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Phenolic Compounds - Biological Activity
Abstract
Phenolic compounds comprise a broad class of natural products formed mainly by plants, but also microorganisms and marine organisms that have the capacity to form them. Nowadays the interest in these compounds has increased mainly due to their diverse chemical structure and wide biological activity valuable in the prevention of some chronic or degenerative diseases. The functional foods are a rich source of these phytochemicals, and this is the starting point for this book, which shows the state of the art of the phenolic compounds and their biological activity. This book integrates eleven chapters that show the state of the art of diverse biological activity of the phenolic compounds, present in some crops or fruits.
... Phenolic compounds, due to their diversity and wide distribution, are the most important group of natural antioxidant metabolites. There are epidemiological evidences that show the health benefits and the contribution of these compounds in the prevention of some degenerative diseases (Soto-Hernández et al., 2017a;Soto-Hernández et al., 2017b). These metabolites are compounds with the ability to chelate heavy metals, modulate some enzymes and neutralize free radicals (reactive oxygen species produced by oxidative stress in the organism, affecting lipoproteins, lipids of blood plasma and other biomolecules) (Delgado-Vargas and Paredes- López, 2002;Georgé et al., 2005). ...
Pitaya (Stenocereus spp.) is an exotic fruit, which has been consumed since ancient times by pre-Hispanic cultures. Recently in Mexico, this cactus has been the target of commercial attention due to the pleasant taste of their succulent fruits with juicy and sweet pulp, and a great variety of colors (white, yellow, purple and red fruits). This fruit has excellent sensory, nutritional, nutraceutical, agroindustrial and medicinal attributes; however, it has been under-utilized. The high content of betalains in this fruit allows us to consider these varieties as a source of natural pigments to be used in the food industry. The aim of this study is to show "the state of the art" of the properties of Stenocereus, to promote its study, dissemination, production, consumption and agroindustrial use. The present study shows a description of its botany, distribution, cultivation, physiology, pre and postharvest aspects, nutritional and nutraceutical composition, as well as agroindustrial and medicinal uses. The production of this fruit represents an opportunity for the economic development of some arid and semi-arid zones of Mexico due to the agronomic, nutraceutical and agroindustrial advantages. Therefore, more studies are required, mainly on physiological, nutraceutical, medicinal and agroindustrial aspects, more specifically on the non-studied species of Stenocereus, and future researches should deal with development of agro-technologies to guarantee high yields and good quality products to enable growers to make a living from it.
Polyphenols are organic chemical compounds naturally present in plants, renowned for their anti-inflammatory, antioxidant, immunomodulatory, anticancer, and cardiovascular protective properties. Their bioactivity and bioavailability can vary widely depending on the methods of food processing and interactions with the gut microbiome. These factors can induce changes in polyphenols, affecting their ability to achieve their intended health benefits. Thus, it is essential to develop and apply food processing methods that optimize polyphenol content while maintaining their bioactivity and bioavailability. This review aims to explore how various food processing techniques affect the quantity, bioactivity, and bioavailability of polyphenols, as well as their interactions with the gut microbiome, which may ultimately determine their health effects.
This study aimed to analyse and evaluate the antimicrobial activity and pheno-lic compounds in the leaf extracts of five Artemisia species (A. alba, A. annua, A. campestris, A. pontica, and A. vulgaris), of which A. annua is of significant medical importance. Although many Artemisia plants are well known from ethnobotani-cal and phytochemical studies, the biological activity of Artemisia species against phytopathogenic strains is scarcely investigated. Therefore, the presence of pheno-lic compounds and the antimicrobial activity of dichloromethane-methanol (1:1) leaf extracts of five Artemisia species against phytopathogenic fungi and bacteria were analysed. The phenolic compounds were determined by liquid chromatography mass spectrometry (LC-MS). In total, 13 phenolic compounds and quinic acid were identified and quantified. Chlorogenic acid was the dominant compound in all the samples, while the second dominant compounds were rutin in the A. alba, A. campestris, and A. pontica extracts, vitexin in A. annua, and esculin in the A. vulgaris extracts. Antifungal activity was tested against 12 micromycetes a using mycelial growth assay and the microdilution method. Antibacterial activity was tested against 18 bacterial strains using the well diffusion and microdilution methods. In each test, the highest activity was shown for the extracts of different Artemisia species. The most sensitive micromycetes were Monillinia laxa, Penicil-lium citreonigrum, and Botrytis cinerea, while Fusarium graminearum B1 was the most resistant. The analysed extracts showed moderate antibacterial activity only against Xanthomonas campestris pv. campestris compared with all the other tested phytopathogens. The study shows that the leaf extracts of certain Artemisia species contain phenolic compounds and showed moderate antimicrobial activity against some species of fungi and bacteria.
