Green Approach to Enhance the Recovery of Polyphenols from Blackcurrant and Bilberry Leaves: Evaluation of Microwave-Assisted and Pressurized Liquid Extraction.

The aim of the present study was to evaluate microwave-assisted (MAE) and pressurized liquid extraction (PLE) for the recovery of polyphenols from blackcurrant and bilberry leaves and the preservation of their antioxidant activity. The extractions were carried out varying the solvent/solid (SS) ratio, temperature and time. During MAE, increasing the SS ratio increased the polyphenol concentration in the extracts from blackcurrant and bilberry leaves, while increasing the temperature had a positive effect only on bilberry polyphenols. During PLE, only a temperature increase was a determining factor for the isolation of blackcurrant leave polyphenols. Based on polyphenol recovery, optimal extraction parameters were established resulting in a yield of 62.10 and 56.06 mg/g dw in the blackcurrant and bilberry MAE extracts and 78.90 and 70.55 mg/g dw in the PLE extracts. The optimized extracts were profiled by UPLC ESI MS2, and their antioxidant capacity was evaluated through FRAP, DPPH, ABTS and ORAC assays. The characterization of the extracts by UPLC ESI MS2 confirmed flavonols as the predominant compounds in both blackcurrant and bilberry leaves, while flavan-3-ols and procyanidins were the main compounds responsible for high antioxidant capacity as confirmed by the ABTS and ORAC assays. Due to the extract composition and antioxidant capacity, PLE proved to be a technique of choice for the production of blackcurrant and bilberry leave extracts with high potential for use as value-added ingredients in the food and nutraceutical industry.

Microencapsulation of Laurus nobilis L. Leaf Extract in Alginate-Based System via Electrostatic Extrusion.

Bay leaves (L. nobilis L.) are a rich source of polyphenols that hold great potential for application in functional food products in which where the main challenges are the polyphenols' low stability and bioaccessibility, which can be overcome through different microencapsulation techniques, such as electrostatic extrusion, which hasn't been applied for the encapsulation of bay leaf polyphenols (BLP) to date. Therefore, the main goal of this research was to evaluate the potential of this technique through monitoring the polyphenolic content, antioxidant activity, release kinetics, and bioaccessibility of the encapsulated BLP. The results showed that electrostatic extrusion was suitable for the encapsulation of BLP, where 1% alginate and 1.5% CaCl2 with 0.5% chitosan resulted in the highest encapsulation efficiency (92.76%) and antioxidant activity in vitro. The use of 1.5% or 2% alginate with 5% CaCl2 + 0.5% chitosan showed the most controlled release of polyphenols, while encapsulation generally increased the bioaccessibility of BLP. The results showed that electrostatic extrusion can be considered an efficient technique for the microencapsulation of BLP.

The Effect of a High-Protein Diet Supplemented with Blackthorn Flower Extract on Polyphenol Bioavailability and Antioxidant Status in the Organs of C57BL/6 Mice.

The health benefits of polyphenols are based on their bioavailability, which is why a significant portion of research focuses on factors that affect their bioavailability. Previous studies suggest that the intake of polyphenols along with macronutrients in food represents one of the key factors influencing the bioavailability of polyphenols and, consequently, their biological activity in the organism. Since polyphenols in the human diet are mainly consumed in food together with macronutrients, this study investigated the in vivo absorption, metabolism, and distribution of polyphenolic compounds from the water extract of blackthorn flower (Prunus spinosa L.) in combination with a protein-enriched diet in the organs (small intestine, liver, kidney) of C57BL/6 mice. The bioaccumulation of polyphenol molecules, biologically available maximum concentrations of individual groups of polyphenol molecules, and their effect on the oxidative/antioxidative status of organs were also examined. The results of this study indicate increased bioabsorption and bioavailability of flavan-3-ols (EC, EGCG) and reduced absorption kinetics of certain polyphenols from the groups of flavonols, flavones, and phenolic acids in the organs of C57BL/6 mice after intragastric administration of the water extract of blackthorn flower (Prunus spinosa L.) in combination with a diet enriched with whey proteins. Furthermore, subchronic intake of polyphenols from the water extract of blackthorn flower (Prunus spinosa L.) in combination with a diet enriched with whey proteins induces the synthesis of total glutathione (tGSH) in the liver and superoxide dismutase (SOD) in the liver and small intestine. The results of this study suggest potential applications in the development of functional foods aimed at achieving the optimal health status of the organism and the possibility of reducing the risk of oxidative stress-related disease.

