Ferrous Ion Chelating Capacity Research Articles

Relationship between Phenolic Compounds and Antioxidant Activity of Some Moroccan Date Palm Fruit Varieties (Phoenix dactylifera L.): A Two-Year Study.

In Morocco, the abundance of low-value varieties in the oases may provide an opportunity to capitalize on this richness to create new nutraceutical food products. In this context, the phenolic profile and antioxidant capacity of four Moroccan date varieties were analyzed. Our results indicate that the levels of total polyphenols, total flavonoids and total condensed tannins vary, respectively, from 91.86 to 364.35 mg GAE/100 g of dry weight (DW), 46.59 to 111.80 mg QE/100 g DW and 16.10 to 42.03 mg CE/100 g DW during the 2021 harvest season. Furthermore, during the 2022 harvest season, these contents vary, respectively, from 119.13 to 410.39 mg GAE/100 g DW, 59.30 to 110.85 mg QE/100 g DW and 21.93 to 53.95 mg CE/100 g DW. The results of the HPLC-UV-VIS analysis revealed that, in all four varieties, gallic acid was and remained one of the major compounds in the date extracts. In addition, a high antioxidant activity of date extracts was particularly observed in the three tests, namely ferric reducing power (FRAP), ferrous ion chelating capacity (FIC) and the phosphomolybdate test. This richness in phenolic compounds makes low-value dates a source of active ingredient that can replace the synthetic antioxidants used in the food and pharmaceutical industries.

Argentine squid (Illex argentinus): A source of mycosporine-like amino acids with antioxidant properties

Here we report on the occurrence of mycosporine-like amino acids (MAAs) in the Argentine shortfin squid, Illex argentinus, the second fishery resource mostly exploited in the Argentinean continental shelf. The total content of four MAAs was evaluated by reverse-phase-HPLC in different tissues (eyes, skin, liver, and gonads). Also, the antioxidant activity of crude extracts was assessed by in-vitro determinations: 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), Folin-Ciocalteu, and ferrous ion-chelating capacity assays. The content of MAAs was found to be almost ten times higher in female gonads than in other tissues (11,89 ± 0,56 mg/g dry weight). Extracts from skin, female gonads and eyes, exhibit higher antioxidant activity than the reference compounds ascorbic acid and TROLOX. Overall, Argentine squid waste is a promising potential source of MAAs with antioxidant and UV photoprotective properties, which could bear interest in food, cosmetic and pharmaceutical industries, thus encouraging maximal and sustainable use of fishing resources.

Biotransformation of Chinese Jujube with Cordyceps militaris to Enhance the Antioxidant Activity In Vitro and the Protective Effect against Ethanol-Induced Oxidative Stress in Zebrafish

Solid-state fermentation (SSF) of Chinese jujube with Cordyceps militaris was performed in the present study. The results revealed that the contents of total phenolic and flavonoid in rice medium with 50% jujube content increased to 1.59 mg GAE/g d.w. and 0.46 mg RE/g, respectively. The changes of phenolic acid composition showed a similar tendency, and three forms of individual phenolic compounds, namely free phenol, free/conjugated phenol, and bound phenol increased with the extension of the fermentation time. The determination of DPPH, ABTS, FRAP, and the ferrous ion chelating capacity showed that the fermentation significantly enhanced the antioxidant activity in vitro, and the protective functions against ethanol-induced oxidative stress in zebrafish were also then investigated. SSF co-treatment with EtOH reduced MDA elevation and enhanced the activities of SOD and GSH-Px, along with the T-AOC levels in a dose-dependent manner in adult and larval zebrafish. Moreover, the qRT-PCR findings demonstrated that SSF-jujube was capable of upregulating the mRNA expressions of Nrf2 and HO-1 and downregulated the levels of NF-κB in zebrafish larvae. In conclusion, solid-state fermented Chinese jujube with C. militaris was an effective process, exhibited a good antioxidant activity, and demonstrated a better protective effect against ethanol-induced oxidative stress.

