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Bioactivity and Bioavailability of Phenols from Plants
Abstract
Many scientific and industrial groups and companies explore the diverse world of plant phenols and organic compounds with a hydroxyl group attached to an aromatic ring. Their structural variety, from simple phenolic acids to complex polyphenols and flavonoids, gives a wide spectrum of bioactive properties, making them crucial in plant biology and ecological dynamics. These properties are not just essential for plant survival and adaptation, serving as defense mechanisms, but also for human health. The chapter addresses two primary aspects: the bioactivity and bioavailability of plant phenols. The bioactivity section explores the different types of phenols found in plants, including polyphenols, flavonoids, and phenolic acids. It highlights common plant sources rich in phenols and the variability in phenol content among species due to genetic and environmental factors. Bioactive properties of phenols, such as antioxidant, anti-inflammatory, and antimicrobial potentials, are explored including the mechanisms of action and implications for human health. Additionally, the discussion about bioavailability outlines how phenols are absorbed, metabolized, and excreted in the human body, emphasizing the factors influencing their bioavailability, such as the food matrix and gut microbiota. The chapter concludes by exploring the therapeutic potential of phenols, dietary recommendations, and the need for continued research in this field.
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Plant products, especially medicinal herbs and spices, have been used for centuries as a remedy to support human health and improve the flavor of food. Therefore, the purpose of this study was to identify plant species distinguished by their high content of phenolic compounds and high antioxidant activity using advanced multivariate statistical techniques such as Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA). To realize the purpose of the study, the total phenolic (TPC) and flavonoids (FC) content, antioxidant activity (TAC) and Fe(II) ion chelating capacity (FIC) of medicinal herbs and spices from plants belonging to three botanical families, Lamiaceae, Apiaceae and Asteraceae were determined. The interpretation of the obtained data revealed that the studied samples are localized in the PCA and HCA plots according to their TPC, FC, TAC and FIC values. Chemometric analysis confirmed that medicinal herbs and spices from plants belonging to the Lamiaceae family are richer sources of phenolic compounds and exhibit stronger antioxidant activity than those raw materials from plants in the Apiaceae family. In addition, no significant differences were found in terms of TPC, FC, TAC and FIC values between medicinal herbs and spices from the same plant species, i.e., oregano (Origanum vulgare), common thyme (Thymus vulgaris), rosemary (Rosmarinus officinalis), caraway (Carum carvi) and lovage (Levisticum officinale). A close relationship between antioxidant properties and contents of phenolic compounds was also confirmed.
Phenolic compounds or polyphenols are among the most common compounds of secondary metabolism in plants. Their biosynthesis is characteristic of all plant cells and is carried out with the participation of the shikimate and acetate-malonate pathways. In this case, polyphenols of various structures are formed, such as phenylpropanoids, flavonoids, and various oligomeric and polymeric compounds of phenolic nature. Their number already exceeds 10,000. The diversity of phenolics affects their biological activity and functional role. Most of their representatives are characterized by interaction with reactive oxygen species, which manifests itself not only in plants but also in the human body, where they enter through food chains. Having a high biological activity, phenolic compounds are successfully used as medicines and nutritional supplements for the health of the population. The accumulation and biosynthesis of polyphenols in plants depend on many factors, including physiological–biochemical, molecular–genetic, and environmental factors. In the review, we present the latest literature data on the structure of various classes of phenolic compounds, their antioxidant activity, and their biosynthesis, including their molecular genetic aspects (genes and transfactors). Since plants grow with significant environmental changes on the planet, their response to the action of abiotic factors (light, UV radiation, temperature, and heavy metals) at the level of accumulation and composition of these secondary metabolites, as well as their metabolic regulation, is considered. Information is given about plant polyphenols as important and necessary components of functional nutrition and pharmaceutically valuable substances for the health of the population. Proposals on promising areas of research and development in the field of plant polyphenols are presented.
Objective:
This review describes the antioxidant activity of flavonoids as a subgroup of polyphenols and a partial or entire substitute for synthetic antioxidants.
Materials and methods:
All relevant databases were searched using the terms "Phytochemical", "Polyphenol", and "Flavonoid".
Results:
The oxidative reaction caused by free radicals is a reason for food spoilage, which causes unpleasant odor, loss of taste, and damaged tissues. The common antioxidants employed in foods include butylated hydroxyanisole, butylated hydroxytoluene, propyl gallate, and tert-butyl hydroquinone. Despite their high efficiency and potency, synthetic antioxidants have adverse effects on the human body, such as causing mutation and carcinogenicity. A whole and a group of them known as polyphenols possess high antioxidant activity. These compounds are potential antioxidants due to their capabilities such as scavenging free radicals, donating hydrogen atoms, and chelating metal cations. The antioxidant mechanism of action of flavonoids is transferring hydrogen atom to free radicals. Accordingly, the more the flavonoid structure makes the hydrogen transfer faster and easier, the more the flavonoid's antioxidant power will be. Therefore, the antioxidant activity of the flavonoids with hydroxyl groups in their structure is the highest among different flavonoids.
Conclusion:
In addition to health promotion and some disease prevention effects, various in vitro investigations have indicated that flavonoids possess high antioxidant activity that is comparable with synthetic antioxidants. However, to be commercially available, these compounds should be extracted from a low-price source with a high-performance method.
The use of natural compounds as an alternative to synthetic molecules has become a significant subject of interest in recent decades. Stilbenoids are a group of phenolic compounds found in many plant species and they have recently gained the focus of a multitude of studies in medicine and chemistry, resveratrol being the most representative molecule. In this review, we focused on the research that illustrates the therapeutic potential of this class of natural molecules considering various diseases with higher incidence rates. PubChem database was searched for bioactivities of natural stilbenoids, while several keywords (i.e., “stilbenoids”, “stilbenoid anticancer”) were used to query PubMed database for relevant studies. The diversity and the simplicity of stilbenes’ chemical structures together with the numerous biological sources are key elements that can simplify both the isolation of these compounds and the drug design of novel bioactive molecules. Resveratrol and other related compounds are heterogeneously distributed in plants and are mainly found in grapes and wine. Natural stilbenes were shown to possess a wide range of biological activities, such as antioxidant, anti-inflammatory, antihyperglycemic, cardioprotective, neuroprotective, and antineoplastic properties. While resveratrol is widely investigated for its benefits in various disorders, further studies are warranted to properly harness the therapeutic potential of less popular stilbenoid compounds.
Secondary metabolites, such as phenols and salicylic, play a crucial role in the regulation of development and tolerance mechanisms against a wide range of stresses. During adverse conditions such as biotic and abiotic stresses, plants induce the biosynthesis of phenolic compounds to provide tolerance. Phenolics are secondary aromatic metabolites synthesized through the shikimate/phenylpropanoid pathway or polyketide acetate/malonate pathway, which produce monomeric and polymeric phenolics. Phenolic compounds in plants not only take part in preventing stresses but also in regulating physiological activities. These compounds significantly regulate both below- and above-ground defense mechanisms. Plants synthesize thousands of phenolic compounds throughout their evolution to survive in changing environments. Environmental factors, such as high light, cold, drought, heavy metals, etc., increase the accumulation of phenolics to neutralize any toxic effects. This review focuses on the biosynthesis of phenolic compounds and their updated studies against abiotic stresses.
