes COVID-19 disease. Through its viral spike (S) protein, the virus enters and infects epithelial cells by utilizing angiotensin-converting enzyme 2 as a host cell's receptor protein. The COVID-19 pandemic had a profound impact on global public health and economies. Although various effective vaccinations and medications are now available to prevent and treat COVID-19, natural compounds derived from medicinal plants, particularly flavonoids, demonstrated therapeutic potential to treat COVID-19 disease. Flavonoids exhibit dual antiviral mechanisms: direct interference with viral invasion and inhibition of replication. Specifically, they target key viral molecules, particularly viral proteases, involved in infection. These compounds showcase significant immunomodulatory and anti-inflammatory properties, effectively inhibiting various inflammatory cytokines. Additionally, emerging evidence supports the potential of flavonoids to mitigate the progression of COVID-19 in individuals with obesity by positively influencing lipid metabolism. This review aims to elucidate the molecular structure of SARS-CoV-2 and the underlying mechanism of action of flavonoids on the virus. This study evaluates the potential anti-SARS-CoV-2 properties exhibited by flavonoid compounds, with a specific interest in their structure and mechanisms of action, as therapeutic applications for the prevention and treatment of COVID-19. Nevertheless, a significant portion of existing knowledge is based on theoretical frameworks and findings derived from in vitro investigations. Further research is required to better assess the effectiveness of flavonoids in combating SARS-CoV-2, with a particular emphasis on in vivo and clinical investigations.

High-Level De Novo Production of (2S)-Eriodictyol in Yarrowia Lipolytica by Metabolic Pathway and NADPH Regeneration Engineering

(2S)-Eriodictyol, a polyphenolic flavonoid, has found widespread applications in health supplements and food additives. However, the limited availability of plant-derived (2S)-eriodictyol cannot meet the market demand. Microbial production of (2S)-eriodictyol faces challenges, including the low catalytic efficiency of flavone 3'-hydroxylase/cytochrome P450 reductase (F3'H/CPR), insufficient precursor supplementation, and inadequate NADPH regeneration. This study systematically engineered Yarrowia lipolytica for high-level (2S)-eriodictyol production. In doing this, the expression of F3'H/CPR was balanced, and the supply of precursors was enhanced by relieving feedback inhibition of the shikimate pathway, promoting fatty acid β-oxidation, and increasing the copy number of synthetic pathway genes. These strategies, combined with NADPH regeneration, achieved an (2S)-eriodictyol titer of 423.6 mg/L. Finally, in fed-batch fermentation, a remarkable 6.8 g/L (2S)-eriodictyol was obtained, representing the highest de novo microbial titer reported to date and paving the way for industrial production.

Systems Metabolic Engineering of Saccharomyces cerevisiae for the High-Level Production of (2S)-Eriodictyol

(2S)-eriodictyol (ERD) is a flavonoid widely found in citrus fruits, vegetables, and important medicinal plants with neuroprotective, cardioprotective, antidiabetic, and anti-obesity effects. However, the microbial synthesis of ERD is limited by complex metabolic pathways and often results in a low production performance. Here, we engineered Saccharomyces cerevisiae by fine-tuning the metabolism of the ERD synthesis pathway. The results showed that the ERD titer was effectively increased, and the intermediate metabolites levels were reduced. First, we successfully reconstructed the de novo synthesis pathway of p-coumaric acid in S. cerevisiae and fine-tuned the metabolic pathway using promoter engineering and terminator engineering for the high-level production of (2S)-naringenin. Subsequently, the synthesis of ERD was achieved by introducing the ThF3'H gene from Tricyrtis hirta. Finally, by multiplying the copy number of the ThF3'H gene, the production of ERD was further increased, reaching 132.08 mg L-1. Our work emphasizes the importance of regulating the metabolic balance to produce natural products in microbial cell factories.