Bioaccessibility of Phenolic Compounds and Antioxidant Properties of Goat-Milk Powder Fortified with Grape-Pomace-Seed Extract after In Vitro Gastrointestinal Digestion

This study deals with the evaluation of the bioaccessibility and antioxidant properties of phenolic compounds from heat-treated skim goat-milk powder fortified with grape-pomace-seed extract, after in vitro gastrointestinal digestion. Ultra-high performance liquid chromatography coupled to diode array detection and mass spectrometry (UHPLC-DAD MS/MS) analysis confirmed the abundant presence of phenolic acids and flavan-3-ols in the grape-pomace-seed extract (SE) and heat-treated skim goat-milk/seed-extract powder (TME). After in vitro digestion of TME powder and recovery of total quantified phenolics, flavan-3-ols and phenolic acids were 18.11%, 24.54%, and 1.17%, respectively. Low recovery of grape-pomace-seed phenolics indicated strong milk protein-phenolic interactions. Electrophoretic analysis of a soluble fraction of digested heat-treated skim goat milk (TM) and TME samples showed the absence of bands originating from milk proteins, indicating their hydrolysis during in vitro gastrointestinal digestion. The digested TME sample had better antioxidant properties in comparison to the digested TM sample (except for the ferrous ion-chelating capacity, FCC), due to the presence of bioaccessible phenolics. Taking into account the contribution of the digestive cocktail, digested TME sample had lower values of total phenolic content (TPC), in vitro phosphomolybdenum reducing capacity (TAC) and ferric reducing power (FRP), compared to the undigested TME sample. These results could be attributed to low recovery of phenolic compounds. TME powder could be a good carrier of phenolics to the colon; thus, TME powder could be a promising ingredient in the formulation of functional food.

HPLC-DAD assay of flavonoids and evaluation of antioxidant activity of some herbal mixtures

Medicinal plants and their combinations can influence various links of the pathogenetic mechanism of diabetes mellitus type 2 and its complications, due to the wide range of biologically active substance that they accumulate. Flavonoids deserve particular attention through their antioxidant properties. Three samples of herbal mixtures (sample 1 – Inula helenium rhizome with roots, Helichrysum arenarium flowers, Zea mays columns with stigmas, Origanum vulgare herb, Rosa majalis fruits, Taraxacum officinale roots; sample 2 – Cichorium intybus roots, Elymus repens rhizome, Helichrysum arenarium flowers, Rosa smajalis fruits, Zea mays columns with stigmas; sample 3 – Urtica dioica leaf, Taraxacum officinale roots, Vaccinium myrtillus leaf, Rosa majalis fruits, Mentha x Menthapiperita herb) were tested for flavonoid content and antioxidant properties. Using HPLC-DAD analysis the content of flavonoids was evaluated and an antioxidant activity by DPPH-radicals scavenging, ferrous ion chelating capacity and ferric reducing power were established for the herbal mixtures. Rutin prevails in sample 3, its content was 2745.66±0.21 μg/g; luteolin – in samples 1 and 2, its content was 371.31±0.07 μg/g and 313.48±0.13 μg/g, respectively. Flavonoids attribute to the antioxidant activity of the herbal mixtures, which was confirmed by DPPH radical scavenging assay, ferric reducing power assay and ferrous ion chelating assay. The highest antioxidant capacity was found for sample 3 – IC50 of inhibition of DPPH radicals was 301.65±2.67 µg/mL compared to control – ascorbic acid (119.24±2.35 µg/mL), the ferric reducing power was 0.382 at 100 µg/mL compared to ascorbic acid (0.412 at 100 µg/mL) and IC50 of chelating capacity was 206.59±2.48 µg/mL compared to EDTA-Na2 (110.55±1.93 µg/mL).