Salvia semiatrata Zucc. (Lamiaceae) is endemic to Oaxaca, Mexico, and is known for its analgesic properties. Terpenoids and phenolic compounds with antinociceptive potential have been characterised from this species. The aim of this research was to determine the variation in terpenoids and flavonoids in ethyl acetate extracts of S. semiatrata collected from ten different localities, as well as to evaluate the antinociceptive effect between plants with higher and lower contents of these secondary metabolites. Quantification of S. semiatrata compounds was performed via HPLC-DAD, whereas in vivo evaluation of the antinociceptive effect was performed via formalin test. The results showed that the most abundant groups of metabolites are oleanolic acid (89.60–59.20 µg/mg), quercetin (34.81–16.28 µg/mg), catechin (11.30–9.30 µg/mg), and 7-keto-neoclerodan-3,13-dien-18,19:15,16-diolide (7-keto) (8.01–4.76 µg/mg). Principal component and canonical correspondence analysis showed that the most contrasting localities in terms of compound content and climatic variables are Miahuatlán and Santiago Huauclilla. The differences in metabolite content between the two locations did not affect the antinociceptive effects evaluated at a dose of 300 mg/kg, p.o. In conclusion, the results indicate that S. semiatrata is effective in relieving pain, regardless of the site of collection, reinforcing its traditional use as analgesic.
The purpose of this study was to obtain additional value of hydrolates (HYs), by-products during essential oil distillation. Chemical compositions of angelica and hop hydrolates were determined and compared with the corresponding essential oils, and their biological potential tested. Steam distilled essential oils and hydrolates were analyzed by GC-MS, and their biological potential was tested for antioxidant (DPPH, ABTS and reduction power) and antimicrobial activities (against nine bacteria and fungi). Hydrolates were additionally tested for allelopathic activity (on corn and redroot pigweed). The investigated essential oils have totally different volatile profiles and aromas in comparison to hydrolates. The most dominant constituents in the angelica essential oil were limonene, β-phellandrene, α-pinene, α-phellandrene and δ-3-carene, while in the hydrolate it was trans-verbenol. In the hop essential oil the most dominant constituents were myrcene and α-humulene, while in the hydrolate isovaleric acid and linalool were dominant. Angelica essential oil showed higher antioxidant activity in comparison with hop, while hydrolates displayed significantly lower antioxidant activity. Low antimicrobial potential of both essential oils was observed in the case of Enterococcus faecalis, Escherichia coli, Saccharomyces cerevisiae and Candida albicans. Antimicrobial activity was not detected in neither of the two hydrolates. In terms of allelopathic activity, hydrolates showed a dose-dependent decreasing activity on germination and seedling growth of corn and redroot pigweed. Angelica and hop essential oils are mainly used in food, cosmetic and pharmaceutical industries because of their aroma. Hydrolates, as by-products, possess potential for application in agriculture as natural herbicides.
Graphical Abstract
The rise in global temperature also favors the multiplication of pests and pathogens, which calls into question global food security. Plants have developed special coping mechanisms since they are sessile and lack an immune system. These mechanisms use a variety of secondary metabolites as weapons to avoid obstacles, adapt to their changing environment, and survive in less-than-ideal circumstances. Plant secondary metabolites include phenolic compounds, alkaloids, glycosides, and terpenoids, which are stored in specialized structures such as latex, trichomes, resin ducts, etc. Secondary metabolites help the plants to be safe from biotic stressors, either by repelling them or attracting their enemies, or exerting toxic effects on them. Modern omics technologies enable the elucidation of the structural and functional properties of these metabolites along with their biosynthesis. A better understanding of the enzymatic regulations and molecular mechanisms aids in the exploitation of secondary metabolites in modern pest management approaches such as biopesticides and integrated pest management. The current review provides an overview of the major plant secondary metabolites that play significant roles in enhancing biotic stress tolerance. It examines their involvement in both indirect and direct defense mechanisms, as well as their storage within plant tissues. Additionally, this review explores the importance of metabolomics approaches in elucidating the significance of secondary metabolites in biotic stress tolerance. The application of metabolic engineering in breeding for biotic stress resistance is discussed, along with the exploitation of secondary metabolites for sustainable pest management.
Phenolic compounds are natural substances that are produced through the secondary metabolism of plants, fungi, and bacteria, in addition to being produced by chemical synthesis. These compounds have anti-inflammatory, antioxidant, and antimicrobial properties, among others. In this way, Brazil represents one of the most promising countries regarding phenolic compounds since it has a heterogeneous flora, with the presence of six distinct biomes (Cerrado, Amazon, Atlantic Forest, Caatinga, Pantanal, and Pampa). Recently, several studies have pointed to an era of antimicrobial resistance due to the unrestricted and large-scale use of antibiotics, which led to the emergence of some survival mechanisms of bacteria to these compounds. Therefore, the use of natural substances with antimicrobial action can help combat these resistant pathogens and represent a natural alternative that may be useful in animal nutrition for direct application in food and can be used in human nutrition to promote health. Therefore, this study aimed to (i) evaluate the phenolic compounds with antimicrobial properties isolated from plants present in Brazil, (ii) discuss the compounds across different classes (flavonoids, xanthones, coumarins, phenolic acids, and others), and (iii) address the structure–activity relationship of phenolic compounds that lead to antimicrobial action.
Chamomile is one of the most consumed medicinal plants worldwide. Various chamomile preparations are widely used in various branches of both traditional and modern pharmacy. However, in order to obtain an extract with a high content of the desired components, it is necessary to optimize key extraction parameters. In the present study, optimization of process parameters was performed using the artificial neural networks (ANN) model using a solid-to-solvent ratio, microwave power and time as inputs, while the outputs were the yield of the total phenolic compounds (TPC). Optimized extraction conditions were as follows: a solid-to-solvent ratio of 1:80, microwave power of 400 W, extraction time of 30 min. ANN predicted the content of the total phenolic compounds, which was later experimentally confirmed. The extract obtained under optimal conditions was characterized by rich composition and high biological activity. Additionally, chamomile extract showed promising properties as growth media for probiotics. The study could make a valuable scientific contribution to the application of modern statistical designs and modelling to improve extraction techniques.
Phenolic compounds (PCs) are widespread secondary metabolites with potent biological activity. Their sources are mainly plants from cultivated and natural states, providing valuable protective and health-promoting extracts. The wide biological activity of PCs (antioxidant, anti-inflammatory, antimicrobial, antiatherosclerotic, antidiabetic, antiallergic, prebiotic, antimutagenic) means that new sources of PCs are constantly being sought, as exemplified by extracting these compounds from tissue culture or agricultural by-products. Plant phenols show marked qualitative and quantitative variation not only at different genetic levels (between and within species and clones) but also between different physiological and developmental stages. Assessing genetic and seasonal variations in phenolic content and activity allows for selecting the best time to harvest the plant. Learning about the causes of PCs’ variability and putting this knowledge into practice can significantly increase PCs’ yields and extract the most valuable compounds. The health-promoting properties resulting from consuming products rich in plant PCs are undeniable, so it is worth promoting high-phenolic products as a regular diet. This paper presents an overview of different sources of PCs for use as potential therapeutic alternatives. Additionally, factors of variation in the phenolic complex at the genome and ontogeny levels, relevant in practical terms and as a basis for further scientific research, are presented.
Bioactive compounds, including terpenoids, polyphenols, alkaloids and other nitrogen-containing constituents, exert various beneficial effects arising from their antioxidant and anti-inflammatory properties. These compounds can be found in vegetables, fruits, grains, spices and their derived foods and beverages such as tea, olive oil, fruit juices, wine, chocolate and beer. Agricultural production and the food supply chain are major sources of food wastes, which can become resources, as they are rich in bioactive compounds. The aim of this review is to highlight recent articles demonstrating the numerous potential uses of products and by-products of the agro-food supply chain, which can have various applications.
Objectives:
In recent decades, the trend for treating diabetes mellitus (DM) has shifted toward alternative medicines that are obtained from plant sources. Existing literature suggests that phenolic compounds derived from plants possess promising health-promoting properties. This study aimed to discuss the role of plant-derived phenolic compounds in the effective treatment and management of diabetes.
Methods:
Information about plant secondary metabolites, phenolic compounds, and their role in the treatment and management of diabetes was collected from different databases, such as Pubmed, ScienceDirect, Scopus, and Google Scholar. Keywords like secondary metabolites, phenolic compounds, simple phenol, flavonoids, lignans, stilbenes, and diabetes were searched. Research and review articles with relevant information were included in the study.
