Quantitative analysis of ToF-SIMS data of a two organic compound mixture using an autoencoder and simple artificial neural networks.

RATIONALE: Matrix effects cause a nonlinear relationship between ion intensities and concentrations in mass spectrometry, including time-of-flight secondary ion mass spectrometry (ToF-SIMS). Here, two artificial neural network (ANN)-based methods, autoencoder-based and simple ANN methods, were employed for the quantitative and qualitative analyses of a two organic compound mixture via ToF-SIMS. METHODS: The multilayer model sample contained a mixture of Irganox 1010 and Fmoc-pentafluoro-L-phenylalanine (Fmoc-PFLPA). The sample's positive and negative ion depth profiles were collected through ToF-SIMS. ToF-SIMS-derived cross-sectional image datasets were analyzed using three unsupervised methods, namely principal component analysis (PCA), multivariate curve resolution (MCR), and use of a sparse autoencoder (SAE). The supervised simple ANN method was optimized based on the spectra and validated by predicting the test dataset ratios of Irganox 1010. RESULTS: The results obtained using the SAE demonstrated linear calibration curves and appropriate material distribution images. The Irganox 1010 and Fmoc-PFLPA positive and negative ion datasets exhibited >0.97 correlation coefficients. The PCA and MCR results demonstrated lower linearity than that of SAE. Moreover, SAE weights indicated the ions important for each organic compound. The simple ANN method accurately predicted the ratios in the test dataset and indicated the important ions. CONCLUSIONS: Both the supervised and unsupervised methods based on ANN, which were employed in regulating nonlinear relationships, were effective in the quantitative and qualitative analyses of the ToF-SIMS data of the two organic compound mixtures. Regarding qualitative analysis, both ANN-based methods indicated specific ions from the molecules in the sample.

A comprehensive review on medicinal plants possessing antioxidant potential.

Many research studies have proposed that about two-thirds of the medicinal plant species of the world possess significant antioxidant potential. Antioxidants are very beneficial as they decrease oxidative stress (OS) in cells and hence play their role in management as well as treatment of numerous diseases like cancers, cardiovascular diseases, as well as many inflammatory illnesses. This review comprises the antioxidant potential of numerous parts of medicinal plants like leaves, stems, roots, seeds, fruits, as well as bark. Synthetic antioxidants named butylated hydroxyanisole (BHA) as well as butylated hydroxytoluene (BHT) are extensively employed in foods because of their role as food preservatives. Several natural antioxidants have better efficacy as compared to synthetic antioxidants. These medicinal plants include Geranium sanguineum L., Rheum ribes L., Diospyros abyssinica, Sargentodoxa cuneata Rehd. Et Wils, Pistacia lentiscus, Ficus microcarpa L. fil., Polyalthia cerasoides (Roxb.) Bedd, Cunn, Teucrium polium L., Crataeva nurvala Buch-Ham., Urtica dioica L., Dracocephalum moldavica L., Momordica Charantia L., Acacia auriculiformis A., Bidens pilosa Linn. The Lamiaceae species, Radiata, Leea indica, Pelargonium endlicherianum, Salvia officinalis L., and Uncaria tomentosa (Willd.) DC. The literature study disclosed more side effects of synthetic antioxidants (including food additives) in comparison with natural antioxidants and for prevention of many diseases.

SCCS scientific opinion on Butylated hydroxytoluene (BHT) - SCCS/1636/21.

OPINION TO BE CITED AS: SCCS (Scientific Committee on Consumer Safety), scientific opinion on Butylated hydroxytoluene (BHT), preliminary version of September 27, 2021, final version of December 2, 2021, SCCS/1636/21.

Synthesis, molecular docking, and antioxidant activity of new fluorescent tetrafluoroterphenyl analogues.