Role of SLC7A11/xCT in Ovarian Cancer

Ovarian cancer is one of the most dangerous gynecologic cancers worldwide and has a high fatality rate due to diagnosis at an advanced stage of the disease as well as a high recurrence rate due to the occurrence of chemotherapy resistance. In fact, chemoresistance weakens the therapeutic effects, worsening the outcome of this pathology. Solute Carrier Family 7 Member 11 (SLC7A11, also known as xCT) is the functional subunit of the Xc- system, an anionic L-cystine/L-glutamate antiporter expressed on the cell surface. SLC7A11 expression is significantly upregulated in several types of cancers in which it can inhibit ferroptosis and favor cancer cell proliferation, invasion and chemoresistance. SLC7A11 expression is also increased in ovarian cancer tissues, suggesting a possible role of this protein as a therapeutic target. In this review, we provide an overview of the current literature regarding the role of SLC7A11 in ovarian cancer to provide new insights on SLC7A11 modulation and evaluate the potential role of SLC7A11 as a therapeutic target.

Protective effect of eriodictyol against hyperglycemia-induced diabetic nephropathy in rats entails antioxidant and anti-inflammatory effects mediated by activating Nrf2

The pathogenesis of diabetic nephropathy (DN) involves cellular activation of oxidative stress and inflammation. Eriodictyol is a citrus-derived flavonoid with multiple pharmacological and protective effects in various conditions. The protective role of Eriodictyol against diabetes and diabetic nephropathy is less investigated. The current research aimed to explore the role of eriodictyol in protecting against DN prompted by streptozotocin in male rats and investigate some possible mechanisms of action. Diabetes was brought about in rats by an i.p injection of a lone dose (65 mg/kg). Five groups of rats were included (n = 8 each) as control (non-diabetic), eriodictyol (20 mg/kg, orally), STZ-diabetic, STZ + eriodictyol (20 mg/kg, orally), and STZ + eriodictyol (20 mg/kg, orally) + ML385 (30 µg/kg, i.p.). Kidney histology and the levels of some markers of kidney function, renal oxidative stress, and renal inflammation were analyzed in all groups of rats. Treatment with eriodictyol prevented the damage in the renal glomeruli and tubules and reduced renal immune cell infiltration in STZ-treated animals. It also spiked urinary creatinine excretion and reduced urine volume and urinary levels of albumin, monocyte chemoattractant protein 1 (MCP-1), urinary kidney injury molecule-1 (KIM-1), and nephrin in these diabetic rats. In addition, eriodictyol stimulated the nuclear protein accumulation of Nrf2 and boosted the expression of superoxide dismutase (SOD), glutathione (GSH), heme oxygenase-1 (HO-1), and catalase (CAT) in the diabetic rat kidneys. In concomitance, it reduced the nuclear levels of NF-κB and levels of interleukine-6 (IL-6), malondialdehyde (MDA), and tumor necrosis factor-α (TNF-α) and attenuated the reduction in renal ATP levels and the increase in the mitochondria transition pore opening (mtTPT). However, the administration of eriodictyol did not affect rats' body weights and fasting glucose and insulin levels but significantly reduced serum levels of cholesterol, triglycerides, LDL-c, and oxidized LDL-c (ox-LDL-c). In conclusion, eriodictyol prevents STZ-induced nephropathy by a hypolipidemic effect and concomitant antioxidant and anti-inflammatory effects mediated by activating Nrf2/NF-κB/antioxidant axis.

Chemical Constituents from Ficus sagittifolia Stem Bark and Their Antimicrobial Activities

The phytochemical investigation of the ethylacetate fraction of an ethanolic extract obtained from the stem bark of Ficus sagittifolia (Moraceae) led to the isolation of four flavonoids: (2R)-eriodictyol (1), 2'- hydroxygenistein (2), erycibenin A (3), and genistein (4); a dihydrobenzofuran: moracin P (5); a coumarin: peucedanol (6); and an apocarotenoid terpenoid: dihydrophaseic acid (7). These were identified via 1D and 2D nuclear magnetic resonance spectroscopy (NMR) and ultra-high-resolution liquid chromatography-quadrupole time-of-flight mass spectroscopy (UHPLC-QTOF MS). Moracin P (5) is being reported for the first time in the genus Ficus, while the others are known compounds (1-4 and 6-7) isolated previously from the genus but being reported for the first time from the species F. sagittifolia. Their antimicrobial activity against various pathogens (five bacteria: Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, and Salmonella typhi; two fungi: Aspergillus niger and Candida albicans) was tested. The mixture of genistein and moracin P (4+5) exhibited strong activity against K. pneumoniae (MIC < 0.0039 mg/mL), whereas dihydrophaseic acid (7) was the most active against P. aeruginosa and A. niger (MIC = 0.0078 and <0.0039 mg/mL, respectively). These compounds might be considered potential antimicrobial agents with the potential to be starting points for the development of antimicrobial drugs.