Results:
Anti-diabetic studies of the four major classes of phenolic compounds were included in this review. The plant-derived phenolic compounds were reported to have potent anti-diabetic activities. However, each class of phenolic compounds was found to behave differently according to various mechanisms.
Conclusion:
The obtained results suggest that phenolic compounds derived from natural sources display promising anti-diabetic activities. Based on the available information, it can be concluded that phenolic compounds obtained from various natural sources play key roles in the treatment and management of diabetes.
The genus Ocimum has many species that are used to treat diverse kinds of illnesses and sicknesses from ancient times. One of them, Ocimum basilicum L., commonly known as basil, has a vital role due to its various medicinal goods. It is best known as a plant with pharmacological activities, but also as an antioxidant, antimicrobial, and larvicidal agent. Although it has been traditionally used in Serbia in traditional medicine for centuries as an insecticidal, antibacterial, and antifungal plant as well as a traditional culinary plant, none of the O. basilicum varieties have been commercialised until today. There are significant numbers of information across the world that oils and by-products are part of the global market, but no references to the essential oil composition of Serbian plants were found. Therefore, the objective of this work was to evaluate the antioxidant and antimicrobial potentials of essential oil and hydrolate of two different varieties: O. basilicum var. genovese and Ocimum. basilicum var. minimum originating from Serbia for further industrial production of antimicrobial- and/or antioxidant-valued products. The results of this study confirm that essential oils of O. basilicum var. genovese and var. minimum represent a significant source of bioactive compounds, especially linalool, with a high rate of biological activities. Similar behaviour is observed for hydrolates, which are the by-product of the essential oil distillation process and can be utilised as bioactive-rich waste in further investigation.
Winter savory (Satureja montana L.) is a well-known spice and medicinal plant with a wide range of activities and applications. Two subspecies of S. montana, subsp. montana and subsp. variegata, were used for the preparation of seven different extracts: steam distillation (essential oil (EO) and hydrolate (HY)), subcritical water (SWE), ultrasound-assisted (UAE-MeOH and UAE-H2O), and microwave-assisted (MAE-MeOH and MAE-H2O) extraction. The obtained EOs, HYs, and extracts were used for an in vitro evaluation of the antioxidant activity (DPPH, ABTS, reducing power, and superoxide anion methods) and in vitro antimicrobial activity against Bacillus cereus, Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Salmonella Typhimurium, Saccharomyces cerevisiae, and Candida albicans. The antimicrobial screening was conducted using disk-diffusion assessment, minimal inhibitory concentration, time–kill kinetics modeling, and pharmacodynamic study of the biocide effect. The total phenolic content (TPC) was highest in EO, followed by SWE, MAE, and UAE, and the lowest was in HY. The highest antimicrobial activity shows EO and SWE for both varieties, while different UAE and MAE extracts have not exhibited antimicrobial activity. The natural antimicrobials in the S. montana extract samples obtained by green extraction methods, indicated the possibility of ecologically and economically better solutions for future in vivo application of the selected plant subspecies.
Quercetin, as a member of flavonoids, has emerged as a potential therapeutic agent in cardiovascular diseases (CVDs) in recent decades. In this comprehensive literature review, our goal was a critical appraisal of the pathophysiological mechanisms of quercetin in relation to the classical cardiovascular risk factors (e.g., hyperlipidemia), atherosclerosis, etc. We also assessed experimental and clinical data about its potential application in CVDs. Experimental studies including both in vitro methods and in vivo animal models mainly outline the following effects of quercetin: (1) antihypertensive, (2) hypolipidemic, (3) hypoglycemic, (4) anti-atherosclerotic, and (5) cardioprotective (suppressed cardiotoxicity). From the clinical point of view, there are human studies and meta-analyses implicating its beneficial effects on glycemic and lipid parameters. In contrast, other human studies failed to demonstrate consistent favorable effects of quercetin on other cardiometabolic risk factors such as MS, obesity, and hypertension, underlying the need for further investigation. Analyzing the reason of this inconsistency, we identified significant drawbacks in the clinical trials’ design, while the absence of pharmacokinetic/pharmacodynamic tests prior to the studies attenuated the power of clinical results. Therefore, additional well-designed preclinical and clinical studies are required to examine the therapeutic mechanisms and clinical efficacy of quercetin in CVDs.
This study aimed to investigate the chemical composition of steam distillate essential oil and corresponding hydrolate obtained from S. officinalis grown in Serbia, as well as the influence of weather conditions (temperature and precipitations) on their chemical profiles. Furthermore, their antimicrobial activity was investigated in vitro. The main compounds in essential oil were cis-thujone, followed by camphor, trans-thujone, and 1,8-cineole, while hydrolate was slightly different from the essential oil, with camphor, cis-thujone, and 1,8-cineole as the main compounds. Among the eight respiratory-associated microorganisms, Klebsiella oxytoca was the most sensitive to the tested EOs (minimum inhibitory concentration (MIC)/minimal bactericidal/fungicidal concentration (MBC/MFC) were 14.20 and 28.4 μL mL⁻¹, respectively). MIC and MBC values of other tested bacteria ranged between 28.40 and 227.25 μL mL⁻¹ while for Candida albicans MIC/MFC ranged from 28.40/56.81 to 56.81–113.63 μL mL⁻¹. Antibiotic susceptibility patterns for the analyzed eight respiratory-associated microorganisms showed an intermediate level of resistance to commonly used antibiotics such as ampicillin, levofloxacin, and ciprofloxacin. As a preliminary approach to the antimicrobial profiling of the tested EO, the obtained results revealed that the tested samples possess remarkable antibacterial activities and could be used to develop pharmaceutical formulations as an alternative to conventional antibiotic therapy.
Steam distillation was used for the isolation of Dracocephalum moldavica L. (Moldavian dragonhead) essential oil (DMEO). This aromatic herbaceous plant is widespread across the Northern Hemisphere regions and has been utilized in health-improving studies and applications. In addition to the DMEO, the hydrolate (DMH), a byproduct of the distillation process, was also collected. The DMEO and DMH were analyzed and compared in terms of their chemical composition, as well as their in vitro biological activities. The main component in DMEO was geranyl acetate, while geranial was dominant in DMH. The DMEO demonstrated better antioxidant and antimicrobial activities compared with the DMH against Staphylococcus aureus, Escherichia coli, Salmonella Typhimurium, and Listeria monocytogenes, which represent sources of food-borne illness at the global level. The DMEO and DMH show promise as antioxidant and antimicrobial additives to various products.
Phenolic compounds are the most abundant secondary metabolites in plants, showing a wide range of distinct biological activities, have received more and more attention in recent years. This review aims to gather and systematize available information on the phenolic compounds from plants by discussing different types of phenolic compounds, extraction, and analysis methods, with an emphasis on their potential biological activities. The research direction and problems that should be paid attention to in the future are also put forward to provide some references for the further study of phenolic compounds.
