-
1.
Flavanols from Nature: A Phytochemistry and Biological Activity Review.
Luo, Y, Jian, Y, Liu, Y, Jiang, S, Muhammad, D, Wang, W
Molecules (Basel, Switzerland). 2022;(3)
Abstract
Flavanols, a common class of secondary plant metabolites, exhibit several beneficial health properties by acting as antioxidant, anticarcinogen, cardioprotective, anti-microbial, anti-viral, and neuroprotective agents. Furthermore, some flavanols are considered functional ingredients in dairy products. Based on their structural features and health-promoting functions, flavanols have gained the attention of pharmacologists and botanists worldwide. This review collects and summarizes 121 flavanols comprising four categories: flavan-3-ols, flavan-4-ols, isoflavan-4-ols, and flavan-3,4-ols. The research of the various structural features and pharmacological activities of flavanols and their derivatives aims to lay the groundwork for subsequent research and expect to provide mentality and inspiration for the research. The current study provides a starting point for further research and development.
-
2.
Antiproliferative and palliative activity of flavonoids in colorectal cancer.
Fernández, J, Silván, B, Entrialgo-Cadierno, R, Villar, CJ, Capasso, R, Uranga, JA, Lombó, F, Abalo, R
Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie. 2021;:112241
Abstract
Flavonoids are plant bioactive compounds of great interest in nutrition and pharmacology, due to their remarkable properties as antioxidant, anti-inflammatory, antibacterial, antifungal and antitumor drugs. More than 5000 different flavonoids exist in nature, with a huge structural diversity and a plethora of interesting pharmacological properties. In this work, five flavonoids were tested for their potential use as antitumor drugs against three CRC cell lines (HCT116, HT-29 and T84). These cell lines represent three different stages of this tumor, one of which is metastatic. Xanthohumol showed the best antitumor activity on the three cancer cell lines, even better than that of the clinical drug 5-fluorouracil (5-FU), although no synergistic effect was observed in the combination therapy with this drug. On the other hand, apigenin and luteolin displayed slightly lower antitumor activities on these cancer cell lines but showed a synergistic effect in combination with 5-FU in the case of HTC116, which is of potential clinical interest. Furthermore, a literature review highlighted that these flavonoids show very interesting palliative effects on clinical symptoms such as diarrhea, mucositis, neuropathic pain and others often associated with the chemotherapy treatment of CRC. Flavonoids could provide a double effect for the combination treatment, potentiating the antitumor effect of 5-FU, and simultaneously, preventing important side effects of 5-FU chemotherapy.
-
3.
Flavonoids as potential phytotherapeutics to combat cytokine storm in SARS-CoV-2.
Gour, A, Manhas, D, Bag, S, Gorain, B, Nandi, U
Phytotherapy research : PTR. 2021;(8):4258-4283
-
-
Free full text
-
Abstract
Emergence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection, COVID-19, has become the global panic since December 2019, which urges the global healthcare professionals to identify novel therapeutics to counteract this pandemic. So far, there is no approved treatment available to control this public health issue; however, a few antiviral agents and repurposed drugs support the patients under medical supervision by compromising their adverse effects, especially in emergency conditions. Only a few vaccines have been approved to date. In this context, several plant natural products-based research studies are evidenced to play a crucial role in immunomodulation that can prevent the chances of infection as well as combat the cytokine release storm (CRS) generated during COVID-19 infection. In this present review, we have focused on flavonoids, especially epicatechin, epigallocatechin gallate, hesperidin, naringenin, quercetin, rutin, luteolin, baicalin, diosmin, ge nistein, biochanin A, and silymarin, which can counteract the virus-mediated elevated levels of inflammatory cytokines leading to multiple organ failure. In addition, a comprehensive discussion on available in silico, in vitro, and in vivo findings with critical analysis has also been evaluated, which might pave the way for further development of phytotherapeutics to identify the potential lead candidatetoward effective and safe management of the SARS-CoV-2 disease.
-
4.
Flavonoids Seen through the Energy Perspective.
Li, Z, Zhang, M, Haenen, GRMM, Vervoort, L, Moalin, M
International journal of molecular sciences. 2021;(1)
Abstract
In all life forms, opposing forces provide the energy that flows through networks in an organism, which fuels life. In this concept, health is the ability of an organism to maintain the balance between these opposing forces, which creates resilience, and a deranged flow of energy is the basis for diseases. Treatment should focus on adjusting the deranged flow of energy, e.g., by the redox modulating activity of antioxidants. A major group of antioxidants is formed by flavonoids, a group of polyphenolic compounds abundantly present in our diet. The objective here is to review how the redox modulation by flavonoids fits in the various concepts on the mode of action of bioactive compounds, so we can 'see' where there is overlap and where the missing links are. Based on this fundament, we should choose our research path aiming to 'understand' the redox modulating profile of specific flavonoids, so we can ultimately rationally apply the redox modulating power of flavonoids to improve our health.
