Strategies for the determination of bioactive phenols in plants, fruit and vegetables

The preservation effect of biodegradable gelatin coating incorporated with grape seed oil on glazed shrimp

BACKGROUND

This study was conducted to investigate the quality and shelf life of shrimps (Parapenaeus longirostris, Lucas 1846) glazed with biodegradable gelatin solutions combined with grape (Vitis vinifera L.) seed oil (GSO). Therefore, shrimps were divided into five groups and were glazed with distilled water (control), G (gelatin), G + 5% GSO (gelatin with 5% GSO), G + 10% GSO (gelatin with 10% GSO) and G + 15% GSO (gelatin with 15% GSO). Glazed shrimps were vacuum packaged and stored at -18 °C for 12 months. Proximate composition of the shrimps was determined, and the microbial (total viable counts, psychrotrophic bacteria count and Enterobacteriaceae), sensorial, chemical (residual sulfite, pH, total volatile basic nitrogen, trimethylamine nitrogen, thiobarbituric acid reactive substances) analysis, colour measurement, and melanosis formation were evaluated throughout the storage period.

RESULTS

According to the analysis results, edible G + GSO coatings improved the meat quality and the brightness of the shrimps. The combined treatment reduced the quality loss of the shrimps which was caused by lipid content and prevented the total psychotropic bacteria growth throughout the storage. Moreover, glazing with G + GSO retarded the melanosis formation of the frozen shrimps.

CONCLUSION

The study results revealed that GSO may be a recommended alternatively to sodium metabisulfite, which is a hazardous chemical substance commonly used against melanosis of shrimps. © 2023 Society of Chemical Industry.

Food phenolics and Lactiplantibacillus plantarum

Phenolic compounds are important constituents of plant food products. These compounds play a key role in food characteristics such as flavor, astringency and color. Lactic acid bacteria are naturally found in raw vegetables, being Lactiplantibacillus plantarum the most commonly used commercial starter for the fermentation of plant foods. Hence, the metabolism of phenolic compounds of L. plantarum has been a subject of study in recent decades. Such studies confirm that L. plantarum, in addition to presenting catalytic capacity to transform aromatic alcohols and phenolic glycosides, exhibits two main differentiated metabolic routes that allow the biotransformation of dietary hydroxybenzoic and hydroxycinnamic acid-derived compounds. These metabolic pathways lead to the production of new compounds with new biological and organoleptic properties. The described metabolic pathways involve the action of specialized esterases, decarboxylases and reductases that have been identified through genetic analysis and biochemically characterized. The purpose of this review is to provide a comprehensive and up-to-date summary of the current knowledge of the metabolism of food phenolics in L. plantarum.

Optimization and Characterization of Phenolic Extraction Conditions and Antioxidant Activity Evaluation of Adenanthera pavonina L. Bark

The presence of high levels of secondary metabolites in medicinal plants can significantly influence the progress of drug development. Here, we aimed to maximize phenolic extraction from Adenanthera pavonina L. stem bark using various solvents such as ethyl acetate, methanol, petroleum ether, and chloroform. A response surface method (RSM) with a central composite design (CCD) statistical technique was applied to optimize the extraction process, employing three important extracting parameters such as extraction time (h), temperature (°C), and solvent composition (% v/v of methanol/water) to obtain the highest phenolic content. Total phenolic content (TPC) and antioxidant activity (IC50 of extract's DPPH radical scavenging activity) were used as response variables to find the influence of these extracting parameters. Among the various solvents used, methanol extract showed the highest contents of phenolics and the maximum level of antioxidant activity with a lower IC50 value. The notable TPC and IC50 value of the extract's DPPH radical scavenging capacity were found to be 181.69 ± 0.20 mg GAE/g dry tissue and 60.13 ± 0.11 mg/mL, respectively, under the optimal conditions with a solvent composition of 71.61% (v/v) of methanol/water, extraction temperature of 42.52 °C, and extraction time of 24 h. The optimized extract of A. pavonina stem bark was further subjected to HPLC analysis, where six phenolic compounds, including coumarin, p-coumaric acid, chlorogenic acid, sinapic acid, gallic acid, and caffeic acid, were identified along with their respective quantities. Overall, the findings of this study uncover a low-cost analytical model for maximizing phenolic extraction from A. pavonina bark with enhanced antioxidant activity.

Visual Sensor Arrays for Distinction of Phenolic Acids Based on Two Single-Atom Nanozymes

Although great achievements have been made in the study of artificial enzymes, the design of nanozymes with high catalytic activities of natural enzymes and the further establishment of sensitive biosensors still remain challenging. Here, two nanozymes, i.e., ZnCoFe three-atom nanozyme (TAzyme) and Sn single-atom nanozyme (SAzyme)/Ti₃C₂T_x, are developed, which show peroxidase-like catalytic activities by catalyzing the reaction of hydrogen peroxide (H₂O₂), 4-aminoantipyrine (4-AAP), and phenolic acids to generate colorimetric reactions. The involvement of different phenolic acids leads to the generation of different color products. These subtle color-variation profiles between these phenolic acids prompt us to exploit an electronic tongue based on the two nanozymes to distinguish phenolic acids. Data interpretation by the pattern recognition method, such as linear discriminant analysis (LDA), displays good clustering separation of six different phenolic acids at concentrations of 0.1 μM to 1 mM, validating the effectiveness of the colorimetric nanozyme sensor array.

Box-Behnken design based optimization of phenolic extractions from Polygonum equisetiforme roots linked to its antioxidant and antibacterial efficiencies

Purpose

The Polygonum equisetifome is a prospective plant source of high protein, unsaturated fatty acids, and useful safe bioactive molecules. Therefore, the aim of this study was to optimize the ultrasonic aqueous extraction of phenols from P. equisetifome roots using Box-Behnken design based statistical modeling, and to evaluate the antioxidant and antibacterial efficiencies of P. equisetifome root extracts against pathogenic bacteria.

Methods

In this study, the box-behnken design was used to optimize the extraction of phenols. The extraction temperature (30–70°C), ultrasound assisted extraction (UAE) time (1–9 min), and liquid-solid ratio (35–45 mL/g) were investigated as the factors that influence the phenolic yield (Y1) and their DPPH (1,1-diphenyl-2-picrylhydrazyl) scavenging activity (Y2).

Results

The optimal conditions for both responses were 50°C, 5 min, and 40 mL/g. At these conditions, Y1 reached its maximum to be 45.321 mg GAE/g dry weight and Y2 to be 120.354 μmol Trolox/g dry weight. The P. equisetifome roots contained water soluble phenol, high anthocyanin, and condensed tannins. Interestingly, the P. equisetifome extracts showed a relation to its antioxidant and antibacterial activities, FRAP (Ferric-reducing/antioxidant power), and ABTS scavenging activity were determined. The morphological and physico-chemical features of the extract were analyzed using SEM-EDX, FT-IR, and minimum inhibitory concentration (MIC) was analyzed against several pathogenic bacteria. The antibacterial activity of the extract showed that the extract is more efficient against Staphylococcus aureus, while the P. equisetifome extracts showed efficient MIC against S. aureus, followed by Bacillus cereus.

Suggestions

The relation of P. equisetifome extracts to its antioxidant, and antibacterial efficiencies open a new avenue of their potential uses in the food and pharmaceutical industries.