Nucleophilic aromatic substitution (SN Ar) chemistry has been applied to develop many functionalized pentafluorobenzene derivatives. Those compounds are highly specific at the para position of the fluorinated ring. Therefore, they are typical adducts for the preparation of antioxidant molecular systems. In this context, we report the use of SN Ar chemistry as a suitable and simple approach for the synthesis of fluorescent antioxidant perfluorinated materials bearing ether bonds in various para-substituted alkoxy chains and with high purity and excellent yields. The fluoroterphenyl core was prepared via alkylation, Cu(I)-assisted decarboxylation, and cross-coupling using the potassium salt of fluorobenzoate, followed by the reaction with different alcohols. The structures of the synthesized fluoroterphenyl adducts were investigated using FT-IR, 1 H NMR, 13 C NMR, and 19 F NMR spectroscopy. The emission spectra and absorption spectra showed solvatochromism. The newly prepared tetrafluoroterphenyl analogues were investigated by antioxidant examination using the 2,2-diphenyl-1-picrylhydrazyl assay. Results were compared with ascorbic acid and butylated hydroxytoluene as references, and revealed that the tetrafluoroterphenyl analogues containing a decyl chain had the highest activity, with an IC50 value of 22.36 ± 0.19 g/ml. The produced tetrafluoroterphenyl analogues were used in molecular docking strategies with a Protein Data Bank protein ID 5IKQ. The antioxidant investigations and docking results were convergent.

The protective effect of butylated hydroxytoluene and 3-hydroxytyrosol on food allergy in mice.

OBJECTIVE: To test the effect of two dietary antioxidants: butylated hydroxytoluene (BHT) and 3-hydroxytyrosol (3-HT) in experimental food allergy. METHODS: BALB/c mice maintained on control diet or diet with BHT or 3-HT were sensitized with ovalbumin (OVA) or saline through transdermal exposure. Plasma OVA-specific IgE (OVA-IgE) and IgG1 (OVA-IgG1) antibody levels were determined using ELISA. Sensitized mice were challenged by oral gavage with OVA. Rectal temperature (RT) was measured before and after challenge. Mast cell degranulation was quantified by measuring the plasma levels of mouse mucosal mast cell protease-1 (mMCP-1). Flow cytometry was carried out to evaluate the percentage Th2 cells from the spleen. RESULTS: Mice on either a 3-HT or BHT diet showed a significantly decreased IgE response to OVA sensitization and less severe anaphylaxis, as evidenced by a diminished drop in body temperature, attenuated clinical signs, a more rapid recovery and decreased mast cell degranulation (as determined by lower plasma mMCP-1 levels). CONCLUSION: The present study indicates two dietary antioxidants: BHT and 3-HT may be protective against experimental food allergy. These results suggest 3-HT and BHT could potentially be useful for prevention of food allergy.

BHT - Butylated Hydroxytoluene.

The Expert Panel for Cosmetic Ingredient Safety reviewed updated information that has become available since their original assessment from 2002, along with updated information regarding product types, and frequency and concentrations of use, and reaffirmed their original conclusion that BHT is safe as a cosmetic ingredient in the practices of use and concentration as described in this report.

Antioxidants Amelioration Is Insufficient to Prevent Acrylamide and Alpha-Solanine Synergistic Toxicity in BEAS-2B Cells.

Cells produce free radicals and antioxidants when exposed to toxic compounds during cellular metabolism. However, free radicals are deleterious to lipids, proteins, and nucleic acids. Antioxidants neutralize and eliminate free radicals from cells, preventing cell damage. Therefore, the study aims to determine whether the antioxidants butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) will ameliorate the maximum dose of acrylamide and alpha (α)-solanine synergistic toxic effects in exposed BEAS-2B cells. These toxic compounds are consumed worldwide by eating potato products. BEAS-2B cells were simultaneously treated with BHA 10 µM and BHT 20 µM and incubated in a 5% CO2 humidified incubator for 24 h, followed by individual or combined treatment with acrylamide (3.5 mM) and α-solanine (44 mM) for 48 h, including the controls. Cell morphology, DNA, RNA, and protein were analyzed. The antioxidants did not prevent acrylamide and α-solanine synergistic effects in exposed BEAS-2B cells. However, cell morphology was altered; polymerase chain reaction (PCR) showed reduced RNA constituents but not DNA. In addition, the toxic compounds synergistically inhibited AKT/PKB expression and its downstream genes. The study showed BHA and BHT are not protective against the synergetic toxic effects of acrylamide and α-solanine in exposed BEAS-2B cells.