Inflammation is a natural protective mechanism that occurs when the body’s tissue homeostatic mechanisms are disrupted by biotic, physical, or chemical agents. The immune response generates pro-inflammatory mediators, but excessive output, such as chronic inflammation, contributes to many persistent diseases. Some phenolic compounds work in tandem with nonsteroidal anti-inflammatory drugs (NSAIDs) to inhibit pro-inflammatory mediators’ activity or gene expression, including cyclooxygenase (COX). Various phenolic compounds can also act on transcription factors, such as nuclear factor-κB (NF-κB) or nuclear factor-erythroid factor 2-related factor 2 (Nrf-2), to up-or downregulate elements within the antioxidant response pathways. Phenolic compounds can inhibit enzymes associated with the development of human diseases and have been used to treat various common human ailments, including hypertension, metabolic problems, incendiary infections, and neurodegenerative diseases. The inhibition of the angiotensin-converting enzyme (ACE) by phenolic compounds has been used to treat hypertension. The inhibition of carbohydrate hydrolyzing enzyme represents a type 2 diabetes mellitus therapy, and cholinesterase inhibition has been applied to treat Alzheimer’s disease (AD). Phenolic compounds have also demonstrated anti-inflammatory properties to treat skin diseases, rheumatoid arthritis, and inflammatory bowel disease. Plant extracts and phenolic compounds exert protective effects against oxidative stress and inflammation caused by airborne particulate matter, in addition to a range of anti-inflammatory, anticancer, anti-aging, antibacterial, and antiviral activities. Dietary polyphenols have been used to prevent and treat allergy-related diseases. The chemical and biological contributions of phenolic compounds to cardiovascular disease have also been described. This review summarizes the recent progress delineating the multifunctional roles of phenolic compounds, including their anti-inflammatory properties and the molecular pathways through which they exert anti-inflammatory effects on metabolic disorders. This study also discusses current issues and potential prospects for the therapeutic application of phenolic compounds to various human diseases.
The presence of nutritional and health-benefiting compounds has increased awareness of orphan leafy vegetables such as Cleome gynandra (CG), whose phytochemicals vary among accessions and organs during growth. This study investigated the polyphenol accumulation and antioxidant activities (AOA) of eight CG accessions from the vegetative stage to the seed set stage. Plants were separated into leaves and stem (LS), flowers, and silique organs, and extracts were analyzed for total phenolic content (TPC), total flavonoid content (TFC), rutin and astragalin content, and AOA using 2,2-diphenyl-1-picrylhydrazyl-hydrate (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS). There were significant interaction effects of growth stages and accessions that contributed to changes in compounds content and AOA. TPC accumulated in plant generative parts, whereas flavonoids accumulated in young plant organs. HPLC profiling revealed that rutin was the most abundant compound in all organs, with flowers having the highest levels, while astragalin was only found in flowers. Silique extracts, particularly accession KF-14, recorded the highest TPC, which corresponded to the strongest radical scavenging activity in ABTS and DPPH assays and a strong linear correlation. The germplasm contained accessions with significantly different and varying levels of bioactive compounds and AOA. These findings potentiate the exploitation of CG organs such as siliques for AOA, flowers for rutin and astragalin, and young shoots for flavonoids. Moreover, the significant accumulation of the compounds in particular accessions of the germplasms suggest that such superior accessions may be useful candidates in genetic breeding programs to improve CG vegetable.
Flavonoids are an important class of secondary metabolites widely found in plants, contributing to plant growth and development and having prominent applications in food and medicine. The biosynthesis of flavonoids has long been the focus of intense research in plant biology. Flavonoids are derived from the phenylpropanoid metabolic pathway, and have a basic structure that comprises a C15 benzene ring structure of C6-C3-C6. Over recent decades, a considerable number of studies have been directed at elucidating the mechanisms involved in flavonoid biosynthesis in plants. In this review, we systematically summarize the flavonoid biosynthetic pathway. We further assemble an exhaustive map of flavonoid biosynthesis in plants comprising eight branches (stilbene, aurone, flavone, isoflavone, flavonol, phlobaphene, proanthocyanidin, and anthocyanin biosynthesis) and four important intermediate metabolites (chalcone, flavanone, dihydroflavonol, and leucoanthocyanidin). This review affords a comprehensive overview of the current knowledge regarding flavonoid biosynthesis, and provides the theoretical basis for further elucidating the pathways involved in the biosynthesis of flavonoids, which will aid in better understanding their functions and potential uses.
Increased effectiveness and decreasing toxicity are prime objectives in drug research. Overwhelming evidence suggests the use of appropriate combination therapy for the better efficacy of drugs owing to their synergistic profile. Dietary active constituents play a major role in health outcomes. Therefore, it is possible to increase the effectiveness of the drug by combining contemporary medication with active natural/semi-synthetic constituents. One such dietary constituent, caffeic acid (CA), is a by-product of the shikimate pathway in plants and is a polyphenol of hydroxycinnamic acid class. Extensive research on CA has proposed its efficacy against inflammatory, neurodegenerative, oncologic, and metabolic disorders. The synergistic/additive effects of CA in combination with drugs like caffeine, metformin, pioglitazone, and quercetin have been reported in several experimental models and thus the present review is an attempt to consolidate outcomes of this research. Multi-target-based mechanistic studies will facilitate the development of effective combination regimens of CA.
ROS (reactive oxygen species) are produced via the noncomplete reduction in molecular oxygen in the mitochondria of higher organisms. The produced ROS are placed in various cell compartments, such as the mitochondria, cytoplasm, and endoplasmic reticulum. In general, there is an equilibrium between the synthesis of ROS and their reduction by the natural antioxidant defense system, called the redox system. Therefore, when this balance is upset, the excess ROS production can affect different macromolecules, such as proteins, lipids, nucleic acids, and sugars, which can lead to an electronic imbalance than oxidation of these macromolecules. Recently, it has also been shown that ROS produced at the cellular level can affect different signaling pathways that participate in the stimulation of transcription factors linked to cell proliferation and, consequently, to the carcinogenesis process. Indeed, ROS can activate the pathway of tyrosine kinase, MAP kinase, IKK, NF-KB, phosphoinositol 3 phosphate, and hypoxia-inducible factor (HIF). The activation of these signaling pathways directly contributes to the accelerated proliferation process and, as a result, the appearance of cancer. In addition, the use of antioxidants, especially natural ones, is now a major issue in the approach to cancer prevention. Some natural molecules, especially phytochemicals isolated from medicinal plants, have now shown interesting preclinical and clinical results.
In recent years, more attention has been paid to natural sources of antioxidants. Flavonoids are natural substances synthesized in several parts of plants that exhibit a high antioxidant capacity. They are a large family, presenting several classes based on their basic structure. Flavonoids have the ability to control the accumulation of reactive oxygen species (ROS) via scavenger ROS when they are formed. Therefore, these antioxidant compounds have an important role in plant stress tolerance and a high relevance in human health, mainly due to their anti-inflammatory and antimicrobial properties. In addition, flavonoids have several applications in the food industry as preservatives, pigments, and antioxidants, as well as in other industries such as cosmetics and pharmaceuticals. However, flavonoids application for industrial purposes implies extraction processes with high purity and quality. Several methodologies have been developed aimed at increasing flavonoid extraction yield and being environmentally friendly. This review presents the most abundant natural flavonoids, their structure and chemical characteristics, extraction methods, and biological activity.
Polyphenols, such as flavonoids and phenolic acids, are a group of specialized metabolites in plants that largely aid in plant defense by deterring biotic stressors and alleviating abiotic stress. Polyphenols offer a wide range of medical applications, acting as preventative and active treatments for diseases such as cancers and diabetes. Recently, researchers have proposed that polyphenols may contribute to certain applications aimed at tackling challenges related to the COVID-19 pandemic. Understanding the beneficial impacts of phytochemicals, such as polyphenols, could potentially help prepare society for future pandemics. Thus far, most reviews have focused on polyphenols in cancer prevention and treatment. This review aims to provide a comprehensive discussion on the critical roles that polyphenols play in both plant chemical defense and human health based on the most recent studies while highlighting prospective avenues for future research, as well as the implications for phytochemical-based applications in both agricultural and medical fields.
