Potential Therapeutic Anti-Inflammatory and Immunomodulatory Effects of Dihydroflavones, Flavones, and Flavonols

Targeting phytoprotection in the COVID-19-induced lung damage and associated systemic effects-the evidence-based 3PM proposition to mitigate individual risks

The risks related to the COVID-19 are multi-faceted including but by far not restricted to the following: direct health risks by poorly understood effects of COVID-19 infection, overloaded capacities of healthcare units, restricted and slowed down care of patients with non-communicable disorders such as cancer, neurologic and cardiovascular pathologies, among others; social risks-restricted and broken social contacts, isolation, professional disruption, explosion of aggression in the society, violence in the familial environment; mental risks-loneliness, helplessness, defenceless, depressions; and economic risks-slowed down industrial productivity, broken delivery chains, unemployment, bankrupted SMEs, inflation, decreased capacity of the state to perform socially important programs and to support socio-economically weak subgroups in the population. Directly or indirectly, the above listed risks will get reflected in a healthcare occupation and workload which is a tremendous long-term challenge for the healthcare capacity and robustness. The article does not pretend to provide solutions for all kind of health risks. However, it aims to present the scientific evidence of great clinical utility for primary, secondary, and tertiary care to protect affected individuals in a cost-effective manner. To this end, due to pronounced antimicrobial, antioxidant, anti-inflammatory, and antiviral properties, naturally occurring plant substances are capable to protect affected individuals against COVID-19-associated life-threatening complications such as lung damage. Furthermore, they can be highly effective, if being applied to secondary and tertiary care of noncommunicable diseases under pandemic condition. Thus, the stratification of patients evaluating specific health conditions such as sleep quality, periodontitis, smoking, chronic inflammation and diseases, metabolic disorders and obesity, vascular dysfunction, and cancers would enable effective managemenet of COVID-19-associated complications in primary, secondary, and tertiary care in the context of predictive, preventive, and personalized medicine (3PM).

Binding and antiplatelet activity of quercetin, rutin, diosmetin, and diosmin flavonoids

Platelets exert an essential role in vascular inflammation and thrombosis. Flavonoids are natural compounds employed for the clinical management of vascular disorders preventing capillary permeability, working as phlebotonics and improving the blood rheology, although their mechanism of action remains partially unknown. The effects of quercetin, rutin, diosmetin and diosmin were investigated in platelet activation utilizing blood from healthy and non-treated volunteers. The arrangement of the different activation states of platelets and GPIIb/IIIa receptor occupation was computed by flow cytometry working with calcium ionophore as pro-aggregant to provoke platelet activation and aggregation. The flavonoids studied demonstrated relevant antiplatelet activity through the blocked of GPIIb/IIIa receptors, the suppression of the platelet activation, as well as the pro-aggregate effect of calcium ionophore. Therefore, whichever of the active ingredients examined could be beneficious in the prevention of cardiovascular disease and this article also contributes to elucidate a new mechanism of action for these drugs.

Antiplatelet Activity of Coumarins: In Vitro Assays on COX-1

Atherosclerotic cardiovascular disease is the leading cause of death in developed countries. Therefore, there is an increasing interest in developing new potent and safe antiplatelet agents. Coumarins are a family of polyphenolic compounds with several pharmacological activities, including platelet aggregation inhibition. However, their antiplatelet mechanism of action needs to be further elucidated. The aim of this study is to provide insight into the biochemical mechanisms involved in this activity, as well as to establish a structure-activity relationship for these compounds. With this purpose, the antiplatelet aggregation activities of coumarin, esculetin and esculin were determined in vitro in human whole blood and platelet-rich plasma, to set the potential interference with the arachidonic acid cascade. Here, the platelet COX activity was evaluated from 0.75 mM to 6.5 mM concentration by measuring the levels of metabolites derived from its activity (MDA and TXB₂), together with colorimetric assays performed with the pure recombinant enzyme. Our results evidenced that the coumarin aglycones present the greatest antiplatelet activity at 5 mM and 6.5 mM on aggregometry experiments and inhibiting MDA levels.