-
5.
Baicalein, Baicalin, and Wogonin: Protective Effects against Ischemia-Induced Neurodegeneration in the Brain and Retina.
Pan, L, Cho, KS, Yi, I, To, CH, Chen, DF, Do, CW
Oxidative medicine and cellular longevity. 2021;:8377362
Abstract
Ischemia is a common pathological condition present in many neurodegenerative diseases, including ischemic stroke, retinal vascular occlusion, diabetic retinopathy, and glaucoma, threatening the sight and lives of millions of people globally. Ischemia can trigger excessive oxidative stress, inflammation, and vascular dysfunction, leading to the disruption of tissue homeostasis and, ultimately, cell death. Current therapies are very limited and have a narrow time window for effective treatment. Thus, there is an urgent need to develop more effective therapeutic options for ischemia-induced neural injuries. With emerging reports on the pharmacological properties of natural flavonoids, these compounds present potent antioxidative, anti-inflammatory, and antiapoptotic agents for the treatment of ischemic insults. Three major active flavonoids, baicalein, baicalin, and wogonin, have been extracted from Scutellaria baicalensis Georgi (S. baicalensis); all of which are reported to have low cytotoxicity. They have been demonstrated to exert promising pharmacological capabilities in preventing cell and tissue damage. This review focuses on the therapeutic potentials of these flavonoids against ischemia-induced neurotoxicity and damage in the brain and retina. The bioactivity and bioavailability of baicalein, baicalin, and wogonin are also discussed. It is with hope that the therapeutic potential of these flavonoids can be utilized and developed as natural treatments for ischemia-induced injuries of the central nervous system (CNS).
-
6.
Tea intake and cardiovascular disease: an umbrella review.
Keller, A, Wallace, TC
Annals of medicine. 2021;(1):929-944
-
-
Free full text
-
Abstract
Brewed tea (Camellia sinensis) is a major dietary source of flavonoids, in particular flavan-3-ols. Tea consumption has been suggested to be inversely associated with a decreased risk of cardiovascular disease (CVD). Several biological mechanisms support the inverse relationship between tea flavonoid intake and CVD risk. Given the recent accumulating evidence from various systematic reviews regarding the role of tea as a beverage in reducing CVD risk and severity, we conducted an umbrella review to describe and critically evaluate the totality of evidence to date. We searched the PubMed, Web of Science, Cochrane Database of Systematic Reviews, and BIOSIS databases for systematic reviews published between January 1, 2010 and February 22, 2020 reporting relationships between tea (C. sinensis) consumption and CVD mortality, CVD diagnosis or incidence, CVD events, stroke events, blood pressure, endothelial function, blood lipids and triglycerides, and inflammatory markers. Herein, we describe results from 23 included systematic reviews. Consistently consuming 2 cups of unsweet tea per day offers the right levels of flavonoids to potentially decrease CVD risk and its progression. This is supported by the consistency between a recent high-quality systematic review and dose-response meta-analyses of population-based studies demonstrating beneficial effects of consumption on CVD mortality, CVD events and stroke events and medium- to high-quality systematic reviews of intervention studies that further elucidate potential benefits on both validated (i.e., SBP, DBP, total cholesterol, and LDL-cholesterol) and emerging risk biomarkers of CVD (TNF-ɑ and IL-6). On the basis of this umbrella review, the consumption of tea as a beverage did not seem to be harmful to health; therefore, the benefits of moderate consumption likely outweigh risk. Future large, clinical intervention studies will provide better mechanistic insight with the ability to confirm the outcome effects shown across observational studies. The review protocol was registered on PROSPERO (https://www.crd.york.ac.uk/PROSPERO/) as CRD42020218159.KEY MESSAGESIt is reasonable to judge that 2 cups of unsweet tea per day has the potential to decrease CVD risk and progression due to its flavonoid content.The primary side effects of tea documented in human studies are hepatotoxicity and gastrointestinal disturbances (i.e., vomiting and diarrhea) after high-dose supplemental intake.Additional clinical research is needed to fully elucidate the effects of tea flavonoids on markers of CVD, as many studies were under-powered to detect changes.[Figure: see text].
-
7.
Impact of Dietary Flavanols on Microbiota, Immunity and Inflammation in Metabolic Diseases.