Tetrastigma angustifolia (Roxb.) Deb is an evergreen shrub belonging to the family Vitaceae. This plant species has been used for thousand years in Ayurvedic medicine. Ethnomedicinal study also documents the use of T. angustifolia leaves in the management of diabetes. On the other hand, Oxalis debilis Kunth. is a tristylous plant commonly known as pink woodsorrel belong to the family Oxalidaceae. This plant has been used traditionally for the treatment of dysentery and diarrhea. Ethnobotanical study also reports the use of leaf decoction of O. debilis in the treatment of diabetes. In our earlier work, the antidiabetic activity of hydro-alcoholic leaf extracts of T. angustifolia and O. debilis have been reported. In spite of ethnomedicinal implications and several scientific studies in the recent past, phytochemical investigations in support of the antidiabetic potential of these plant species are yet to be explored. Therefore, the present study was aimed at the isolation of bioac-tive phytoconstituents as antidiabetic principle(s) from T. angustifolia and O. debilis leaves. In this paper, two bioactive compounds, namely apigenin derivative (AGD) and stigmasterol (STM) were isolated from the methanolic leaf extracts of T. angustifolia and O. debilis, respectively by column chromatographic technique. The structures of the isolated compounds were established by spectroscopic/ spectrometric techniques including FT-IR, 1 H NMR and 13 C NMR and Mass. The isolated flavonoids were identified as 8-hydroxyapige-nin 7-O-b-D-glucopyranoside, a derivative of apigenin (AGD) and stigmasta-5,22-dien-3b-ol i.e., stigmas-terol (STM). The antidiabetic potential of AGD and STM was evaluated by in vitro a-glucosidase and a-amylase inhibitory assays. To validate the antidiabetic efficacy, molecular docking and dynamics studies were performed using AutoDock Vina and GROMACS software. In vitro assays revealed the antidiabetic potential of AGD and STM with a-glucosidase and a-amylase inhibitory activities. From docking and MD simulation studies, promising binding affinity of AGD and STM for human lysosomal a-glucosidase (5NN8) and human pancreatic a-amylase enzymes (1B2Y) with favorable binding modes, stable protein-ligand complexes and well defined protein-ligand interactions were observed. Based on in vitro and in silico studies, our study reports the antidiabetic potential of the isolated apigenin derivative, AGD (a new flavonoid molecule) and stigmasterol, STM (an existing plant sterol) with a-glucosidase and a-amylase inhibitory activities. However , the flavonoid molecule, AGD possesses better antidiabetic profile than the steroid molecule, STM particularly against human a-amylase enzyme. Our present investigation successfully validates the traditional as well as ethnomedicinal claims of T. angustifolia and O. debilis as antidiabetic medicines.
Background
Natural plants and plant-derived formulations have been used by mankind from the ancient period of time. For the past few years, many investigations elaborated the therapeutic potential of various secondary chemicals present in the plants. Literature revealed that the various secondary metabolites, viz. phenolics and flavonoids, are responsible for a variety of therapeutic action in humans.
Main body
In the present review, an attempt has been made to compile the exploration of natural phenolic compounds with major emphasis on flavonoids and their therapeutic potential too. Interestingly, long-term intake of many dietary foods (rich in phenolics) proved to be protective against the development and management of diabetes, cancer, osteoporosis, cardiovascular diseases and neurodegenerative diseases, etc.
Conclusion
This review presents an overview of flavonoid compounds to use them as a potential therapeutic alternative in various diseases and disorders. In addition, the present understanding of phenolics and flavonoids will serve as the basis for the next scientific studies.
Polyphenols are a group of phytochemicals with potential health-promoting effects. They are classified as flavonoid (flavonols, flavanols, flavones, flavanones, isoflavones, and anthocyanins) and non-flavonoid molecules (phenolic acids, hydroxycinnamic acids, lignans, stilbenes, and tannins). Although an increasing number of trials have shown a correlation among polyphenol consumption and a reduction in risk factors for chronic diseases, discrepancies in explaining their positive effects have been found in terms of the bioavailability. In fact, polyphenols show a low bioavailability due to several factors: interaction with the food matrix, the metabolic processes mediated by the liver (phase I and II metabolism), intestine and microbiota. On the other hand, the biological activities of phenol compounds may be mediated by their metabolites, which are produced in vivo, and recent studies have confirmed that these molecules may have antioxidant and anti-phlogistic properties. This review discusses the studies performed in vivo, which consider the polyphenol bioavailability and their different food sources. Factors influencing the biological effects of the main classes of polyphenols are also considered.
The purpose of this study was to investigate if baicalein and chlorogenic acid could inhibit the inflammatory responses induced by- and protect against- infectious bursal disease virus (IBDV) in chicken embryonic eggs. Nine-day-old embryonated chicken eggs were randomly divided into 3 groups of 50 eggs per group: 1) treatment with varying concentrations of baicalein, 2) treatment with varying concentrations of chlorogenic acid, or 3) left untreated as a control. Forty-eight hours after hatching, each group was inoculated with a vvIBDV isolate, and the survival of the embryo was monitored daily until the embryonic livers were collected 72 h after inoculation. Following IBDV infection, the viral loads in the embryonic livers were evaluated using qRT-PCR, and the hepatic content of inflammatory mediators, such as histamine, IL-1β, TNF-a, and nuclear factor-kappa B (NF-κB), were examined. Significant anti-viral potential was demonstrated at concentrations of 108 and 215 μg/egg of baicalein and chlorogenic acid, respectively. We observed a concentration-dependent response in the anti-viral properties of these chemicals. Treating the embryos with baicalein and chlorogenic acid significantly reduced histamine production. Moreover, pretreatment with baicalein and chlorogenic acid significantly inhibited NF-κB activation, and this inhibited the subsequent production of the proinflammatory cytokines TNF-a and IL-1β in the context of IBDV infection. These findings suggest that baicalein and chlorogenic acid have anti-IBDV properties, and they may be useful in the prevention of inflammation-related diseases.
Abiotic stressors such as extreme temperatures, drought, flood, light, salt, and heavy metals alter biological diversity and crop production worldwide. Therefore, it is important to know the mechanisms by which plants cope with stress conditions. Polyphenols, which are the largest group of plant-specialized metabolites, are generally recognized as molecules involved in stress protection in plants. This diverse group of metabolites contains various structures, from simple forms consisting of one aromatic ring to more complex ones consisting of large number of polymerized molecules. Consequently, all these molecules, depending on their structure, may show different roles in plant growth, development, and stress protection. In the present review, we aimed to summarize data on how different polyphenol structures influence their biological activity and their roles in abiotic stress responses. We focused our review on phenolic acids, flavonoids, stilbenoids, and lignans.
Flavonoids participate in several plant processes such as growth and physiological protection in adverse environments. In this study, we investigated the combined effects of eCO2 and cadmium (Cd)-contaminated soils on the total flavonoid and monomer contents in the leaves of Robinia pseudoacacia L. seedlings. Elevated CO2, Cd, and eCO2+ Cd increased the total flavonoids in the leaves relative to the control, and eCO2 mostly increased (p < 0.05) the total flavonoid content under Cd exposure. Elevated CO2 increased (p < 0.05) robinin, rutin, and acacetin contents in the leaves of 45-day seedlings and decreased (p < 0.05) the content of robinin and acacetin at 90 and 135 d under Cd exposure except for robinin at day 45 under Cd1 and acacetin on day 135 under Cd1. Quercetin content decreased (p < 0.05) under the combined conditions relative to Cd alone. Kaempferol in the leaves was only detected under eCO2 on day 135. The responses of total chlorophyll, total soluble sugars, starch, C, N, S, and the C/N ratio in the leaves to eCO2 significantly affected the synthesis of total flavonoids and monomers under Cd exposure. Overall, rutin was more sensitive to eCO2+ Cd than the other flavonoids. Cadmium, CO2, and time had significant interactive effects on the synthesis of flavonoids in the leaves of R. pseudoacacia L. seedlings. Elevated CO2 may improve the protection and defense system of seedlings grown in Cd-contaminated soils by promoting the synthesis of total flavonoids, although robinin, rutin, quercetin, and acacetin yields may reduce with time. Additionally, increased Cd in the leaves suggested that eCO2 could improve the phytoremediation of Cd-contaminated soils.
