Estimation of free radical-quenching activity of leaf pigment extracts

Development of a Holistic In Vitro Cell-Free Approach to Determine the Redox Bioactivity of Agricultural Products

In recent years, there has been a strong consumer demand for food products that provide nutritional benefits to human health. Therefore, the assessment of the biological activity is considered as an important parameter for the promotion of high-quality food products. Herein, we introduce a novel methodology comprising a complete set of in vitro cell-free screening techniques for the evaluation of the bioactivity of various food products on the basis of their antioxidant capacity. These assays examine the free radical scavenging activities, the reducing properties, and the protective ability against oxidative damage to biomolecules. The adoption of the proposed battery of antioxidant assays is anticipated to contribute to the holistic characterization of the bioactivity of the food product under examination. Consumer motivations and expectations with respect to nutritious food products with bio-functional properties drive the global food market toward food certification. Therefore, the development and application of scientific methodologies that examine the quality characteristics of food products could increase consumers' trust and promote their beneficial properties for human health.

Shelf-Stability of Kiln- and Liquid-Smoked Inulin-Fortified Emulsion-Type Pangasius Mince Sausage at Refrigerated Temperature

The objective of this study was to investigate the effects of the kiln (SK-S) and liquid smoking (LS-S) processes on the quality of inulin-fortified emulsion-type Pangasius mince sausages. The moisture content during the storage significantly (p < 0.05) decreased in C-S (control) sausages and increased (p < 0.05) in SK-S and LS-S sausages. The protein content decreased (p < 0.05) in C-S, SK-S, and LS-S throughout the storage period. Initially, among the three processed sausages, LS-S showed a lower pH value, and as the days of storage progressed, all the treatments exhibited a declining trend (p < 0.05). A significant (p < 0.05) increase in the PV was observed in all the sausages during the storage days at 5 ± 1 °C, but the intensity of the increase was lower in SK-S and LS-S. The total viable count of C-S and SK-S sausages reached the limit of acceptability (6 log10cfu g-1) on the 20th day and on the 24th day of storage. The electrophoretic protein pattern of LS-S samples exhibited retention of all bands, indicating the lower proteolysis of MHC, actin, and troponin T in comparison with other treatments. The hardness (p < 0.05) and cohesiveness (p > 0.05) values of both SK-S and LS-S reduced as the storage days progressed. The present study indicates that the emulsion-type Pangasius sausages incorporated with inulin powder (2%) exposed to kiln smoking and commercial liquid smoking retained good-to-better sensory attributes up to day 16 (C-S) and day 20 (SK-S and LS-S) under refrigerated storage at 5 ± 1 °C in low-density vacuum polyethylene (LDPE) pouches.

Optimization of the Black Garlic Processing Method and Development of Black Garlic Jam Using High-Pressure Processing

Black garlic has many beneficial effects, and it has a less spicy flavor. However, its aging conditions and related products still need to be further investigated. The present study aims to analyze the beneficial effects under different processing conditions and utilize high-pressure processing (HPP) in the production of black garlic jam. The highest antioxidant activities, including the DPPH scavenging, total antioxidant capacity, and reducing power (86.23%, 88.44%, and A₇₀₀ = 2.48, respectively), were observed in black garlic that had been aged for 30 days. Similarly, the highest total phenols and flavonoids were observed in black garlic that had been aged for 30 days (76.86 GAE/g dw and 13.28 mg RE/g dw, respectively). The reducing sugar in black garlic was significantly increased to about 380 (mg GE/g dw) after 20 days of aging. The free amino acids in black garlic were decreased time-dependently to about 0.2 mg leucine/g dw after 30 days of aging. For the browning indexes of black garlic, the uncolored intermediate and browning products were increased in a time-dependent manner and reached a plateau at day 30. Another intermediate product in the Maillard reaction, 5-hydroxymethylfurfural (5-HMF), was observed in concentrations that increased to 1.81 and 3.04 (mg/g dw) at day 30 and 40, respectively. Furthermore, the black garlic jam made by HPP was analyzed for its texture and sensory acceptance, showing that a 1:1.5:2 ratio of black garlic/water/sugar was the most preferred and was classified as "still acceptable". Our study suggests suitable processing conditions for black garlic and outlines the prominent beneficial effects after 30 days of aging. These results could be further applied in HPP jam production and increase the diversity of black garlic products.