Effect of processing on the antioxidant activities of porridges and Pittu prepared from finger millets (Eleusine coracana)

Finger millets are important coarse grains that exhibit high levels of phenolic compounds and antioxidant activities among other cereals. Grains are subjected to a number of thermal treatments and this could affect the contents and bioactivities of phenolic compounds. The aim of the present study was to determine the phenolic contents and antioxidant activities of finger millet flour and foods, namely porridges and Pittu subjected to several thermal treatments such as roasting, parboiling, and parboiled roasting of flour and open boiling and steaming of foods prepared using flour. The effect of the addition of spices on phenolic content and antioxidant activities to open boiled foods was determined. Antioxidant activities of phenolic extracts obtained from finger millet flour and foods were studied for their total phenolic, flavonoids and proanthocyanidins contents, radical scavenging capacities, reducing power, ferrous ion chelating capacity, and antioxidant activity in a β-carotene/linoleate emulsion. The roasted flour and foods had higher total phenolic content (TPC) than other counterparts and ranged from 21.58 to 28.63 µmol ferulic acid equivalents/g dry matter. All flour and food preparations exhibited effective inhibition of radicals, reducing power, ferrous ion chelating activity, and antioxidant activity in the β-carotene/linoleate emulsion and the degree of activity depended on the processing conditions adopted in food preparations.Foods prepared using steaming showed lower phenolic content and antioxidant activities in general than those of open-boiled counterparts. The addition of spices, namely garlic and cinnamon improved the phenolic contents and antioxidant activities of open-boiled porridges. The knowledge generated from this study may help to exploit the use of finger millets as a functional food ingredient to promote health and wellness.Graphical abstract

Standardized method to extract phenolic compounds from Lagerstroemia speciosa L. (Jarul) for enhanced antioxidant activity

Phenolic compounds contribute to the antioxidant property of plants and the efficient extraction of plant phenolics could enhance its antioxidant potential. Lagerstroemia speciosa (L.) Pers. has been investigated for its pharmacological activities, but comparing its antioxidant activities of phenolics derived from its various parts has a key role in developing natural antioxidants. This study was conducted to standardize the extraction of phenolics from leaves, pods and branches of L. speciosa plant, followed by determination of antioxidant activities of their solvent fractions. Phenolic compounds were extracted from the leaves, pods and branches under different parameters such as temperature, pH, type of solvent and volume of the solvent. The extracted phenolic compounds were subjected to solvent fractions and antioxidant assays were performed. Among the various extraction methods tested, the best method was 50% ethanol +1% HCl, refluxing temperature, 100 ml of solvent and 1 hour extraction time. The best solvent fractions were determined as NaHCO3 + ethyl acetate for pods and ethyl acetate alone for leaves and branches with extracted phenolics content of 150.2 mg/g, 136.2 mg/g and 82.9 mg/g, respectively. The chloroform fraction was best among the fractions with maximum ascorbic acid equivalent (ASE) in all the parts of L. speciosa tested. Ferrous ion chelating capacity indicated that butanol fraction had the highest chelation and the same was recorded in ferric ion chelating assay with an EC50 value of 28.2. Hydroxyl radical scavenging activity of the fractions indicated that NaHCO3 + EtOAc fraction of pods had potential activity. Thus, the phenolic compounds from L. speciosa are excellent sources for future investigation on potent natural antioxidant compounds.

Antioxidant Activity of Spiranthes sinensis and Its Protective Effect against UVB-Induced Skin Fibroblast Damage

Spiranthes sinensis (S. sinensis), a species of orchid, is a well-known herb medicine used to treat disorders such as stomachache, diabetes, shingles, and certain inflammatory diseases. Presently, the antioxidant activity of S. sinensis as well as its protective effect on UVB-induced skin injury are unclear. In this study, S. sinensis was extracted with boiling water or 75% (v/v) ethanol, and then its antioxidant composition and antioxidant activity were determined. The protective effects of S. sinensis against UVB-induced damage in human skin fibroblasts (CCD-966SK) were also investigated. Our data showed that the extraction yield of boiling water was higher than that of 75% ethanol. However, compared to the aqueous extracts, the ethanol extracts not only had higher phenolic, flavonoid, and condensed tannin contents, but also exhibited higher free radical scavenging activity, higher reducing power, and higher ferrous ion-chelating capacity. When fibroblasts were pre-cultured with the water or ethanol extracts of S. sinensis (1500 μg/mL) for 24 h before applying UVB irradiation, the S. sinensis extracts restored 17% to 27% of cell viability compared to a control only irradiated with UVB. Overall, our study suggests that S. sinensis extracts can be used as effective antioxidants and have the potential to protect skin fibroblasts from UVB irradiation.