The Traditional Uses, Phytochemistry, Pharmacology, Toxicology, and Clinical Uses of Metagentiana Rhodantha (Franch.) T.N.Ho and S.W.Liu, an Ethnomedicine in Southwest China

Background: Metagentiana rhodantha (Franch.) T.N.Ho and S.W.Liu (MR) belongs to Gentianales, and it is often called Hong-hua-long-dan in Chinese. Traditionally, it has been used to cure acute icteric hepatitis, sore throat, dysentery, acute gastritis, carbuncle, and furuncle based on traditional Chinese medicine (TCM) concepts. Aim of Study: This review manages to provide a critical and comprehensive analysis on the traditional uses, phytochemistry, pharmacology, toxicology, and clinical uses of MR and to evaluate the therapeutic potential of this plant. Methods: Relevant data mainly literatures on MR were selected from available database. All the papers reviewed provided evidence that the source herbs were reliably identified. Results: The heat-clearing and removing the phlegm, and purging fire and removing toxicity of MR contribute to its dispelling jaundice, and clearing lung heat and cough. The compounds isolated from this plant include iridoids and secoiridoids, phenolic acids, ketones, triterpenoids, flavonoids, benzophenone glycosides, and others. Mangiferin (MAF) is a characteristic substance from this plant. The pharmacological studies show that some extracts and compounds from MR exhibit anti-inflammatory, antinociceptive, antibacterial, hepatoprotective, cardioprotective, and other effects which are associated with the traditional uses of this plant. The toxicological studies suggest that MAF is less toxic in mice and dogs. Nowadays, Chinese patent drugs such as Feilike Jiaonang and Kangfuling Jiaonang containing MR have been used to cure cough, asthma, chronic bronchitis, dysmenorrhea, and appendagitis. Conclusion: Although the current studies provide related research information of MR, it is still necessary to systemically evaluate the chemistry, pharmacology, toxicity, and safety of the extracts or compounds from this plant before clinical trials in the future. In addition, except for lung infection-related diseases, analgesia, anti-tumor, and hypertriglycemia may be new and prior therapeutic scopes of this ethnomedicine in the future.

Antioxidants in Potatoes: A Functional View on One of the Major Food Crops Worldwide

With a growing world population, accelerating climate changes, and limited arable land, it is critical to focus on plant-based resources for sustainable food production. In addition, plants are a cornucopia for secondary metabolites, of which many have robust antioxidative capacities and are beneficial for human health. Potato is one of the major food crops worldwide, and is recognized by the United Nations as an excellent food source for an increasing world population. Potato tubers are rich in a plethora of antioxidants with an array of health-promoting effects. This review article provides a detailed overview about the biosynthesis, chemical and health-promoting properties of the most abundant antioxidants in potato tubers, including several vitamins, carotenoids and phenylpropanoids. The dietary contribution of diverse commercial and primitive cultivars are detailed and document that potato contributes much more than just complex carbohydrates to the diet. Finally, the review provides insights into the current and future potential of potato-based systems as tools and resources for healthy and sustainable food production.

Flavonoids against the SARS-CoV-2 induced inflammatory storm

The disease severity of COVID-19, especially in the elderly and patients with co-morbidities, is characterized by hypercytokinemia, an exaggerated immune response associated with an uncontrolled and excessive release of proinflammatory cytokine mediators (cytokine storm). Flavonoids, important secondary metabolites of plants, have long been studied as therapeutic interventions in inflammatory diseases due to their cytokine-modulatory effects. In this review, we discuss the potential role of flavonoids in the modulation of signaling pathways that are crucial for COVID-19 disease, particularly those related to inflammation and immunity. The immunomodulatory ability of flavonoids, carried out by the regulation of inflammatory mediators, the inhibition of endothelial activation, NLRP3 inflammasome, toll-like receptors (TLRs) or bromodomain containing protein 4 (BRD4), and the activation of the nuclear factor erythroid-derived 2-related factor 2 (Nrf2), might be beneficial in regulating the cytokine storm during SARS-CoV-2 infection. Moreover, the ability of flavonoids to inhibit dipeptidyl peptidase 4 (DPP4), neutralize 3-chymotrypsin-like protease (3CL^pro) or to affect gut microbiota to maintain immune response, and the dual action of angiotensin-converting enzyme 2 (ACE-2) may potentially also be applied to the exaggerated inflammatory responses induced by SARS-CoV-2. Based on the previously proven effects of flavonoids in other diseases or on the basis of newly published studies associated with COVID-19 (bioinformatics, molecular docking), it is reasonable to assume positive effects of flavonoids on inflammatory changes associated with COVID-19. This review highlights the current state of knowledge of the utility of flavonoids in the management of COVID-19 and also points to the multiple biological effects of flavonoids on signaling pathways associated with the inflammation processes that are deregulated in the pathology induced by SARS-CoV-2. The identification of agents, including naturally occurring substances such as flavonoids, represents great approach potentially utilizable in the management of COVID-19. Although not clinically investigated yet, the applicability of flavonoids against COVID-19 could be a promising strategy due to a broad spectrum of their biological activities.