Chemical Characterization and Several Bioactivities of Cladanthus mixtus from Morocco

The purpose of this work was to investigate, for the first time to our knowledge, the chemical composition and bioactivity of methanolic extracts (roots, stems, leaves, and flowers) from Cladanthus mixtus (L.) Chevall. that grows wild in northern Morocco (the Tangier-Tetouan-Al Hoceima region). The phenolic and flavonoid contents were determined by spectrophotometer methods, and the composition of derivatized methanolic extracts from C. mixtus using N-O-bis(trimethylsilyl) trifluoroacetamide (BSTFA) was analyzed by gas chromatography–mass spectrometry (GC-MS). The antioxidant activity was carried out by applying the 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and DPPH (2,2-diphenyl-1-picrylhydrazyl) tests. The micro-dilution technique was chosen to investigate the antimicrobial activity of methanolic extracts against two bacterial strains and three fungal species. The results showed that the values of total phenolic and flavonoid contents were found to be higher in flower extracts (30.55 ± 0.85 mg of gallic acid equivalents (GAE)/g of dried weight (DW) and 26.00 ±1.34 mg of quercetin equivalents (QE)/g DW, respectively). Other groups of chemical compounds were revealed by GC-MS, such as carbohydrates (27.25–64.87%), fatty acids (1.58–9.08%), organic acids (11.81–18.82%), and amino acids (1.26–7.10%). Root and flower methanolic extracts showed the highest antioxidant activity using ABTS (39.49 mg of Trolox equivalents (TE)/g DW) and DPPH (36.23 mg TE/g DW), respectively. A positive correlation between antioxidant activity and polyphenol and flavonoid amounts was found. Antibacterial tests showed that the best activity was presented by the leaf extract against Staphylococcus aureus (minimum inhibitory concentration (MIC) = minimum bactericidal concentration (MBC) = 20 mg/mL) and Escherichia coli (MIC of 30 mg/mL and MBC of 35 mg/mL). S. aureus was more sensitive to the extracts compared to E. coli. All extracts showed antifungal activity against Trichophyton rubrum, with the best efficacy reported by the flower and leaf extracts (MIC = 1.25 mg/mL and minimum fungicidal concentration (MFC) = 2.5 mg/mL). In general, extracts of C. mixtus appeared less effective against Candida albicans and Aspergillus fumigatus.

Bioactive Potential of Elderberry (Sambucus nigra L.): Antioxidant, Antimicrobial Activity, Bioaccessibility and Prebiotic Potential

Due to its abundance of physiologically active ingredients, one of the oldest medicinal herbs, elderberry (EB) Sambucus nigra L., is beneficial for both therapeutic and dietary purposes. This study determined the bioaccessibility of the phenolic compounds and the prebiotic potential of the polyphenols from freeze-dried EB powder (FDEBP), along with the antioxidant and antimicrobial activities of this extract. The most significant phenolic compounds in black EB are represented by anthocyanins (41.8%), predominating cyanidin-sambubiosides and cyanidin-glucosides (90.1% of the identified anthocyanins). The FRAP assay obtained the highest antioxidant activity value (185 ± 0.18 μmol Fe2+/g DW). The most sensitive to the antimicrobial activity of the extract was proven to be Staphylococcus aureus, and Pseudomonas aeruginosa had the lowest minimum inhibitory concentration of 1.95 mg/mL. To determine the prebiotic potential of the polyphenols, the cell growth of five probiotic strains (Lactobacillus plantarum, L. casei, L. rhamnosus, L. fermentum and Saccharomyces boulardii) was tested. The influence on cell growth was positive for all five probiotic strains used. Overall, the most significant increase (p < 0.05) was recorded at 1.5% FDEBP, on S. boulardii with a growth index (GI) of 141.02%, very closely followed by GI at 0.5% and 1% concentrations. The stability of the total phenolic compounds through simulated gastronitestinal digestion was increased (93%), and the bioaccessibility was also elevated (75%).

Phytochemical Characterization and Biological Evaluation of Origanum vulgare L. Essential Oil Formulated as Polymeric Micelles Drug Delivery Systems

This study presents phytochemical characterization and biological evaluation of Origanum vulgare L. essential oil (OEO) formulated as polymeric micelles drug delivery systems as a possible non-invasive approach for the management of skin tags. GC-MS analysis of Romanian OEO revealed the identification and quantification of 43 volatile compounds (thymol and carvacrol being the main ones). The antioxidant activity was shown by four consecrated methods: CUPRAC, ABTS, ORAC and DPPH. OEO was incorporated by micellar solubilization into a binary hydrogel based on a Pluronic F 127/L 31 block-copolymers mixture. The pH, consistency, spreadability, particle size, polydispersity index and zeta potential of the OEO-loaded poloxamer-based binary hydrogel (OEO-PbH) were investigated. OEO-PbH was skin compatible in terms of pH and exhibited adequate spreadability and consistency. The minimal inhibitory concentrations of the tested OEO were similar to those obtained for the formulation, lower (2.5 µg/mL) for yeast and higher (40-80 µg/mL) for Gram-negative bacilli. As keratinocytes are among main components of skin tags, an in vitro evaluation was conducted in order to see the effect of the formulation against HaCaT human keratinocytes. OEO-PbH decreased HaCaT cells migration and proliferation and elicited a cytotoxic and pro-apoptotic effect in a dose- and time-dependent manner. No harmful effect on the viability of dendritic cells (DCs) was detected following the incubation with different concentrations (0-200 µg/mL) of the 5% formulation. Treatment in inflammatory DCs (+LPS) indicated a decrease in cytokine production of IL-6, TNF-α and IL-23 but no significant effect on IL-10 in any of the tested concentrations.