Electroactive Phenolic Contributors and Antioxidant Capacity of Flesh and Peel of 11 Apple Cultivars Measured by Cyclic Voltammetry and HPLC-DAD-MS/MS.

In this study, 11 apple cultivars were characterized by their total phenolic content (TPC) and total flavonoid content (TFC) and antioxidant, reducing, and chelating capacity by 2,2-diphenyl-1-picrylhydrazyl (DPPH) test, cyclic voltammetry (CV), and ferric reducing antioxidant power (FRAP) assays; and ferrous ion chelating capacity. The phenolic compounds in flesh and peel were determined by liquid chromatography coupled to mass spectrometry and diode array detector (HPLC–DAD–MS/MS) and their electroactivity by CV. The results showed higher TPC, TFC, and antioxidant capacity by DPPH test in the peels of all apple cultivars as compared to the respective flesh. The peel extracts also showed two-fold higher FRAP values as compared to the flesh extracts. The reducing capacity of the peel and flesh determined by CV measurements confirmed the results achieved by spectrophotometric methods of evaluating antioxidant capacity. There was no significant difference in chelating capacity in the peel and flesh. The HPLC–DAD–MS/MS analysis showed the presence of 11 phenolic compounds in the peel and flesh which varied in antioxidant, reducing, and chelating activity. The order of the phenolic compound content in flesh and peel in Quinte cultivar, which showed the highest antioxidant capacity, was as follows: epicatechin > chlorogenic acid > quercetin 3-arabinoside > quercetin 3-glucoside > cyanidin 3-galactoside > quercetin 3-rhamnoside > catechin > phloridzin > rutin > phloretin = quercetin. CV results were highly correlated with those obtained by spectrophotometry and HPLC–DAD–MS/MS, providing evidence to support the use of cyclic voltammetry as a rapid method to determine the phenolic profile and reducing the power of apple flesh and peel. The association between antioxidant assays and phenolic compound content showed that the highest contribution to the antioxidant capacity of apple peel and flesh was provided by catechin, epicatechin, and cyadinin-3-galactoside, while phloretin, phloridzin, and chlorogenic acid were the main contributors to chelating activity. Results from this study clearly indicate that removing the peel from apples may induce a significant loss of antioxidants.

Identification and screening of multiple tropical microalgal strains for antioxidant activity in vitro

To exploit indigenous microalgae with potential for antioxidant activity, 10 microalgal strains (expressed as genus and species) were isolated from fresh and sea waters in Hainan Province, China, according to their high biomass, strong antioxidant capacity and antioxidant enzyme activity. The strains were identified based on their morphology, 18s rDNA and internal transcribed spacer (ITS) sequence analysis. Five strains were identified as Dictyosphaerium sp. 1A10, Desmodesmus armatus (D. armatus) B38, Masaia oloidia 2Fg, Chlorella vulgaris B43 and Chlamydomonas chlamydogama WC11. Microalgal antioxidant capacity was determined. Dictyosphaerium sp. 1A10 showed the highest superoxide dismutase activity (940 ± 10 U/g tissue), 2,2′-diphenyl-1-picryhydrazyl radical scavenging capacity (100 ± 10%) and oxygen radical absorbance capacity (620 ± 10 μmol Trolox/g); D. armatus B38 showed the highest glutathione peroxidase activity (110 ± 10 U/g tissue), ferrous ion chelating capacity (93 ± 7%) and hydroxyl radical-scavenging capacity (97 ± 2%); Scenedesmus ecornis (S. ecornis) G2 showed the highest 2,2′-azinobis-(3-ethylbenzthiazoline-6-sulphonate) scavenging capacity (92 ± 5%). PCA also suggested that D. armatus B38, Dictyosphaerium sp. 1A10 and S. ecornis G2 with highest comprehensive scores (1.83, 1.23, and 0.59, respectively) could be the most appropriate candidates for antioxidants.