Recent discovery of tyrosinase inhibitors in traditional Chinese medicines and screening methods

ETHNOPHARMACOLOGICAL RELEVANCE

Tyrosinase, the key rate-limiting enzyme for melanogenesis, is one of the main targets for skin senescence and some pigmented skin diseases, such as albinism and melanoma. Tyrosinase inhibitors are capable of reducing melanin generation and deposition in the skin through blocking the reaction chain of formation. Thus, it has been used for anti-melanoma and showed the potential to be developed into novel skin whitening and spot removing products. With the trend of back-to-nature, natural tyrosinase inhibitors are receiving more and more attention. Traditional Chinese medicines (TCMs) as the promising source of novel chemotypes and pharmacophores, are huge treasures for the discovery of natural tyrosinase inhibitors characterized with green, safe, and highly efficient.

AIM OF THIS REVIEW

This review aims to provide a systematic overview of natural tyrosinase inhibitors and a detailed summary of the types of TCMs from which they originate. In addition, this paper also highlights the screening methods developed for exploring tyrosinase inhibitors in recent years, compares the advantages and disadvantages of various methods under the guidance of different screening principles, and predicts their applications in the future.

MATERIALS AND METHODS

Relevant literature have been obtained using the keywords "tyrosinase inhibitors", "traditional Chinese medicines", "whitening", and "screening" in scientific databases, such as "PubMed", "SciFinder", "Web of Science", "Elsevier", "China Knowledge Resource Integrated databases". Information was also collected from Chinese pharmacopoeia, Chinese herbal classics books, "Google Scholar", "Baidu Scholar", and other literature sources, etc. RESULTS: An overview about the tyrosinase inhibitors derived from TCMs since 2002 has been compiled via the above-mentioned sources. Up to now, 186 components, mainly belonging to flavonoids, lignans, terpenoids, Diels-Alder adducts, simple phenylpropanoids and stilbenes, from 61 kinds of TCMs have been reported to possess tyrosinase inhibitory activity, among which flavonoids are mainly focused on. Furthermore, on the basis of bioactive detection strategies, the screening methods for tyrosinase inhibitors have been classified into bioaffinity-based, intrinsic enzymatic-based, and computer-aided drug design (CADD). Precisely because screening approaches are essential for rapid identification of tyrosinase inhibitors from TCMs, the principles, advantages and disadvantages, and specific applications of each method are presented along with a comparison of applicability.

CONCLUSIONS

The summary of TCMs-derived inhibitors gives a clue on the discovery of candidates with the property to whiten the skin. Meanwhile, the outlook of developed screening methods provides technical references for the efficient exploration of safer and more effective tyrosinase inhibitors from TCMs.

Microbiological stability and sensorial valorization of thyme and oregano essential oils alone or combined with ethanolic pomegranate extracts in wine marinated pork meat

In the present study, wine-based marinades containing ethanolic extract from pomegranate (Punica granatum L.), alone or in combination with two Essential Oils (Thyme & Oregano), were used for pork fillets marination and their antimicrobial activity, as well as their sensorial impact were evaluated. Likewise, the marinades exhibited promising results concerning their recorded antimicrobial activity versus Enterobacteriaceae, Total Mesophilic Bacteria, Yeasts/molds, Staphylococcus spp., Pseudomonas spp. & Lactic Acid Bacteria (LAB). The outcome demonstrated that pork fillets marinated with wine containing ethanolic extract of pomegranate and Oregano Essential Oil were more resistant to spoilage compared to all other samples; thus, their shelf-life was significantly extended (4 days in some cases). Triterpenes (maslinic, oleanolic and betulinic acid), monoterpenes (p-cymene, carvacrol, thymol, limonene), organic acids (citric & malic acid) and phenols, were the main constituents found in the plant extract, the wine and Essential Oils applied, as determined through LC-QTOF/MS and HPLC analysis. Additionally, the sensorial properties (color, tenderness, flavor and juiciness) of the marinated meat samples were not negatively influenced. Consequently, marinades of this type could be used as natural preservatives in meat products, with satisfying antimicrobial and organoleptic results.

Phytochemical profiling, antimicrobial, and antioxidant activities of hydroethanolic extracts of prickly pear ( Opuntia ficus indica ) fruit and pulp

Phenolic compounds in prickly pear [Opuntia ficus indica (L.) Mill.] are known to contribute to the antioxidant and antimicrobial activities of the prickly pear. The present study aimed to evaluate the antioxidants and in vitro antimicrobial potential in the hydroethanolic extracts of different parts (fruit, cladode, and pulp) of prickly pear. Different polyphenolic compounds were analyzed by using high-performance liquid chromatography. The results indicated that cladode possessed a higher quantity of phenolics compared with that observed in fruit and pulp. The most important phenolic compound in high quantity was gallic acid (66.19 μg/g) in cladode. The 100% aqueous extract of cladode exhibited the highest antioxidant (92%) and antimicrobial activities against Salmonella typhi (3.40 mg/ml), Helicobacter pylori (1.37 mg/ml), Escherichia coli (1.41 mg/ml), and Staphylococcus aureus (1.41 mg/ml). Principal component analysis (PCA) indicated that antioxidant activity and minimum inhibitory concentration (MIC) responses had a significant negative correlation with each other. Overall, the current results provided basic data for choosing prickly pear cladode with high antioxidant capacity for the development and consumption of antioxidant-based alternative medicines and value addition of formulated foods.

In vitro bioactivities and preparation of nanoemulsion from coconut oil loaded Curcuma aromatica extracts for cosmeceutical delivery systems

Curcuma aromatica (CA) is a herbaceous plant in the Zingiberaceae family. It has antioxidative activity and anti-inflammatory properties. The purpose of this study was to investigate the effect of solvents and extraction methods on CA rhizomes. The crude extracts were tested for phenolic and flavonoid contents, antioxidative activity by DPPH and lipid peroxidation assay, and protein denaturation inhibition. The crude extracts with 95% ethanol by maceration technique showed good results. It had phenolic content at 99.28 ± 1.09 mg GAE/g extract, flavonoid content at 397.00 ± 27.54 mg QE/g extract, antioxidative activity by DPPH assay and lipid peroxidation assay at IC₅₀ value of 0.55 ± 0.02 mg/ml and 0.60 ± 0.10 mg/ml, respectively. The percentage of protein denaturation inhibition was 65.97 ± 4.68%. The crude extract with 95% ethanol by maceration technique was selected to formulate nanoemulsion. Nanoemulsion formulation consisted of DI water, Tween 80, CA extract, coconut oil and Span 80 at 72.50, 12.93, 7.07, 5.00 and 2.5%w/w, respectively. Its appearance was an opaque yellow liquid with no precipitation and no phase separation at room temperature. The particle size, pH, and viscosity were 70.20 ± 0.38 nm, 5.87 ± 0.01 and 3.56 ± 0.24 cP, respectively. Nanoemulsion loaded CA extract had bioactivities and highly stable characteristics after heating–cooling test for 6 cycles. This study has demonstrated the potential of nanoemulsion from coconut oil loaded CA extract for further development to novel cosmetic products.

Carbon dioxide expanded liquid: an effective solvent for the extraction of quercetin from South African medicinal plants

BACKGROUND

Quercetin is one of the most important bioflavonoids having positive effects on the biological processes and human health. Typically, it is extracted from plant matrices using conventional methods such as maceration, sonication, infusion, and Soxhlet extraction with high solvent consumption. Our study aimed to optimize the environmentally friendly carbon dioxide-based method for the extraction of quercetin from quince fruit with an emphasis on extraction yield, repeatability, and short extraction time.

RESULTS

A two-step design of experiments was used for the optimization of the key parameters affecting physicochemical properties, including CO₂/co-solvent ratio, co-solvent type, temperature, and pressure. Finally, gas expanded liquid combining CO₂/ethanol/H₂O in a ratio of 10/81/9 (v/v/v) provided the best extraction yield. Extraction temperature 66 °C and pressure 22.3 MPa were the most suitable conditions after careful optimization, although both parameters did not significantly affect the process. It was confirmed by experiments in various pressure and temperature conditions and statistical comparison of obtained data. The optimized extraction procedure at a flow rate of 3 mL/min took 30 min. The repeatability of the extraction method exhibited an RSD of 20.8%.