Anti-inflammatory activities of flavonoid derivates

Background and purpose

Flavonoids are a group of phytochemicals found abundantly in various plants. Scientific evidence has revealed that flavonoids display potential biological activities, including their ability to alleviate inflammation. This activity is closely related to their action in blocking the inflammatory cascade and inhibiting the production of pro-inflammatory factors. However, as flavonoids typically have poor bioavailability and pharmacokinetic profile, it is quite challenging to establish these compounds as a drug. Nevertheless, progressive advancements in drug delivery systems, particularly in nanotechnology, have shown promising approaches to overcome such challenges.

Review approach

This narrative review provides an overview of scientific knowledge about the mechanism of action of flavonoids in the mitigation of inflammatory reaction prior to delivering a comprehensive discussion about the opportunity of the nanotechnology-based delivery system in the preparation of the flavonoid-based drug.

Key results

Various studies conducted in silico, in vitro, in vivo, and clinical trials have deciphered that the anti-inflammatory activities of flavonoids are closely linked to their ability to modulate various biochemical mediators, enzymes, and signalling pathways involved in the inflammatory processes. This compound could be encapsulated in nanotechnology platforms to increase the solubility, bioavailability, and pharmacological activity of flavonoids as well as reduce the toxic effects of these compounds.

Conclusion

In Summary, we conclude that flavonoids and their derivates have given promising results in their development as new anti-inflammatory drug candidates, especially if they formulate in nanoparticles.

Flavonoids: Overview of Biosynthesis, Biological Activity, and Current Extraction Techniques

Recently, increased attention has been paid to natural sources as raw materials for the development of new added-value products. Flavonoids are a large family of polyphenols which include several classes based on their basic structure: flavanones, flavones, isoflavones, flavonols, flavanols, and anthocyanins. They have a multitude of biological properties, such as anti-inflammatory, antioxidant, antiviral, antimicrobial, anticancer, cardioprotective, and neuroprotective effects. Current trends of research and development on flavonoids relate to identification, extraction, isolation, physico-chemical characterization, and their applications to health benefits. This review presents an up-to-date survey of the most recent developments in the natural flavonoid classes, the biological activity of representative flavonoids, current extraction techniques, and perspectives.

Mechanisms of ferroptosis in Alzheimer's disease and therapeutic effects of natural plant products: A review

Neurodegenerative diseases, such as Alzheimer's disease (AD), are characterized by massive loss of specific neurons. It is a progressive disabling, severe and fatal complex disease. Due to its complex pathogenesis and limitations of clinical treatment strategies, it poses a serious medical challenge and medical burden worldwide. The pathogenesis of AD is not clear, and its potential biological mechanisms include aggregation of soluble amyloid to form insoluble amyloid plaques, abnormal phosphorylation of tau protein and formation of intracellular neurofibrillary tangles (NFT), neuroinflammation, ferroptosis, oxidative stress and metal ion disorders. Among them, ferroptosis is a newly discovered programmed cell death induced by iron-dependent lipid peroxidation and reactive oxygen species. Recent studies have shown that ferroptosis is closely related to AD, but the mechanism remains unclear. It may be induced by iron metabolism, amino acid metabolism and lipid metabolism affecting the accumulation of iron ions. Some iron chelating agents (deferoxamine, deferiprone), chloroiodohydroxyquine and its derivatives, antioxidants (vitamin E, lipoic acid, selenium), chloroiodohydroxyquine and its derivatives Fer-1, tet, etc. have been shown in animal studies to be effective in AD and exert neuroprotective effects. This review summarizes the mechanism of ferroptosis in AD and the regulation of natural plant products on ferroptosis in AD, in order to provide reference information for future research on the development of ferroptosis inhibitors.

