Cytotoxic, Cellular Antioxidant, and Antiglucuronidase Properties of the Ethanol Leaf Extract from Bulbine asphodeloides.

Bulbine asphodeloides (L.) Spreng (Xanthorrhoeaceae family), popularly known in South Africa as "ibhucu" or "Balsamkopieva," is a perennial plant traditionally used to treat skin diseases, including sunburns, rough skin, dressing burns, itches, and aging. The present study reports the cytotoxic, cellular antioxidant, and antiglucuronidase properties of the ethanol leaf extract from B. asphodeloides. The cytotoxic effect of the plant extract on human dermal fibroblast (MRHF) cells was evaluated by the bis-Benzamide H 33342 trihydrochloride/propidium iodide (Hoechst 33342/PI) dual-staining method. A validated biological cell-based assay was used to determine the cellular antioxidant activity of the extract. The antiglucuronidase and metal chelating activities were evaluated using standard in vitro methods. Lipopolysaccharide- (LPS-) induced RAW 264.7 cell model was used to determine the anti-inflammatory effect of the plant extract, and the immune-modulatory activity was performed using RAW 264.7 cells. The extract demonstrated no cytotoxic effect towards the MRHF cells at all the tested concentrations. Furthermore, the extract also possessed significant cellular antioxidant and antiglucuronidase activities, but a weak effect of metal chelating activity in a dose-dependent manner. However, the extract showed no significant anti-inflammatory and immune-stimulatory activities. Overall, the results showed that B. asphodeloides may be a useful therapeutic agent for the treatment of skin diseases, therefore supporting its ethnomedicinal usage.

In Vitro and In Vivo Antioxidant Activity of Agave sisalana Agro-Industrial Residue.

Agave sisalana agro-industrial residue has considerable potential against damage associated with oxidative stress and skin aging. This study aims to demonstrate, in vitro and in vivo, the potential of Agave sisalana agro-industrial residue as a safe and effective alternative for the prevention of damage caused by oxidative stress and aging. The antioxidant activity was evaluated in vitro (total antioxidant capacity, reducing power, DPPH radical scavenging, metal chelating (Fe2+ and Cu2+), and hydroxyl radical scavenging) and in vivo using the Caenorhabditis elegans organism model. The extract showed in vitro antioxidant activity in all tests performed. Tests with C. elegans showed that the extract was able to reduce the intracellular levels of reactive oxygen species (ROS) and increase the survival rate of worms. A downregulation of gst-4::GFP expression suggests a direct action against free radicals. Agave sisalana agro-industrial residue extract (AsRE) can therefore be considered as a source of antioxidant biomolecules, and the use of this agro-industrial residue in a new production process can lead to sustainability and socioeconomic development.

Milk thistle (Silybum Marianum) as an antidote or a protective agent against natural or chemical toxicities: a review.

Biological and chemical agents cause dangerous effects on human health via different exposing ways. Recently, herbal medicine is considered as a biological and safe treatment for toxicities. Silybum marianum (milk thistle), belongs to the Asteraceae family, possesses different effects such as hepatoprotective, cardioprotective, neuroprotective, anti-inflammatory and anti-carcinogenic activities. Several studies have demonstrated that this plant has protective properties against toxic agents. Herein, the protective effects of S. marianum and its main component, silymarin, which is the mixture of flavonolignans including silibinin, silydianin and silychristin acts against different biological (mycotoxins, snake venoms, and bacterial toxins) and chemical (metals, fluoride, pesticides, cardiotoxic, neurotoxic, hepatotoxic, and nephrotoxic agents) poisons have been summarized. This review reveals that main protective effects of milk thistle and its components are attributed to radical scavenging, anti-oxidative, chelating, anti-apoptotic properties, and regulating the inflammatory responses.

Inhibition of Amyloid ß Aggregation Using Optimized Nano-Encapsulated Formulations of Plant Extracts with High Metal Chelator Activities.