CONCLUSIONS

The optimized procedure enabled very fast extraction in 30 min using environmentally friendly solvents and it was successfully applied to 16 different plant samples, including 14 bulbs and 2 fruits from South Africa. The quercetin content in extracts was quantified using ultra-high performance liquid chromatography (UHPLC) with tandem mass spectrometry. UHPLC hyphenated with high-resolution mass spectrometry was used to confirm chemical identity of quercetin in the analyzed samples. We quantified quercetin in 11 samples of all 16 tested plants. The quercetin was found in Agapanthus praecox from the Amaryllidaceae family and its presence in this specie was reported for the first time.

White rot fungal impact on the evolution of simple phenols during decay of silver fir wood by UHPLC-HQOMS

INTRODUCTION

Silver fir (Abies alba Mill.) is one of the most valuable conifer wood species in Europe. Among the main opportunistic pathogens that cause root and butt rot on silver fir are Armillaria ostoyae and Heterobasidion abietinum. Due to the different enzymatic pools of these wood-decay fungi, different strategies in metabolizing the phenols were available.

OBJECTIVE

This work explores the changes in phenolic compounds during silver fir wood degradation.

METHODOLOGY

Phenols were analyzed before and after fungus inoculation in silver fir macerated wood after 2, 4 and 6 months. All samples were analyzed using high-performance liquid chromatography coupled to a hybrid quadrupole-orbitrap mass spectrometer.

RESULTS

Thirteen compounds, including simple phenols, alkylphenyl alcohols, hydroxybenzoketones, hydroxycinnamaldehydes, hydroxybenzaldehydes, hydroxyphenylacetic acids, hydroxycinnamic acids, hydroxybenzoic acids and hydroxycoumarins, were detected. Pyrocatechol, coniferyl alcohol, acetovanillone, vanillin, benzoic acid, 4-hydroxybenzoic acid and vanillic acid contents decreased during the degradation process. Methyl vanillate, ferulic acid and p-coumaric were initially produced and then degraded. Scopoletin was accumulated. Pyrocatechol, acetovanillone and methyl vanillate were found for the first time in both degrading and non-degrading wood of silver fir.

CONCLUSIONS

Despite differences in the enzymatic pool, both fungi caused a significant decrease in the amounts of phenolic compounds with the accumulation of the only scopoletin. Principal component analysis revealed an initial differentiation between the degradation activity of the two fungal species during degradation, but similar phenolic contents at the end of wood degradation.

Can Polyphenols Inhibit Ferroptosis?

Polyphenols, a diverse group of naturally occurring molecules commonly found in higher plants, have been heavily investigated over the last two decades due to their potent biological activities—among which the most important are their antioxidant, antimicrobial, anticancer, anti-inflammatory and neuroprotective activities. A common route of polyphenol intake in humans is through the diet. Since they are subjected to excessive metabolism in vivo it has been questioned whether their much-proven in vitro bioactivity could be translated to in vivo systems. Ferroptosis is a newly introduced, iron-dependent, regulated mode of oxidative cell death, characterized by increased lipid peroxidation and the accumulation of toxic lipid peroxides, which are considered to be toxic reactive oxygen species. There is a growing body of evidence that ferroptosis is involved in the development of almost all chronic diseases. Thus, ferroptosis is considered a new therapeutic target for offsetting many diseases, and researchers are putting great expectations on this field of research and medicine. The aim of this review is to critically analyse the potential of polyphenols to modulate ferroptosis and whether they can be considered promising compounds for the alleviation of chronic conditions.

Standardized artichoke extract: physiological effects, possibilities of use in medical practice

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Changes in physicochemical properties at different development stages of Hexachlamys edulis fruit, an underutilized South American species

The aim of this work was to study the evolution of fruit size and weight together with the soluble solid and total titratable acidity contents during development of Hexachlamys edulis fruit. Also, the patterns of accumulation of chlorophylls, carotenoids, phenols and antioxidant activity were analysed to define the optimal time for harvesting to obtain maximum nutraceutical characteristics. Fruits were harvested from H. edulis plants growing at the experimental field of the University of Morón (Moreno, Buenos Aires, 34°35′4.98″ SL, 58°48′52.09″ WL, 14 m.a.s.l.). Fresh fruit weight was significantly higher in Medium ripe, Ripe and Overripe fruits (40.1, 39.6 and 38.5 g, respectively) than in Unripe fruits (19.5 g). Soluble solids/total titratable acidity was significantly higher in Overripe fruits (7.3) than in Unripe, Medium ripe and Ripe fruits (3.7–4.5). Total polyphenols were maximum in Unripe fruits (905.8 mg tannic acid/100 g fresh fruit weight) decreasing during the fruit development (426.2–130.4 mg tannic acid/100 g fresh fruit weight). Also, DPPH radical scavenging activity was significantly higher in Unripe fruits (75.7%) compared with Medium ripe, Ripe and Overripe fruits (64.1–17.0%). Positive and significant correlations were observed between total polyphenol content and DPPH radical scavenging activity at each extract concentration (r = 0.74, 0.87, 0.74 and 0.60 for 1.25; 2.50; 5.00 and 12.50 mg/mL, respectively). Total carotenoid content increased during fruit development while at the same time decreased chlorophyll content. Chlorophyll b is the main chlorophyll found. Chromatographic analysis showed that lutein is the main carotenoid found in H. edulis fruits, followed by β-cryptoxanthin and β-carotene. As shown by the chromatograms at 280 nm, the concentration of biophenols and the complexity of the biophenol profile decreases during fruit development. Levels of polyphenols and pigments together with the antioxidant activity allow us to consider H. edulis fruit as a functional food.

Nanomicellar Extraction of Polyphenols-Methodology and Applications Review

The selection of the appropriate extraction method is crucial, especially for the receiving of active substances from plant material. The extraction using supercritical liquids and micellar-mediated extraction (MME) is the most advantageous among the alternative methods to classical solid-liquid extraction. However, the latter seems to be the best solution when the desired actives are polar. The following article presents a comprehensive review of the micellar-mediated extraction method in the last decade. The theoretical principle of the process was also refreshed and the current state of knowledge on the applications for analytical and manufacturing purposes was summarized.

Simultaneous determination of four phenolic acids in traditional Chinese medicine by capillary electrophoresis-chemiluminescence

Chlorogenic, ferulic, vanillic, and caffeic acids are phenolic acids found in natural drugs. They possess the biological activities of scavenging free radicals and inhibiting thrombus formation. Phenolic acids can inhibit the oxidation of low-density lipoprotein, as well as have anti-inflammatory effects. This paper reports for the first time a capillary electrophoresis-chemiluminescence (CE-CL) method for the simultaneous determination of the four phenolic acids found in traditional and proprietary Chinese medicine, including Lycium chinense Miller, Shuanghuanglian oral liquid, and Taraxacum mongolicum granules. Capillary electrophoretic separation was performed on a self-assembled CE-CL device with an uncoated fused-silica capillary (66 cm effective length, 50 μm i.d.), and the background electrolyte was composed of 3.0 × 10-5 M Ag(iii) (pH = 12.01), 3.0 mM luminol (pH = 9.20), and 10 mM sodium tetraborate solution. The injection time was 12 s (under gravity) and the separation voltage was 22 kV. The combination of solid-phase extraction (SPE) and CE-CL improves the sensitivity. Under optimal conditions, calibration graphs displayed a linear range between 0.625 and 20.0, 1.000 and 30.0, 0.150 and 1.50, and 0.045 and 1.00 μg mL-1 for chlorogenic, ferulic, vanillic, and caffeic acid, respectively. The detection limit ranged from 0.014 to 0.300 μg mL-1. The practicality of using the proposed method to determine the four target analytes in traditional Chinese medicine was also validated, in which recoveries ranged from 90.9% to 119.8%. Taken together, these results indicate that the developed method is sensitive and reliable. Furthermore, the method was successfully applied to real traditional Chinese medicine samples.