Optimization of the Spray-Drying Encapsulation of Sea Buckthorn Berry Oil.

The aim of this study was to evaluate the effect of spray-drying parameters on the physicochemical properties of encapsulated sea buckthorn berry oil. Different carriers (gum arabic, ß-cyclodextrin, and their mixture (1:1, w/w)), inlet air temperatures (120, 150, and 180 °C), and carrier-to-oil ratios (2, 3, and 4, w/w) were evaluated. The obtained powders were characterized in terms of the product yield (36.79-64.60%), encapsulation efficiency (73.08-93.18%), moisture content (0.23-3.70%), hygroscopicity (1.5-7.06 g/100 g), solubility (19.55-74.70%), bulk density (0.25-0.44 g/L), total carotenoid content (mg/100 g dm), and antioxidant capacity (871.83-1454.39 µmol TE/100 g dm). All physicochemical properties were significantly affected by the carrier-to-oil ratio and inlet air temperature. Higher carrier-to-oil ratios increased the product yield, encapsulation efficiency, solubility, and bulk density and decreased the powder hygroscopicity. Elevating the drying temperatures during spray drying also increased the product yield, encapsulation efficiency, and solubility, while it decreased the powder moisture content, total carotenoid content, and antioxidant capacity. Based on the physicochemical properties, the use of ß-cyclodextrin as a carrier, a drying temperature of 120 °C, and a carrier-to-oil ratio of 4 were selected as optimal conditions for the production of sea buckthorn berry oil powder. The obtained powder is a valuable material for a wide range of applications in the food and nutraceutical industries.

Physicochemical Properties, Antioxidant Capacity, and Bioavailability of Laurus nobilis L. Leaf Polyphenolic Extracts Microencapsulated by Spray Drying.

Laurel (Laurus nobilis L.) leaves are a rich source of polyphenols with the potential for use in functional foods, where the main obstacle is their low stability and bioavailability, which can be improved by spray drying (SD). This research examined the influence of SD parameters, including inlet temperature (120, 150, and 180 °C), carrier type (ß-cyclodextrin (ß-CD); ß-CD + maltodextrin (MD) 50:50; ß-CD + gum arabic (GA) 50:50), and sample:carrier ratio (1:1, 1:2 and 1:3) on the physicochemical properties, encapsulation efficiency, polyphenolic profile, antioxidant capacity and bioaccessibility of laurel leaf polyphenols. The highest encapsulation efficiency was achieved at a sample:carrier ratio 1:2 and the temperature of 180 °C by using either of the applied carriers. However, the application of ß-CD + MD 50:50 ensured optimal solubility (55.10%), hygroscopicity (15.32%), and antioxidant capacity (ORAC 157.92 µmol Trolox equivalents per g of powder), while optimal moisture content (3.22%) was determined only by temperature, demanding conditions above 150 °C. A total of 29 polyphenols (dominantly flavonols) were identified in the obtained powders. SD encapsulation increased the bioaccessibility of laurel flavonols in comparison to the non-encapsulated extract by ~50% in the gastric and ~10% in the intestinal phase, especially for those powders produced with carrier mixtures.

Phenolic, Headspace and Sensory Profile, and Antioxidant Capacity of Fruit Juice Enriched with Salvia officinalis L. and Thymus serpyllum L. Extract: A Potential for a Novel Herbal-Based Functional Beverages.