BACKGROUND: The role of Fe+2, Cu+2 and Zn+2 in facilitating aggregation of Amyloid ß (Aß) and consequently, the progression of Alzheimer's disease (AD) is well established. OBJECTIVE: Development of non-toxic metal chelators is an emerging era in the treatment of AD, in which complete success has not been fully achieved. The purpose of this study was to determine plant extracts with high metal chelator and to encapsulate them in nano-micellar systems with the ability to pass through the Blood Brain Barrier (BBB). METHODS: Extracts of 36 different Anatolian plants were prepared, total phenolic and flavonoid contents were determined, and the extracts with high content were examined for their Fe+2, Cu+2 and Zn+2 chelating activities. Apolipoprotein E4 (Apo E) decorated nano-formulations of active extracts were prepared using Poly (Lactide-co-Glycolide) (PLGA) (final product ApoEPLGA) to provide BBB penetrating property. RESULTS: Verbascum flavidum aqueous extract was found as the most active sample, incubation of which, with Aß before and after metal-induced aggregation, resulted in successful inhibition of aggregate formation, while re-solubilization of pre-formed aggregates was not effectively achieved. The same results were obtained using ApoEPLGA. CONCLUSION: An optimized metal chelator nano-formulation with BBB penetrating ability was prepared and presented for further in-vivo studies.

Evaluating the efficacy of a ferrous-ion-chelating peptide from Alaska pollock frame for the improvement of iron nutritional status in rats.

This study aimed to investigate the effects of ferrous-ion-chelating peptides from Alaska pollock frames (APFP-Fe) on iron deficiency in anaemic rats. We hydrolysed the Alaska pollock frames to obtain a peptide with an average molecular weight of 822 Da. The bioavailability of APFP-Fe was tested using animal experiments. Wistar rats were randomly divided into six groups: an iron deficiency control group, a normal control group, and iron deficiency groups treated with ferrous sulfate (FeSO4) or low-, medium-, or high-dose APFP-Fe. Rats in the iron deficiency groups were fed an iron-deficient diet to establish the iron deficiency anaemia (IDA) model. After the model was established, different iron supplements were given to rats once per day via intragastric administration for 21 days. The results showed that APFP-Fe had restorative effects, returning the body weight, weight gain, height, and haematological parameters in IDA rats to normal levels. In addition, compared with FeSO4, APFP-Fe promoted significant weight gain and effectively improved haemoglobin, serum iron and transferrin levels, and recovery of the capacity of iron binding with transferrin, especially at the medium and high doses. These findings suggest that APFP-Fe is an effective source of iron for improving the iron nutritional status in IDA rats and shows promise as a new source of iron supplementation.

An overview of plant-based interventions to ameliorate arsenic toxicity.

The industrial and technological advancements in the world have also contributed to the rapid deterioration in the environment quality through introduction of obnoxious pollutants that threaten to destroy the subtle balance in the ecosystem. The environment contaminants cause severe adverse effects to humans, flora and fauna that are mostly irreversible. Chief among these toxicants is arsenic, a metalloid, which is considered among the most dangerous environmental toxins that leads to various diseases which affect the quality of life even when present in small quantities. Treatment of arsenic-mediated disorders still remains a challenge due to lack of effective options. Chelation therapy has been the most widely used method to detoxify arsenic. But this method is associated with deleterious effects leading various toxicities such as hepatotoxicity, neurotoxicity and other adverse effects. It has been discovered that indigenous drugs of plant origin display effective and progressive relief from arsenic-mediated toxicity without any side-effects. Further, these phytochemicals have also been found to aid the elimination of arsenic from the biological system and therefore can be more effective than conventional therapeutic agents in ameliorating arsenic-mediated toxicity. This review presents an overview of the toxic effects of arsenic and the therapeutic strategies that are available to mitigate the toxic effects with emphasis on chelation as well as protective and detoxifying activities of different phytochemicals and herbal drugs against arsenic. This information may serve as a primer in identifying novel prophylactic as well as therapeutic formulations against arsenic-induced toxicity.