Antioxidant and Antimicrobial Evaluations of Moringa oleifera Lam Leaves Extract and Isolated Compounds.

Moringa oleifera, native to India, grows in tropical and subtropical regions around the world and has valuable pharmacological properties such as anti-asthmatic, anti-diabetic, anti-inflammatory, anti-infertility, anti-cancer, anti-microbial, antioxidant, and many more. The purpose of this study was to assess the free radical scavenging ability of two extracts and two pure compounds of M. oleifera Lam (hexane, ethanol, compound E3, and compound Ra) against reactive oxygen species, as well as their reducing power and antimicrobial activities. Bioautography antioxidant assay, 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydrogen peroxide (H2O2) free radical scavenging, and iron (iii) (Fe3+ to Fe2+) chloride reducing power assays were used to assess the extracts' qualitative and quantitative free radical scavenging activities. Furthermore, the extract and the compounds were tested against both Gram-positive and Gram-negative bacterial strains suspended in Mueller-Hinton Broth. The extracts and pure compounds showed noteworthy antioxidant potential, with positive compound bands in the Rf range of 0.05-0.89. DPPH), H2O2, and Fe3+ to Fe2+ reduction assays revealed that ethanol extract has a high antioxidant potential, followed by compound E3, compound Ra, and finally hexane extract. Using regression analysis, the half maximal inhibitory concentration (IC50) values for test and control samples were calculated. Compound Ra and ethanol exhibited high antioxidant activity at concentrations as low as ≈0.28 mg/mL in comparison with n-hexane extract, compound E3, ascorbic acid, and butylated hydroxytoluene standards. The radical scavenging activity of almost all M. oleifera plant extracts against DPPH was observed at 0.28 mg/mL; however, the highest activity was observed at the same concentration for ascorbic acid and butylated hydroxytoluene (BHT) with a low IC50 value of 0.08 mg/mL and compound Ra and ethanol with a low IC50 of 0.4 mg/mL, respectively. The extracts and pure compounds of M. oleifera have little to no antibacterial potential. M. oleifera extracts contain antioxidant agents efficient to alleviate degenerative conditions such as cancer and cardiovascular disease but have little activity against infectious diseases.

Heterologous expression of C30 carotenoid biosynthetic gene crtNM from Lactiplantibacillus plantarum.

BACKGROUND: Probiotic lactic acid bacterium Lactiplantibacillus plantarum is widely used in the dairy and other fermented food industries. L. plantarum AR113 harbors a C30 carotenoid operon crtNM based on genomic analysis, but the yield of C30 carotenoid is only 8.1 µg g-1 DCW. RESULTS: To improve the productivity of C30 carotenoid, crtNM from L. plantarum AR113 was cloned and reconstructed in Escherichia coli BL21(DE3). The proteins crtN and crtM were successfully expressed based on a sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis, and the carotenoid was detected using high-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS). In comparison with the constitutive promoter P44 , the use of the inducible T7 promoter significantly increased the carotenoid content in E. coli. The fermentation conditions were also optimized with induction by 0.5 mmol/L IPTG at 20 °C for 7 h. The yield of C30 carotenoid reached 154.5 µg g-1 DCW, which was 18-fold higher than that of L. plantarum AR113. The 2,2-diphenyl-1-picryl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6sulfonic acid (ABTS) radical scavenging capacity of C30 carotenoids synthesized by heterologous expression in E. coli was also higher than that of the antioxidant food additive butylated hydroxytoluene. CONCLUSIONS: Our findings suggest that E. coli has strong potential as a basic chassis for the production of C30 carotenoids from Lactiplantibacillus with high antioxidant activity. © 2022 Society of Chemical Industry.

A polypyrrole-cotton pad sorbent as micro-solid phase extractor enclosed in tea bag envelope for determination of synthetic antioxidants in non-alcoholic beverage products.

