Extraction and characterization of polyphenols from non-conventional edible plants and their antioxidant activities

Plant-derived and dietary phenolic cinnamic acid derivatives: Anti-inflammatory properties

Cinnamic acids are aromatic acids primarily found in plants and plant-derived food. Phenolic cinnamic acids, with one or more hydroxyl groups in the aromatic ring, often contribute to the biological activities attributed to these compounds. The presence of hydroxyl groups and a carboxyl group makes cinnamic acids very hydrophilic, preventing them from crossing biological membranes and exerting their biological activities. To alleviate this condition, a panel of synthetic modifications have been made leading to a diverse set of phenolic cinnamic structures. In this review, an overview of the natural phenolic cinnamic acid derivatives and their plant sources (more than 200) is described. The synthetic approaches to obtain the referred derivatives (more than 200) namely esters and amides are reviewed. Further, their anti-inflammatory activity (more than 70 compounds) is scrutinized. Finally, future directions will be indicated to translate the research on phenolic cinnamic derivatives into potentially effective anti-inflammatory drugs.

Influence of myoglobin on the antibacterial activity of carvacrol and the binding mechanism between the two compounds

BACKGROUND

Myoglobin (MB), a pigmentation protein, can adversely affect the antibacterial activity of carvacrol (CAR) and weaken its bacteriostasis effect. This study aimed to clarify the influence of MB on the antibacterial activity of CAR and ascertain the mechanism involved in the observed influence, especially the interaction between the two compounds.

RESULTS

Microbiological analysis indicated that the presence of MB significantly suppressed the antibacterial activity of CAR against Listeria monocytogenes. Ultraviolet-visible spectrometry and fluorescence spectroscopic analysis confirmed the interaction between CAR and MB. The stoichiometric number was determined as ~0.7 via double logarithmic Stern-Volmer equation analysis, while thermodynamic analysis showed that the conjugation of the two compounds occurred as an exothermal reaction (ΔH° = -32.3 ± 11.4 kJ mol-1 and ΔS° = -75 J mol-1  K-1 ). Circular dichroism, Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy showed hydrogen bonding in the carvacrol-myoglobin complex (CAR-MB). Molecular docking analysis confirmed that amino acid residues, including GLY80 and HIS82, were most likely to form hydrogen bonds with CAR, while hydrogen bonds represented the main driving force for CAR-MB formation.

CONCLUSION

CAR antibacterial activity was significantly inhibited by the presence of MB in the environment due to the notable reduction in the effective concentration of CAR caused by CAR-MB formation. © 2023 Society of Chemical Industry.

Polyphenols in Agricultural Grassland Crops and Their Health-Promoting Activities-A Review

Grassland crops are emerging reservoirs of undisturbed, natural antioxidants and phytochemicals, such as phenolic acids and flavonoids. The present review will focus on the most commonly cultivated crops, namely Lolium perenne L, Cichorium intybus L, Plantago lanceolata L. and Trifolium pratense L, which have been recognized for their polyphenolic composition. However, these crops are often undervalued and underutilized, yet have the means of potentially creating novel, value-added food and nutraceutical products. Previous studies relating to these crops have identified them as rich sources of caffeic acid, chlorogenic acid, daidzein, kaempferol, luteolin, and quercetin. The key to harnessing the hidden potential of these species is the recovery, identification, and characterization of the phytochemicals they contain. Considering the upsurge of research studies on alternative plant-based diets for the health of humans and the planet earth, there is a necessity to understand the phytochemical composition and the bioactivity that they possess. This review summarizes recovery methods of phytochemicals from the aforementioned grassland crops and their compositional and functional (antioxidant, anti-cancer, and anti-diabetic) characterization and discusses the potential for grassland crops as an abundant reservoir of health-promoting ingredients which can increase the nutritional composition within novel food innovations or within nutraceuticals.