New Sources of Calcium (Chicken Eggshells, Chelates) - Preparation of Raw Material and Tablets.

BACKGROUND: There are many calcium supplements available in the market, especially those containing calcium in the form of carbonate, which unfortunately is not absorbed by the body to a sufficient degree. METHOD: Therefore, an attempt was made to prepare new sources of calcium, consuming the chicken eggshells as natural raw materials, which were used in preparation of tablets containing calcium carbonate and calcium citrate as well as tablets with calcium carbonate and calcium bisglycinate. The influence of raw material properties on the pharmaceutical availability of calcium from the obtained tablets was investigated. RESULTS: Based on the obtained calcium release profiles from the prepared tablets, it was found that the optimal source of calcium is a preparation containing calcium from chicken eggshells. It was found that both chicken eggshells and calcium bisglycinate (chelate) may be new, prospective sources of calcium. Calcium citrate prepared using eggshells as starting materials and bisglycinate is completely released within no more than 150 minutes. CONCLUSION: In turn, calcium carbonate added to calcium bisglycinate statistically significantly prolonges the release of calcium ions to 4 hours.

Reduction of heavy metal (Pb2+) biosorption in zebrafish model using alginic acid purified from Ecklonia cava and two of its synthetic derivatives.

Heavy metal contamination has become a major problem that causes severe environmental and health issues due to their biosorption, bioaccumulation, and toxicity. This study was designed to evaluate heavy metal chelating abilities of alginic acid (AA) extracted from the brown seaweed Ecklonia cava and two of its derivatives prepared by the partial oxidation of the 2° OH groups (OAA) and partial carboxylation of the monomeric units (CAA) upon reducing the heavy metal biosorption in zebrafish (Danio rerio) modal. Metal ions were quantified using ICP-OES and biopolymers were characterized by FTIR and XRD analysis. All investigated biopolymers indicated potential ability for chelating Pb2+, Cu2+, Cd2+, As3+, and Ag+. The sorption capacities were in the order of CAA>OAA>AA. All biopolymers indicated a comparatively higher chelation towards Pb2+. AA, OAA, and CAA could effectively reduce Pb2+ induced toxicity and Pb2+ stress-induced ROS production in zebrafish embryos. Besides, they could reduce the biosorption of Pb2+ in adult zebrafish which could lead to bioaccumulation. Since alginic acid purified from E. cava and its derivatives could be utilized as seaweed derived biopolymers to purify heavy metals contaminated water and as a dietary supplement to reduce heavy metal biosorption in organisms.

Phytochelatin 2 accumulates in roots of the seagrass Enhalus acoroides collected from sediment highly contaminated with lead.

Phytochelatins (PCs), the heavy metal-binding peptides of plants, play a main function in heavy metal detoxification. In this study, Enhalus acoroides samples collected at six distinct seagrass beds from the coast of Khanh Hoa province, Viet Nam, were evaluated for their PCs. The contents of different PCs in each organ including leaf, rhizome, and root were determined by using HPLC analysis. Significant differences of PC2 contents among specific organs and their relation were tested by ANOVA, Tukey test, and Pearson's correlation. The results showed that higher PC2, appearance of PC3 and a strong correlation between PC2 and Pb concentration were found in the root organ collected from a Pb contaminated area. We conclude that high Pb in the sediment induce high PC2 and PC3 production in the root. This first report on in situ detection of PCs of seagrass encourages future investigation on the ability to use seagrass for phytoremediation and as a bioindicator of heavy metals based on PC contents.

Antioxidant, anticholinesterase and antibacterial activities of Stachys guyoniana and Mentha aquatica.