Phytochemical Content and Antioxidant Activity of Malus domestica Borkh Peel Extracts

Apple is an important dietary source of carotenoids and phenolic compounds, and its regular consumption is associated with several health benefits. The aim of this study was to evaluate the phytochemical composition of fresh peels of four red-skinned (“Champion”, “Generos”, “Idared”, “Florina”) and two yellow-skinned (“Golden Delicious”, “Reinette Simirenko”) apple varieties. Antioxidant activity of apple peel extracts was determined by ferric reducing antioxidant power (FRAP) and ABTS radical scavenging capacity assays. Total carotenoid and polyphenolic contents were determined spectrophotometrically, while the profile of individual carotenoids and anthocyanins (in red-skinned varieties) was analyzed using high-performance liquid chromatography coupled to a photodiode array detector (HPLC-PDA). Carotenoid composition was specific for each variety, and total carotenoid content was slightly higher in yellow-skinned apple peels compared to red-skinned varieties. In contrast, total phenolic content was higher in the peels of red-skinned cultivars. Anthocyanin profile was predominated by cyanidin-3-O-galactoside. Antioxidant potential followed the trend of the total polyphenolic content, being highest in “Florina”, as measured by both FRAP and ABTS assays. Our results demonstrated apple peels have high phytochemical content with diverse compositions, and their regular consumption can be an excellent source of antioxidants.

Comparison of Morphological, Antidiabetic and Antioxidant Properties of Goji Fruits

There is a growing public interest in fruits labeled as „superfood” (functional food). A “superfood” should have a high content of bioactive substances with a positive impact on human health. Seven different cultivars of goji berry fruits (Lycium chinense Mill.) grown in north-western Poland were evaluated for its physicochemical parameters, antidiabetic and antioxidant activity, and polyphenol content. The length of 1-year-old shoots ranged from 36 cm (‘Big Lifeberry’) to 82 cm (‘Korean Big’). Cultivars from the group of Big were characterized by the biggest fruits (17.3-24.2 mm) with the greatest weight of 100 fruits (96.7­122.1 g). ‘Big Lifeberry’ contained high amounts of L-ascorbic acid (408 mg 1000/g) and provitamin A (190 mg 1000/g) and showed high antidiabetic (α-amylase IC50=33.4 mg/mL; α-glucosidase IC50=9.9 mg/mL) and antioxidant activity (ABTS·+ 6.21 and FRAP 5.58 mmol T/100 g). ‘Big Lifeberry’ was also characterized by a high total content of polyphenols (43.64 mg 100/g). Furthermore, the nitrite content in all the cultivars tested was at a relatively low level. Among the examined cultivars, the most attractive one concerning the consumers’ point of view of the size, weight and high content of health-promoting compounds is ‘Big Lifeberry’.

Phytochemical Characterization of Five Edible Purple-Reddish Vegetables: Anthocyanins, Flavonoids, and Phenolic Acid Derivatives

Vegetables comprise a significant portion of our daily diet with their high content in nutrients including fiber, vitamins, minerals, as well as phenolic compounds. Vegetable consumption has been shown to be positively associated with the prevention of several degenerative diseases thanks to their bioactive compounds. Accordingly, five selected vegetables, namely, red chicory, red onion, eggplant, purple sweet potato, and black carrot were thoroughly assessed for their phenolic content in this study. For this purpose, the total phenolic and flavonoid content of these five vegetables and their antioxidant activities that are based on three common methods ABTS radical cation decolorization assay (ABTS), Cupric Ion Reducing Antioxidant Capacity (CUPRAC), and DPPH scavenging activity assay were determined. Additionally, HPLC-PDA/Electrospray ionization coupled with mass spectrometry (HPLC-PDA/-ESI⁺-MS)-based identification and quantification of the members belonging to polyphenols present in each vegetable were determined. Statistical correlations between antioxidant activities and the specific type of phenolic compounds, such as anthocyanins, flavonoids, anthocyanins, and phenolic acids were further elucidated. Phenolic acids (chlorogenic and syringic acids) were found to be the most abundant compounds that are present in all samples. Among the anthocyanins, cyaniding derivatives were present in all vegetables. In terms of their antioxidant activities, the analyzed vegetables were ranked as red chicory > purple sweet potato > black carrot > eggplant > red onion, in descending order. Superior antioxidant activities exhibited by red chicory and purple sweet potato were attributed to the high content of phenolic compounds, especially flavonols (quercetin-3,4-O-diglucoside) in red chicory and anthocyanins (peonidin-3-caffeoyl p-hydroxybenzoylsophoroside-5-glucoside) in purple sweet potato.