Since certain constituents are not naturally present in pure fruit juices, incorporating herbal extracts can provide specific sensory properties to the beverages and improve their biopotential. In our previous research, it was found that sage (Salvia officinalis L.), wild thyme (Thymus serpyllum L.), and combinations of their extracts had the highest total phenolic content and a unique composition of volatile compounds, which can contribute to the aromatic and antioxidant qualities of functional products. Therefore, this research aimed to investigate the potential of sage and wild thyme extracts, as well as their mixture (wild thyme:sage at 3:1, v/v), to enrich fruit juices (apple, pineapple, and orange). Obtained beverages were evaluated for sensory properties as well as phenolic and headspace composition (UPLC-MS/MS and HS-SPME/GC-MS analysis) and antioxidant capacity (ORAC assay). The incorporation of wild thyme extract in pineapple juice provided the most harmonious flavor and the highest content of volatile compounds (on PDMS/DVB fiber). The orange juice formulations were the most enriched with phenolic and volatile compounds (on DVB/CAR/PDMS fibers). The highest antioxidant capacity was observed in the formulation with orange juice and sage extract (22,925.39 ± 358.43 µM TE). This study demonstrated that enriching fruit juices with sage and wild thyme extracts could create functional beverages with improved sensory and health-promoting properties, providing valuable insights for the food and beverage industry to meet the growing demand of health-conscious consumers for natural and functional products.

The Effects of Nettle Extract Consumption on Liver PPARs, SIRT1, ACOX1 and Blood Lipid Levels in Male and Female C57Bl6 Mice.

The aim of this study was to evaluate how nettle (Urtica dioica L.) water extract consumption would interact with regulators of peroxysomal lipid oxidation, histone deacetylase, and markers of oxidative stress in the liver and blood lipid levels in male and female C57Bl6 mice. Metabolically unchallenged (healthy) mice (n = 5 per sex) were treated with a nettle extract in a dose of 40 mg of total polyphenols in the extract per kg mice body weight. The nettle extract was applied daily along with normal diet for 15 days. The serum triglycerides, cholesterol, HDL, LDL, and liver PPAR-α, PPAR-γ, PGC-1-α, ACOX1, SIRT1, MDA, SOD, CAT, and GSH were compared between exposed and unexposed (control) animals. In males, the PPAR-α, PGC1-α, and ACOX1 levels together with systemic HDL cholesterol were significantly (p ≤ 0.05) increased while the LDL cholesterol decreased (p ≤ 0.05). In females, no changes in PPAR-α and PGC1-α or serum lipids were noted, but the ACOX1 content in the liver was significantly (p ≤ 0.05) increased. The SIRT1 activity increased (p ≤ 0.05) only in females. In both sexes, the PPAR-γ levels were not significantly (p ≤ 0.05) affected in either sex. The results indicate that nettle plant extract has the potential to modulate selected transcriptional factors and histone deacetylase in vivo, with certain sex differences, which should be studied further in similar models.

Effect of Spray Drying Encapsulation on Nettle Leaf Extract Powder Properties, Polyphenols and Their Bioavailability.

Nettle (Urtica dioica L.) is a plant rich in a health-promoting compounds such as polyphenols, which are sensitive and unstable compounds with low bioavailability, that need to be stabilized and protected from external influences. Therefore, the aim of this study was to examine how the temperature, type of carrier and sample to carrier ratio influence the physicochemical properties and encapsulation and loading capacity of the nettle leaf extract powder and examine the effect of encapsulation on the antioxidant capacity and bioavailability of polyphenols. The process yield ranged from 64.63-87.23%, moisture content from 1.4-7.29%, solubility from 94.76-98.53% and hygroscopicity from 13.35-32.92 g 100 g-1. The highest encapsulation (98.67%) and loading (20.28%) capacities were achieved at 160 °C, ß-CD:GA (3:1) and sample:carrier ratio of 1:3. Extracts encapsulated at selected conditions showed high antioxidant capacity and distinct polyphenolic profile comprised of 40 different compounds among which cinnamic acids were the most abundant. Moreover, the encapsulation increased the bioavailability of nettle leaf polyphenols, with the highest amount released in the intestinal phase. Thus, the obtained encapsulated extract represents a valuable source of polyphenols and may therefore be an excellent material for application in value-added and health-promoting products.

Pressurized Liquid Extraction as a Novel Technique for the Isolation of Laurus nobilis L. Leaf Polyphenols.