Male date palm flowers: Valuable nutritional food ingredients and alternative antioxidant source and antimicrobial agent

The aim of this study was to assess the nutritional properties of male date palm flower (MDPF) via determining its mineral, amino acid and bioactive compounds profiles and to investigate its antioxidant and antibacterial activities in order to prove its possible use as a healthy and potential natural source in human dietary diets. Results showed that MDPF is an excellent source of minerals especially regarding its high potassium and phosphorus contents (2684.23 and 318.66 mg/100 g, respectively). Moreover, the amino acids profile of MDPF showed considerable amounts supplying the human requirements. The phytochemical compounds analysis showed high content of polyphenol and flavonoids (3829.22 mg EAG/100 g and 168.31 mg EQ/100 g, respectively) promoting high antioxidant activity. The quantitative and qualitative analysis (LC-ESI-MS) of phenolic acids and flavonoids led to the identification of 18 phenolic compounds that were dominated by quinic acid (84.52%). The MDPF extract showed a potential antioxidant activity determined by different tests, namely DPPH radicals scavenging activity, ferric reducing power assay, ferrous ion chelating capacity and β-carotene bleaching assay. The MDPF also exhibited significant antibacterial activity against some tested bacteria. In conclusion, owing to its nutritional profile and biological activities, MDPF could be considered as potential functional-ingredient for food applications.

Antinociceptive Effect of the Essential Oil of Schinus terebinthifolius (female) Leaves on Adult Zebrafish (Danio rerio).

Schinus terebinthifolius Raddi (Anacardiaceae) is popularly known in Brazil as aroeira-da-praia and has pharmacological use as an astringent, antidiarrheal, anti-inflammatory, depurative, diuretic, and antifebrile agent. Although the neuropathic antinociceptive potential of S. terebinthifolius fruits has already been investigated, this study is the first one to analyze the acute antinociceptive effect of the essential oil of S. terebinthifolius (female) leaves (EOFSt) on adult zebrafish. EOFSt was submitted to antioxidant activity evaluation by two methods (ferrous ion-chelating capacity [FIC] and β-carotene). The animals (n = 6/group) were treated orally (20 μL) with EOFSt (0.1, 0.5, or 1.0 mg/mL) or vehicle (0.9% sodium chloride [NaCl]; 20 μL), and submitted to nociception (formalin, cinnamaldehyde, capsaicin, glutamate, acidic saline, and hypertonic saline). Possible neuromodulation mechanisms, as well motor alterations and toxicity were also evaluated. In the FIC assay, EOFSt showed ferrous ion-chelating capacity in ∼40% to 90%. Regarding the β-carotene bleaching assay, EOFSt showed inhibition in a 58% to 80% range. Oral administration of EOFSt showed no acute toxicity and did not alter the locomotor system of aZF, and reduced the nociceptive behavior in all tested models. These effects of EOFSt were significantly similar to those of morphine, used as a positive control. The antinociceptive effect of EOFSt was inhibited by naloxone, L-NAME, ketamine, camphor, ruthenium red, and amiloride. The antinociceptive effect of the EOFSt cornea was inhibited by capsazepine. EOFSt has the pharmacological potential for acute pain treatment and this effect is modulated by the opioid system, NMDA receptors, and transient receptor potential ankyrin 1 (TRPA1), transient receptor potential vanilloid 1 (TRPV1), and acid-sensing ion channels. The EOFSt also has the pharmacological potential for corneal pain treatment and this effect is modulated by the TRPV1 channel.

Ultrasound-Assisted Extraction of Total Flavonoids from Pteris cretica L.: Process Optimization, HPLC Analysis, and Evaluation of Antioxidant Activity.