Effects of dietary polyphenols on maternal and fetal outcomes in maternal diabetes

The incidences of short-term or long-term adverse maternal and fetal outcomes caused by maternal diabetes are increasing. Due to toxicity or side effects, economic pressures, and other problems associated with injections or oral hypoglycemic drugs, many researchers have investigated natural treatment methods. Polyphenols can protect against chronic pathologies by regulating numerous physiological processes and provide many health benefits. Moreover, polyphenols have anti-diabetic properties and can be used to treat diabetic complications. Diets rich in polyphenols are beneficial to pregnant women with diabetes. Here, we review the epidemiological and experimental evidence on the impact of dietary polyphenols on maternal and fetal outcomes in pregnant women with diabetes, and the effects of polyphenols on biological changes and possible mechanisms. Previous data (mainly from in vitro and animal experiments) showed that polyphenols can alleviate gestational diabetes mellitus and diabetic embryopathy by reducing maternal hyperglycemia and insulin resistance, alleviating inflammation and oxidative stress, and regulating related signaling pathways. Although polyphenols have shown many health benefits, further research is needed to better understand the complex interactions between polyphenols and maternal diabetes.

Optimized Extraction of Polyphenols from Unconventional Edible Plants: LC-MS/MS Profiling of Polyphenols, Biological Functions, Molecular Docking, and Pharmacokinetics Study

Plant bioactive phenolic metabolites have recently attracted the attention of researchers due to their numerous health advantages. Therefore, this study aimed to investigate with advanced techniques the bioactive metabolites and antioxidant and antidiabetic capacity of four unconventional edible plant leaves: lemongrass (Cymbopogon citratus (DC.) Stapf), chicory (Cichorium intybus L.), moringa (Moringa oleifera Lam.), and ryegrass (Lolium perenne L.). The extraction process was optimized using different solvents. These plants' phenolic composition, identification, and characterization have been determined herein using LCESI-QTOF-MS/MS. This research identified 85 phenolic compounds, including 24 phenolic acids, 31 flavonoids, 7 stilbenes and lignans, and 17 other metabolites. Moreover, the study determined that moringa has the highest total phenolic content (TPC; 18.5 ± 1.01 mg GAE/g), whereas ryegrass has the lowest (3.54 ± 0.08 mg GAE/g) among the selected plants. It seems that, compared to other plants, moringa was found to have the highest antioxidant potential and antidiabetic potential. In addition, twenty-two phenolic compounds were quantified in these chosen edible plants. Rosmarinic acid, chlorogenic acid, chicoric acid, ferulic acid, protocatechuic acid, and caffeic acid were the most abundant phenolic acids. In silico molecular docking was also conducted to investigate the structure-function relationship of phenolic compounds to inhibit the alpha-glucosidase. Finally, the simulated pharmacokinetic characteristics of the most common substances were also predicted. In short, this investigation opens the way for further study into these plants' pharmaceutical and dietary potential.

Geographic Pattern of Variations in Chemical Composition and Nutritional Value of Cinnamomum camphora Seed Kernels from China

Cinnamomum camphora (camphor tree) is an important non-conventional edible plant species found in East Asia. Here, a detailed characterization for the chemical composition and nutritional value of C. camphora seed kernels (CCSKs) collected from different regions in China is provided. The results showed that there were significant differences among the CCSK samples in weights (1000 fruits, 1000 seeds and 1000 kernels), proximate composition, minerals, phenolics, flavonoids and amino acid contents. The highest contents of oil (62.08%) and protein (22.17%) were found in the CCSK samples collected from Chongqing and Shanghai, respectively. The highest content of mineral in the CCSK samples was K (4345.05-7186.89 mg/kg), followed by P (2735.86-5385.36 mg/kg), Ca (1412.27-3327.37 mg/kg) and Mg (2028.65-3147.32 mg/kg). The CCSK sample collected from Guizhou had the highest levels of total phenolic and flavonoid contents (TPC and TFC), while that from Chongqing had the lowest levels. In addition, the most abundant fatty acid in the CCSK samples was capric acid (57.37-60.18%), followed by lauric acid (35.23-38.29%). Similarities in the fatty acid composition among the CCSK samples were found. The CCSK sample collected from Guizhou had the highest percentage (36.20%) of essential amino acids to total amino acids, and Chongqing had the lowest value (28.84%). These results indicated that CCSK may be developed as an excellent source of plant-based medium-chain oil, protein, dietary fiber, minerals, phytochemicals and essential amino acids.