CONTEXT: Stachys guyoniana Noë ex. Batt. and Mentha aquatica L. are two Algerian Lamiaceae used in folk medicine. OBJECTIVE: To investigate their antioxidant, anticholinesterase and antibacterial activities. MATERIAL AND METHODS: n-Butanol (BESG), ethyl acetate (EESG) and chloroform (CESG) extracts of S. guyoniana and methanol (MEMA) and chloroform (CEMA) aerial part extracts of M. aquatica and methanol (MERMA) and acetone (AERMA) roots extracts of M. aquatica were evaluated for their antioxidant activity by the ß-carotene-linoleic acid, DPPH• and ABTS•+ scavenging, CUPRAC and metal chelating assays. The anticholinesterase activity was tested against AChE and BChE. The antibacterial activity was assessed by MICs determination against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella heidelberg, Klebsiella pneumoniae, Enterobacter aerogenes and Morganella morganii strains. RESULTS: In the ß-carotene test, the CESG (IC50: 2.3 ± 1.27 µg/mL) exhibited the highest activity. The BESG was the best scavenger of DPPH• (IC50: 2.91 ± 0.14 µg/mL). In the ABTS test, AERMA was the most active (IC50: 4.21 ± 0.28 µg/mL). However, with the CUPRAC, the BESG exhibited the best activity (A0.50: 0.15 ± 0.05 µg/mL) and was active in metal chelating assay with 48% inhibition at 100 µg/mL. The BESG was the best AChE inhibitor (IC50: 5.78 ± 0.01 µg/mL) however, the AERMA showed the highest BChE inhibitory activity (IC50: 19.23 ± 1.42 µg/mL). The tested extracts exhibited a good antibacterial activity. CONCLUSION: This study demonstrated good antioxidant, anticholinesterase and antibacterial potential of S. guyoniana and M. aquatica, which fits in well with their use in folk medicine.

Yerba mate (Ilex paraguariensis St. Hill.)-based beverages: How successive extraction influences the extract composition and its capacity to chelate iron and scavenge free radicals.

Chimarrão or mate is a popular beverage from South America that is drank with successive infusions. Although yerba mate extracts have been widely studied, few studies have described the extract contents in beverages. Using yerba mate samples from Brazil, Argentina, and Uruguay, we examined the extract chromatographic profiles, total polyphenol content and their capacities to chelate iron. In addition, we analyzed antioxidant activity by examining the ability of the extracts to scavenge DPPH and NO. Our results showed that the amount of extracted compound was highest in yerba mate extract from Uruguay, followed by Argentina, then Brazil. Herbs from all three areas had a significant capacity to inhibit DPPH and NO free radicals. The Brazilian and Uruguayan herbs had an 80% iron chelation capacity (p<0.001), while the iron chelation capacity of the Argentinean herb was lower but still significant (p⩽0.05). We conclude that the compound concentration decreases with successive extractions, while the antioxidant capacity is maintained at significant levels.

Chelating Properties of Peptides from Red Seaweed Pyropia columbina and Its Effect on Iron Bio-Accessibility.

The aim of this work was to evaluate copper-chelating, iron-chelating and anticariogenic activity of peptides obtained by enzymatic hydrolysis of P. columbina protein concentrate and to study the effects of chelating peptides on iron bio-accessibility. Two hydrolyzates were obtained from P. columbina protein concentrate (PC) using two hydrolysis systems: alkaline protease (A) and alkaline protease + Flavourzyme (AF). FPLC gel filtration profile of PC shows a peak having molecular weight (MW) higher than 7000 Da (proteins). A and AF hydrolyzates had peptides with medium and low MW (1013 and 270 Da), respectively. Additionally, AF presented free amino acids with MW around 82 Da and higher content of His and Ser. Peptides from AF showed the highest chelating properties measured as copper-chelating activity (the lowest ß-carotene oxidation rate: Ro; 0.7 min(-1)), iron-chelating activity (33%), and phosphorous and Ca(2+) release inhibition (87 and 81%, respectively). These properties could indicate antioxidant properties, promotion of iron absorption and anticariogenic activity, respectively. In fact, hydrolyzates promoted iron dialyzability (≈ 16%), values being higher than that found for P. columbina seaweed. Chelating peptides from both hydrolyzates can maintain the iron in a soluble and bio-accessible form after gastrointestinal digestion.