In the present work, the ultrasonic-assisted extraction (UAE) of total flavonoids (TF) from Pteris cretica L. was optimized by response surface methodology (RSM) on the basis of a single-factor experiment. The optimized UAE parameters were as follows: Ethanol concentration 56.74%, extraction time 45.94 min, extraction temperature 74.27 °C, and liquid/solid ratio 33.69 mL/g. Under the optimized conditions, the total flavonoids yield (TFY) was 4.71 ± 0.04%, which was higher than that obtained by heat reflux extraction (HRE). The extracts were further analyzed by HPLC, and five major flavonoids, including rutin, quercitrin, luteolin, apigenin, and luteolin-7-O-glucoside, were identified and quantified. Furthermore, the results of the antioxidant test showed that the TF extract obtained under optimized UAE conditions exhibited good 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•) and 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical (ABTS+•), nitric oxide radical (NO•) scavenging activities, and ferrous ion (Fe2+) chelating capacity, with IC50 values of 74.49, 82.92, 89.12, and 713.41 µg/mL, respectively. Results indicated that the UAE technique developed in this work was an efficient, rapid, and simple approach for the extraction of flavonoids with antioxidant activity from P. cretica.

EVALUATION OF FREE RADICAL SCAVENGING ABILITY AND ANTIRADICAL ACTIVITIES OF XIMENIA CAFFRA FRUIT EXTRACTS AT DIFFERENT RIPENING STAGES

Methods: Using standard procedures, Ximenia caffra fruit extracts were determined for ferrous ions chelating ability, nitric oxide and hydroxyl radical scavenging ability. Antiradical activities were assessed using 1,1-diphenyl-2-picrylhydrazyl (DPPH) in which the fruit extracts were evaluated for the number of antiradical units (AU515), the number of antiradical units per 1 mg of extracts (EAU515) and the total number of antiradical units per 1g of raw fruits (TAU515).Results: The fruit extracts exhibited significant higher ferrous ion chelating and free radical scavenging capacity compared to synthetic antioxidants (standard). Fruit extracts in early ripening stage (ERS) exhibited stronger ion chelation, nitric oxide and hydroxyl radical scavenging ability with low effective fruit extract concentration required to reduce free radicals by 50% (EC50) that were 14, 25 and 30µg/ml respectively than the late ripening stage (LRS) extracts. The fruit extracts also showed high AU515, EAU515 and TAU515. The values of AU515 ranged from 0.93 to 0.95, while EAU515 from 78.30 to 79.34 and TAU515 ranged from 19762.46 to 23821.23 of the extracts in LRS and ERS respectively.Conclusion: Based on these observations Ximenia caffra is potentially beneficial to human health due to its strong ability to scavenge free radicals. Its utilization can potentially reduce the risk of degenerative diseases to human beings.

Effects of intrinsic metal ions of lentinan with different molecular weights from Lentinus edodes on the antioxidant capacity and activity against proliferation of cancer cells

In this study, effects of intrinsic metal ions in lentinan on its bioactivities were evaluated. Lentinan extracted from Lentinus edodes was separated to four fractions with different molecular weights with Sephadex G-200 gel chromatography, and intrinsic metal ions were removed by EDTA. The ferrous ion chelating capacity of ELWs was measured to estimate EDTA residue after extensive dialysis. Antioxidant and antitumor activities of the isolated lentinans (LWs and ELWs) were investigated in vitro and compared, respectively. The results indicated that all of the isolated lentinan contained a large amount of intrinsic metal ions and the fraction with the lowest Mw had highest metal content. After removing intrinsic metal ions, the polysaccharides showed lower ABTS and DPPH radicals scavenging capacity and the reduced inhibition of the proliferation of BXPC-3 and Hela cells. Our results indicated that the metal ions in lentinan had positive effects on its bioactivities.