Optimized De Novo Eriodictyol Biosynthesis in Streptomyces albidoflavus Using an Expansion of the Golden Standard Toolkit for Its Use in Actinomycetes

Eriodictyol is a hydroxylated flavonoid displaying multiple pharmaceutical activities, such as antitumoral, antiviral or neuroprotective. However, its industrial production is limited to extraction from plants due to its inherent limitations. Here, we present the generation of a Streptomyces albidoflavus bacterial factory edited at the genome level for an optimized de novo heterologous production of eriodictyol. For this purpose, an expansion of the Golden Standard toolkit (a Type IIS assembly method based on the Standard European Vector Architecture (SEVA)) has been created, encompassing a collection of synthetic biology modular vectors (adapted for their use in actinomycetes). These vectors have been designed for the assembly of transcriptional units and gene circuits in a plug-and-play manner, as well as for genome editing using CRISPR-Cas9-mediated genetic engineering. These vectors have been used for the optimization of the eriodictyol heterologous production levels in S. albidoflavus by enhancing the flavonoid-3'-hydroxylase (F3'H) activity (by means of a chimera design) and by replacing three native biosynthetic gene clusters in the bacterial chromosome with the plant genes matBC (involved in extracellular malonate uptake and its intracellular activation into malonyl-CoA), therefore allowing more malonyl-CoA to be devoted to the heterologous production of plant flavonoids in this bacterial factory. These experiments have allowed an increase in production of 1.8 times in the edited strain (where the three native biosynthetic gene clusters have been deleted) in comparison with the wild-type strain and a 13 times increase in eriodictyol overproduction in comparison with the non-chimaera version of the F3'H enzyme.

Natural flavonols: actions, mechanisms, and potential therapeutic utility for various diseases

Background

Flavonols are phytoconstituents of biological and medicinal importance. In addition to functioning as antioxidants, flavonols may play a role in antagonizing diabetes, cancer, cardiovascular disease, and viral and bacterial diseases. Quercetin, myricetin, kaempferol, and fisetin are the major dietary flavonols. Quercetin is a potent scavenger of free radicals, providing protection from free radical damage and oxidation-associated diseases.

Main body of the abstract

An extensive literature review of specific databases (e.g., Pubmed, google scholar, science direct) were conducted using the keywords "flavonol," "quercetin," "antidiabetic," "antiviral," "anticancer," and "myricetin." Some studies concluded that quercetin is a promising antioxidant agent while kaempferol could be effective against human gastric cancer. In addition, kaempferol prevents apoptosis of pancreatic beta-cells via boosting the function and survival rate of the beta-cells, leading to increased insulin secretion. Flavonols also show potential as alternatives to conventional antibiotics, restricting viral infection by antagonizing the envelope proteins to block viral entry.

Short conclusion

There is substantial scientific evidence that high consumption of flavonols is associated with reduced risk of cancer and coronary diseases, free radical damage alleviation, tumor growth prevention, and insulin secretion improvement, among other diverse health benefits. Nevertheless, more studies are required to determine the appropriate dietary concentration, dose, and type of flavonol for a particular condition to prevent any adverse side effects.

Therapeutic potential of natural molecules against Alzheimer's disease via SIRT1 modulation

Alzheimer's disease (AD) is a neurodegenerative disease mainly characterized by progressive cognitive dysfunction and memory impairment. Recent studies have shown that regulating silent information regulator 1 (SIRT1) expression has a significant neuroprotective effect, and SIRT1 may become a new therapeutic target for AD. Natural molecules are an important source of drug development for use in AD therapy and may regulate a wide range of biological events by regulating SIRT1 as well as other SIRT1-mediated signaling pathways. This review aims to summarize the correlation between SIRT1 and AD and to identify in vivo and in vitro studies investigating the anti-AD properties of natural molecules as modulators of SIRT1 and SIRT1-mediated signaling pathways. A literature search was conducted for studies published between January 2000 and October 2022 using various literature databases, including Web of Science, PubMed, Google Scholar, Science Direct, and EMBASE. Natural molecules, such as resveratrol, quercetin, icariin, bisdemethoxycurcumin, dihydromyricetin, salidroside, patchouli, sesamin, rhein, ligustilide, tetramethoxyflavanone, 1-theanine, schisandrin, curcumin, betaine, pterostilbene, ampelopsin, schisanhenol, and eriodictyol, have the potential to modulate SIRT1 and SIRT1 signaling pathways, thereby combating AD. The natural molecules modulating SIRT1 discussed in this review provide a potentially novel multi-mechanistic therapeutic strategy for AD. However, future clinical trials need to be conducted to further investigate their beneficial properties and to determine the safety and efficacy of SIRT1 natural activators against AD.