The Effectiveness of Dietary Byproduct Antioxidants on Induced CYP Genes Expression and Histological Alteration in Piglets Liver and Kidney Fed with Aflatoxin B1 and Ochratoxin A

The purpose of this study was to investigate the potential of a byproduct mixture derived from grapeseed and sea buckthorn oil industry to mitigate the harmful damage produced by ochratoxin A and aflatoxin B1 at hepatic and renal level in piglets after weaning. Forty cross-bred TOPIGS-40 hybrid piglets after weaning were assigned to three experimental groups (E1, E2, E3) and one control group (C), and fed with experimental diets for 30 days. The basal diet was served as a control and contained normal compound feed for starter piglets without mycotoxins. The experimental groups were fed as follows: E1-basal diet plus a mixture (1:1) of two byproducts (grapeseed and sea buckthorn meal); E2-the basal diet experimentally contaminated with mycotoxins (479 ppb OTA and 62ppb AFB1); and E3-basal diet containing 5% of the mixture (1:1) of grapeseed and sea buckthorn meal and contaminated with the mix of OTA and AFB1. After 4 weeks, the animals were slaughtered, and tissue samples were taken from liver and kidney in order to perform gene expression and histological analysis. The gene expression analysis showed that when weaned piglets were fed with contaminated diet, the expression of most analyzed genes was downregulated. Among the CYP450 family, CYP1A2 was the gene with the highest downregulation. According to these results, in liver, we found that mycotoxins induced histomorphological alterations in liver and kidney and had an effect on the expression level of CYP1A2, CYP2A19, CYP2E1, and CYP3A29, but we did not detect important changes in the expression level of CY4A24, MRP2 and GSTA1 genes.

Naringenin suppresses Toll-like receptor 2-mediated inflammatory responses through inhibition of receptor clustering on lipid rafts

Toll-like receptors (TLRs) are important innate immune receptors that sometimes cause excessive inflammatory responses and a perpetuated inflammatory loop that can be involved in inflammatory and autoimmune diseases. TLR2 recognizes bacterial lipoproteins in association with TLR1 or TLR6, and triggers inflammatory responses through activation of the transcription factor NF-κB. Naringenin, a type of citrus flavonoid, has been shown to possess anti-inflammatory properties, but its detailed action against TLR2 remains to be fully elucidated. The present study was designed to determine whether naringenin affects the inflammatory responses triggered by TLR2. Naringenin inhibited proinflammatory cytokine production and attenuated NF-κB activation in cells stimulated with a synthetic triacylated-type lipopeptide known as a TLR2/TLR1 ligand, as well as a synthetic diacylated-type lipopeptide known as a TLR2/TLR6 ligand. Moreover, a similar inhibitory effect was observed in cells stimulated with a crude lipophilic fraction extracted from Staphylococcus aureus cell walls and in cells stimulated with S. aureus cells. Furthermore, we showed that such an effect is caused by inhibition of TLR2 clustering in lipid rafts on the cell membrane. These results suggest that naringenin suppresses the inflammatory responses induced by TLR2 signal transduction. Our findings indicate a novel anti-inflammatory property of naringenin, mediated through the regulation of cell surface TLR2 functioning.

Flavonols as potential antiviral drugs targeting SARS-CoV-2 proteases (3CLpro and PLpro), spike protein, RNA-dependent RNA polymerase (RdRp) and angiotensin-converting enzyme II receptor (ACE2)

The novel coronavirus outbreak (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) represents the actual greatest global public health crisis. The lack of efficacious drugs and vaccines against this viral infection created a challenge for scientific researchers in order to find effective solutions. One of the promising therapeutic approaches is the search for bioactive molecules with few side effects that display antiviral properties in natural sources like medicinal plants and vegetables. Several computational and experimental studies indicated that flavonoids especially flavonols and their derivatives constitute effective viral enzyme inhibitors and possess interesting antiviral activities. In this context, the present study reviews the efficacy of many dietary flavonols as potential antiviral drugs targeting the SARS-CoV-2 enzymes and proteins including Chymotrypsin-Like Protease (3CLpro), Papain Like protease (PLpro), Spike protein (S protein) and RNA-dependent RNA polymerase (RdRp), and also their ability to interact with the angiotensin-converting enzyme II (ACE2) receptor. The relationship between flavonol structures and their SARS-CoV-2 antiviral effects were discussed. On the other hand, the immunomodulatory, the anti-inflammatory and the antiviral effects of secondary metabolites from this class of flavonoids were reported. Also, their bioavailability limitations and toxicity were predicted.