Identification of Phenolic Compounds from Seed Coats of Differently Colored European Varieties of Pea (Pisum sativum L.) and Characterization of Their Antioxidant and In Vitro Anticancer Activities

ABSTRACTTo date little has been done on identification of major phenolic compounds responsible for anticancer and antioxidant properties of pea (Pisum sativum L.) seed coat extracts. In the present study, phenolic profile of the seed coat extracts from 10 differently colored European varieties has been determined using ultrahigh-performance liquid chromatography–linear trap quadrupole orbitrap mass spectrometer technique. Extracts of dark colored varieties with high total phenolic content (up to 46.56 mg GAE/g) exhibited strong antioxidant activities (measured by 2,2-diphenyl-1-picrylhydrazyl or DPPH assay, and ferric ion reducing and ferrous ion chelating capacity assays) which could be attributed to presence of gallic acid, epigallocatechin, naringenin, and apigenin. The aqueous extracts of dark colored varieties exert concentration-dependent cytotoxic effects on all tested malignant cell lines (human colon adenocarcinoma LS174, human breast carcinoma MDA-MB-453, human lung carcinoma A594, and myelogenous leukemia K562). Correlation analysis revealed that intensities of cytotoxic activity of the extracts strongly correlated with contents of epigallocatechin and luteolin. Cell cycle analysis on LS174 cells in the presence of caspase-3 inhibitor points out that extracts may activate other cell death modalities besides caspase-3-dependent apoptosis. The study provides evidence that seed coat extracts of dark colored pea varieties might be used as potential cancer-chemopreventive and complementary agents in cancer therapy.

Antioxidant and toxicological evaluation of a Tamarindus indica L. leaf fluid extract

In the scientific community, there is a growing interest in Tamarindus indica L. leaves, both as a valuable nutrient and as a functional food. This paper focuses on exploring its safety and antioxidant properties. A tamarind leaf fluid extract (TFE) wholly characterised was evaluated for its anti-DPPH activity (IC50 = 44.36 μg/mL) and its reducing power activity (IC50 = 60.87 μg/mL). TFE also exhibited a high ferrous ion-chelating capacity, with an estimated binding constant of 1.085 mol L− 1 while its influence over nitric oxide production in human leucocytes was irregular. At low concentrations, TFE stimulated NO output, but it significantly inhibited it when there was an increase in concentration. TFE was also classified as a non-toxic substance in two toxicity tests: the acute oral toxicity test and the oral mucous irritability test. Further toxicological assays are needed, although results so far suggest that TFE might become a functional dietary supplement.

Identification of seed coat phenolic compounds from differently colored pea varieties and characterization of their antioxidant activity

The phenolic composition of seed coats in four differently colored pea varieties (Pisum sativum L.) was investigated using UHPLC-LTQ OrbiTrap MS. The obtained findings revealed that the seed coats of the examined pea genotypes possess a unique phenolic composition compared to previously studied European cultivars. In total, 41 phenolic compounds have been identified. The seed coats of the studied cultivars contained certain amounts of rosmarinic acid, rutin, galangin, morin, naringin, hesperetin and pinocembrin as well as ten flavonol glycosides that had not been reported previously. Additionally, the total phenolic content, antioxidant activity and metal chelating capacity of extracts was determined using Folin-Ciocalteu?s method, 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay, ferric ion-reducing capacity and ferrous ion-chelating capacity assay, respectively. Dark colored genotypes MBK 168 and MBK 173 possessed the highest total phenolic contents as well the strongest antioxidant activities. On the other hand, bright colored genotypes MBK 88 and MBK 90 exhibited the strongest metal-chelating capacities. The examined pea seed coats may be considered as important potential contributors to human health due to the presence of bioactive phenolic constituents. In addition, our results could be used as a guideline for breeding new pea cultivars with high antioxidant activities applicable in the formulation of functional food products.