Antioxidant and neuroprotector effect of Lepidium meyenii (maca) methanol leaf extract against 6-hydroxy dopamine (6-OHDA)-induced toxicity in PC12 cells

Reactive oxygen species (ROS) are normally produced during cell metabolism, there is strong evidence to suggest that ROS produced in excess impair the cell and may be etiologically related to various neurodegenerative diseases. This study was undertaken to examine the effects of Lepidium meyenii (MACA) methanol leaf extract on neurotoxicity in PC12 cell exposed to 6-hydroxydopamine (6-OHDA). Fresh samples of "maca" leaves were processed in order to obtain foliar extracts and to evaluate the neurobiological activity on PC12 cells, subjected to the cytotoxic effect of 6-OHDA through the determination of the capacity antioxidant, cell viability and cytotoxicity assays on PC12 cells. The results of the tests of antioxidant activity, showed maximum values of 2262.37 and 1305.36 expressed in Trolox equivalents (TEAC), for the methanolic and aqueous fractions respectively. Cell viability assays at a dose of 10 μg extract showed an increase of 31% and 60% at 6 and 12 h of pretreatment, respectively. Cytotoxicity assays at the same dose and exposure time showed a 31.4% and 47.8% reduction in lactate dehydrogenase (LDH) activity and an increase in superoxide dismutase (SOD) activity. The results allow us to affirm that the methanolic foliar extract of "maca" presents in vitro neurobiological activity of antioxidant protection, increase in cell viability and reduction of cytotoxicity against oxidative stress generated by 6-OHDA. In conclusion, the present study shows a protective role for Lepidium meyenii leaf extract on 6-OHDA-induced toxicity by an antioxidant effect.

Antioxidant activities of the polysaccharides of Chuanminshen violaceum

The water-soluble polysaccharides were extracted and purified from the root of Chuanminshen violaceum (CVPS). The antioxidant activities of the CVPS were evaluated both with in vitro and in vivo experiments. The results of the in vitro antioxidant assay suggested that the CVPS scavenged DPPH, hydroxyl, and superoxide anion radicals. The oral administration of three different doses of CVPS administered over a period of 6 weeks to D-galactose induced aging mice models, enhanced the activities of T-SOD, Mn-SOD, Cu, Zn-SOD, and CAT, and markedly decreased the content of MDA. Therefore, significant up-regulation of mRNA expression levels of Cu, Zn-SOD, Mn-SOD, CAT, glutathione peroxidase 1 (GPx), thioredoxin 1 (Trx1), and thioredoxin 2 (Trx1) occurred. Finally, the results demonstrated that the CVPS are a novel potential resource for natural antioxidants and anti-aging drugs.

New Insight into Quinoa Seed Quality under Salinity: Changes in Proteomic and Amino Acid Profiles, Phenolic Content, and Antioxidant Activity of Protein Extracts

Quinoa (Chenopodium quinoa Willd) is an ancient Andean seed-producing crop well known for its exceptional nutritional properties and resistance to adverse environmental conditions, such as salinity and drought. Seed storage proteins, amino acid composition, and bioactive compounds play a crucial role in determining the nutritional value of quinoa. Seeds harvested from three Chilean landraces of quinoa, one belonging to the salares ecotype (R49) and two to the coastal-lowlands ecotype, VI-1 and Villarrica (VR), exposed to two levels of salinity (100 and 300 mM NaCl) were used to conduct a sequential extraction of storage proteins in order to obtain fractions enriched in albumins/globulins, 11S globulin and in prolamin-like proteins. The composition of the resulting protein fractions was analyzed by one- and two-dimensional polyacrylamide gel electrophoresis. Results confirmed a high polymorphism in seed storage proteins; the two most representative genotype-specific bands of the albumin/globulin fraction were the 30- and 32-kDa bands, while the 11S globulin showed genotype-specific polymorphism for the 40- and 42-kDa bands. Spot analysis by mass spectrometry followed by in silico analyses were conducted to identify the proteins whose expression changed most significantly in response to salinity in VR. Proteins belonging to several functional categories (i.e., stress protein, metabolism, and storage) were affected by salinity. Other nutritional and functional properties, namely amino acid profiles, total polyphenol (TPC) and flavonoid (TFC) contents, and antioxidant activity (AA) of protein extracts were also analyzed. With the exception of Ala and Met in R49, all amino acids derived from protein hydrolysis were diminished in seeds from salt-treated plants, especially in landrace VI-1. By contrast, several free amino acids were unchanged or increased by salinity in R49 as compared with VR and VI-1, suggesting a greater tolerance in the salares landrace. VR had the highest TPC and AA under non-saline conditions. Salinity increased TPC in all three landraces, with the strongest increase occurring in R49, and enhanced radical scavenging capacity in R49 and VR. Overall, results show that salinity deeply altered the seed proteome and amino acid profiles and, in general, increased the concentration of bioactive molecules and AA of protein extracts in a genotype-dependent manner.