Alzheimer’s disease (AD) is a progressive cortex and hippocampal neurodegenerative disease which ultimately causes cognitively impaired decline in patients. The AD pathogen is a very complex process, including aggregation of Aβ (β-amyloid peptides), phosphorylation of tau-proteins, and chronic inflammation. Exactly, resveratrol, a polyphenol present in red wine, and many plants are indicated to show the neuroprotective effect on mechanisms mostly above. Resveratrol plays an important role in promotion of non-amyloidogenic cleavage of the amyloid precursor protein. It also enhances the clearance of amyloid beta-peptides and reduces the damage of neurons. Most experimental research on AD and resveratrol has been performed in many species, both in vitro and in vivo, during the last few years. Nevertheless, resveratrol’s effects are restricted by its bioavailability in the reservoir. Therefore, scientists have tried to improve its efficiency by using different methods. This review focuses on recent work done on the cell and animal cultures and also focuses on the neuroprotective molecular mechanisms of resveratrol. It also discusses about the therapeutic potential onto the treatment of AD.
Luteolin, kaempferol, apigenin and quercetin are four common flavonol glycoside compounds found in many plants that possess multiple biological activities. The current study focused on their anti-inflammatory and antioxidant activities in vitro by assaying the NO content, phagocytosis, DPPH and ABTS radical scavenging activities and ferric reducing antioxidant power. This study indicated that all four compounds at concentrations of 50, 100 and 200 μM could reduce both the concentration of NO and phagocytosis; their antioxidant activities increased as the concentration increased from 0.5 to 32.0 μg/ml; the IC50 DPPH values were 2.099, 5.318, 1.84, 10.5 and 3.028 μg/ml for luteolin, kaempferol, quercetin, BHT and VC, respectively; the IC50 ABTS values were 0.59, 0.8506, 0.8243, 0.5083, 1.4497 and 2.1563 μg/ml for luteolin, kaempferol, apigenin, quercetin, BHT and VC, respectively; and the FRAP values ranged from 0.0101 to 0.0402 mmol Fe²⁺/μg/ml for the six compounds. Compared with the test results, quercetin is a perfect anti-inflammatory and antioxidant agent that has potential as an adjuvant treatment for inflammatory diseases and oxidative stress. In addition, this research preliminarily revealed that antioxidant activity is directly proportional to the number of phenolic hydroxyl groups, and after comparison of the anti-inflammatory and antioxidant activities, the compounds with enol groups were superior to those without enol groups, which will be further verified in future in vivo experiments.
Background:
Long-term corticosteroid (CS) use is associated with increased mortality in patients with asthma, and comorbid bronchiectasis is also associated with frequent asthma exacerbation and increased healthcare use. However, there is limited information on whether bronchiectasis further increases mortality in patients with CS-dependent asthma. This study examined the impact of bronchiectasis on mortality in patients with CS-dependent asthma.
Methods:
A retrospective cohort of patients with CS-dependent asthma ⩾18 years old was established using records from the Korean National Health Insurance Service database from 2005 to 2015. Patients with CS-dependent asthma with and without bronchiectasis were matched by age, sex, type of insurance, and Charlson comorbidity index. We evaluated the hazard ratio (HR) for all-cause mortality in patients with bronchiectasis compared with those without bronchiectasis.
Results:
The study cohort included 754 patients with CS-dependent asthma with bronchiectasis and 3016 patients with CS-dependent asthma without bronchiectasis. Patients with CS-dependent asthma with bronchiectasis had a higher all-cause mortality than those without bronchiectasis (8429/100,000 versus 6962/100,000 person-years, p < 0.001). The adjusted HR for mortality in patients with CS-dependent asthma with bronchiectasis relative to those without bronchiectasis was 1.33 (95% confidence interval, 1.18–1.50), and the association was primarily significant for respiratory diseases (subdistribution HR = 1.65, 95% confidence interval, 1.42–1.92).
Conclusions:
Bronchiectasis further increases all-cause mortality in patients with CS-dependent asthma, a trend that was especially associated with respiratory diseases including chronic obstructive pulmonary disease. Strategies to improve treatment outcomes in patients with CS-dependent asthma with bronchiectasis are urgently needed to improve long-term survival.
The diversity of secondary compounds in the plant kingdom is huge. About 200,000 compounds are known, which are grouped into amines, non-protein amino acids, peptides, alkaloids, glucosinolates, cyanogenic glucosides, organic acids, terpenoids, quinones, polyacetylenes, and phenolics. The group of phenolic compounds consists of polyphenols, oligophenols and monophenols or simple phenolic compounds such as benzoic and cinnamic acids and their hydroxylated derivatives. Among the thousands of compounds present in ecological interactions, simple phenolic acids are the most abundant in soils, and many are described as allelochemicals. Given the physiological and biochemical importance of these compounds, we review their biosynthesis and metabolic actions in plants.
The mechanisms of cellular absorption and transport underlying the differences between flavonoid aglycones and glycosides and the effect of the structural feature are not well established. In this study, aglycone, mono-, and diglycosides of quercetin and cyanidin were selected to examine the effects of the structural feature on the bioavailability of flavonoids using hexose transporters SGLT1 and GLUT2 in a Caco-2 BBe1 cell model. Cellular uptake and transport of all glycosides were significantly different. The glycosides also significantly inhibited cellular uptake of d-glucose, indicating the involvement of the two hexose transporters SGLT1 and GLUT2 in the absorption, and the potential of the glycosides in lowering the blood glucose level. The in silico prediction model also supported these observations. The absorption of glycosides, especially diglycosides but not the aglycones, was significantly blocked by SGLT1 and GLUT2 inhibitors (phloridzin and phloretin) and further validated in SGLT1 knockdown Caco-2 BBe1 cells.
Background:
There has been comparatively little patient information about bronchiectasis, a chronic lung disease with rising prevalence. Patients want more information, which could improve their understanding and self-management. A novel information resource meeting identified needs has been co-developed in prior work. We sought to establish the feasibility of conducting a multi-centre randomised controlled trial to determine effect of the information resource on understanding, self-management and health outcomes.
Methods/design:
We conducted an unblinded, single-centre, randomised controlled feasibility trial with two parallel groups (1:1 ratio), comparing a novel patient information resource with usual care in adults with bronchiectasis. Integrated qualitative methods allowed further evaluation of the intervention and trial process. The setting was two teaching hospitals in North East England. Participants randomised to the intervention group received the information resource (website and booklet) and instructions on its use. Feasibility outcome measures included willingness to enter the trial, in addition to recruitment and retention rates. Secondary outcome measures (resource use and satisfaction, quality of life, unscheduled healthcare presentations, exacerbation frequency, bronchiectasis knowledge and lung function) were recorded at baseline, 2 weeks and 12 weeks.
Results:
Sixty-two participants were randomised (control group = 30; intervention group = 32). Thirty-eight (61%) were female, and the participants' median age was 65 years (range 15-81). Median forced expiratory volume in 1 s percent predicted was 68% (range 10-120). Sixty-two of 124 (50%; 95% CI, 41-59%) of potentially eligible participants approached were recruited. Sixty (97%) of 62 participants completed the study (control group, 29 of 30 [97%]; 95% CI, 83-99%; 1 unrelated death; intervention group, 31 [97%] of 32; 95% CI, 84-99%; 1 withdrawal). In the intervention group, 27 (84%) of 32 reported using the information provided, and 25 (93%) of 27 of users found it useful, particularly the video content. Qualitative data analysis revealed acceptability of the trial and intervention. Web analytics recorded over 20,000 page views during the 16-month study period.
Conclusion:
The successful recruitment process, high retention rate and study form completion rates indicate that it appears feasible to conduct a full trial based on this study design. Worldwide demand for online access to the information resource was high.