Phytochemicals from Dodonaea viscosa and their antioxidant and anticholinesterase activities with structure-activity relationships.

Context Dodonaea viscosa (L.) Jacq (Sapindaceae) has been used in traditional medicine as antimalarial, antidiabetic and antibacterial agent, but further investigations are needed. Objective This study determines the antioxidant and anticholinesterase activities of six compounds (1-6) and two crystals (1A and 3A) isolated from D. viscosa, and discusses their structure-activity relationships. Materials and methods Antioxidant activity was evaluated using six complementary tests, i.e., ß-carotene-linoleic acid; DPPH(•), ABTS(•+), superoxide scavenging, CUPRAC and metal chelating assays. Anticholinesterase activity was performed using the Elman method. Results Clerodane diterpenoids (1 and 2) and phenolics (3-6) - together with three crystals (1A, 3A and 7A) - were isolated from the aerial parts of D. viscosa. Compound 3A exhibited good antioxidant activity in DPPH (IC50: 27.44 ± 1.06 µM), superoxide (28.18 ± 1.35% inhibition at 100 µM) and CUPRAC (A0.5: 35.89 ± 0.09 µM) assays. Compound 5 (IC50: 11.02 ± 0.02 µM) indicated best activity in ABTS assay, and 6 (IC50: 14.30 ± 0.18 µM) in ß-carotene-linoleic acid assay. Compounds 1 and 3 were also obtained in the crystal (1A and 3A) form. Both crystals showed antioxidant activity. Furthermore, crystal 3A was more active than 3 in all activity tests. Phenol 6 possessed moderate anticholinesterase activity against acetylcholinesterase and butyrylcholinesterase enzymes (IC50 values: 158.14 ± 1.65 and 111.60 ± 1.28 µM, respectively). Discussion and conclusion This is the first report on antioxidant and anticholinesterase activities of compounds 1, 2, 5, 6, 1A and 3A, and characterisation of 7A using XRD. Furthermore, the structure-activity relationships are also discussed in detail for the first time.

Antioxidant, anticholinesterase and tyrosinase inhibition activities, and fatty acids of Crocus mathewii - A forgotten endemic angiosperm of Turkey.

Context We report the first ever chemical/biochemical study on Crocus mathewii Kerndorff (Iridaceae) - a Turkish endemic angiosperm. This plant has never been explored for its phytochemistry and bioactivities. Objective This study explores C. mathewii corm and aerial parts for the chemical and biological properties of hexane, ethyl acetate, methanol and water fractions of the extracts. Material and methods Plant material (20 g) was extracted by methanol (250 mL × 5, 3 days each) and fractioned into hexane, ethyl acetate, methanol and water. All fractions were subjected to ß-carotene-linoleic acid, DPPH(·), ABTS(·)(+), CUPRAC, metal chelating and tyrosinase inhibition activities. Hexane fractions were submitted to GC-MS analysis. Results Ethyl acetate fractions showed excellent IC50 values in DPPH(·) (aerial 36.21 ± 0.76 and corm 33.87 ± 0.02 mg/L) and ABTS(·)(+) (aerial 33.01 ± 0.79 and bulb 27.87 ± 0.33 mg/L); higher than the IC50 of the standard α-tocopherol (DPPH 116.25 ± 1.97; ABTS 52.64 ± 0.37 mg/L), higher than BHA in DPPH (57.31 ± 0.25 mg/L), but slightly lower in ABTS (19.86 ± 2.73 mg/L). Methanol extract of aerial parts also showed higher activity than α-tocopherol in DPPH (85.56 ± 11.51 mg/L) but slightly less (72.90 ± 3.66 mg/L) than both the standards in ABTS. Linoleic (aerial 53.9%, corm 43.9%) and palmitic (aerial 22.2%, corm 18%) were found as the major fatty acids. Discussion and conclusion Some fractions of C. mathewii showed higher antioxidant activities than the standards. There is a need to explore more about this plant.