Comparative Physiological and Transcriptomic Analyses Reveal the Actions of Melatonin in the Delay of Postharvest Physiological Deterioration of Cassava

Melatonin plays important roles in various aspects of biological processes. However, it is less known on the effects and mechanism of melatonin on the postharvest physiological deterioration (PPD) process of cassava, which largely restricts the potential of cassava as a food and industrial crop. In this study, we found that exogenous application of melatonin significantly delayed PPD of cassava tuberous roots by reducing H2O2 content and improving activities of catalase and peroxidase. Moreover, 3425 differentially expressed genes by melatonin during the PPD process were identified by transcriptomic analysis. Several pathways were markedly affected by melatonin treatments, including metabolic-, ion homeostasis-, and enzyme activity-related processes. Further detailed analysis revealed that melatonin acted through activation of ROS-scavenging and ROS signal transduction pathways, including antioxidant enzymes, calcium signaling, MAPK cascades, and transcription factors at early stages. Notably, the starch degradation pathway was also activated at early stages, whereas it was repressed by melatonin at middle and late stages, thereby indicating its regulatory role in starch metabolism during PPD. Taken together, this study yields new insights into the effect and underlying mechanism of melatonin on the delay of PPD and provides a good strategy for extending shelf life and improvement of cassava tuberous roots.

Comparative metabolomic analysis highlights the involvement of sugars and glycerol in melatonin-mediated innate immunity against bacterial pathogen in Arabidopsis

Melatonin is an important secondary messenger in plant innate immunity against the bacterial pathogen Pseudomonas syringe pv. tomato (Pst) DC3000 in the salicylic acid (SA)- and nitric oxide (NO)-dependent pathway. However, the metabolic homeostasis in melatonin-mediated innate immunity is unknown. In this study, comparative metabolomic analysis found that the endogenous levels of both soluble sugars (fructose, glucose, melibose, sucrose, maltose, galatose, tagatofuranose and turanose) and glycerol were commonly increased after both melatonin treatment and Pst DC3000 infection in Arabidopsis. Further studies showed that exogenous pre-treatment with fructose, glucose, sucrose, or glycerol increased innate immunity against Pst DC3000 infection in wild type (Col-0) Arabidopsis plants, but largely alleviated their effects on the innate immunity in SA-deficient NahG plants and NO-deficient mutants. This indicated that SA and NO are also essential for sugars and glycerol-mediated disease resistance. Moreover, exogenous fructose, glucose, sucrose and glycerol pre-treatments remarkably increased endogenous NO level, but had no significant effect on the endogenous melatonin level. Taken together, this study highlights the involvement of sugars and glycerol in melatonin-mediated innate immunity against bacterial pathogen in SA and NO-dependent pathway in Arabidopsis.

Comparative physiological and proteomic analyses reveal the actions of melatonin in the reduction of oxidative stress in Bermuda grass (Cynodon dactylon (L). Pers.)

The fact of melatonin as an important antioxidant in animals led plant researchers to speculate that melatonin also acts in the similar manner in plants. Although melatonin has significant effects on alleviating stress-triggered reactive oxygen species (ROS), the involvement of melatonin in direct oxidative stress and the underlying physiological and molecular mechanisms remain unclear in plants. In this study, we found that exogenous melatonin significantly alleviated hydrogen peroxide (H2O2)-modulated plant growth, cell damage, and ROS accumulation in Bermuda grass. Additionally, 76 proteins significantly influenced by melatonin during mock or H2O2 treatment were identified by gel-free proteomics using iTRAQ (isobaric tags for relative and absolute quantitation). Metabolic pathway analysis showed that several pathways were markedly enhanced by melatonin and H2O2 treatments, including polyamine metabolism, ribosome pathway, major carbohydrate metabolism, photosynthesis, redox, and amino acid metabolism. Taken together, this study provides more comprehensive insights into the physiological and molecular mechanisms of melatonin in Bermuda grass responses to direct oxidative stress. This may relate to the activation of antioxidants, modulation of metabolic pathways, and extensive proteome reprograming.