Trial registration:
ISRCTN Registry, ISRCTN84229105. Registered on 25 July 2014.
Bronchiectasis, the presence of bronchial wall thickening with airway dilatation, is a particularly challenging complication of primary antibody deficiencies. While susceptibility to infections may be the primary factor leading to the development of bronchiectasis in these patients, the condition may develop in the absence of known infections. Once bronchiectasis is present, the lungs are subject to a progressive cycle involving both infectious and non-infectious factors. If bronchiectasis is not identified or not managed appropriately, the cycle proceeds unchecked and yields advanced and permanent lung damage. Severe symptoms may limit exercise tolerance, require frequent hospitalizations, profoundly impair quality of life (QOL), and lead to early death. This review article focuses on the appropriate identification and management of bronchiectasis in patients with primary antibody deficiencies. The underlying immune deficiency and the bronchiectasis need to be treated from combined immunology and pulmonary perspectives, reflected in this review by experts from both fields. An aggressive multidisciplinary approach may reduce exacerbations and slow the progression of permanent lung damage.
Background: Polyphenols are natural compounds synthesized exclusively by plants with chemical features related to phenolic substances and eliciting strong antioxidants properties. Objective: The aim of this paper is to give a reliable overview of the chemical classification of natural polyphenols. Methods: Literature survey was done through google scholar, pubmed and scopus search engine. Results and Discussion: These molecules or classes of natural substances are characterized by two phenyl rings at least and one or more hydroxyl substituents. This description comprehends a large number of heterogeneous compounds with reference to their complexity. Therefore, polyphenols can be simply classified into flavonoids and non-flavonoids, or be subdivided in many sub-classes depending on the number of phenol units within their molecular structure, substituent groups, and/or the linkage type between phenol units. Polyphenols are widely distributed in plant tissues where they mainly exist in form of glycosides or aglycones. The structural diversity of flavonoid molecules arises from variations in hydroxylation pattern and oxidation state resulting in a wide range of compounds: flavanols, anthocyanidins, anthocyanins, isoflavones, flavones, flavonols, flavanones, and flavanonols.
Glaucosciadium cordifolium (Apiaceae) is traditionally used against stomach ailments, as aphrodisiac and appetizer. This study endeavored to characterize several extracts of G. cordifolium aerial parts (prepared by various isolation procedures (ASE: Accelerated solvent extraction; HAE: homogenizer-assisted extract; MAE: Microwave-assisted extraction; MAC: Maceration; SFE: supercritical CO2 extraction; SOX: Soxhlet; UAE: Ultrasound-assisted extraction) and evaluate the antioxidant activity and inhibitory activity against clinical enzymes. In order to describe the composition of the extracts liquid chromatography-mass spectrometry (LC-MS) analysis was employed. Of the total number of confirmed polyphenol components (15 in total), four were dominant in their content: 5-O-caffeoylquinic acid, p-coumaric acid, quercetin-3-O-glucoside and quercetin-3-O-rhamnoside. Spectrophotometric analysis showed that the total phenolic and flavonoid contents differed among the extracts, which was influenced by extraction technique used for their preparation. The phenolic content of the different extracts varied in the order HAE > UAE > MAC > SOX > MAE > ASE > SFE. HAE extract yielded the highest phenolic content (49.97 mg gallic acid equivalent (GAE)/g) while SFE demonstrated the lowest phenolic content (21.65 mg GAE/g). MAC extracts contained the highest flavonoids (50.35 mg rutin equivalent (RE)/g) while SFE extract showed the lowest flavonoid content (10.87 mg RE/g). UAE, MAC, MAE, HAE, SOX and ASE showed significant DPPH antioxidant activities and the values of radical inhibitory capacity varied in the range of 55.79–54.99 mg TE/g. SFE demonstrated weak DPPH (1,1-diphenyl-2-picrylhydrazyl) radical inhibitory activity with a value 7.0 mg TE/g. UAE showed the highest ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) cation radical inhibitory potential (122.41 mg trolox equivalent (TE)/g). The CUPRAC (cupric reducing antioxidant capacity) activity of UAE was remarkable with a value of 193.58 mg TE/g. A gradual decrease in activity was observed with extracts obtained from other extraction techniques with the lowest antioxidant activity (77.0 mg TE/g) obtained from SFE extract. The highest antioxidant recorded by Phosphomolybdenum was found in HAE extract (1.62 mmol TE/g). SFE showed the highest metal chelating activity (27.30 mg ethylenediamine tetraacetic acid (EDTAE)/g). Regarding the acetylcholinesterase (AChE) inhibitory activity, MAE and ASE extracts showed the highest potential with a value of 4.06 and 4.05 mg galanthamine equivalent (GALAE)/g respectively. All tested extracts showed considerable whitening activity and SFE revealed the highest activity against tyrosinase (93.82 mg kojic acid equivalent (KAE)/g). In addition, SFE showed the best inhibitory ability against amylase (0.71 mmol acarbose equivalent (ACAE)/g). However, the extracts had similar glucosidase inhibitory effects (1.64–1.71 mmol ACAE/g). The rich chemical composition of the extracts and joint action of different classes of polyphenolic compounds in them may be responsible for their high biological activity. Extracts with the highest activity could serve in the future as an important tool for controlling the activity of clinically important enzymes and take their place in the official formulation after additional pharmacological tests.
Oxidative stress, a result of an overproduction and accumulation of free radicals, is the leading cause of several degenerative diseases such as cancer, atherosclerosis, cardiovascular diseases, ageing and inflammatory diseases. Polyphenols form an important class of naturally occurring antioxidants, having innumerable biological activities such as anticancer, antifungal, antibacterial, antiviral, antiulcer and anticholesterol, to name a few. Among various polyphenols, gallic acid (3,4,5-trihydroxybenzoic acid), a naturally occurring low molecular weight triphenolic compound, has emerged as a strong antioxidant and an efficient apoptosis inducing agent. Starting from the bioavailability and the biosynthetic pathway of gallic acid, this review includes various in vitro, in vivo and in silico studies providing the mode of action, radical scavenging activity, ability to inhibit lipid peroxidation, maintenance of endogenous defense systems and metal ion chelation by this triphenolic molecule, along with a comprehensive overview of factors responsible for its high antioxidant activity. Gallic acid derivatives have also been found in a number of phytomedicines with diverse biological and pharmacological activities, including radical scavenging, interfering with the cell signaling pathways and apoptosis of cancer cells. The diverse range of applications of this simple polyphenol is due to a fine amalgam between its antioxidant and prooxidant potential. The existing literature on this dual behavior of gallic acid and its derivatives is reviewed here. This is followed by an account of their potential clinical and industrial applications.
The plant species Opopanax hispidus is known in traditional Turkish medicine and nutrition. In addition to all the advantages that are known by the traditions of old generations, O. hispidus has been insufficiently examined, and its potential could be used in treatment in modern medicine and diet. In this paper, O. hispidus extracts obtained by conventional (maceration (MAC), and Soxhlet (SOX)) and contemporary (accelerated solvent extraction (ASE), homogenizer assisted extraction (HAE), microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE), supercritical fluid extraction (SFE)) methods were examined in terms of their chemical composition and biological potential. The extract obtained by HAE extraction had the highest content of total phenolics and flavonoids (36.98 mg GAE/g and 15.04 mg RE/g, respectively). The highest antioxidant activity was recorded for HAE and ASE extracts. O. hispidus extracts achieved inhibitory activity against acetylcholinesterase (4.12–6.44 mg GALAE/g), tyrosinase (44.78–76.72 mg KAE/g), α-amylase (0.35–0.46 mmol ACAE/g), and α-glucosidase (1.67–1.77 mmol ACAE/g) enzymes. LC-MS technique was used for the quantitative analysis of the extracts, allowing the quantification of chlorogenic acid, neochlorogenic acid, and p-coumaric acid, rutin, luteolin, and kaempferol 3-O-glucoside as the most abundant phenolic components. Results suggested that the green extraction techniques for obtaining extracts that are rich in bioactive compounds have advantages compared to conventional extraction. Therefore, these extracts can be used as antioxidants, neuroprotective, antityrosinase, and antidiabetic agents while respecting the principles of sustainable development and green chemistry.