A polypyrrole (PPy)-cotton pad sorbent enclosed in tea bag envelope was developed and used in micro-solid phase extraction (µ-SPE) for the determination of butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT). After extraction, the extract was qualified and quantified by a gas chromatograph equipped with a flame ionization detector (GC-FID). Parameters influencing this developed method and the efficiency of µ-SPE were studied and optimized. Under the optimal conditions, the developed method provided good linearity in a concentration range of 0.100-100 µg L-1 for BHA and 0.050-50 µg L-1 for BHT, respectively. The limits of detection were 39.27 ± 0.52 ng L-1 for BHA and 16.96 ± 0.17 ng L-1 for BHT. Satisfactory relative recoveries of BHA and BHT were achieved in the range from 86.8 ± 1.9 to 117.1 ± 2.3% with acceptable relative standard deviation (RSD) below 8.1%. Good reproducibility was obtained with RSDs < 3.1%, for n = 6. The developed adsorbent is easy to operate, low cost, eco-friendly, reusable, with high extraction efficiency, and was successfully applied in the simultaneous synthetic antioxidant determination of non-alcoholic beverage samples.

Methionine, cysteine, and butylated hydroxytoluene enhance cryosurvival of ram semen on post-thaw and post-incubation time points.

Despite there have been many experiments conducted about antioxidants, the best sole or combination use of antioxidants to include as a standard ingredient to freezing extenders is yet to be found. This study was designed to investigate the different doses of methionine (2.5 and 5 mM), cysteine (1 and 2 mM), and butylated hydroxytoluene (BHT) (1 and 2 mM) for ram semen cryopreservation on post-thaw and post-incubation (6 h) time points over spermatological parameters. Semen samples were collected from Kivircik rams via electro-ejaculator in breeding season. After essential spermatological evaluations, appropriate samples were pooled then split into 7 equal aliquots to create study groups (antioxidant free control, 2.5 mM methionine, 5 mM methionine, 1 mM cysteine, 2 mM cysteine, 1 mM BHT, and 2 mM BHT). Semen samples were put into French straws (0.25 mL), and freezing procedure (two-step) was conducted via a programmable gamete freezer. At both time points, motility, HOST, PSA-FITC, and TUNEL assays were made to discover the impacts of cryopreservation and incubation process over sperm cells. Antioxidant supplemented groups yielded better results compared to the control groups in terms of various spermatological parameters not only at post-thaw time point but after incubation for 6 h of time. The study demonstrated that supplementing sperm freezing extenders with previous antioxidants may create new approaches to cryopreservation procedures, and through increasing success rate of freezing, fertility results may increase to better results in near future.

Efficient production of retinol in Yarrowia lipolytica by increasing stability using antioxidant and detergent extraction.

The demand for bio-based retinol (vitamin A) is currently increasing, however its instability represents a major bottleneck in microbial production. Here, we developed an efficient method to selectively produce retinol in Yarrowia lipolytica. The ß-carotene 15,15'-dioxygenase (BCO) cleaves ß-carotene into retinal, which is reduced to retinol by retinol dehydrogenase (RDH). Therefore, to produce retinol, we first generated ß-carotene-producing strain based on a high-lipid-producer via overexpressing genes including heterologous ß-carotene biosynthetic genes, GGS1F43I mutant of endogenous geranylgeranyl pyrophosphate synthase isolated by directed evolution, and FAD1 encoding flavin adenine dinucleotide synthetase, while deleting several genes previously known to be beneficial for carotenoid production. To produce retinol, 11 copies of BCO gene from marine bacterium 66A03 (Mb.Blh) were integrated into the rDNA sites of the ß-carotene overproducer. The resulting strain produced more retinol than retinal, suggesting strong endogenous promiscuous RDH activity in Y. lipolytica. The introduction of Mb.Blh led to a considerable reduction in ß-carotene level, but less than 5% of the consumed ß-carotene could be detected in the form of retinal or retinol, implying severe degradation of the produced retinoids. However, addition of the antioxidant butylated hydroxytoluene (BHT) led to a >20-fold increase in retinol production, suggesting oxidative damage is the main cause of intracellular retinol degradation. Overexpression of GSH2 encoding glutathione synthetase further improved retinol production. Raman imaging revealed co-localization of retinol with lipid droplets, and extraction of retinol using Tween 80 was effective in improving retinol production. By combining BHT treatment and extraction using Tween 80, the final strain CJ2104 produced 4.86 g/L retinol and 0.26 g/L retinal in fed-batch fermentation in a 5-L bioreactor, which is the highest retinol production titer ever reported. This study demonstrates that Y. lipolytica is a suitable host for the industrial production of bio-based retinol.