Melatonin induces nitric oxide and the potential mechanisms relate to innate immunity against bacterial pathogen infection in Arabidopsis

Melatonin (N-acetyl-5-methoxytryptamine) is a naturally occurring small molecule, serving as important secondary messenger in the response of plants to various biotic and abiotic stresses. However, the interactions between melatonin and other important molecules in the plant stress response, especially in plant immunity, are largely unknown. In this study, we found that both melatonin and nitric oxide (NO) levels in Arabidopsis leaves were significantly induced by bacterial pathogen (Pst DC3000) infection. The elevated NO production was caused by melatonin as melatonin application enhanced endogenous NO level with great efficacy. Moreover, both melatonin and NO conferred improved disease resistance against Pseudomonas syringe pv. tomato (Pst) DC3000 infection in Arabidopsis. NO scavenger significantly suppressed the rise of NO which was induced by exogenous application of melatonin. As a result, the beneficial effects of melatonin on the expression of salicylic acid (SA)-related genes and disease resistance against bacterial pathogen infection were jeopardized by use of a NO scavenger. Consistently, melatonin application significantly lost its effect on the innate immunity against P. syringe pv. tomato (Pst) DC3000 infection in NO-deficient mutants of Arabidopsis. The results indicate that melatonin-induced NO production is responsible for innate immunity response of Arabidopsis against Pst DC3000 infection.

Chokeberry Anthocyanin Extract as Pancreatic β-Cell Protectors in Two Models of Induced Oxidative Stress

The aim of this study was to investigate the protective effects of a chokeberry anthocyanin extract (CAE) on pancreatic β-cells (βTC3) exposed to hydrogen peroxide- (H2O2-) and high glucose- (HG-) induced oxidative stress conditions. In order to quantify individual anthocyanins high performance liquid chromatography (HPLC) coupled to photodiode array (PDA) was used. The identification of the fragment ion pattern of anthocyanins was carried out by electrospray ionization mass spectrometry (LC-ESI-MS). The results showed that physiologically achievable concentrations of CAE (1, 5, and 10 μM) protect βTC3 against H2O2- and HG-induced cytotoxicity. Antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) were increased in pancreatic β-cells pretreated with CAE compared to cells exposed to the prooxidant agents. GSH levels initially reduced after exposure to H2O2 and HG were restored by pretreatment with CAE. Insulin secretion in βTC3 cells was enhanced by CAE pretreatment. CAE restored the insulin pool and diminished the intracellular reactive oxygen species level in glucose-induced stress condition in βTC3 cells. These results demonstrate that anthocyanins from CAE were biologically active, showing a secretagogue potential and an antioxidative protection of enzymatic systems, conferring protection against H2O2 and glucose toxicity in βTC3 cells.

Antioxidant and α-glucosidase inhibitory activities of Achillea tenorii

CONTEXT

There is a need for the discovery of novel natural remedies to prevent and treat metabolic disorders such as hyperglycemia, type II non-insulin-dependent diabetes mellitus, and obesity. Several Achillea species have been utilized for centuries all around the world and are generally considered effective as hypoglycemic.

OBJECTIVE

Considering the ethnobotanical uses of Achillea genus, we evaluated the in vitro inhibitory activity of Achillea tenorii Grande (Asteraceae) extract on α-glucosidase, which is a valuable target to prevent and treat metabolic disorders. We also tested its antioxidant activity. Moreover, the phytochemical profile was discussed from a chemotaxonomic point of view.

MATERIALS AND METHODS

In vitro α-glucosidase inhibition of crude ethanolic extract obtained from the aerial parts was assayed as well as the in vitro antioxidant activity (ABTS, DPPH, and FRAP-FZ tests) was measured. The extract was characterized from a phytochemical point of view by means of spectroscopic analysis.

RESULTS

The extract results endowed with α-glucosidase inhibitory activity (IC50 32 µg/mL) with a particular mechanism of action definable as un-competitive, which differed from the mechanism observed for the best-known α-glucosidase inhibitor (acarbose and miglitol). In addition, a considerable antioxidant potential has been found for A. tenorii extract, which resulted mainly constituted by phenolic compounds such as caffeoylquinic acids and flavonoids.

DISCUSSION AND CONCLUSIONS

These results suggest the potential of A. tenorii as a possible natural remedy to prevent and treat metabolic disorders of carbohydrates.

Comparative physiological, metabolomic, and transcriptomic analyses reveal mechanisms of improved abiotic stress resistance in bermudagrass [Cynodon dactylon (L). Pers.] by exogenous melatonin

Melatonin (N-acetyl-5-methoxytryptamine), a well-known animal hormone, is also involved in plant development and abiotic stress responses. In this study, it is shown that exogenous application of melatonin conferred improved salt, drought, and cold stress resistances in bermudagrass. Moreover, exogenous melatonin treatment alleviated reactive oxygen species (ROS) burst and cell damage induced by abiotic stress; this involved activation of several antioxidants. Additionally, melatonin-pre-treated plants exhibited higher concentrations of 54 metabolites, including amino acids, organic acids, sugars, and sugar alcohols, than non-treated plants under abiotic stress conditions. Genome-wide transcriptomic profiling identified 3933 transcripts (2361 up-regulated and 1572 down-regulated) that were differentially expressed in melatonin-treated plants versus controls. Pathway and gene ontology (GO) term enrichment analyses revealed that genes involved in nitrogen metabolism, major carbohydrate metabolism, tricarboxylic acid (TCA)/org transformation, transport, hormone metabolism, metal handling, redox, and secondary metabolism were over-represented after melatonin pre-treatment. Taken together, this study provides the first evidence of the protective roles of exogenous melatonin in the bermudagrass response to abiotic stresses, partially via activation of antioxidants and modulation of metabolic homeostasis. Notably, metabolic and transcriptomic analyses showed that the underlying mechanisms of melatonin could involve major reorientation of photorespiratory and carbohydrate and nitrogen metabolism.