The ethanolic extract of peanut shell attenuates the depressive-like behaviors of mice through modulation of inflammation and gut microbiota

Peanut shell is an agricultural byproduct being wasted on a large scale, which is in urgent need to be recycled. To fully utilize its pharmacological ingredients, e.g. luteolin, eriodyctiol, and 5,7-dihydroxychromone, we evaluated the curative effect of ethanol extract deriving from peanut shell (PSE) in treating chronic unpredictable mild stress (CUMS)-induced depressive mice. The chronic stress lasted for 10 weeks, and PSE at 100-900 mg/kg/day was gavaged to mice in the last 2 weeks of modeling. The depressive behaviors were assessed by analyses of sucrose preference, tail suspension, and forced swimming. The brain injury was demonstrated by Hematoxylin and Eosin (H&E), Nissl body, and TdT-mediated dUTP nick end labeling (TUNEL) stainings in the mouse hippocampus. Biochemical indicators were analyzed, including levels of neurotrophic factors, neurotransmitters, stress hormones, and inflammatory mediators. The feces were collected for the 16S rDNA sequencing of gut microbiome. Administration of PSE improved the sucrose water consumption of depressive mice, while it decreased the immobile time in tail suspension and forced swimming tests. Meanwhile, the anti-depressive effect of PSE was supported by ameliorated histochemical staining, increased levels of neurotrophic factors and neurotransmitters, as well as down-regulated stress hormones. Furthermore, the treatment of PSE was able to mitigate the levels of inflammatory cytokines in brain, serum, and small intestine. Besides, the tight junction proteins, e.g., occludin and ZO-1, of gut showed elevated expressions, which coincided with the elevated abundance and diversity of gut microbiota upon PSE treatment. This study validated the therapeutic efficacy of PSE in fighting against depression, as well as its modulatory action on inflammation and gut microbiota, which promoted the recycling of this agricultural waste to be health supplements of added value.

Naringenin and Hesperidin as Promising Alternatives for Prevention and Co-Adjuvant Therapy for Breast Cancer

Citrus (genus Citrus L.) fruits are essential sources of bioactive compounds with antioxidant properties, such as flavonoids. These polyphenolic compounds are divided into subclasses, in which flavanones are the most prominent. Among them, naringenin and hesperidin are emerging compounds with anticancer potential, especially for breast cancer (BC). Several mechanisms have been proposed, including the modulation of epigenetics, estrogen signaling, induction of cell death via regulation of apoptotic signaling pathways, and inhibition of tumor invasion and metastasis. However, this information is sparse in the literature and needs to be brought together to provide an overview of how naringenin and hesperidin can serve as therapeutic tools for drug development and as a successful co-adjuvant strategy against BC. This review detailed such mechanisms in this context and highlighted how naringenin and hesperidin could interfere in BC carcinogenesis and be helpful as potential alternative therapeutic sources for breast cancer treatment.

Role of SARS-CoV-2 Spike-Protein-Induced Activation of Microglia and Mast Cells in the Pathogenesis of Neuro-COVID

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19). About 45% of COVID-19 patients experience several symptoms a few months after the initial infection and develop post-acute sequelae of SARS-CoV-2 (PASC), referred to as "Long-COVID," characterized by persistent physical and mental fatigue. However, the exact pathogenetic mechanisms affecting the brain are still not well-understood. There is increasing evidence of neurovascular inflammation in the brain. However, the precise role of the neuroinflammatory response that contributes to the disease severity of COVID-19 and long COVID pathogenesis is not clearly understood. Here, we review the reports that the SARS-CoV-2 spike protein can cause blood-brain barrier (BBB) dysfunction and damage neurons either directly, or via activation of brain mast cells and microglia and the release of various neuroinflammatory molecules. Moreover, we provide recent evidence that the novel flavanol eriodictyol is particularly suited for development as an effective treatment alone or together with oleuropein and sulforaphane (ViralProtek®), all of which have potent anti-viral and anti-inflammatory actions.