Extraction, characterization and gelling behavior enhancement of pectins from the cladodes of Opuntia ficus indica.

Total Pectins Fraction (TPF) was extracted at room temperature from dried cladodes of Opuntia ficus indica. TPF is constituted of three pectic fractions WSP, CSP and ASP, which are made up of 66.6%, 44.3% and 81.1% (w/w) of galacturonic acid, respectively. The antioxidant ability of TPF increased with the concentration increasing. It scavenged hydroxyl radical by 90% and chelated 90% of ferrous ions at 5 g/L. FTIR study was carried out. Strong characteristic absorption peaks at 1,618 cm(-1) assigned to the vibration of COO(-) group of galacturonic acid. In the fingerprint region, we noticed three well-defined peaks at 1054, 1085, and 1,154 cm(-1) characteristic of pectic polysaccharides. TPF are non-gelling pectins. The co-crosslinking of TPF with carrageenan was carried out and the gelling behavior was successfully improved. Thermo-sensitive hydrogel was obtained with 82% of TPF and 18% of carrageenan (w/w).

A comparative evaluation of biological activities and bioactive compounds of the seagrasses Zostera marina and Zostera noltei from southern Portugal.

This work assessed the antioxidant potential, acetylcholinesterase (AChE) inhibition and the in vitro cytotoxic activity of extracts of the seagrasses Zostera marina and Zostera noltei collected from southern Portugal. The total phenolic contents (TPCs), the rosmarinic acid (RA) concentration (HPLC/DAD) and the fatty acid (FA) profile (GC/MS) are also described. Z. marina had the highest TPC, radical scavenging activity against DPPH radicals and copper chelating activity. Z. noltei had metal chelation capacity to copper and iron ions. None of the species was able to inhibit AChE. Both seagrasses had high levels of polyunsaturated FAs. Z. marina significantly and selectively reduced the viability of tumorous neuronal cells. Z. noltei was highly toxic for the three cell lines tested and was selective against hepatocarcinoma cells at the concentration of 100 µg/mL. RA was the main compound identified in Z. marina, but not in Z. noltei.

Antioxidant Activity of Different Fractions of Methanolic Extract of the Golden Chanterelle Mushroom Cantharellus cibarius (Higher Basidiomycetes) from Iran.

Natural compounds with antioxidant activity can be useful for treatment of reactive oxygen species-related diseases, comprising atherosclerosis, inflammatory injury, cardiovascular disease, cancer, diabetes, Alzheimer's disease, cataracts, autism, and aging. The current study was perform to assay the antioxidant activity different fractions of methanolic extract of golden chanterelle mushroom Cantharellus cibarius, a mushroom found in the north of Iran. Different fractions of methanolic extract of this mushroom, including n-hexane, chloroform, ethyl acetate, n-butanol, and water, were evaluated for antioxidant activity using six in vitro assay systems. Mushroom fruit was obtained from the local market, Sari (northern Iran). The n-hexane fraction had higher amounts of flavonoids contents (40.01 ± 1.30 mg quercetin equivalent g-1 of extract) and the highest exhibition of nitric oxide scavenging activity (77.21 ± 1.48%). The highest content of phenol was observed in the n-butanol fraction, which was 40.97 ± 0.99 mg gallic acid equivalent g-1 of extract. Among all the fractions, the ethyl acetate fraction was found to show higher DPPH scavenging activity (33.43 ± 1.30%) and the aqueous fraction to display the most reducing power. The highest Fe2+ chelating activity was observed in the chloroform fraction and then in the n-hexane fraction (86.13 ± 1.61 and 80.68 ± 2.07, respectively). The results all together signify C. cibarius as a valuable source of natural bioactive compounds with antioxidant activity.