Anthocyanin determination in blueberry extracts from various cultivars and their antiproliferative and apoptotic properties in B16-F10 metastatic murine melanoma cells

Blueberry consumption is associated with health benefits contributing to a reduced risk for cardiovascular disease, diabetes and cancer. The aim of this study was to determine the anthocyanin profile of blueberry extracts and to evaluate their effects on B16-F10 metastatic melanoma murine cells. Seven blueberry cultivars cultivated in Romania were used. The blueberry extracts were purified over an Amberlite XAD-7 resin and a Sephadex LH-20 column, in order to obtain the anthocyanin rich fractions (ARF). The antioxidant activity of the ARF of all cultivars was evaluated by ABTS, CUPRAC and ORAC assays. High performance liquid chromatography followed by electrospray ionization mass spectrometry (HPLC-ESI-MS) was used to identify and quantify individual anthocyanins. The anthocyanin content of tested cultivars ranged from 101.88 to 195.01 mg malvidin-3-glucoside/100g fresh weight. The anthocyanin rich-fraction obtained from cultivar Torro (ARF-T) was shown to have the highest anthocyanin content and antioxidant activity, and inhibited B16-F10 melanoma murine cells proliferation at concentrations higher than 500 μg/ml. In addition, ARF-T stimulated apoptosis and increased total LDH activity in metastatic B16-F10 melanoma murine cells. These results indicate that the anthocyanins from blueberry cultivar could be used as a chemopreventive or adjuvant treatment for metastasis control.

Glucosinolates profile and antioxidant capacity of Romanian Brassica vegetables obtained by organic and conventional agricultural practices

The profile of glucosinolates in relation to the antioxidant capacity of five Brassica vegetables (Broccoli, Cauliflower, Kohlrabi, White and Red Cabbage) grown by organic and conventional agricultural practices in Transylvania region-Romania, were determined and compared. The qualitative and quantitative compositions of glucosinolates were determined by HPLC-PDA technique. The antioxidant capacity was comparatively determined by ABTS, DPPH, FRAP and Folin-Ciocalteu assays. The highest glucosinolates levels were found in the Broccoli samples grown under conventional practices (14.24 μmol/g dry weight), glucoraphanin, glucobrassicin and neo-glucobrassicin being the major components. The total glucosinolates content was similar in Kohlrabi and Cauliflower (4.89 and 4.84 μmol/g dry weight, respectively), the indolyl glucosinolates were predominant in Kohlrabi, while the aliphatic derivatives (sinigrin and glucoiberin) were major in Cauliflower. In Cabbage samples, the aliphatic glucosinolates were predominat against indolyl derivatives, glucoraphanin and glucoiberin being the main ones in Red Cabbage. The principal component analysis was applied to discriminate among conventional and organic samples and demonstrated non-overlaps between these two agricultural practices. Meanwhile it was shown that glucosinolates may represent appropriate molecular markers of Brassica vegetables, their antioxidant capacity being higher in organic crops, without significant differences among different Brassica varieties.

Dihydroasparagusic acid: antioxidant and tyrosinase inhibitory activities and improved synthesis

Dihydroasparagusic acid (DHAA) is the reduced form of asparagusic acid, a sulfur-containing flavor component produced by Asparagus plants. In this work, DHAA was synthetically produced by modifying some published protocols, and the synthesized molecule was tested in several in vitro assays (DPPH, ABTS, FRAP-ferrozine, BCB, deoxyribose assays) to evaluate its radical scavenging activity. Results show that DHAA is endowed with a significant in vitro antioxidant activity, comparable to that of Trolox. DHAA was also evaluated for its inhibitory activity toward tyrosinase, an enzyme involved, among others, in melanogenesis and in browning processes of plant-derived foods. DHAA was shown to exert an inhibitory effect on tyrosinase activity, and the inhibitor kinetics, analyzed by a Lineweaver-Burk plot, exhibited a competitive mechanism. Taken together, these results suggest that DHAA may be considered as a potentially active molecule for use in various fields of application, such as pharmaceutical, cosmetics, agronomic and food.