Laurus nobilis L., known as laurel or bay leaf, is a Mediterranean plant which has been long known for exhibiting various health-beneficial effects that can largely be attributed to the polyphenolic content of the leaves. Pressurized liquid extraction (PLE) is a green extraction technique that enables the efficient isolation of polyphenols from different plant materials. Hence, the aim of this research was to determine optimal conditions for PLE (solvent, temperature, number of extraction cycles and static extraction time) of laurel leaf polyphenols and to assess the polyphenolic profile of the optimal extract by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) as well as to evaluate the antioxidant activity determined by FRAP, DPPH and ORAC assays. The optimal PLE conditions were 50% ethanol, 150 °C, one extraction cycle and 5 min static time. The polyphenolic extract obtained at optimal PLE conditions comprised 29 identified compounds, among which flavonols (rutin and quercetin-3-glucoside) were the most abundant. The results of antioxidant activity assays demonstrated that PLE is an efficient green technique for obtaining polyphenol-rich laurel leaf extracts with relatively high antioxidant activity.

Non-Volatile and Volatile Bioactives of Salvia officinalis L., Thymus serpyllum L. and Laurus nobilis L. Extracts with Potential Use in the Development of Functional Beverages.

Functional beverages based on herbal extracts are highly demanded products due to the presence of bioactives with promising health benefits and interesting and characteristic sensory properties. Mediterranean medicinal and aromatic herbs contain a wide range of bioactives (non-volatile polyphenols, volatile terpenes) that are important constituents of herbal extracts and essential oils. The antioxidant capacity and potential health benefits of these bioactives could be associated with their synergistic effects. Therefore, this study aimed to characterize the non-volatile and volatile bioactives of sage (Salvia officinalis L.), wild thyme (Thymus serpyllum L.) and laurel (Laurus nobilis L.) aqueous extracts and their two- and three-component mixtures as well as their antioxidant capacity. The content of total phenols, flavonoids, hydroxycinnamic acids and flavonols was determined spectrophotometrically. Individual polyphenols were analyzed by LC-MS/MS, the volatiles were analyzed by HS-SPME/GC-MS, and the antioxidant capacity was analyzed by ORAC and DPPH assays. The results showed that aqueous extracts of all examined herbs and their mixtures contained a high content of phenolic compounds ranging from 0.97 to 2.79 g L-1 of the sample, among which the most common were flavonols. At the same time, mono- and sesquiterpenes were the main volatiles. All extracts showed high antioxidant capacity, especially L. nobilis (781.62 ± 5.19 µmol TE mL-1 of the sample in the DPPH assay; 1896.10 ± 8.77 µmol TE mL-1 of the sample in the ORAC assay) and the two-component mixture of L. nobilis and T. serpyllum (679.12 ± 5.19 µmol TE mL-1 in the DPPH assay; 1913.38 ± 8.77 µmol TE mL-1 in the ORAC assay). Mixtures of herbal extracts have been shown to possess additive or synergistic effects, consequently contributing to higher antioxidant capacity. Therefore, two-component mixtures of herbal extracts showed promising potential for the production of functional beverages.

Isolation of Laurus nobilis Leaf Polyphenols: A Review on Current Techniques and Future Perspectives.

In recent years, the market demand for products enhanced with ingredients derived from natural products, such as polyphenols, is rapidly increasing. Laurus nobilis L., known as bay, sweet bay, bay laurel, Roman laurel or daphne is an evergreen Mediterranean shrub whose leaves have traditionally been used in cuisines and folk medicine due to their beneficial health effects, which can nowadays be scientifically explained by various biological activities of the leaf extracts. Many of these activities can be attributed to phenolic compounds present in L. nobilis leaves which include flavonoids, phenolic acids, tannins (proanthocyanidins) and lignans. In order to enable efficient industrial utilization of these valuable compounds, it is crucial to establish optimal extraction procedures resulting in the highest yields and quality of the extracts. This paper offers the first systematic review of current literature on the influence of conventional and advanced extraction techniques, including microwave-assisted, ultrasound-assisted, enzyme-assisted, supercritical-CO2 and mechanochemical-assisted extraction on the phenolic content of L. nobilis leaf extracts, allowing more efficient planning of further research and simplifying the steps towards industrial utilization of this plant.