Phenolic compounds are the main phytochemical constituents of many higher plants. They play an important role in synthesizing metal nanoparticles using green technology due to their ability to reduce metal salts and stabilize them through physical interaction/conjugation to the metal surface. Six pure phenolic compounds were isolated from licorice (Glycyrrhiza glabra) and employed in synthesizing gold nanoparticles (AuNPs). The isolated compounds were identified as liquiritin (1), isoliquiritin (2), neoisoliquiritin (3), isoliquiritin apioside (4), liquiritin apioside (5), and glabridin (6). The synthesized AuNPs were characterized using UV, zeta sizer, HRTEM, and IR and tested for their stability in different biological media. The phenolic isolates and their corresponding synthesized NP conjugates were tested for their potential in vitro cytotoxicity. The anti-inflammatory effects were investigated in both normal and inflammation-induced settings, where inflammatory biomarkers were stimulated using lipopolysaccharides (LPSs) in the RAW 264.7 macrophage cell line. LPS, functioning as a mitogen, promotes cell growth by reducing apoptosis, potentially contributing to observed outcomes. Results indicated that all six pure phenolic isolates inhibited cell proliferation. The AuNP conjugates of all the phenolic isolates, except liquiritin apioside (5), inhibited cell viability. LPS initiates inflammatory markers by binding to cell receptors and setting off a cascade of events leading to inflammation. All the pure phenolic isolates, except isoliquiritin, neoisoliquiritin, and isoliquiritin apioside inhibited the inflammatory activity of RAW cells in vitro.
Myrtus communis L. is a species of the Myrtaceae family that is found in the Mediterranean region, and it is traditionally recognized for its importance and different uses. The objective of this study was to determine the effect of M. communis L. leaf extract (MCLE), which was incorporated directly into alginate spheres and films, on preserving oil-in-water emulsions from oxidation. For this purpose, the solvent extraction (with ethanol at 40, 60, and 80%) of the antioxidant compounds was optimized (total phenolic compounds (TPCs) and total flavonoid content (TFC)) along with the scavenging activity. The best condition for the extraction corresponded with 60% ethanol (MCLE60), with a TPC of ~66.06 g GAE/L and a TFC of ~18.91 g QE/L, which was selected for use in the following assays. MCLE60 showed a considerable radical scavenging activity (24.85 mmol TE/L in FRAP, 28.75 mmol TE/L in DPPH, 30.61 mmol TE/L in ABTS, and 14.94 mmol TE/L in ORAC), which was probably due to its content in the phenolic compounds arbutin (122.08 mg/L), epicatechin (73.89 mg/L), sinapic acid (51.85 mg/L), and gallic acid (36.72 mg/L). The oil-in-water emulsions with the MCLE60 spheres showed the best oxidative stability (TBARS ~2.64 mg MDA/kg of emulsion, PV ~35.7 meq hydroperoxides/kg of emulsion) in comparison to the control. The film was also able to protect the emulsion from oxidation for more than a week at 30 °C (TBARS ~1.9 mg MDA/kg of emulsion). The alginate films with MCLE60 presented an important release of phenolic compounds in water and acetic food simulants, while in both ethanol simulants, the release of TPC remained more stable over time. Thus, this study highlights the potential uses of MCLE as a natural ingredient for emulsion oxidative preservation and the production of alginate delivery systems (spheres and films).
The goal of the paper is to analyze the results of the research and present the general characteristics of flavonoids, including their biosynthetic pathway and peculiarities of secondary metabolism, through a review of available published works. Also, the work follows the antioxidant, antimicrobial and antitumor properties, and capacity of flavonoids. Flavonoids including flavones, isoflavones and anthocyanidins are formed by the condensation of phenylpropanoids with the participation of three molecules of malonyl coenzyme A. Flavonoid synthesis begins with phenylalanine, using the enzyme phenylalanine ammonium lyase (PAL) which catalyzes the release of phenylalanine and phenylalanine. Various experimental studies have shown that phenylalanine is a precursor of a large product of the secondary metabolism of phenolic compounds. The professional literature points out that o-dihydroxylation of the B-ring contributes to the antioxidant activity of flavonoids, while its antimicrobial properties are determined by the presence of (+) - catechin and quercetin against gram-positive and gram-negative bacteria. When it comes to antitumor properties, antioxidant activity, regulation of p53 protein, inhibition of protein kinase activity and apoptosis have an impact.