HPTLC and ATR/FTIR Characterization of Antioxidants in Different Rosemary Extracts

The effect of spontaneous fermentation by lactic acid bacteria on the extraction yield of bioactive compounds and antioxidant activity from rosemary leaf extracts was investigated using high-performance thin-layer chromatography (HPTLC). Brining and spontaneous fermentation with lactic acid bacteria more than doubled extraction of polyphenolics and antioxidants from the rosemary leaves. The results show that lactic acid fermentation enhances antioxidant activity in extracts by increasing the total phenolic content but does not increase extraction of phytosterols. Increased extraction of phenolic oxidants during fermentation assisted extraction, results from the in situ generated natural eutectic solvent from the plant sample. ATR-FTIR spectra from the bioactive bands suggests that this increased antioxidant activity is associated with increased extraction of rosmarinic acid, depolymerised lignin, abietane diterpenoids and 15-hydroxy-7-oxodehydroabietic acid.

UV-B light and its application potential to reduce disease and pest incidence in crops

Ultraviolet-B radiation (280-315 nm), perceived by the plant photoreceptor UVR8, is a key environmental signal that influences plant growth and development and can reduce disease and pest incidence. The positive effect of UV-B on disease resistance and incidence in various plant species supports the implementation of supplemental UV-B radiation in sustainable crop production. However, despite many studies focusing on UV-B light, there is no consensus on the best mode of application. This review aims to analyze, evaluate, and organize the different application strategies of UV-B radiation in crop production with a focus on disease resistance. We summarize the physiological effects of UV-B light on plants and discuss how plants perceive and transduce UV-B light by the UVR8 photoreceptor as well as how this perception alters plant specialized metabolite production. Next, we bring together conclusions of various studies with respect to different UV-B application methods to improve plant resistance. In general, supplemental UV-B light has a positive effect on disease resistance in many plant-pathogen combinations, mainly through the induction of the production of specialized metabolites. However, many variables (UV-B light source, plant species, dose and intensity, timing during the day, duration, background light, etc.) make it difficult to compare and draw general conclusions. We compiled the information of recent studies on UV-B light applications, including e.g., details on the UV-B light source, experimental set-up, calculated UV-B light dose, intensity, and duration. This review provides practical insights and facilitates future research on UV-B radiation as a promising tool to reduce disease and pest incidence.

Extraction of phenolic compounds: A review

Phenolic compounds are parts of secondary metabolites mostly found in plant species with enormous structural diversities. They can exist as glycosides or aglycones; matrix or free-bound compounds; and comprising mostly polymerized or monomer structures. Additionally, these compounds are not universally dispensed within plants with varied stability. This has contributed to challenging extraction processes; implying that employing a single step or inappropriate extraction technique might change the recovery of phenolic components from the plant samples. Hence, it is important to select an appropriate extraction method so as to recover the targeted phenolic compounds. This is will helps to recover substantial yields from the sample matrix. Therefore, this review mainly focuses on the phenolic compounds and several methods of extraction that are used to obtaining them from plant materials. These extraction methods includes both conventional and unconventional techniques.

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Phenolic compounds from natural sources.

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Methods of extracting phenolic compounds.

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Selection of an appropriate extraction method to recover the targeted phenolic compounds from plant materials.

Novel Active Food Packaging Films Based on Whey Protein Incorporated with Seaweed Extract: Development, Characterization, and Application in Fresh Poultry Meat

Algae and seaweeds are used in cookery since the beginnings of human civilization, particularly in several Asian cultures. Phenolic compounds are secondary metabolites produced by aquatic and terrestrial plants for their natural defense against external stimuli, which possess powerful antimicrobial and antioxidant properties that can be very important for the food industry. The main objective of this study was to develop a whey protein concentrate active coating, incorporated with a Fucus vesiculosus extract in order to delay the lipid oxidation of chicken breasts. Ten hydroethanolic extracts from F. vesiculosus were obtained and their antioxidant capacity was evaluated through two antioxidant activity assays: the DPPH radical scavenging activity and β-carotene bleaching assay. The total content in phenolics compounds was also determined by Folin-Ciocalteu method. The chosen extract was the one obtained from the freeze-dried F. vesiculosus using 75% (v/v) ethanol as extraction solvent. The extract was successfully incorporated into a whey protein film and successfully strengthened the thickness, tensile strength, and elastic modulus. The active film also was able to inhibit the chicken breasts lipid oxidation for 25 days of storage.

Determination of Post-Harvest Biochemical Composition, Enzymatic Activities, and Oxidative Browning in 14 Apple Cultivars

Phenolic compounds in fruit provide human health benefits, and they contribute to color, taste, and the preservation of post-harvest fruit quality. Phenolic compounds also serve as modifiers of enzymatic activity, whether inhibition or stimulation. Polyphenol oxidases (PPO) and peroxidases (POD) use phenolic compounds as substrates in oxidative browning. Apple browning leads to flesh color, taste, texture, and flavor degradation, representing a drawback for the variety and its’ market appraisal. This study was conducted to investigate the process of browning in 14 apple cultivars throughout post-harvest at three-time points: immediately (T0), one hour (T1), and 24 h (T2) after apples were cut in half. Color parameters L* (lightness), a* (red/green), b* (yellow/blue) were measured, and chroma (ΔC*) and color (ΔE) were calculated to quantify differences between T0₋T1 and T1₋T2 on the fruit surface. Enzymatic activity (PPO, POD) and phenolic composition were also quantified for each cultivar. ‘Granny Smith’ and ‘Cripps Pink’ browned minimally. In contrast, ‘Fiesta’ and ‘Mondial Gala’ browned severely, reporting high enzymatic activity and quantified phenolic concentration (QPC). Phenolic compound polymerization appears to play a significant role in enzymatic inhibition. ‘Topaz’ does not fit the high QPC, PPO, and browning formula, suggesting alternative pathways that contribute to apple browning.

Antimicrobial activity of polyphenolic compounds from Spirulina against food-borne bacterial pathogens

Food-borne drug-resistant bacteria have adverse impacts on both food manufacturers and consumers. Disillusionment with the efficacy of current preservatives and antibiotics for controlling food-borne pathogens, especially drug-resistant bacteria, has led to a search for safer alternatives from natural sources. Spirulina have been recognized as a food supplement, natural colorant, and enriched source of bioactive secondary metabolites. The main objectives of this study were to isolate polyphenolic compounds from Spirulina and analyze their antibacterial potential against drug-resistant food-borne bacterial pathogens. We found that fraction B of methanol extract contained a high quantity of polyphenols exhibiting broad spectrum antimicrobial effects against drug-resistant food-borne bacterial pathogens. Potential secondary metabolites, such as benzophenone, dihydro-methyl-phenylacridine, carbanilic acid, dinitrobenzoate, propanediamine, isoquinoline, piperidin, oxazolidin, and pyrrolidine, were identified by gas chromatography and mass spectrophotometry (GCMS). These metabolites are active against both gram-positive and gram-negative pathogens. Our work suggests that phenolic compounds from Spirulina provide a natural and sustainable source of food preservatives for future use.