Natural Active Ingredients and TRPV1 Modulation: Focus on Key Chemical Moieties Involved in Ligand-Target Interaction

Diseases such as cancer, neurological pathologies and chronic pain represent currently unmet needs. The existing pharmacotherapeutic options available for treating these conditions are limited by lack of efficiency and/or side effects. Transient receptor potential vanilloid 1 ion channel emerged as an attractive therapeutic target for developing new analgesic, anti-cancer and antiepileptic agents. Furthermore, various natural ingredients were shown to have affinity for this receptor. The aim of this narrative review was to summarize the diverse natural scaffolds of TRPV1 modulators based on their agonistic/antagonistic properties and to analyze the structure-activity relationships between the ligands and molecular targets based on the results of the existing molecular docking, mutagenesis and in vitro studies. We present here an exhaustive collection of TRPV1 modulators grouped by relevant chemical features: vanilloids, guaiacols, phenols, alkylbenzenes, monoterpenes, sesquiterpenoids, alkaloids, etc. The information herein is useful for understanding the key structural elements mediating the interaction with TRPV1 and how their structural variation impacts the interaction between the ligand and receptor. We hope this data will contribute to the design of novel effective and safe TRPV1 modulators, to help overcome the lack of effective therapeutic agents against pathologies with high morbidity and mortality.

Potential of natural flavonols and flavanones in the treatment of ulcerative colitis

Ulcerative colitis (UC) is an inflammatory bowel disease generally characterized by chronic, persistent, recurrent, and non-specific ulcers of the intestine. Its main clinical manifestations include abdominal pain, diarrhea, and bloody stools. This disease is difficult to cure and even carries the risk of canceration. It has been listed as a modern refractory disease by the World Health Organization. Though a large amount of drugs are available for the inhibition of UC, the conventional treatment such as aminosalicylic acids, glucocorticoids, immunosuppressors, and biological agents possess certain limitations and serious side effects. Therefore, it is urgently needed for safe and effective drugs of UC, and natural-derived flavonols and flavanones showed tremendous potential. The present study concentrated on the progress of natural-derived flavonols and flavanones from edible and pharmaceutical plants for the remedy of UC over the last two decades. The potential pharmaceutical of natural-derived flavonols and flavanones against UC were closely connected with the modulation of gut microflora, gut barrier function, inflammatory reactions, oxidative stress, and apoptosis. The excellent efficacy and safety of natural flavonols and flavanones make them prospective drug candidates for UC suppression.

Isolation and Identification of Flavanone Derivative Eriodictyol from the Methanol Extract of Afzelia africana Bark and Its Antimicrobial and Antioxidant Activities

Background

Afzelia africana is a plant species with well-documented ethnobotanical and medicinal properties. The plant is reported to have various secondary metabolites and had been applied for the treatment of various diseased conditions.

Objectives

The study objectives include fractionation, isolation, purification, and characterization of eriodictyol from the bark of A. africana, and the determination of its antimicrobial and antioxidant activities. Methodology. The series of methodologies that were employed include fractionations and purification (column chromatography), characterization (HPLC, LC-MS, IR, ¹H, ¹³C, DEPT-135, HSQC, and HMBC), antimicrobial assays (microbroth dilution and checkerboard assay), and antioxidant activities assays (ABTS and DPPH scavenging capacity).

Results

The study reports the identification and characterization of eriodictyol from the bark of A. africana which exhibited potent antioxidant activities against ABTS and DPPH radicals with scavenging capacities (SC₅₀) of 2.14 ± 0.05 and 2.51 ± 0.06 µg/mL, respectively. The compound exhibited its antimicrobial activity by reporting good bacteriostatic activities (MBC/MIC > 4) against Staphylococcus aureus (SA), methicillin-resistant Staphylococcus aureus (MRSA), and fluconazole-resistant Candida albicans (CA2). Moreover, a broad spectrum of bactericidal effects (MBC/MIC ≤ 4) was reported against Streptococcus mutans (SM), Escherichia coli (EC), Bacillus subtilis (BS), Klebsiella pneumonia (KP), Pseudomonas aeruginosa (PA), Salmonella typhi (ST), and standard Candida albicans (CA1). The compound further exhibited synergistic effects against EC, KP, ST, and MRSA; ST; and CA2 when combined with ciprofloxacin, tetracycline, and nystatin, respectively. However, antagonistic effects were observed against PA and CA1 when combined with ciprofloxacin and ketoconazole, respectively.

Conclusion

The study reports for the first time the identification of eriodictyol from the bark of A. africana which exhibited significant antioxidant and antimicrobial properties.