Discrimination of Green Coffee (Coffea arabica and Coffea canephora) of Different Geographical Origin Based on Antioxidant Activity, High-Throughput Metabolomics, and DNA RFLP Fingerprinting

The genus Coffea is known for the two species C. arabica (CA) and C. canephora (CC), which are used to prepare the beverage coffee. Proper identification of green beans of coffee varieties is based on phenotypic and phytochemical/molecular characteristics. In this work, a combination of chemical (UV/Vis, HPLC-DAD-MS/MS, GC-MS, and GC-FID) and molecular (PCR-RFLP) fingerprinting was used to discriminate commercial green coffee accessions from different geographical origin. The highest content of polyphenols and flavonoids was always found in CC accessions, whereas CA showed lower values. ABTS and FRAP assays showed a significant correlation between phenolic content and antioxidant activity in most CC accessions. We identified 32 different compounds, including 28 flavonoids and four N-containing compounds. The highest contents of caffeine and melatonin were detected in CC accessions, whereas the highest levels of quercetin and kaempferol derivatives were found in CA accessions. Fatty acids of CC accessions were characterized by low levels of linoleic and cis octadecenoic acid and high amounts of elaidic acid and myristic acid. Discrimination of species according to their geographical origin was achieved using high-throughput data analysis, combining all measured parameters. Lastly, PCR-RFLP analysis was instrumental for the identification of recognition markers for the majority of accessions. Using the restriction enzyme AluI on the trnL-trnF region, we clearly discriminated C. canephora from C. arabica, whereas the cleavage performed by the restriction enzymes MseI and XholI on the 5S-rRNA-NTS region produced specific discrimination patterns useful for the correct identification of the different coffee accessions. This work extends our previous studies and provides new information on the complete flavonoid profile, combining high-throughput data with DNA fingerprinting to assess the geographical discrimination of green coffee.

Amoxicillin degradation by iron photonanocatalyst synthetized by green route using pumpkin (Tetsukabuto) peel extract

Amoxicillin is a pharmaceutical compound that is not degraded in wastewater treatment plants, causing harm to the environment. In this work, an iron nanoparticle (IPP) was synthesized using pumpkin (Tetsukabuto) peel extract for the degradation of amoxicillin under UV light. The IPP was characterized using scanning electron microscopy/energy dispersive x-ray spectroscopy, transmission electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, thermogravimetric analysis, and Raman spectroscopy techniques. The photocatalytic efficiency of IPP was analyzed by investigating the effect of IPP dosage (1-3 g L^-1), initial amoxicillin concentration (10-40 mg L^-1), pH (3-9), reaction time (10-60 min), and the effect of inorganic ions (1 g L^-1). The optimum conditions for the maximum photodegradation removal (≈60%) were IPP = 2.5 g L^-1, initial amoxicillin concentration = 10 mg L^-1, pH = 5.6, and irradiation time = 60 min. The results of this study showed that inorganic ions (Mg²⁺, Zn²⁺, and Ca²⁺) negatively affect the photodegradation of amoxicillin by IPP; the quenching test showed that hydroxyl radical (OH^•) is the primary reactive species of the reaction; NMR analysis revealed changes in amoxicillin molecules after photoreaction; the subproducts of photodegradation were identified by LC-MS; the proposed kinetic model demonstrated good applicability, predicting the behavior of OH^• and determining the kinetic constant, and the cost analysis based on required energy (238.5 kWh m^-3 order^-1) indicated that the amoxicillin degradation method by IPP is economically viable. This study developed a new efficient iron nanocatalyst for the removal of antibiotics from aqueous environments and provided optimal conditions and relevant information in the area of advanced oxidative processes.

Can botanically-diverse pastures positively impact the nutritional and antioxidant composition of ruminant meat? - Invited review

A desire for more sustainable pasture-based ruminant feeding systems has led to growing interest in utilising botanically-diverse pastures (BDP) over monoculture pastures. Research suggests that, from a human consumption viewpoint, grass-based ruminant feeding leads to more nutritionally desirable fatty acid (FA) and antioxidant concentrations in meat compared with concentrate feeding, which can affect meat quality. The FA, antioxidant and secondary metabolite content of plants differ, depending on species, maturity and seasonality, offering the potential through targeted feeding of BDP to produce meat with superior nutritional and antioxidant profiles. This review explores the effect, if any, that grazing ruminants on BDP has on the FA profile, fat-soluble vitamin, and antioxidant content of meat. The input-output relationship between forage and red meat constituents is complex and is likely affected by species diversity, forage consumption patterns and modulation of rumen fermentation processes. Further investigation is required to fully understand the effect that BDP may have on the composition and quality of ruminant meat.