Phenolic Profile, Antioxidant Capacity and Antimicrobial Activity of Nettle Leaves Extracts Obtained by Advanced Extraction Techniques.

Nettle is a widely known plant whose high biological activity and beneficial medicinal effects are attributed to various bioactive compounds, among which polyphenols play an important role. In order to isolate polyphenols and preserve their properties, advanced extraction techniques have been applied to overcome the drawbacks of conventional ones. Therefore, microwave-assisted extraction (MAE) has been optimized for the isolation of nettle leaves polyphenols and it was compared to pressurized liquid extraction (PLE) and conventional heat-reflux extraction (CE). The obtained extracts were analyzed for their individual phenolic profile by UPLC MS2 and for their antioxidant capacity by ORAC assay. MAE proved to be the more specific technique for the isolation of individual phenolic compounds, while PLE produced extracts with higher amount of total phenols and higher antioxidant capacity. Both techniques were more effective compared to CE. PLE nettle extract showed antimicrobial activity against bacteria, especially against Gram-negative Pseudomonas fragi ATCC 4973 and Campylobacter jejuni NCTC 11168 strains. This suggests that PLE is suitable for obtaining a nettle extract with antioxidant and antimicrobial potential, which as such has great potential for use as a value-added ingredient in the food and pharmaceutical industry.

Microwave Assisted Extraction and Pressurized Liquid Extraction of Sulfated Polysaccharides from Fucus virsoides and Cystoseira barbata.

Sulfated polysaccharide fucoidan isolated from brown algae shows a wide range of biological activities that are significantly dependent on its chemical composition, which is closely related to the applied technique and extraction parameters. Therefore, the objective of this study was to evaluate the influence of microwave assisted extraction (MAE) and pressurized liquid extraction (PLE) parameters (solvent, temperature, time, and number of cycles) on the Fucus virsoides and Cystoseira barbata polysaccharide yield (%PS) and chemical composition (total sugar, fucose, and sulfate group). The optimal MAE parameters that resulted in the highest polysaccharide extraction from F. virsoides and C. barbata were 0.1 M H2SO4 for 10 min at 80 °C, while the optimal PLE parameters were 0.1 M H2SO4, for two cycles of 15 min at 140 °C. Furthermore, the %PS, chemical structure, molecular properties, and antioxidant activity of the F. virsoides and C. barbata polysaccharide extracts obtained with MAE, PLE, and conventional extraction (CE) performed under previously determinate optimal conditions were compared. PLE resulted in a significantly higher %PS from F. virsoides, while for C. barbata, a similar yield was achieved with CE and PLE, as well as CE and MAE, for both algae. Furthermore, the polysaccharides obtained using PLE had the highest polydispersity index, fucose, and sulfate group content, and the lowest uronic acid content; however their antioxidant activity was lower.

Bioactive Compounds in Wild Nettle (Urtica dioica L.) Leaves and Stalks: Polyphenols and Pigments upon Seasonal and Habitat Variations.

This study evaluated the presence of bioactives in wild nettle leaves and stalks during the phenological stage and in the context of natural habitat diversity. Thus, wild nettle samples collected before flowering, during flowering and after flowering from 14 habitats situated in three different regions (continental, mountain and seaside) were analyzed for low molecular weight polyphenols, carotenoids and chlorophylls using UPLC-MS/MS and HPLC analysis, while the ORAC method was performed for the antioxidant capacity measurement. Statistical analysis showed that, when compared to the stalks, nettle leaves contained significantly higher amounts of analyzed compounds which accumulated in the highest yields before flowering (polyphenols) and at the flowering stage (pigments). Moreover, nettle habitat variations greatly influenced the amounts of analyzed bioactives, where samples from the continental area contained higher levels of polyphenols, while seaside region samples were more abundant with pigments. The levels of ORAC followed the same pattern, being higher in leaves samples collected before and during flowering from the continental habitats. Hence, in order to provide the product's maximum value for consumers' benefit, a multidisciplinary approach is important for the selection of a plant part as well as its phenological stage with the highest accumulation of bioactive compounds.