Role of Nrf2 in aging, Alzheimer's and other neurodegenerative diseases

Nuclear Factor-Erythroid Factor 2 (Nrf2) is an important transcription factor that regulates the expression of large number of genes in healthy and disease states. Nrf2 is made up of 605 amino acids and contains 7 conserved regions known as Nrf2-ECH homology domains. Nrf2 regulates the expression of several key components of oxidative stress, mitochondrial biogenesis, mitophagy, autophagy and mitochondrial function in all organs of the human body, in the peripheral and central nervous systems. Mounting evidence also suggests that altered expression of Nrf2 is largely involved in aging, neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, Huntington's diseases, Amyotrophic lateral sclerosis, Stroke, Multiple sclerosis and others. The purpose of this article is to detail the essential role of Nrf2 in oxidative stress, antioxidative defense, detoxification, inflammatory responses, transcription factors, proteasomal and autophagic/mitophagic degradation, and metabolism in aging and neurodegenerative diseases. This article also highlights the Nrf2 structural and functional activities in healthy and disease states, and also discusses the current status of Nrf2 research and therapeutic strategies to treat aging and neurodegenerative diseases.

Phytochemical Analysis, Antioxidant, and Antimicrobial Activities of Ducrosia flabellifolia: A Combined Experimental and Computational Approaches

Ducrosia flabellifolia Boiss. is a rare desert plant known to be a promising source of bioactive compounds. In this paper, we report for the first time the phytochemical composition and biological activities of D. flabellifolia hydroalcoholic extract by using liquid chromatography-electrospray tandem mass spectrometry (ESI-MS/MS) technique. The results obtained showed the richness of the tested extract in phenols, tannins, and flavonoids. Twenty-three phytoconstituents were identified, represented mainly by chlorogenic acid, followed by ferulic acid, caffeic acid, and sinapic acid. The tested hydroalcoholic extract was able to inhibit the growth of all tested bacteria and yeast on agar Petri dishes at 3 mg/disc with mean growth inhibition zone ranging from 8.00 ± 0.00 mm for Enterococcus cloacae (E. cloacae) to 36.33 ± 0.58 mm for Staphylococcus epidermidis. Minimal inhibitory concentration ranged from 12.5 mg/mL to 200 mg/mL and the hydroalcoholic extract from D. flabellifolia exhibited a bacteriostatic and fungistatic character. In addition, D. flabellifolia hydroalcoholic extract possessed a good ability to scavenge different free radicals as compared to standard molecules. Molecular docking studies on the identified phyto-compounds in bacterial, fungal, and human peroxiredoxin 5 receptors were performed to corroborate the in vitro results, which revealed good binding profiles on the examined protein targets. A standard atomistic 100 ns dynamic simulation investigation was used to further evaluate the interaction stability of the promising phytocompounds, and the results showed conformational stability in the binding cavity. The obtained results highlighted the medicinal use of D. flabellifolia as source of bioactive compounds, as antioxidant, antibacterial, and antifungal agent.

A Comparison of the Flavonoid Biosynthesis Mechanisms of Dendrobium Species by Analyzing the Transcriptome and Metabolome

Dendrobium huoshanense, Dendrobium officinale, and Dendrobium moniliforme, as precious Chinese medicinal materials, have a variety of medicinal properties. Flavonoids are important medicinal components of Dendrobium, but their accumulation rules and biosynthesis mechanisms remain unclear. To explore the similarities and differences of flavonoid accumulation and biosynthesis in these three Dendrobium species, we performed flavonoid content determination, widely-targeted metabolomics and transcriptome sequencing on 1-4 years old Dendrobium species. The results showed that in different growth years, D. huoshanense stems had the highest flavonoid content in the second year of growth, while D. officinale and D. moniliforme stems had the highest flavonoid content in the third year of growth. A total of 644 differentially accumulated metabolites (DAMs) and 10,426 differentially expressed genes (DEGs) were identified by metabolomic and transcriptomic analysis. It was found that DAMs and DEGs were not only enriched in the general pathway of "flavonoid biosynthesis", but also in multiple sub-pathways such as "Flavone biosynthesis", and "Flavonol biosynthesis" and "Isoflavonoid biosynthesis". According to a combined transcriptome and metabolome analysis, the expression levels of the F3'H gene (LOC110096779) and two F3'5'H genes (LOC110101765 and LOC110103762) may be the main genes responsible for the differences in flavonoid accumulation. As a result of this study, we have not only determined the optimal harvesting period for three Dendrobium plants, but also identified the key genes involved in flavonoid biosynthesis and provided a basis for further study of the molecular mechanism of flavonoid synthesis.