Comparative study of the effects of diosmin and diosmetin on fat accumulation, dyslipidemia, and glucose intolerance in mice fed a high-fat high-sucrose diet

This study compared the effects of diosmin and its aglycone, diosmetin, on body weight, liver fat, serum cholesterol, and glucose intolerance in male C57BL/6 mice fed a high-fat high-sucrose (HFHS) diet for 12 weeks. The mice were divided into four groups that received the following diets: normal diet (ND), HFHS diet, HFHS diet with 0.5% diosmin, and HFHS diet with 0.5% diosmetin. The body weight increased significantly in the HFHS diet group but decreased significantly in the HFHS diet with 0.5% diosmin group. The diosmin and diosmetin treatment inhibited fat accumulation in liver and epididymal tissues, and improved glucose intolerance by lowering glucose levels during a glucose tolerance test; these effects were greater in the diosmin group than those in the diosmetin group. Furthermore, only diosmin significantly ameliorated dyslipidemia, by reducing TC and LDL-C levels, while diosmetin had little effect on these parameters. Taken together, the results showed that diosmin and diosmetin can prevent fat accumulation and glucose intolerance; however, diosmin was more effective and also showed an antidyslipidemic effect.

Special Issue "Flavonoids and Their Disease Prevention and Treatment Potential": Recent Advances and Future Perspectives

In recent years, the interest in flavonoids as dietary bioactives to prevent human diseases, as well as their candidacy as pharmaceutical leads, has exponentially expanded [...].

Interstitial Fluid in Lipedema and Control Skin

Background: Fluid in lymphedema tissue appears histologically as spaces around vessels and between dermal skin fibers. Lipedema is a painful disease of excess loose connective tissue (fat) in limbs, almost exclusively of women, that worsens by stage, increasing lymphedema risk. Many women with lipedema have hypermobile joints suggesting a connective tissue disorder that may affect vessel structure and compliance of tissue resulting in excess fluid entering the interstitial space. It is unclear if excess fluid is present in lipedema tissue. The purpose of this study is to determine if fluid accumulates around vessels and between skin fibers in the thigh tissue of women with lipedema.

Methods: Skin biopsies from the thigh and abdomen from 30 controls and 80 women with lipedema were evaluated for dermal spaces and abnormal vessel phenotype (AVP): (1) rounded endothelial cells; (2) perivascular spaces; and (3) perivascular immune cell infiltrate. Women matched for body mass index (BMI) and age were considered controls if they did not have lipedema on clinical examination. Data were analyzed by analysis of variance (ANOVA) or unpaired t-tests using GraphPad Prism Software 7. p < 0.05 was considered significant.

Results: Lipedema tissue mass increases beginning with Stage 1 up to Stage 3, with lipedema fat accumulating more on the limbs than the abdomen. AVP was higher in lipedema thigh (p = 0.003) but not abdomen skin compared with controls. AVP was higher in thigh skin of women with Stage 1 (p = 0.001) and Stage 2 (p = 0.03) but not Stage 3 lipedema versus controls. AVP also was greater in the thigh skin of women with lipedema without obesity versus lipedema with obesity (p < 0.0001). Dermal space was increased in lipedema thigh (p = 0.0003) but not abdomen versus controls. Dermal spaces were also increased in women with lipedema Stage 3 (p < 0.0001) and Stage 2 (p = 0.0007) compared with controls.

Conclusion: Excess interstitial fluid in lipedema tissue may originate from dysfunctional blood vessels (microangiopathy). Increased compliance of connective tissue in higher stages of lipedema may allow fluid to disperse into the interstitial space, including between skin dermal fibers. Lipedema may be an early form of lymphedema. ClinicalTrials.gov: NCT02838277.

Role of Rutin in 5-Fluorouracil-Induced Intestinal Mucositis: Prevention of Histological Damage and Reduction of Inflammation and Oxidative Stress