Genipap (Genipa americana L.), also known as caruto, is a fruit native to Central and South America and presents a novel source of a crosslinking substance containing genipin for biopolymers in various applications. In this study, the fruit's core was used to extract the genipin-rich genipap oil, and a complete characterization of the oil as an inexpensive replacement for commercial genipin powder is included. The extracted genipap oil shows a high phenolic content and remarkable non-hemolytic, antioxidant, and antimicrobial activity. The potential of genipap oil is further demonstrated by its advantage over commercial genipin powder, which did not show antioxidant activity. The crosslinking capacity of the genipap oil was tested with chitosan films and hot-pressed sheets of protein blends from agro-industrial biomass, including zein, wheat gluten, and potato protein. The results indicated that incorporating genipap oil in these blends allowed for manufacturing homogenous structures and improved their mechanical performance compared to the non-crosslinked blends. The use of the oil represents an advantage from a material engineering perspective as it allows for better distribution of genipin during the thermal processing of the materials compared with the commercial genipin. Further, commercial genipin requires solvents and extensive purification processes, which hinders its upscalability. These results support the use of the extracted fruit oil as a green, inexpensive, efficient crosslinking agent, opening new avenues for several applications.
The current nanomedicinal approach combines medicinal plants and nanotechnology to create new scaffolds with enhanced bioavailability, biodistribution and controlled release. In an innovative approach to herb encapsulation in nanosized chitosan matrices, wild-grown Romanian Helleborus purpurascens was used to prepare two new chitosan nanocarriers. The first carrier preparation involved the nanoencapsulation of hellebore in chitosan. The second carrier emerged from two distinct stages: hellebore-AgNPs phyto-carrier system succeeded by nanoencapsulation in chitosan. The morphostructural characteristics and thermal behavior of these newly prepared nanocarriers were examined using FT-IR, XRD, DLS, SEM, EDS and thermogravimetric analyses. In addition, the encapsulation yield, encapsulation efficiency and encapsulation contents were investigated. The antioxidant activity was estimated using four in vitro, noncompetitive methods: total phenolic assay; 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay; phosphomolybdate (i.e., total antioxidant capacity); and iron(III)-phenanthroline antioxidant assay. Moreover, this study reports the first low-molecular-weight metabolite profile of wild-grown Romanian Helleborus purpurascens Waldst. & Kit. A total of one hundred and five secondary metabolites were identified in the mass spectra (MS)-positive mode from fourteen secondary metabolite categories (alkaloids, butenolides, bufadienolides, phytoecdysteroids, amino acids and peptides, terpenoids, fatty acids, flavonoids, phenolic acids, sterols, glycosides, carbohydrates, nucleosides and miscellaneous). The collective results suggest the potential application is a promising new antioxidant vehicle candidate in tumor therapeutic strategy.
The microbial quality of raw milk artisanal cheeses is not always guaranteed due to the possible presence of pathogens in raw milk that can survive during manufacture and maturation. In this work, an overview of the existing information concerning lactic acid bacteria and plant extracts as antimicrobial agents is provided, as well as thermisation as a strategy to avoid pasteurisation and its negative impact on the sensory characteristics of artisanal cheeses. The mechanisms of antimicrobial action, advantages, limitations and, when applicable, relevant commercial applications are discussed. Plant extracts and lactic acid bacteria appear to be effective approaches to reduce microbial contamination in artisanal raw milk cheeses as a result of their constituents (for example, phenolic compounds in plant extracts), production of antimicrobial substances (such as organic acids and bacteriocins, in the case of lactic acid bacteria), or other mechanisms and their combinations. Thermisation was also confirmed as an effective heat inactivation strategy, causing the impairment of cellular structures and functions. This review also provides insight into the potential constraints of each of the approaches, hence pointing towards the direction of future research.
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