Plant-Derived Natural Antioxidants in Meat and Meat Products

The global meat industry is constantly evolving due to changes in consumer preferences, concerns and lifestyles, as well as monetary, geographical, political, cultural and religious factors. Part of this evolution is the introduction of synthetic antioxidants to increase meat and meat products' shelf-life, and reduce meat spoilage due to lipid and protein oxidation. The public perception that natural compounds are safer and healthier per se has motivated the meat industry to replace synthetic antioxidants with plant-derived ones in meat systems. Despite several promising results from in vitro and in situ studies, the effectiveness of plant-derived antioxidants against lipid and protein oxidation has not been fully documented. Moreover, the utility, usability, marketability and potential health benefits of natural antioxidants are not yet fully proven. The present review aims to (i) describe the major chemical groups of plant-derived antioxidants and their courses of action; (ii) present the application of spices, herbs and fruits as antioxidants in meat systems; and (iii) discuss the legislative framework, future trends, challenges and limitations that are expected to shape their acceptance and mass exploitation by the meat industry.

Interaction between cross-linked cationic starch microgranules and chlorogenic acid isomers in artichoke and green coffee bean aqueous extracts

In the present study, the adsorption of phenolic compounds, first of all, chlorogenic acid isomers (chlorogenic, neo-chlorogenic and crypto-chlorogenic acids) predominant in the artichoke (AE) or green coffee bean (GCBE) extracts on cross-linked cationic starch having quaternary ammonium groups (CCS) has been investigated. The equilibrium adsorption studies showed that adsorption closely followed the Langmuir adsorption model, i.e. anionic substances of the extracts were interacting with quaternary ammonium groups of CCS. The UPLC-UV-MS/MS analysis showed that 8% and 17% of chlorogenic acid isomers of the total amount of adsorbed phenolics form AE and GCBE, respectively, were immobilized on CCS. The desorption study of phenolics from AE/CCS and GCBE/CCS complexes revealed that amount of desorbed AE or GCBE phenolics depended on the desorption medium. The antioxidant activity investigation showed that the immobilization of active components of extracts on CCS prevented the rapid loss of antioxidant activity. The results suppose that adsorption on modified starch technique can be successfully employed to remove important amounts of bioactive compounds from plant extracts by employing effective, sustainable and environmental friendly procedures.

Determination of Biochemical Composition in Peach (Prunus persica L. Batsch) Accessions Characterized by Different Flesh Color and Textural Typologies

The rising interest in beneficial health properties of polyphenol compounds in fruit initiated this investigation about biochemical composition in peach mesocarp/exocarp. Biochemical evaluation of phenolic compounds and ascorbic acid were quantified through high-performance liquid chromatography (HPLC) in relation to three flesh colors (white, yellow and red) and four flesh typologies (melting, non-melting, slow softening and stony hard) within six commercial cultivars and eight breeding selections of peach/nectarine in 2007. While in 2008, quality and sensorial analyses were conducted on only three commercial cultivars (‘Big Top’, ‘Springcrest’ and ‘Ghiaccio 1’). The red flesh selection demonstrated the highest levels of phenolic compounds (in mesocarp/exocarp) and ascorbic acid. Total phenolic concentration was approximately three-fold higher in the exocarp than the mesocarp across all accessions. Breeding selections generally reported higher levels of phenolics than commercial cultivars. Flesh textural typologies justified firmness differences at harvest, but minimally addressed variations in quality and phenolic compounds. Flesh pigmentation explained variation in the biochemical composition, with the red flesh accession characterized by an abundancy of phenolic compounds and a high potential for elevated antioxidant activity. Sensorial analyses ranked the cultivar with high soluble solids concentration:titratable acidity (SSC:TA) and reduced firmness the highest overall. Red flesh is a highly desirable trait for breeding programs aiming to improve consumption of peaches selected for nutraceutical properties.

Methodology optimization for the analysis of phenolic compounds in chestnut (Castanea sativa Mill.)

Phenols are bioactive substances of great interest because of their involvement in plant physiology, their use in many industrial processes, and their impact on human health. This work aims to summarize the varied approaches to the phenolic analysis of chestnut (bark and wood of trunk and branches, leaves, catkins, burs, and fruit) and to collate the optimal conditions into an easy to follow and execute protocol. Phenolic compounds were extracted by solid-liquid extraction and separated by liquid-liquid extraction. Total phenols content was determined by Folin-Ciocalteu assay, condensed tannins by vanillin assay, and hydrolyzable tannins (gallotannins and ellagitannins) by high-performance liquid chromatography quantification of methyl gallate and ellagic acid following acid methanolysis. The lowest temperature for conservation (-80 ℃), lyophilization, and milling (liquid N₂) were the most effective pretreatments for samples. For quantification of tannins, the use of water clearly reduced the sensitivity of the analysis of condensed tannins, whilst the more efficient degradation capacity of sulfuric acid improved the methanolysis of hydrolyzable tannins. These findings were validated using a range of chestnut tissues, and thus confirm the utility and effectiveness of this easy to implement, cost-effective, and efficient protocol.

Development and validation of RRLC–UV method for determination of chlorogenic acid in green coffee

Coffee is one of the most widely consumed beverages in the world. It contains many bioactive compounds, including chlorogenic acid which possesses various biological properties. In this study, in order to determine concentration of chlorogenic acid in green coffee, a reverse-phase rapid resolution liquid chromatography (RP-RRLC) method with diode-array detection (DAD) was developed. Successful separation was achieved on a Poroshell 120 EC-C18 (50 mm × 3 mm; 2.7 μm) column using acetonitrile–water with 1% phosphoric acid (10:90, v/v) as a mobile phase, at a flow rate of 1 mL/min, and with UV detection at 325 nm. The identification was made with comparison of the retention time of pure analytical standard with the retention time of chlorogenic acid in the analyzed samples. The developed method was validated using the following parameters: linearity, sensitivity, selectivity, precision, and accuracy. Excellent linearity over the range 12.33–143.50 μg/mL was achieved with R2 values greater than 0.99. The intra-day precision was validated with the %RSD values, which confirmed that the method for determination of chlorogenic acid was repeatable. The mean recovery rate of the method ranged between 97.87% and 106.67% with %RSD values lower than 1%. The limit of detection and limit of quantification values under the used chromatographic conditions were 0.29 and 0.96 pg, respectively. This method was successfully employed for quantitative determination of chlorogenic acid in green coffee samples.

Incorporation of bioflavonoids from Bidens tripartite into micelles of non-ionic surfactants - experimental and theoretical studies

Classical extraction methods used for an isolation of active substances from the plant material are expensive, complicated and often environmentally unfriendly. The ultrasonic assistance micelle-mediated extraction method (UAMME) seems to be an interesting alternative. The aim of this work was to compare an efficiency of water solutions of three non-ionic surfactants: C9-11 Pareth-5, PPG-6 Steareth-7 and PPG-4 Laureth-5 in UAMME of Bidens tripartita. Subsequently, the obtained extracts were separated into two immiscible phases, a polyphenols rich surfactants phase and an aqueous phase by its heating above surfactants cloud points (CPC) or by salting out with NaCl. Along with decreasing the Hydrophilic/Lipophilic Balance (HLB) factor value of surfactants, i.e. increase of the hydrophobicity, a significant decreasing of the flavonoid content was observed. While polyphenols content and antioxidant activity increased. The good surface properties of all surfactants correspond to the high content of phenolic compounds in extracts and both concentration methods resulted in even a 50-fold increase of polyphenols content. Dynamic light scattering measurements (DLS) provided that solubilization of polyphenols, i.e. their incorporation into surfactants' micelles, occurred with significant enlarging of particle size. Based on the molecular dynamic simulations, the mechanism of polyphenols incorporation into micelles was discussed.