Intestinal mucositis, characterized by inflammatory and/or ulcerative processes in the gastrointestinal tract, occurs due to cellular and tissue damage following treatment with 5-fluorouracil (5-FU). Rutin (RUT), a natural flavonoid extracted from Dimorphandra gardneriana, exhibits antioxidant, anti-inflammatory, cytoprotective, and gastroprotective properties. However, the effect of RUT on inflammatory processes in the intestine, especially on mucositis promoted by antineoplastic agents, has not yet been reported. In this study, we investigated the role of RUT on 5-FU-induced experimental intestinal mucositis. Swiss mice were randomly divided into seven groups: Saline, 5-FU, RUT-50, RUT-100, RUT-200, Celecoxib (CLX), and CLX + RUT-200 groups. The mice were weighed daily. After treatment, the animals were euthanized and segments of the small intestine were collected to evaluate histopathological alterations (morphometric analysis); malondialdehyde (MDA), myeloperoxidase (MPO), and glutathione (GSH) concentrations; mast and goblet cell counts; and cyclooxygenase-2 (COX-2) activity, as well as to perform immunohistochemical analyses. RUT treatment (200 mg/kg) prevented 5-FU-induced histopathological changes and reduced oxidative stress by decreasing MDA concentrations and increasing GSH concentrations. RUT attenuated the inflammatory response by decreasing MPO activity, intestinal mastocytosis, and COX-2 expression. These results suggest that the COX-2 pathway is one of the underlying protective mechanisms of RUT against 5-FU-induced intestinal mucositis.

The effect of Achillea Millefolium L. on vulvovaginal candidiasis compared with clotrimazole: A randomized controlled trial

INTRODUCTION

Vulvovaginal candidiasis is the second most common cause of vulvovaginal infections. The aim of this study is to evaluate the effectiveness of vaginal cream of Achillea millefolium extract in women with vulvovaginal candidiasis in comparison with vaginal clotrimazole.

MATERIALS AND METHODS

This double-blind randomized clinical trial study was conducted on 80 women diagnosed with vulvovaginal candidiasis clinically and by laboratory test; 40 women received vaginal cream clotrimazole 1 % and 40 received vaginal cream containing the aqueous extract of A. millefolium for 7 days. Clinical and laboratory assessments were performed before and after the intervention. Minimum inhibitory concentration of the extract was evaluated with Broth micro-dilution procedure.

RESULTS

The Dermatology life quality index score showed significant reduction in both groups after treatment, but it was significantly more reduced in control group (p < 0.05). Improvement in vulvar erythema was observed in both groups with no statistically difference (p = 0.1). Vaginal culture was negative in term of Candida in 28(77 %) patients of control group and in 18(53 %) patient of experimental group (p < 0.05). The Minimum inhibitory concentration of the extract was 37.5 mg/mL for the standard strain.

DISCUSSION AND CONCLUSION

Study results showed that vaginal cream containing A. millefolium could reduce the complaints of vulvovaginal candidiasis. But, future studies with a larger sample size and different dosages are recommended to assess the outcomes of this new treatment.

Therapeutic Potential of Quercetin as an Antiatherosclerotic Agent in Atherosclerotic Cardiovascular Disease: A Review

Atherosclerotic cardiovascular disease (ASCVD) is one of the diseases with the highest morbidity and mortality globally. It causes a huge burden on families and caregivers and high costs for medicine and surgical interventions. Given expensive surgeries and failures of most conventional treatments, medical community tries to find a more cost-effective cure. Thus, attentions have been primarily focused on food or herbs. Quercetin (Qu) extracted from food, a flavonoid component, develops potentials of alternative or complementary medicine in atherosclerosis. Due to the wide range of health benefits, researchers have considered to apply Qu as a natural compound in therapy. This review is aimed to identify the antiatherosclerosis functions of Qu in treating ASCVD such as anti-inflammatory, antioxidant properties, effects on endothelium-dependent vasodilation, and blood lipid-lowering.

Phenolic Compounds Exerting Lipid-Regulatory, Anti-Inflammatory and Epigenetic Effects as Complementary Treatments in Cardiovascular Diseases

Atherosclerosis is the main process behind cardiovascular diseases (CVD), maladies which continue to be responsible for up to 70% of death worldwide. Despite the ongoing development of new and potent drugs, their incomplete efficacy, partial intolerance and numerous side effects make the search for new alternatives worthwhile. The focus of the scientific world turned to the potential of natural active compounds to prevent and treat CVD. Essential for effective prevention or treatment based on phytochemicals is to know their mechanisms of action according to their bioavailability and dosage. The present review is focused on the latest data about phenolic compounds and aims to collect and correlate the reliable existing knowledge concerning their molecular mechanisms of action to counteract important risk factors that contribute to the initiation and development of atherosclerosis: dyslipidemia, and oxidative and inflammatory-stress. The selection of phenolic compounds was made to prove their multiple benefic effects and endorse them as CVD remedies, complementary to allopathic drugs. The review also highlights some aspects that still need clear scientific explanations and draws up some new molecular approaches to validate phenolic compounds for CVD complementary therapy in the near future.

Metabolism and pharmacological activities of the natural health-benefiting compound diosmin

Diosmin is a famous natural flavonoid for treating chronic venous insufficiency and varicose veins.