Pilosocereus arrabidae (Byles & Rowley) of the Grumari sandbank, RJ, Brazil: Physical, chemical characterizations and antioxidant activities correlated to detection of flavonoids

The fruits of Pilosocereus arrabidae (Cactaceae) is found in the Grumari shoal, located in the Rio de Janeiro state, Brazil and, several studies have already highlighted the importance of consuming its fruits. This work aims to investigate the physical, mineral and physicochemical properties of its fruits as well as to establish the knowledge about their chemical constituents and antioxidant properties. The peel (Pe) and pulp (Pu) extracts were obtained by maceration with the following solvents: hexane (HX), dichloromethane (DCL), ethyl acetate (EAC) and ethanol 70% (ET). The extracts were analyzed by Gas Chromatography coupled to Mass Spectrometry (GC–MS) and, by High Performance Liquid Chromatography (HPLC–DAD and HPLC–MS) for its chemical investigation. For the antioxidant activity investigations the ORAC, DPPH and ferrous ion chelating capacity (FICC) tests were performed. As results, we found higher yields for peels (72%) compared to pulps (28%). By the physical–chemical analyses we point out the fruits as a good source of fiber (pulp: 6.01mg/100g; peel: 8.02mg/100g). The minerals were analyzed by the method of issuing flames and indicated high levels of selenium (DRI for pulp and peel: 147%) and manganese (DRI pulp: 97.69% and DRI peel: 269.56%). The total flavonoid contents of the fruits performed by HPLC–DAD presented 0.45μg equiv. in quercetin/mL of peel EAC extract and 0.25μg equiv. in rutin/mL of pulp EAC extract. The antioxidant activities by the ORAC, FICC and DPPH methods indicated that the ET extracts showed antioxidant activities above the standards adopted for the tests. Among these, we highlight the ET extract of the pulp with EC50 of 17.57±0.27μg/mL, lower than Ginkgo biloba EGB761® (23.40±0.04mg/mL). By the FICC test the EAC extract of the peel and pulp showed 70.0% and 53.4% activity, respectively, at 500mg/mL, higher than the standard quercetin (50.0%). By the HPLC–DAD and HPLC–MS methods there were detected, for the first time on this species, the presence of the following flavonoids on the EAC extracts: quercetin, rutin, catechin, dihydrokaempferol, quercetin 3 or 4′-O-glucoside, kaempferol and isorhamnetin. By the GC–MS analysis there were detected on the DCL extracts saturated fatty acids (palmitic and stearic) and, on the HX extracts, methylated sugars (peel) and menthol (pulp). To sum up, the fruits of P. arrabidae display antioxidant potential correlated to flavonoid presence, and, high levels of selenium, manganese and fibers, characteristics that can promote beneficial effects on human health.

Phytochemical screening, antioxidant activity, total polyphenols and flavonoids content of different extracts of propolis from Tekel (Ngaoundal, Adamawa region, Cameroon)

Five extracts of propolis of Adamawa Cameroon were obtained by percolation and maceration with five different solvents: hexane, ethyl acetate, ethanol, methanol and water, in order of increasing polarity. Phytochemical screening was carried out on the extracts and the total content in flavonoids and polyphenols were evaluated by photometric methods. The total flavonoid content was evaluated using the Neu reagent (2-aminodiethyl diphenylborinate) and quercetin as standard and the results varied from 0.84±0.02 gQE/100gRM in ethyl acetate extract to 1.52±0.06 gQE/100gRM in ethanol extract. The total polyphenol content was evaluated using Folin-Ciocalteu reagent and gallic acid as standard and results varied from 2.32±0.37 gGAE/100gRM in the ethyl acetate extract which is the least to 8.64±0.47 gGAE/100gRM in the aqueous extract. The antiradical activities of the extracts were evaluated through their inhibition on DPPH• and IC50 values varied from 1.88 mg/mL in the aqueous extract which showed highest antioxidant power to 5.06 mg/mL in the ethyl acetate extract with the least antioxidant power. BHT and vitamin C were used as synthetic and natural standards respectively and they showed higher antioxidant power compared to the propolis extracts. Ferrous iron chelating capacities of the extracts were determined using potassium ferricyanide reagent and EDTA as standard. Using Stat Graphics software and Durbin-Watson statistics test, the extracts showed significant correlation between flavonoid content and polyphenol content with DPPH• scavenging activity. The ethyl acetate extract showed least ferrous ion chelating capacity while the methanol extract showed highest ferrous ion chelating capacity.