Lignans have long been known for their abundant therapeutic properties due to their polyphenolic structure. Linseed is the richest plant source of lignans and has been studied widely for their properties. The most prevalent lignan, secoisolariciresinol diglucoside (SDG), is consumed with linseed and converted into mammalian lignans, enterodiol (END) and enterolactone (ENL), by the gut microbiota. SDG can easily be assessed using HPLC and its deglycosylated form viz secoisolariciresinol can be asses using GC–MS techniques. Variety of extraction and analysis methods has been reported for plant lignans. SDG is known to have therapeutic properties including anti-oxidant, anti-cancerous, anti-inflammatory, modulation of gene expression, anti-diabetic, estrogenic and anti-estrogenic. Despite a large number of bioactivities, strong evidences for the underlying mechanisms for most of the properties are still unknown. SDG is most studied for its anti-cancerous properties. But the use of lignans as anti-carcinogenic agent is limited and commercially not reported due to challenges of purification at commercial level, rapid metabolism, untargeted delivery and toxic compounds associated with lignans. Exploration of more prominent and active derivatives of SDG and their targeted drug delivery should be an important research toward the use of bioactive lignans of linseed.
Cellular senescence, classically defined as stable cell cycle arrest, is implicated in biological processes such as embryogenesis, wound healing and ageing. Senescent cells have a complex senescence-associated secretory phenotype (SASP), involving a range of pro-inflammatory factors with important paracrine and autocrine effects on cell and tissue biology. Clinical evidence and experimental studies link cellular senescence, senescent cell accumulation, and the production and release of SASP components with age-related cardiac pathologies such as heart failure, myocardial ischaemia and infarction, and cancer chemotherapy-related cardiotoxicity. However, the precise role of senescent cells in these conditions is unclear and, in some instances, both detrimental and beneficial effects have been reported. The involvement of cellular senescence in other important entities, such as cardiac arrhythmias and remodelling, is poorly understood. In this Review, we summarize the basic biology of cellular senescence and discuss what is known about the role of cellular senescence and the SASP in heart disease. We then consider the various approaches that are being developed to prevent the accumulation of senescent cells and their consequences. Many of these strategies are applicable in vivo and some are being investigated for non-cardiac indications in clinical trials. We end by considering important knowledge gaps, directions for future research and the potential implications for improving the management of patients with heart disease.
As the main goal of this study was the verification of Satureja kitaibelii Wierzb. ex Heuff. in form of the crude extract obtained by subcritical water extraction (SWE) technique in terms of polyphenolic composition, in vitro antioxidant capacity, antihyperglycemic, and anti-inflammatory activities as well as an antimicrobial effect against 10 microorganisms. HPLC analysis showed the presence of ten compounds in a total concentration of 89.33 mg/g of the SWE extract, and demonstrated that subcritical water polarity was the most selective for extracting syringic and caffeic acid, as well as epicatechin (37.88 18.06, and 10.04 mg/g, respectively), while flavonoids like rutin, luteolin, and apigenin were present in low concentration (<2 mg/g). Results of antioxidant activity assays revealed that superoxide anion and ABTSradical dot+ radical models expressed the highest scavenging abilities (437.35 and 412.09 μmol TE/g, respectively), followed by lipid radicals (69.61 μmol TE/g), and DPPHradical dot (32.28 μmol TE/g), while in the case of ferric ion reducing ability was noted a high value (118.19 μmol TE/g). S. kitaibelii SWE was less efficient in the antihyperglycemic assay (AhgA = 30.72 %), but the high anti-inflammatory activity of S. kitaibelii SWE was observed (30.35 %). The antimicrobial activity was demonstrated against Bacillus cereus, Staphylococcus aureus, Enterococcus faecalis, Listeria monocytogenes as well as Saccharomyces cerevisiae, Candida albicans, and Aspergillus brasiliensis through antimicrobial screening, minimal inhibitory concentration, and pharmacodynamics study.
Diabetes is a metabolic disorder that has caused enormous harm to the public health worldwide. In this study, we evaluated the potential of phenolic compounds on diabetes management, addressing their mechanisms of action, in addition to discussing the digestion, absorption, metabolism, bioavailability, and toxic effects of these compounds. The intake of phenolic compounds can play a fundamental role on diabetes management, since they can reduce blood glucose levels, oxidative stress, protein glycation, inhibit the activity of dipeptidyl peptidase - IV and other key enzymes related to carbohydrate metabolism, activate various biochemical pathways to improve pancreatic β cell functions, increase insulin secretion, and improve insulin resistance. In this way, they can be considered a potential strategy in the development of pharmaceutical approaches that aim to reduce complications resulting from the progression of this metabolic pathology.
Laurus nobilis (bay laurel) form Serbia (SRBL) and Russia (RFBL) were analyzed in order to establish the chemical profile, thermal properties and biological activity. The GC/MS analysis showed that α-pinene (31.97%) is principal compound in the RFBL followed by eucalyptol (27.95%) and α-terpineol (10.28%). In the case of the SRBL, eucalyptol (40.51%) is the most abundant compound followed by α-terpineol (15.46%), while α-pinene was found in much lower amount (4.45%). Thermal analysis showed that the evaporation process of both oils was complex process and took place in two phases. Moreover, results indicated that the SRBL evaporated slower at the higher temperatures than the RFBL. In order to assess biological activity, the antioxidant and antimicrobial activities were investigated. The SRBL was more potent antioxidant agent in the case of both assays (DPPH and total reduction capacity). In the case of the antimicrobial activity, the SRBL showed greater potential of antimicrobial activities toward all tested microorganisms, while RFBL was found to be effective against all the bacteria and yeast, but did not possess any inhibitory action against fungi. Results indicate that both oils may be used in the food and pharmaceutical industries as antioxidant and antimicrobial agent.
Polyphenols are secondary metabolites widely distributed in many plant foods, such a tea, coffee, chocolate and fruits. The consumption of these compounds is related to the improvement or amelioration of many diseases, including diabetes. Nevertheless, the great barrier to the therapeutic use of polyphenols is the low bioavailability of these compounds once ingested. For that reason, the encapsulation of polyphenols in different matrices may protect them from digestion and improve their release and subsequent absorption to obtain target-specific health effects. Some studies have reported the beneficial effect of encapsulation to increase both bioavailability and bioaccessibility. However, these works have mostly been carried out in vitro and few studies are specifically addressed at improving diabetes. In the current work, an overview of the knowledge related to nanoparticles and their use in the diabetic condition has been reviewed.
Cardiovascular diseases comprise of non-communicable disorders that involve the heart and/or blood vessels and have become the leading cause of death worldwide with increased prevalence by age. mTORis a serine/threonine-specific protein kinase which play a central role in many physiological processes including cardiovascular diseases, and also integrates various proliferative signals, nutrient and energy abundance and stressful situations. mTOR also act as central regulator during chronic stress, mitochondrial dysfunction and deregulated autophagy which are associated with senescence. Under oxidative stress, mTOR has been reported to exert protective effects regulating apoptosis and autophagy processes and favoring tissue repair. On the other hand, inhibition of mTOR has been suggested to have beneficial effects against atherosclerosis, cardiac hypertrophy and heart failure, and also in extending the lifespan. In this aspect, the use of drugs or natural compounds, which can target mTOR is an interesting approach in order to reduce the number of deaths caused by cardiovascular disease. In the present review, we intend to shed light on the possible effects and molecular mechanism of natural agents like polyphenols via regulating mTOR.