Response surface methodology and artificial neural network approach for the optimization of ultrasound-assisted extraction of polyphenols from garlic

This paper aimed to establish the optimal conditions for ultrasound-assisted extraction of polyphenols from domestic garlic (Allium sativum L.) using response surface methodology (RSM) and artificial neural network (ANN) approach. A 4-factor-3-level central composite design was used to optimize ultrasound-assisted extraction (UAE) to obtain a maximum yield of target responses. Maximum values of the two output parameters: 19.498 mg GAE/g fresh weight of sample total phenolic content and 1.422 mg RUT/g fresh weight of sample total flavonoid content were obtained under optimum extraction conditions: 13.50 min X₁, 59.00 °C X₂, 71.00% X₃ and 20.00 mL/g X₄. Root mean square error for training, validation, and testing were 0.0209, 3.6819 and 1.8341, respectively. The correlation coefficient between experimentally obtained total phenolic content and total flavonoid content and values predicted by ANN were 0.9998 for training, 0.9733 for validation, and 0.9821 for testing, indicating the good predictive ability of the model. The ANN model had a higher prediction efficiency than the RSM model. Hence, RSM can demonstrate the interaction effects of basic inherent UAE parameters on target responses, whereas ANN can reliably model the UAE process with better predictive and estimation capabilities.

Ultrasonic-assisted extraction and high-speed counter-current chromatography purification of zeaxanthin dipalmitate from the fruits of Lycium barbarum L

Zeaxanthin dipalmitate (ZDP) is a major non-saponified carotenoid in fully ripe fruits of Lycium barbarum L. In the present study, response surface methodology was used to optimize the ultrasonic-assisted extraction (UAE) conditions of carotenoids from the fruits of L. barbarum, and the optimal extraction conditions were determined as follows: ultrasonic power of 360 W, ultrasonic time of 40 min and the ratio of extraction solvent to sample of 30 mL/g. An actual value of ZDP content of 5.40 mg/g and short extraction time indicated the efficiency of UAE. Furthermore, a promising high-speed counter-current chromatography (HSCCC) method was established for the purification of ZDP from the fruits of L. barbarum. With a developed two-phase solvent system composed of n-hexane/dichloromethane/acetonitrile (10/3/7, v/v/v), ZDP with a purity of higher than 95% was successfully isolated from the crude extract. This is the first report on the purification of ZDP by using HSCCC.

Analysis of Wild Raspberries (Rubus idaeus L.): Optimization of the Ultrasonic-Assisted Extraction of Phenolics and a New Insight in Phenolics Bioaccessibility

A simple and efficient ultrasonic-assisted extraction (UAE) technique was developed in order to find optimal conditions for the extraction of total phenolic compounds, flavonoids and anthocyanins in wild raspberry (Rubus idaeus L.) fruits. Several extraction variables, including methanol composition (v/v, %), solid-solvent ratio (g/mL), time (min) and extraction temperature (°C) were optimized using response surface methodology (RSM). Under optimal conditions for extraction, the total phenolics were found in the concentration of 383 mg GAE/100 g of fresh fruit weight, while HPLC-PDA analysis of the optimized extract showed the presence of cyanidin-3-glucoside, cyanidin-3-sophoroside, catechin, gallic and ellagic acid. The experimental values of DPPH and ABTS radical scavenging activities were 29.0 and 39.5 μmol Trolox/g of fresh fruit weight, respectively. In vitro simulated gastrointestinal digestion showed great raspberry phenolics stability. Our study assessed the bioaccessible phenolics in wild raspberry fruits and showed optimal conditions for the effective extraction of bioactive compounds for their analysis.

Phenolic acids: Natural versatile molecules with promising therapeutic applications

Plant phenolics are considered to be a vital human dietary component and exhibit a tremendous antioxidant activity as well as other health benefits. Epidemiology evidence indicates that a diet rich in antioxidant fruits and vegetables significantly reduces the risk of many oxidative stress related diseases viz. cancers, diabetes and cardiovascular. The number and position of hydroxyl group in a particular phenolic compound leads to the variation in their antioxidant potential. Polyphenols are the main source of dietary antioxidants, and are effortlessly absorbed in the intestine. Phenolic acids, a sub class of plant phenolics, possess phenol moiety and resonance stabilized structure which causes the H-atom donation results in antioxidant property through radical scavenging mechanism. Other mode such as radical quenching via electron donation and singlet oxygen quenching are also known for the antioxidant activity of phenolic acids. Furthermore, phenolic acids are found ubiquitously and well documented for other health protective effects like antimicrobial, anticancer, anti-inflammatory, anti-mutagenic etc. The contribution emphasize on the phenolic acids potential in drug discovery. In addition their occurrence, biosynthesis, metabolism and health effects are discussed in detail.

Role of Dietary Flavonoids in Iron Homeostasis

Balancing systemic iron levels within narrow limits is critical for human health, as both iron deficiency and overload lead to serious disorders. There are no known physiologically controlled pathways to eliminate iron from the body and therefore iron homeostasis is maintained by modifying dietary iron absorption. Several dietary factors, such as flavonoids, are known to greatly affect iron absorption. Recent evidence suggests that flavonoids can affect iron status by regulating expression and activity of proteins involved the systemic regulation of iron metabolism and iron absorption. We provide an overview of the links between different dietary flavonoids and iron homeostasis together with the mechanism of flavonoids effect on iron metabolism. In addition, we also discuss the clinical relevance of state-of-the-art knowledge regarding therapeutic potential that flavonoids may have for conditions that are low in iron such as anaemia or iron overload diseases.

Aldose Reductase, Protein Glycation Inhibitory and Antioxidant of Peruvian Medicinal Plants: the Case of Tanacetum parthenium L. and Its Constituents

Diabetes complications, including peripheral neuropathy, cataracts, impaired wound healing, vascular damage, arterial wall stiffening and retinopathy diseases, are among the most predominant health problems facing the world's population today. The 22 Peruvian plant extracts were screened for their potential inhibitory activity against rat lens aldose reductase (RLAR) and DPPH radical scavenging. Among them, we have found that Tanacetum parthenium L. (TP) has the RLAR, AGEs and DPPH radical scavenging activities. We used for screening of active components in TP against RLAR and DPPH for the first time by ultrafiltration (UF) and DPPH. Compounds in TP were isolated by Sephadex column chromatography and their structures were established by MS and NMR spectroscopic analyses. Among the isolated compounds, ferulic acid, apigenin, luteolin-7-O-glucoside, luteolin, chrysosplenol, and kaempferol showed potent inhibition with IC50 values of 1.11-3.20 and 6.44-16.23 μM for RLAR and DPPH radical scavenging. Furthermore, these compounds suppressed sorbitol accumulation in rat lenses and ferulic acid, luteolin-7-O-glucoside, and luteolin have AGEs inhibitory activities with IC50 values of 3.43-6.73 μM. In summary, our study provides interesting plants for further study with respect to the treatment and prevention of diabetic complication of Peruvian plant and can provide the scientific base of the traditional uses.