Silencing of an odorant binding protein (SaveOBP10) involved in the behavioural shift of the wheat aphid Sitobion avenae (Fabricius).

Insects are highly reliant on their active olfactory system in which odorant binding proteins play a role to selectivity and sensitivity during odour perception and processing. This study sets out to determine whether and to which extent the antennal loaded SaveOBP10 in English grain aphid Sitobion avenae, contributes in olfactory processing during host selection. To understand this possible relationship, we purified the SaveOBP10 recombinant protein and performed fluorescence ligand binding tests, molecular docking, RNA interference (RNAi) and behavioural trials. The results showed that SaveOBP10 had strong binding affinities (Ki ≤5 µM) with most of wheat plant volatiles at pH 5.0 as compared to pH 7.4. In Y-tube olfactometer bioassays, the S. avenae was attracted behaviourally towards pentadecane, butylated hydroxytoluene, tetradecane and ß-caryophyllene however repelled by naphthalene. After RNAi of SaveOBP10, the aphid showed nonattraction towards ß-caryophyllene and nonsignificant behavioural response to pentadecane, butylated hydroxytoluene and tetradecane. Furthermore, the three-dimensional structure modelling and molecular docking of SaveOBP10 were performed to the volatiles with high binding abilities. Together these findings indicate that SaveOBP10 can bind more strongly to the volatiles that involved in S. avenae behaviour regulation and possibly will contribute effectively in S. avenae integrated pest management.

Using Physical Organic Chemistry Knowledge to Predict Unusual Metabolites of Synthetic Phenolic Antioxidants by Cytochrome P450.

Biotransformation, especially by human CYP450 enzymes, plays a crucial role in regulating the toxicity of organic compounds in organisms, but is poorly understood for most emerging pollutants, as their numerous "unusual" biotransformation reactions cannot retrieve examples from the textbooks. Therefore, in order to predict the unknown metabolites with altering toxicological profiles, there is a realistic need to develop efficient methods to reveal the "unusual" metabolic mechanism of emerging pollutants. Combining experimental work with computational predictions has been widely accepted as an effective approach in studying complex metabolic reactions; however, the full quantum chemical computations may not be easily accessible for most environmentalists. Alternatively, this work practiced using the concepts from physical organic chemistry for studying the interrelationships between structure and reactivity of organic molecules, to reveal the "unusual" metabolic mechanism of synthetic phenolic antioxidants catalyzed by CYP450, for which the simple pencil-and-paper and property-computation methods based on physical organic chemistry were performed. The phenol-coupling product of butylated hydroxyanisole (BHA) (based on spin aromatic delocalization) and ipso-addition quinol metabolite of butylated hydroxytoluene (BHT) (based on hyperconjugative effect) were predicted as two "unusual" metabolites, which were further confirmed by our in vitro analysis. We hope this easily handled approach will promote environmentalists to attach importance to physical organic chemistry, with an eye to being able to use the knowledge gained to efficiently predict the fates of substantial unknown synthesized organic compounds in the future.

Remote Stereoelectronic Effects in Pyrrolidone- and Caprolactam-Substituted Phenols: Discrepancies in Antioxidant Properties Evaluated by Electrochemical Oxidation and H-Atom Transfer Reactivity.