Martín, MÁ, Ramos, S
Nutrients. 2021;(3)
Abstract
Flavanols are natural occurring polyphenols abundant in fruits and vegetables to which have been attributed to beneficial effects on health, and also against metabolic diseases, such as diabetes, obesity and metabolic syndrome. These positive properties have been associated to the modulation of different molecular pathways, and importantly, to the regulation of immunological reactions (pro-inflammatory cytokines, chemokines, adhesion molecules, nuclear factor-κB [NF-κB], inducible enzymes), and the activity of cells of the immune system. In addition, flavanols can modulate the composition and function of gut microbiome in a prebiotic-like manner, resulting in the positive regulation of metabolic pathways and immune responses, and reduction of low-grade chronic inflammation. Moreover, the biotransformation of flavanols by gut bacteria increases their bioavailability generating a number of metabolites with potential to affect human metabolism, including during metabolic diseases. However, the exact mechanisms by which flavanols act on the microbiota and immune system to influence health and disease remain unclear, especially in humans where these connections have been scarcely explored. This review seeks to summarize recent advances on the complex interaction of flavanols with gut microbiota, immunity and inflammation focus on metabolic diseases.
-
8.
Establishing Relationship between Vitamins, Total Phenolic and Total Flavonoid Content and Antioxidant Activities in Various Honey Types.
Zawawi, N, Chong, PJ, Mohd Tom, NN, Saiful Anuar, NS, Mohammad, SM, Ismail, N, Jusoh, AZ
Molecules (Basel, Switzerland). 2021;(15)
Abstract
Honey is a well-known natural sweetener and is rich in natural antioxidants that prevent the occurrence of oxidative stress, which is responsible for many human diseases. Some of the biochemical compounds in honey that contribute to this property are vitamins and phenolic compounds such as phenolic acids and flavonoids. However, the extent to which these molecules contribute towards the antioxidant capacity in vitro is inconsistently reported, especially with the different analytical methods used, as well as other extrinsic factors that influence these molecules' availability. Therefore, by reviewing recently published works correlating the vitamin, total phenolic, and flavonoid content in honey with its antioxidant activities in vitro, this paper will establish a relationship between these parameters. Based on the literature, vitamins do not contribute to honey's antioxidant capacity; however, the content of phenolic acids and flavonoids has an impact on honey's antioxidant activity.
-
9.
Flavonoids as Inhibitors of Bacterial Efflux Pumps.
Waditzer, M, Bucar, F
Molecules (Basel, Switzerland). 2021;(22)
Abstract
Flavonoids are widely occurring secondary plant constituents, and are abundant in vegetable and fruit diets as well as herbal medicines. Therapeutic treatment options for bacterial infections are limited due to the spread of antimicrobial resistances. Hence, in a number of studies during the last few years, different classes of plant secondary metabolites as resistance-modifying agents have been carried out. In this review, we present the role of flavonoids as inhibitors of bacterial efflux pumps. Active compounds could be identified in the subclasses of chalcones, flavan-3-ols, flavanones, flavones, flavonols, flavonolignans and isoflavones; by far the majority of compounds were aglycones, although some glycosides like kaempferol glycosides with p-coumaroyl acylation showed remarkable results. Staphylococcus aureus NorA pump was the focus of many studies, followed by mycobacteria, whereas Gram-negative bacteria are still under-investigated.
-
10.
Potential role of flavonoids against SARS-CoV-2 induced diarrhea.
Paul, AK, Jahan, R, Bondhon, TA, Jannat, K, Hasan, A, Rahmatullah, M, Nissapatorn, V, Pereira, ML, Wiart, C
Tropical biomedicine. 2021;(3):360-365
Abstract
COVID-19, caused by the SARS-CoV-2 virus, can lead to massive inflammation in the gastrointestinal tract causing severe clinical symptoms. SARS-CoV-2 infects lungs after binding its spike proteins with alveolar angiotensin-converting enzyme 2 (ACE2), and it also triggers inflammation in the gastrointestinal tract. SARS-CoV-2 invades the gastrointestinal tract by interacting with Toll-like receptor-4 (TLR4) that induces the expression of ACE2. The influx of ACE2 facilitates cellular binding of more SARS-CoV-2 and causes massive gastrointestinal inflammation leading to diarrhea. Diarrhea prior to COVID-19 infection or COVID-19-induced diarrhea reportedly ends up in a poor prognosis for the patient. Flavonoids are part of traditional remedies for gastrointestinal disorders. Preclinical studies show that flavonoids can prevent infectious diarrhea. Recent studies show flavonoids can inhibit the multiplication of SARS-CoV-2. In combination with vitamin D, flavonoids possibly activate nuclear factor erythroid-derived-2-related factor 2 that downregulates ACE2 expression in cells. We suggest that flavonoids have the potential to prevent SARS-CoV-2 induced diarrhea.