Phytosynthesized metal oxide nanoparticles for pharmaceutical applications

Developments in nanotechnology field, specifically, metal oxide nanoparticles have attracted the attention of researchers due to their unique sensing, electronic, drug delivery, catalysis, optoelectronics, cosmetics, and space applications. Physicochemical methods are used to fabricate nanosized metal oxides; however, drawbacks such as high cost and toxic chemical involvement prevail. Recent researches focus on synthesizing metal oxide nanoparticles through green chemistry which helps in avoiding the involvement of toxic chemicals in the synthesis process. Bacteria, fungi, and plants are the biological sources that are utilized for the green nanoparticle synthesis. Due to drawbacks such as tedious maintenance and the time needed for the nanoparticle formation, plant extracts are widely used in nanoparticle production. In addition, plants are available all over the world and phytosynthesized nanoparticles show comparatively less toxicity towards mammalian cells. Secondary metabolites including flavonoids, terpenoids, and saponins are present in plant extracts, and these are highly responsible for nanoparticle formation and reduction of toxicity. Hence, this article gives an overview of recent developments in the phytosynthesis of metal oxide nanoparticles and their toxic analysis in various cells and animal models. Also, their possible mechanism in normal and cancer cells, pharmaceutical applications, and their efficiency in disease treatment are also discussed.

Natural antioxidants of plant origin

Interest in the content of natural antioxidants in plant-based foods can be from the human health perspective, in terms of how these compounds might help promote one's health and wellness, or from the storage point-of-view, as the endogenous antioxidant constituents aid to extend a foodstuff's shelf-life. This chapter reports essential information about the mechanism of antioxidant action and methods employed for determination of their activity, classes of phenolic compounds (phenolic acids, flavonoids, lignans, stilbenes, tannins), sources of plant antioxidants (oil seeds, cereals, legumes, plants of the Lamiaceae family, tea and coffee, tree nuts, fruits, and berries), extraction strategies of phenolic compounds from plant material, and the influence of processing and storage on the content of natural antioxidants in foods and their antioxidant activity. Thermal processing, if not releasing bound phenolics from the structural matrices of the food, tends to decrease the antioxidant potential or, in the best case scenario, has no significant negative impact. Gentler sterilization processes such as high-pressure processing tend to better retain the antioxidant potential of a foodstuff than thermal treatments such as steaming, boiling, or frying. The impact of processing can be assessed by determining the antioxidant potential of foodstuffs either at the point of formulation or after different periods of storage under specified conditions.

Extraction of bioactive compounds from mango (Mangifera indica L. var. Carabao) seed kernel with ethanol-water binary solvent systems

Mango seed kernel, a by-product of the processing industry, can be valorized as a potential source of bioactive compounds. Binary mixtures of ethanol and water, used in solid-liquid extraction (SLE), have drawn interest as an effective means of recovering phytochemicals from plant materials because these solvents can be used in food applications and their synergistic effect makes them a superior solvent over their pure counterparts. Total phenolic content (TPC) and HPLC chromatograms of each ethanolic extract revealed that ethanol concentration had a significant effect on phenolic compound recovery, wherein, TPC of mango kernel varied from 18.19 to 101.68 mg gallic acid equivalence (GAE) per gram of sample. Subsequently, the antioxidant activities (AOAc) of the extracts, measured by scavenging activities with the DPPH⁺ (1,1-diphenyl-2-picrylhydrazyl) radical and ferric reducing antioxidant power (FRAP) assay, ranged from 8.19 to 85.45 mmol/L and 3.82-55.61 mmol/L Trolox equivalence, respectively. The solvent containing 50% (w/w) ethanol-water had the highest TPC and exhibited the most potent reducing and radical scavenging activities. With the use of an HPLC-UV/Vis, gallic acid, caffeic acid, rutin and penta-O-galloyl-β-d-glucose were identified to be present in the mango seed kernel. Results show that the mango seed kernel is a viable source of bioactive compounds which can be recovered with water-ethanol binary solvent systems.

The Action of Polyphenols in Diabetes Mellitus and Alzheimer's Disease: A Common Agent for Overlapping Pathologies

Diabetes Mellitus (DM) and Alzheimer's disease (AD) are two prevalent diseases in modern societies, which are caused mainly by current lifestyle, aging and genetic alterations. It has already been demonstrated that these two diseases are associated, since individuals suffering from DM are prone to develop AD. Conversely, it is also known that individuals with AD are more susceptible to DM, namely type 2 diabetes (T2DM). Therefore, these two pathologies, although completely different in terms of symptomatology, end up sharing several mechanisms at the molecular level, with the most obvious being the increase of oxidative stress and inflammation. Polyphenols are natural compounds widely spread in fruits and vegetables whose dietary intake has been considered inversely proportional to the incidence of DM and AD. So, it is believed that this group of phytochemicals may have preventive and therapeutic potential, not only by reducing the risk and delaying the development of these pathologies, but also by improving brain's metabolic profile and cognitive function. The aim of this review is to understand the extent to which DM and AD are related pathologies, the degree of similarity and the relationship between them, to detail the molecular mechanisms by which polyphenols may exert a protective effect, such as antioxidant and anti-inflammatory effects, and highlight possible advantages of their use as common preventive and therapeutic alternatives.

Optimization of an extraction method for the simultaneous quantification of sixteen polyphenols in thirty-one pulse samples by using HPLC-MS/MS dynamic-MRM triple quadrupole

Pulses are an important source of proteins, carbohydrates, and dietary fibre, and also contain polyphenols, which are bioactive compounds with antioxidant activity. A new analytical method that uses high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was developed for the quantification of sixteen polyphenols in thirty-one pulse varieties. Different extraction procedures were tested (acidic hydrolysis, alkaline hydrolysis and extraction without hydrolysis), and acidic hydrolysis at pH 2, extraction temperature of 20 °C and extraction time of 2 h was proven to be the best in terms of recovery percentages (99.7-107.6%). The highest polyphenol levels were found in beans, particularly black beans (459 mg kg-1) and ruviotto beans (189 mg kg-1); significant levels of polyphenols were also observed in lentils, particularly black lentils (137 mg kg-1) and quality gold lentils (132 mg kg-1). This study provides new information about legume polyphenols, offering reasons to promote legumes as part of a healthy diet.

Screening and investigation of triplex DNA binders from Stephania tetrandra S. Moore by a combination of peak area-fading ultra high-performance liquid chromatography with orbitrap mass spectrometry and optical spectroscopies

The identification and screening of triplex DNA binders are important because these compounds, in many cases, are potential anticancer agents as well as promising drug candidates. Therefore, the ability to screen for these compounds in a high-throughput mode could dramatically improve the drug screening process. A method involving a combination of 96-well plate format and peak area-fading ultra high-performance liquid chromatography coupled with Orbitrap mass spectrometry was employed for screening bioactive compounds binding to the triplex DNA from the extracts of Stephania tetrandra S. Moore. Two compounds were screened out and identified as fangchinoline and tetrandrine based on the comparison of retention time and tandem mass spectrometry data with those of standards. The binding mechanisms of fangchinoline and tetrandrine at the molecular level were explored using tandem mass spectrometry, fluorescence spectroscopy, ultraviolet-visible spectroscopy, and circular dichroism. Collision-induced dissociation experiments showed that the complexes with fangchinoline and tetrandrine were dissociated by ligand elimination. According to these measurements, an intercalating binding is the most appropriate binding mode of these two alkaloids to the triplex DNA. The current work provides not only deep insight into alkaloid-triplex DNA complexes but also useful guidelines for the design of efficient anticancer agents.