Assessment of the Biological Activity and Phenolic Composition of Ethanol Extracts of Pomegranate (Punica granatum L.) Peels.

Pomegranate (Punica granatum L.) is a rich source of constituents with confirmed strong biological activities. However, pomegranate peel, which encompasses approximately 30-40% of its weight, is treated as a biological waste. The aim of this paper was to evaluate the potential of pomegranate peel extracts and to propose its functional properties that can be used for development of functional products. Eight ethanol extracts of pomegranate peels (PPEs) were characterized by use of direct infusion quadrupole-time of flight (Q-TOF), and afterwards tested on their antioxidant, antibacterial and antiproliferative activities. Mass spectrometry analysis revealed that the most prevalent compounds in pomegranate peels were punicalagin, granatin and their derivatives. Analysed extracts had high total phenolic contents that ranged from 5766.44 to 10599.43 mg GAE/100 g, and strong antioxidant activity (7551.31-7875.42 and 100.25-176.60 µmol TE/100 g for DPPH and FRAP assays, respectively). The results of biological activity assays showed that all PPEs possessed antibacterial activity, and that S. aureus was the most sensitive specie with minimum inhibitory concentration and minimum bactericidal concentrations ranging from 0.8 to 6.4 mg/mL. Additionally, the analysis of antiproliferative activity revealed high potency of PPEs, as the IC50 values ranged from 0.132 mg/mL to 0.396 mg/mL. Multivariate analysis pointed out the most discriminative metabolites for antioxidant or antiproliferative activity. Overall, the pomegranate peel confirmed to be a highly valuable source of bioactive compounds that could be used to improve the food functional characteristics.

Evaluation of Polyphenolic Profile and Antioxidant Activity of Pistacia lentiscus L. Leaves and Fruit Extract Obtained by Optimized Microwave-Assisted Extraction.

Pistacia lentiscus L. is a Mediterranean shrub known for its health promoting effects attributed to a large extent to polyphenols accumulated in all parts of the plant. Microwave-assisted extraction is a green extraction technique enabling fast and effective isolation of plant polyphenols. Therefore, the aim of this research was to optimize the microwave-assisted extraction of polyphenols from Pistacia lentiscus L. leaves and fruit in terms of temperature, extraction time and microwave power and to evaluate their polyphenolic profile by UPLC/ESI-MS2 and antioxidant capacity by ORAC assay. Optimal extraction conditions for leaf polyphenols were 69 °C, 512 W and 12 min, while for fruit were slightly more intensive-75 °C, 602 W and 15 min. Obtained total phenolic content in leaves and fruit was similar to that obtained after 30 min of the heat-reflux method. The polyphenolic profile of extracts included 34 compounds, with myricetin glycosides being the most abundant compounds among flavonoids in Pistacia lentiscus L. leaves and fruit and gallic acid and its derivates among the phenolic acids. ORAC assay showed higher antioxidant capacity for Pistacia lentiscus L. leaves extract than for fruit, which is in correlation with their respective phenolic content.

Insight into High-Hydrostatic Pressure Extraction of Polyphenols from Tomato Peel Waste.

In this paper, high-hydrostatic pressure extraction (HHPE) as an emerging food processing and preservation technique constitutes an alternative to conventional thermal treatment that has been used for extraction of polyphenols from tomato peel waste generated by the canning industry. The impact of time (5 and 10 min), temperature (25, 35, 45 and 55 °C) and solvents (water, 1% HCl, 50 and 70% methanol with and without addition of HCl, and 50 and 70% ethanol), at a constant pressure of 600 MPa, has been evaluated in this paper with respect to polyphenols' yields. The results showed a significant (p < 0.05) variation in the contents of a great number of phenolic compounds in respect of the applied temperatures and solvents. On the other hand, the time invested in HHPE had no effect on polyphenols' yields. Among phenolic compounds, the p-coumaric acid (p-CA) and chlorogenic acid derivative (ChA der) are predominant, i.e., 0.57 to 67.41 mg/kg and 1.29 to 58.57 mg/kg, respectively, depending on the solvents and temperatures used. In particular, methanol (50 and 70%) at temperatures of 45 and 55 °C enhanced the recovery of polyphenols in comparison to other utilised solvents. In conclusion, this paper puts forth the theory that by applying HHPE with minimal expenditure of time, it is possible to achieve efficient production of polyphenols from low-cost tomato peel waste, generating income both for producers and agri-food industries.