The impact of aromatic plant-derived bioactive compounds on seafood quality and safety

Plant-derived bioactive compounds have been extensively studied and used within food industry for the last few decades. Those compounds have been used to extend the shelf-life and improve physico-chemical and sensory properties on food products. They have also been used as nutraceuticals due to broad range of potential health-promoting properties. Unlike the synthetic additives, the natural plant-derived compounds are more acceptable and often regarded as safer by the consumers. This chapter summarizes the extraction methods and sources of those plant-derived bioactives as well as recent findings in relation to their health-promoting properties, including cardio-protective, anti-diabetic, anti-inflammatory, anti-carcinogenic, immuno-modulatory and neuro-protective properties. In addition, the impact of applying those plant-derived compounds on seafood products is also investigated by reviewing the recent studies on their use as anti-microbial, anti-oxidant, coloring and flavoring agents as well as freshness indicators. Moreover, the current limitations of the use of plant-derived bioactive compounds as well as future prospects are discussed. The discoveries show high potential of those compounds and the possibility to apply on many different seafood. The compounds can be applied as individual while more and more studies are showing synergetic effect when those compounds are used in combination providing new important research possibilities.

Eriodictyol Suppresses Porphyromonas gingivalis-Induced Reactive Oxygen Species Production by Gingival Keratinocytes and the Inflammatory Response of Macrophages

Porphyromonas gingivalis is a key pathogen of periodontitis, an inflammatory disease that affects the tooth-supporting tissues. The aim of the present study was to investigate the effects of the flavanone eriodictyol on P. gingivalis-induced reactive oxygen species (ROS) production by gingival keratinocytes and the inflammatory response of macrophages. Porphyromonas gingivalis and H2O2 acted synergistically to induce ROS production by keratinocytes. The presence of eriodictyol significantly attenuated ROS production in a dose-dependent manner. We used a macrophage model to show that eriodictyol decreases the secretion of IL-1β, IL-6, IL-8, and TNF-α induced by P. gingivalis. Evidence has been brought that this anti-inflammatory property of eriodictyol may be related to its ability to prevent the activation of the NF-κB signaling pathway by P. gingivalis. This periodontal pathogen was also found to be a potent inducer of matrix metalloproteinase (MMP) production by macrophages, including MMP-2, MMP-8, and MMP-9. Eriodictyol dose-dependently inhibited the production of all three MMPs. Lastly, eriodictyol inhibited the catalytic activity of both MMP-9 and P. gingivalis collagenase. In conclusion, eriodictyol may be a potential therapeutic agent for preventing and/or treating periodontal disease due to its antioxidant, anti-inflammatory, and anti-proteinase properties.

Diversity of Chemical Structures and Biosynthesis of Polyphenols in Nut-Bearing Species

Nuts, such as peanut, almond, and chestnut, are valuable food crops for humans being important sources of fatty acids, vitamins, minerals, and polyphenols. Polyphenols, such as flavonoids, stilbenoids, and hydroxycinnamates, represent a group of plant-specialized (secondary) metabolites which are characterized as health-beneficial antioxidants within the human diet as well as physiological stress protectants within the plant. In food chemistry research, a multitude of polyphenols contained in culinary nuts have been studied leading to the identification of their chemical properties and bioactivities. Although functional elucidation of the biosynthetic genes of polyphenols in nut species is crucially important for crop improvement in the creation of higher-quality nuts and stress-tolerant cultivars, the chemical diversity of nut polyphenols and the key biosynthetic genes responsible for their production are still largely uncharacterized. However, current technical advances in whole-genome sequencing have facilitated that nut plant species became model plants for omics-based approaches. Here, we review the chemical diversity of seed polyphenols in majorly consumed nut species coupled to insights into their biological activities. Furthermore, we present an example of the annotation of key genes involved in polyphenolic biosynthesis in peanut using comparative genomics as a case study outlining how we are approaching omics-based approaches of the nut plant species.