Extraction, Antimicrobial, and Antioxidant Activities of Crude Polysaccharides from the Wood Ear Medicinal Mushroom Auricularia auricula-judae (Higher Basidiomycetes).

In this study, crude polysaccharides of culinary-medicinal mushroom Auricularia auricular-judae were extracted by hot water extraction and alcohol precipitation, and their antimicrobial and antioxidant activities were investigated. An optimum extraction condition was obtained at a ratio of liquid to solid 70 mL/g, temperature 90°C, time 4 h and extraction number 4. Accordingly, the best yield of crude polysaccharides was 6.89% with 76.12% in purity. Some bacteria and fungi were used for antimicrobial studies. It was found that crude A. auricula-judae had great antimicrobial activities against Escherichia coli and Staphylococcus aureus, but no activities on the others. The inhibitory diameters of antimicrobial zones for the two were 5.55 ± 0.182 and 9.84 ± 0.076 mm, respectively. Moreover, crude A. auricula-judae had significant antioxidant activities in scavenging free radicals, reducing power assays, and Fe2+ chelating ability assay. Results revealed that crude A. auricula-judae has a great potential as antimicrobial and antioxidant, and it can be a supplementary food for human health.

Biological Activities and Chemical Composition of Methanolic Extracts of Selected Autochthonous Microalgae Strains from the Red Sea.

Four lipid-rich microalgal species from the Red Sea belonging to three different genera (Nannochloris, Picochlorum and Desmochloris), previously isolated as novel biodiesel feedstocks, were bioprospected for high-value, bioactive molecules. Methanol extracts were thus prepared from freeze-dried biomass and screened for different biological activities. Nannochloris sp. SBL1 and Desmochloris sp. SBL3 had the highest radical scavenging activity against 1,1-diphenyl-2-picrylhydrazyl, and the best copper and iron chelating activities. All species had potent butyrylcholinesterase inhibitory activity (>50%) and mildly inhibited tyrosinase. Picochlorum sp. SBL2 and Nannochloris sp. SBL4 extracts significantly reduced the viability of tumoral (HepG2 and HeLa) cells with lower toxicity against the non-tumoral murine stromal (S17) cells. Nannochloris sp. SBL1 significantly reduced the viability of Leishmania infantum down to 62% (250 µg/mL). Picochlorum sp. SBL2 had the highest total phenolic content, the major phenolic compounds identified being salicylic, coumaric and gallic acids. Neoxanthin, violaxanthin, zeaxanthin, lutein and ß-carotene were identified in the extracts of all strains, while canthaxanthin was only identified in Picochlorum sp. SBL2. Taken together, these results strongly suggest that the microalgae included in this work could be used as sources of added-value products that could be used to upgrade the final biomass value.

Affinity purification and characterisation of zinc chelating peptides from rapeseed protein hydrolysates: possible contribution of characteristic amino acid residues.

Zinc is an essential trace element for human growth and development. In this work, zinc-chelating peptides from rapeseed protein hydrolysates produced with alcalase were investigated by affinity chromatography with immobilized zinc and Sephadex G-25 gel filtration. Four small peptides, namely, Ala-Arg, Asn-Ser-Met (NSM), Gly-Lys-Arg, and Glu-Pro-Ser-His, were obtained and identified by reversed-phase high-performance liquid chromatography and electrospray ionization mass spectrometry. The zinc-chelating ability of the four peptides was further validated by inductively coupled plasma atomic emission spectrometry (ICP-AES). NSM was found to exhibit the highest zinc-chelating rate, which was better than that of reduced glutathione. We speculated that the Asn residue at the amino-terminus might facilitate this zinc-chelating ability. Therefore, utilizing small peptides from rapeseed protein as novel carriers for zinc supplement was feasible.