New antioxidants are commonly evaluated via two main approaches, i.e., the ability to donate an electron and the ability to intercept free radicals. We compared these approaches by evaluating the properties of 11 compounds containing both antioxidant moieties (mono- and polyphenols) and auxiliary pharmacophores (pyrrolidone and caprolactam). Several common antioxidants, such as butylated hydroxytoluene (BHT), 2,3,5-trimethylphenol (TMP), quercetin, and dihydroquercetin, were added for comparison. The antioxidant properties of these compounds were determined by their rates of reaction with 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and their oxidation potentials from cyclic voltammetry. Although these methods test different chemical properties, their results correlate reasonably well. However, several exceptions exist where the two methods give opposite predictions! One of them is the different behavior of mono- and polyphenols: polyphenols can react with DPPH more than an order of magnitude faster than monophenols of a similar oxidation potential. The second exception stems from the size of a "bystander" lactam ring at the benzylic position. Although the phenols with a seven-membered lactam ring are harder to oxidize, the sterically nonhindered compounds react with DPPH about 2× faster than the analogous five-membered lactams. The limitations of computational methods, especially those based on a single parameter, are also evaluated and discussed.

Prenatal Exposure to Emerging Plasticizers and Synthetic Antioxidants and Their Potency to Cross Human Placenta.

Gestational exposure to environmental chemicals and subsequent permeation through the placental barrier represents potential health risks to both pregnant women and their fetuses. In the present study, we explored prenatal exposure to a suite of 46 emerging plasticizers and synthetic antioxidants (including five transformation products of 2,6-di-tert-butyl-4-hydroxytoluene, BHT) and their potency to cross human placenta based on a total of 109 maternal and cord serum pairs. Most of these chemicals have rarely or never been investigated for prenatal exposure and associated health risks. Eleven of them exhibited detection frequency greater than 50% in maternal blood, including dibutyl fumarate (DBF), 2,6-di-tert-butylphenol (2,4-DtBP), 1,3-diphenylguanidine (DPG), methyl-2-(benzoyl)benzoate (MBB), triethyl citrate (TEC), BHT, and its five metabolites, with a median concentration from 0.05 to 3.1 ng/mL. The transplacental transfer efficiency (TTE) was determined for selected chemicals with valid measurements in more than 10 maternal/cord blood pairs, and the mean TTEs exhibited a large variation (i.e., 0.29-2.14) between chemicals. The determined TTEs for some of the target chemicals were comparable to the predicted values by our previously proposed models developed from molecular descriptors, indicating that their transplacental transfer potency could be largely affected by physicochemical properties and molecular structures. However, additional biological and physiological factors may influence the potency of environmental chemicals to cross human placenta. Overall, our study findings raise concern on human exposure to an increasing list of plastic additives during critical life stages (e.g., pregnancy) and potential health risks.

44-Year Retrospective Analysis of Ultraviolet Absorbents and Industrial Antioxidants in Seabird Eggs from the Canadian Arctic (1975 to 2019).

Ultraviolet (UV) absorbents and industrial antioxidants are contaminants of emerging concern (CECs), but little is known about their distribution in Arctic wildlife, as well as how these contaminants vary over time, across regions, and between species. We used archived egg samples to examine the temporal patterns of 26 UV absorbents and industrial antioxidants in three seabird species (black-legged kittiwakes Rissa tridactyla, thick-billed murres Uria lomvia, northern fulmars Fulmarus glacialis) sampled in Arctic Canada between 1975 and 2019. Various synthetic phenolic antioxidants, aromatic secondary amines, benzotriazole UV stabilizers, and organic UV filters were detected in the seabird eggs. Overall, kittiwakes had higher levels of several UV absorbents and industrial antioxidants. Most target contaminants reached their peak concentrations at different points during the 44-year study period or did not vary significantly over time. None of these contaminant concentrations have increased in recent years. The antioxidant 2-6-di-tert-butyl-4-methylphenol (BHT) was the most frequently detected contaminant in seabird eggs, and its level significantly declined over the course of the study period in kittiwake eggs but did not change in the eggs of murres and fulmars. Future research should examine the effects of these CECs on the health of avian species, the sources, and exposure pathways of these contaminants.

Physicochemical Evaluation of Personal Care Products Developed with Chondrus crispus Fractions Processed by Ecofriendly Methodologies.