Autofluorescence study and selected cyanidin quantification in the Jewel orchids Anoectochilus sp. and Ludisia discolor

Anoectochilus sp. and Ludisia discolor are known as Jewel orchids. Both species are terrestrial wild orchids that grow in shaded areas of forests. The Jewel orchids are renowned for the beauty of their leaves, which are dark-green laced with silvery or golden veins. The orchids are used as a cure in various parts of Asia. Overharvesting and anthropogenic disturbances threaten the existence of the Jewel orchids in the wild, necessitating human intervention in their survival. An understanding of the structure and adaptations of a plant may assist in its survival when propagated outside of its habitat. In this study, ex vitro leaves of Anoectochilus sp. and L. discolor were subjected to freehand sectioning, and then inspected through brightfield and fluorescence microscopy. The study indicated that all parts of both plants presented typical monocotyledonous characteristics except the leaves. The leaves displayed dorsiventrality with distinct palisade and spongy mesophyll layers. The spongy mesophyll layer contained cells which fluoresced a bright red when exposed to ultraviolet, blue, and green light wavelengths, hinting at the presence of anthocyanins for photoprotection. Cyanidin was detected in the leaves of L. discolor, as enumerated through high performance liquid chromatography (HPLC). The observations indicated that Anoectochilus sp. and L. discolor are well-adapted to live under shaded conditions with minimal exposure to light.

Taraxacum officinale and Urtica dioica extracts inhibit dengue virus serotype 2 replication in vitro

Background

Urtica dioica, Taraxacum officinale, Calea integrifolia and Caesalpinia pulcherrima are widely used all over the world for treatment of different illnesses. In Mexico, these plants are traditionally used to alleviate or counteract rheumatism and inflammatory muscle diseases. In the present study we evaluated the activity of aqueous and methanolic extracts of these four plants, on the replication of dengue virus serotype 2 (DENV2).

Methods

Extraction process was carried out in a Soxtherm® system at 60, 85 and 120 °C; a chemical fractionation in silica gel chromatography was performed and compounds present in the active fractions were identified by HPLC-DAD-ESI/MSn. The cytotoxic concentration and the inhibitory effect of extracts or fractions on the DENV2 replication were analyzed in the BHK-21 cell line (plaque forming assay). The half maximal inhibitory concentration (IC₅₀) and the selectivity index (SI) were calculated for the extracts and fractions.

Results

The methanolic extracts at 60 °C of T. officinale and U. dioica showed the higher inhibitory effects on DENV2 replication. After the chemical fractionation, the higher activity fraction was found for U. dioica and T. officinale, presenting IC₅₀ values of 165.7 ± 3.85 and 126.1 ± 2.80 μg/ml, respectively; SI values were 5.59 and 6.01 for each fraction. The compounds present in T. officinale, were luteolin and caffeoylquinic acids derivatives and quercertin diclycosides. The compounds in the active fraction of U. dioica, were, chlorogenic acid, quercertin derivatives and flavonol glycosides (quercetin and kaempferol).

Conclusions

Two fractions from U. dioica and T. officinale methanolic extracts with anti-dengue activity were found. The compounds present in both fractions were identified, several recognized molecules have demonstrated activity against other viral species. Subsequent biological analysis of the molecules, alone or in combination, contained in the extracts will be carried out to develop therapeutics against DENV2.

Qualitative and Quantitative Analysis of Ethanolic Extract and Phenolic Fraction of Jatropha aethiopica (Euphorbiaceae) Leaves and Their Hypoglycemic Potential

Although Jatropha aethiopica, popularly known in Cuba as "mata diabetes", is used in salads and as a dietary supplement, its chemical composition and antidiabetic properties yet remains unclear. In this work, we evaluate the qualitative and quantitative composition of ethanolic extract (EE) and phenolic fraction (PF) of Jatropha aethiopica leaves and their hypoglycemic and hypolipidemic activity. Chemical fractionation of the ethanolic extract yielded nine compounds, which included protocatechuic acid (1), chlorogenic acid (2), caffeic acid (3), quercetin 3-O-α-l-rhamnopyranosyl-(1 → 2)-[α-l-rhamnopyranolsyl-(1 → 6)]-β-d-galactopyranoside (4), a new kaempferol 3-O-α-l-rhamnopyranosyl-(1 → 4)-[α-l-rhamnopyranolsyl-(1 → 6)]-β-d-galactopyranoside (5), kaempferol 3-O-α-l-rhamnopyranosyl-(1 → 2)-[α-l-rhamnopyranolsyl-(1 → 6)]-β-d-glucopyranoside (6), rutin (7), kaempferol 3-O-α-l-rhamnopyranosyl-(1 → 6)-β-d-glucopyranoside (8), and quercetin (9). The compounds (1, 4-7) were quantified by high-performance liquid chromatography photodiode array detection (HPLC-PDA) in both the ethanolic extract (62.65 ± 0.15 mg/g) and phenolic fraction (61.72 ± 0.23 mg/g). The results obtained show that both ethanolic extract and phenolic fraction contributed toward the improvement of glucose tolerance, which in turn led to a decline in the glucose levels. Remarkably, the ethanolic extract presented a relatively higher promising effect compared to metformin.

Latest advances in the extraction and determination of saffron apocarotenoids

Saffron, the dried red stigmas of Crocus sativus L. plant, is the most expensive spice in the world. It is highly valued not only for the color and flavor that exerts to various foods and drinks but also for its functional properties. Various classes of apocarotenoids such as crocetin sugar esters, picrocrocin and safranal are responsible for these characteristics. In the present review, the evolution of the methods proposed by the ISO standard for extraction and determination of saffron apocarotenoids since 1980 is presented in parallel to other approaches proposed by various scientists to overcome limitations of the standard. Moreover, the latest advances regarding applications of novel extraction techniques and powerful analytical tools that require limited or no sample preparation are critically discussed.

Application of HPLC and ESI-MS techniques in the analysis of phenolic acids and flavonoids from green leafy vegetables (GLVs)

Diets containing high proportions of fruits and vegetables reduce the risk of onset of chronic diseases. The role of herbal medicines in improving human health is gaining popularity over the years, which also increases the need for safety and efficiency of these products. Green leafy vegetables (GLVs) are the richest source of phenolic compounds with excellent antioxidant properties. Increased consumption of diets containing phenolic compounds may give positive and better results to human health and significantly improves the immune system. Highly selective, susceptible and versatile analytical techniques are necessary for extraction, identification, and quantification of phenolic compounds from plant extracts, which helps to utilize their important biological properties. Recent advances in the pre-treatment procedures, separation techniques and spectrometry methods are used for qualitative and quantitative analysis of phenolic compounds. The online coupling of liquid chromatography with mass spectrometry (LC-MS) has become a useful tool in the metabolic profiling of plant samples. In this review, the separation and identification of phenolic acids and flavonoids from GLVs by LC-MS have been discussed along with the general extraction procedures and other sources of mass spectrometer used. The review is devoted to the understanding of the structural configuration, nature and accumulation pattern of phenolic acids and flavonoids in plants and to highlighting the recent developments in the chemical investigation of these compounds by chromatographic and spectroscopic techniques. It concludes with the advantages of the combination of these two methods and prospects.

Screening In Vitro Targets Related to Diabetes in Herbal Extracts from Peru: Identification of Active Compounds in Hypericum laricifolium Juss. by Offline High-Performance Liquid Chromatography

This study investigates in vitro targets related to diabetes in 30 herbal extracts from Peru, for the first time, using α-glucosidase, aldose reductase (AR) inhibitory assays and 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) scavenging assays. Among the 30 herbal extracts, Hypericum laricifolium Juss. (HL) was the herb which showed more than 50% inhibition in all assays, presenting 97.2 ± 2.0%, 56.9 ± 5.6%, 81.9 ± 2.5%, and 58.8 ± 4.6% inhibition for the α-glucosidase, AR, DPPH, and ABTS assays, respectively. Finally, six bioactive compounds, namely, protocatechuic acid, chlorogenic acid, caffeic acid, kaempferol 3-O-glucuronide, quercetin, and kaempferol were identified in HL by offline high-performance liquid chromatography (HPLC). Quercetin exhibited the strongest inhibition in all enzyme assays and the strongest antioxidant activity. The results suggest that HL shows great potential for the complementary treatment of diabetes and its complications.