Toxic activity of Prunus spinosa L. flower extract in hepatocarcinoma cells.

Prunus spinosa L. (blackthorn) is used in traditional medicine as a remedy for various diseases. To establish its anticancer properties, we exposed human liver cancer cells (Hep G2) to a range of blackthorn flower extract concentrations (10-200 µg/mL) and determined cytotoxic activity with the neutral red and kenacid blue methods after 24, 48, and 72 h of incubation. Statistically significant inhibitory effects on Hep G2 cellular proliferation were observed at concentrations above 50 µg/mL (p<0.001-0.05). Cell viability was lower when determined with neutral red than kenacid blue method. In addition, we evaluated antioxidant/prooxidant effects of the blackthorn flower extract by measuring reactive oxygen species (ROS), and the results confirmed its prooxidant behaviour within the applied concentration range. Flow cytometry determined primarily necrotic and apoptotic cell death, which provides additional evidence of its cytotoxic effect on liver carcinoma.

Effect of Microwave-Assisted Extraction on Polyphenols Recovery from Tomato Peel Waste.

This study describes the application of microwave-assisted extraction (MAE) as an innovative technique for isolation of polyphenols from tomato peel waste. Effects of solvents, temperatures (25, 55 and 90 °C) and times (5 and 10 min) were evaluated with regard to total phenols (TP), total flavonoids (TF) and phenolic compound contents. Tomato peel extracts contain high amounts of kaemferol-3-O-rutinoside (8.5 to 142.5 mg kg-1), p-coumaric acid (3 to 111.5 mg kg-1) and chlorogenic acid derivative (10.5 to 109 mg kg-1). Results revealed that extraction time has no significant (p > 0.05) influence on TP, TF and phenolic compounds recovery (exception is cis-p-coumaric acid hexoside). On the other hand, the influence of temperature and chosen solvent on polyphenols yield is significant. Considering interest of consumers to intake natural compounds exhibiting antioxidant properties, this work suggests that tomato peel waste can be used as one of sustainable resources for polyphenols production by MAE.

UPLC-MS2 Profiling of Blackthorn Flower Polyphenols Isolated by Ultrasound-Assisted Extraction.

Ultrasound-assisted extraction (UAE) was optimized for fast and effective isolation of blackthorn flower polyphenols. The effects of ethanol concentration (50% and 70%) in extraction solvent, ultrasound amplitude (50%, 75%, and 100%) and extraction time (3, 6, and 9 min) were evaluated. UPLC-MS2 was used to determine phenolic profile of blackthorn flowers extracts. A total of 28 different phenolic compounds were identified, belonging to the classes of hydroxycinnamic acids, flavonol glycosides and flavanols. Kaempferol and quercetin derivatives were the most abundant compounds represented by kaempferol-pentoside and rhamnoside in concentrations up to 494.94 and 436.62 mg/100 g and quercetin-pentoside in concentration up to 226.75 mg/100 g. Observed parameters of UAE did not affect the qualitative phenolic composition of blackthorn flower extracts. On the contrary, the concentration of polyphenols increased with higher ethanol concentration in solvent, higher ultrasound amplitude and prolongation of extraction time. The established conditions for optimal extraction of blackthorn flower polyphenols using ultrasound were: 70% ethanol as extraction solvent, 75% of ultrasound amplitude and 9 min extraction time, resulting in extract rich in polyphenols with a great potential for use in pharmaceutical and food industry. PRACTICAL APPLICATION: In this study, ultrasound-assisted extraction (UAE) was optimized in order to establish fast and effective method for production of crude blackthorn flower extract rich in polyphenols. UPLC-MS2 analysis showed 28 different phenolic compounds belonging to the classes of hydroxycinnamic acids, flavonol glycosides, and flavanols with quercetin and kaempferol glycosides in the highest concentrations, implicating high potential of blackthorn flowers' extract for use in food and pharmaceutical industries.