The Importance of Dietary Antioxidants on Oxidative Stress, Meat and Milk Production, and Their Preservative Aspects in Farm Animals: Antioxidant Action, Animal Health, and Product Quality-Invited Review

The biological effects of oxidative stress and associated free radicals on farm animal performance, productivity, and product quality may be managed via dietary interventions-specifically, the provision of feeds, supplements, and forages rich in antioxidants. To optimize this approach, it is important first to understand the development of free radicals and their contributions to oxidative stress in tissue systems of farm animals or the human body. The interactions between prooxidants and antioxidants will impact redox homeostasis and, therefore, the well-being of farm animals. The impact of free radical formation on the oxidation of lipids, proteins, DNA, and biologically important macromolecules will likewise impact animal performance, meat and milk quality, nutritional value, and longevity. Dietary antioxidants, endogenous antioxidants, and metal-binding proteins contribute to the 'antioxidant defenses' that control free radical formation within the biological systems. Different bioactive compounds of varying antioxidant potential and bio-accessibility may be sourced from tailored feeding systems. Informed and successful provision of dietary antioxidants can help alleviate oxidative stress. However, knowledge pertaining to farm animals, their unique biological systems, and the applications of novel feeds, specialized forages, bioactive compounds, etc., must be established. This review summarized current research to direct future studies towards more effective controls for free radical formation/oxidative stress in farm animals so that productivity and quality of meat and milk can be optimized.

A Comparative Photographic Review on Higher Plants and Macro-Fungi: A Soil Restoration for Sustainable Production of Food and Energy

The Kingdom of Plantae is considered the main source of human food, and includes several edible and medicinal plants, whereas mushrooms belong to the Kingdom of fungi. There are a lot of similar characteristics between mushrooms and higher plants, but there are also many differences among them, especially from the human health point of view. The absences of both chlorophyll content and the ability to form their own food are the main differences between mushrooms and higher plants. The main similar attributes found in both mushrooms and higher plants are represented in their nutritional and medicinal activities. The findings of this review have a number of practical implications. A lot of applications in different fields could be found also for both mushrooms and higher plants, especially in the bioenergy, biorefinery, soil restoration, and pharmaceutical fields, but this study is the first report on a comparative photographic review between them. An implication of the most important findings in this review is that both mushrooms and plants should be taken into account when integrated food and energy are needed. These findings will be of broad use to the scientific and biomedical communities. Further investigation and experimentation into the integration and production of food crops and mushrooms are strongly recommended under different environmental conditions, particularly climate change.

Assessment of Feed Value of Chicory and Lucerne for Poultry, Determination of Bioaccessibility of Their Polyphenols and Their Effects on Caecal Microbiota

Chicory and lucerne possess high feed value for poultry being good sources of protein and fiber. In addition, they are rich in polyphenols that help the body build an integrated antioxidant system to prevent damage from free radicals and positively modulate microbial populations in the gastrointestinal tract. These health-promoting effects of polyphenols depend on their bioaccessibility and absorption in the animal body. The present paper aimed to study the bioaccessibility of polyphenols from chicory and lucerne after subjecting the samples to gastric and intestinal phases of digestion in an in vitro model of chicken gut and assessment of their feed value by measuring the presence of fermentable substrates (in terms of gas production), SCFAs produced and their effects on gut microbiota population during in vitro cecal fermentation. Results revealed that the bioaccessibility of polyphenols varied with different polyphenol compounds. The highest bioaccessibility was recorded for p-hydroxybenzoic acid (90.8%) from chicory following the intestinal phase of digestion. The lowest bioaccessibility was observed for quercetin-3-rhamnoside (12.6%) from chicory after the gastric phase of digestion. From lucerne, the highest bioaccessibility was recorded for kaempferol-3-glucoside (77.5%) after the intestinal phase of digestion. Total gas production was higher for lucerne (39.9 mL/g) than chicory (28.1 mL/g). Similarly, total SCFAs production was higher after 24 h of cecal fermentation with lucerne (42.2 mmol L−1) as compared to chicory (38.1 mmol L−1). Results also revealed that the relative abundance of Clostridium was reduced with chicory (0.225%) and lucerne (0.176%) as compared to the control (0.550%) after 24 h of cecal fermentation. The relative abundance of Streptococcus was reduced by lucerne (4.845%) but was increased with chicory (17.267%) as compared to the control (5.204%) after 24 h of fermentation. These findings indicated that chicory and lucerne differentially affected the microbial populations during in vitro cecal fermentation.