Antioxidant activities of chokeberry extracts and the cytotoxic action of their anthocyanin fraction on HeLa human cervical tumor cells

The present study evaluates the antioxidant activity of two Aronia melanocarpa cultivars-Viking and Aron-and of Aronia prunifolia hybrid in relationship with their phytochemical composition regarding the contents of total phenolics, flavonoids, procyanidins, and monomeric anthocyanins. The antioxidant capacity of the mentioned extracts of chokeberries was evaluated through five complementary assays: 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), H(2)O(2) scavenging potential, oxygen radical absorbance capacity, ferric reducing antioxidant power, and cupric ion reducing antioxidant capacity. A. prunifolia hybrid was found to have the highest antioxidant activity and to be the richest in polyphenols, procyanidins, and anthocyanins compared with the A. melanocarpa cultivars. A good correlation was observed between antioxidant activity and total procyanidin and anthocyanin content. Cyanidin glycosides inhibited HeLa human cervical tumor cell proliferation and increased generation of reactive oxygen species after 48 h of treatment, suggesting that they could be responsible for the antiproliferative activity. These results may be significant for industry concerning food quality and disease prevention.

Changes in hydrophilic antioxidant activity in Avena sativa and Triticum aestivum leaves of different age during de-etiolation and high-light treatment

The steady-state of reactive oxygen species (ROS) in plant cells is controlled by ROS-producing and scavenging agents. A large cellular pool of antioxidant metabolites is involved in their control. Variations in this antioxidant pool may be monitored by measuring changes in hydrophilic antioxidant activity (free radical-quenching activity of water-soluble components) and ascorbic acid levels. The de-etiolation process and induction of light stress in Avena sativa and Triticum aestivum leaves were used as physiological models to study the antioxidant status at different ages. The data showed that five-day-old green plants and de-etiolated plants of the same age have similar hydrophilic antioxidant activity ( approximately 8 mumol ASC equivalents g FW(-1)), which increases during the de-etiolation process. In oat and wheat, young leaves (five days old) had higher antioxidant status (hydrophilic antioxidant activity and ascorbic acid level) than old leaves (10 and 20 days old). High-light treatment caused a decrease in antioxidant status, especially in young leaves. Hydrophilic antioxidant activity and ascorbic acid levels recovered totally or partially after 30 or 60 min in the dark. This capacity also depends on age and species. The ascorbic acid/hydrophilic antioxidant activity ratio is presented as an indicator of antioxidant variations in response to stress, but taking into account the absolute levels of antioxidants.

Generation of reactive oxygen species and radiation response in lymphocytes and tumor cells

Several types of lymphoid and myeloid tumor cells are known to be relatively resistant to radiation-induced apoptosis compared to normal lymphocytes. The intracellular generation of reactive oxygen species was measured in irradiated spleen cells from C57BL/6 and BALB/c mice and murine tumor cells (EL-4 and P388) by flow cytometry using dichlorodihydrofluoresceindiacetate and dihydrorhodamine 123 as fluorescent probes. The amount of reactive oxygen species generated per cell was low in the tumor cells compared to spleen cells exposed to 1 to 10 Gy of gamma radiation. This could be due to the higher total antioxidant levels in tumor cells compared to normal cells. Further, the changes in mitochondrial membrane potential and cytoplasmic Ca2+ content were appreciable in lymphocytes even at a dose of 1 Gy. In EL-4 cells, no such changes were observed at any of the doses used. About 65% of spleen cells underwent apoptosis 24 h after 1 Gy irradiation. However, under the same conditions, EL-4 and P388 cells failed to undergo apoptosis, but they accumulated in G2/M phase. Thus the intrinsic radioresistance of tumor cells may be due to a decreased generation of reactive oxygen species after irradiation and down-regulation of the subsequent events leading to apoptosis.

On-line antioxidant activity determination: comparison of hydrophilic and lipophilic antioxidant activity using the ABTS*+ assay

The ABTS/H(2)O(2)/HRP decoloration method is capable of determining both hydrophilic (in buffered media) and lipophilic (in organic media) antioxidant properties in complex samples. Now, we have adapted this method for on-line chromatographic determination. The easy, rapid and controlled generation of the ABTS radical and its great stability in buffered and organic media were important characteristics in the measurement of antioxidant activities. The HPLC-ABTS method used two pumps (one for isocratic eluting-phase and the other for preformed ABTS radical) and an UV-VIS diode array detector. The dual analysis of samples -- conventional (with UV-VIS detection) and ABTS-scavenging (at 600 nm) -- provided valuable on-line information about the correspondence between the presence of a determined compound and its possible antioxidant activity, and was applicable to both hydrophilic and lipophilic antioxidants (HAA and LAA). A comparison between HAA and LAA determined by the end-point method and by the on-line HPLC method is presented. The application to juices showed that both methods are suitable, sensitive and selective, gave similar values, and the HPLC-ABTS method contributed additional information about the antioxidant activity profile.