Novel personal care products are necessary to cope with the growing market demand for sustainable green products. In this context, this work deals with the formulation and fundamental physicochemical and rheological characterization of different natural personal care products using bioactive fractions from Chondrus crispus red macroalgae extracted under optimized green conditions. Body milks, body oils and shampoos were supplemented with soluble extracts with antioxidant features recovered after hydrothermal (200 °C) and microwave (170 °C)- and ultrasound (80 °C)-assisted extraction of the red macroalgae used as raw material. Formulated products were also compared with those prepared using (±)-α-tocopherol and butylhydroxytoluene standards. Body scrubs were formulated with the remaining solids (<2.25%) after microwave hydrodiffusion and gravidity treatment of the macroalgae. Results indicated that selected extracts provided personal care products with similar or even better physicochemical, color and viscous features than those supplemented with (±)-α-tocopherol or butylhydroxytoluene commercial antioxidants. Rheological profiles indicated that it is possible to develop personal care products with adequate viscous behavior (102−105 mPa s, at 1 s−1), comparable with their synthetic counterparts. To conclude, the addition of antioxidant extracts led to lower apparent viscosity values suggesting an advantage from the skin applicability point of view, jointly with the absence of both the hysteresis phenomenon and water syneresis of the proposed formulations.

A comparison of cell death mechanisms of antioxidants, butylated hydroxyanisole and butylated hydroxytoluene.

Butylated hydroxyanisole (BHA) and the chemically similar butylated hydroxytoluene (BHT) are widely used as antioxidants. Toxicity of BHA and BHT has been reported under in vitro and in vivo experimental conditions. However, the mechanism of BHA-induced toxic effects in cells is unclear. In this study, the cytotoxic effects of BHA and differences in cell death mechanism for BHA and BHT were investigated in rat thymocytes by flow cytometric analysis using a fluorescent probe. We observed a significant increase in propidium iodide fluorescence in the population of cells treated with 100 µM and 300 µM BHA (dead cells). Thymocytes treated with 100 µM BHA showed increased intracellular Ca2+ and Zn2+ levels and depolarized cell membranes. BHA (30-100 µM) decreased non-protein thiol content of cells, indicating decreased glutathione content. Co-stimulation with 100 µM BHA and 300 µM H2O2 acted synergistically to increase cell lethality. Moreover, BHA significantly increased caspase-3 activity and the number of annexin-V-positive cells in a concentration-dependent manner, indicating apoptosis. However, BHT reduced caspase-3 activity and increased the number of annexin-V-negative dead cells, indicating non-apoptotic cell death. Our results reveal the toxicity of BHA could be attributed to increased levels of intracellular Ca2+ and Zn2+, resulting in an increased vulnerability of rat thymocytes to oxidative stress. In addition, we demonstrate that whereas BHA induced apoptosis, BHT induced non-apoptotic cell death in rat thymocytes. Therefore, these results may support the safety of BHA, but also demonstrate the importance of performing toxicity evaluation at the cellular level besides the tissue level.

Bioactive Metabolites of Microalgae from Canary Islands for Functional Food and Feed Uses.

Three freshwater microalgae (Spirogyra sp., Cosmarium sp., and Cosmarium blytii) collected from several locations in Gran Canaria have been studied to explore their potential as a novel source of bioactive compounds for biotechnological applications. Soluble carbohydrates were quantified after extraction with 3 M HCl at 100 °C, ranging from 35.8 to 43.3 %, and with water at room temperature, ranging from 19 to 22.8 %. Amino acids glutamic acid, proline and aspartic acid were quantified by RP-HPLC. Glutamic acid was the most abundant, ranging from 12.2 to 3.63 mg g-1 of dry biomass. Cosmarium blytii was the richest sample in amino acids (24.02 mg g-1 of dry weight). In addition, Cosmarium blytii and Spyrogira sp. exhibited higher radical scavenging activity (RSA) against 1,1-diphenyl-2-picrylhydrazyl (DPPH) than that of the synthetic antioxidant butylhydroxytoluene (BHT), commonly used as food additive. These results show a great potential of these microalgae for exploitation in the food, feed and pharmaceutical industries.