Effect of perforated low-density polyethylene films on postharvest quality of avocado fruit.

Avocado (Persea americana Mill.) being a climacteric fruit, is very prone to quality deterioration and spoilage due to high metabolic activities which leads to postharvest and economic losses. The purpose of this study was to evaluate the impact of perforated low-density polyethylene (LDPE) packaging films on postharvest quality and shelf life of 'Fuerte' avocado. Fruit were packaged in LDPE plastics (20 and 40 µm) whereas unpackaged fruit were considered as control. Fruit were kept at ambient environments (21 ± 1 °C and 60.0 ± 5% RH) for 12 days and sampled at 4 days interval. The in-pack avocado created a suitable headspace with low O2 and high CO2 concentrations, which yielded improved preservation of postharvest quality and prolonged shelf life of the avocado. Fruit packed in both 20 and 40 µm LDPE films had lower ethylene production and respiration rates, weight loss, firmness loss, preserved fruit size, high pH, titratable acidity, low soluble solid content, sugar:acid ratio, malondialdehyde content and lipoxygenase activity compared to control. Fruit in LDPE films had no symptoms of decay (20 µm) and slight incidence and decay (40 µm) and were markable during shelf life compared to control fruit had severe decay symptoms and were unmarkable at the end of shelf life. These findings indicated that LDPE films were effective in preserving postharvest quality and extending shelf life of avocado fruit.

The effect of different pre-treatments on unformulated pulse-based milk analogs: physicochemical properties and consumer acceptance.

This is the first part of a study on developing pulse-based milk analogs using chickpea, faba bean, and cowpea as raw materials. The objectives of the present study were to determine the processing conditions for pulse-based milk analog production at laboratory-scale and to investigate the effects of some pre-treatments such as dry milling (control), soaking and wet milling, blanching, blanching and dehulling, vacuum, and germination on lipoxygenase (LOX) activity of the raw material and some physicochemical and sensory properties of the final products. Dry milling provided the lowest LOX activity and the highest yield while soaking and wet milling resulted in a substantial increase in LOX activity, lower product yield, and a final product with lower whiteness value, regardless of the pulse type. Germination caused a significant decrease in LOX activity in all pulse types, while milk analogs produced from germinated pulses received the lowest acceptability scores from consumers. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-023-05836-7.

Low expression of lipoxygenase 3 (LOX3) enhances the retention of kernel tocopherols in maize during storage.

BACKGROUND: Deficiency of vitamin E results in several neurological and age-related disorders in humans. Utilization of maize mutants with favourable vte4-allele led to the development of several α-tocopherol (vitamin E) rich (16-19 µg/g) maize hybrids worldwide. However, the degradation of tocopherols during post-harvest storage substantially affects the efficacy of these genotypes. METHODS AND RESULTS: We studied the role of lipoxygenase enzyme and Lipoxygenase 3 (LOX3) gene on the degradation of tocopherols at monthly intervals under traditional storage up to six months in two vte4-based contrasting-tocopherol retention maize inbreds viz. HKI323-PVE and HKI193-1-PVE. The analysis revealed significant degradation of tocopherols across storage intervals in both the inbreds. Lower retention of α-tocopherol was noticed in HKI193-1-PVE. HKI323-PVE with the higher retention of α-tocopherol showed lower lipoxygenase activity throughout the storage intervals. LOX3 gene expression was higher (~ 1.5-fold) in HKI193-1-PVE compared to HKI323-PVE across the storage intervals. Both lipoxygenase activity and LOX3 expression peaked at 120 days after storage (DAS) in both genotypes. Further, a similar trend was observed for LOX3 expression and lipoxygenase activity. The α-tocopherol exhibited a significantly negative correlation with lipoxygenase enzyme and expression of LOX3 across the storage intervals. CONCLUSIONS: HKI323-PVE with high tocopherol retention, low -lipoxygenase activity, and -LOX3 gene expression can act as a potential donor in the vitamin E biofortification program. Protein-protein association network analysis also indicated the independent effect of vte4 and LOX genes. This is the first comprehensive report analyzing the expression of the LOX3 gene and deciphering its vital role in the retention of α-tocopherol in biofortified maize varieties under traditional storage.

Effect of biotic stress on the presence of secondary metabolites in field pea grains.

BACKGROUND: The presence of secondary metabolites responsible for off-flavours in peas may influence consumers' acceptance. These undesirable compounds may increase due to biotic stress or cultivar. Therefore, grains from two pea (Pisum sativum L.) cultivars (Crécerelle and Firenza) exposed to biotic stress were studied in terms of protein content, electrophoretic polypeptide profile, lipoxygenase activity, saponin content and volatile compounds. RESULTS: No differences were observed in the electrophoretic polypeptide profile of pea samples across cultivar or biotic stress. The cultivar noticeably affected the volatile compounds and lipoxygenase activity. The biotic stress significantly increased the saponin content. CONCLUSION: The cultivar showed more noticeable impact on the presence of off-flavour compounds than the biotic stress. The development of pea protein ingredients needs the thorough choice of raw materials in terms of cultivar and control of biotic stress in order to ensure acceptance by consumers. © 2022 Society of Chemical Industry.

Antidepressant and Anxiolytic Effects of Fermented Huauzontle, a Prehispanic Mexican Pseudocereal.

This study aimed to assess the potential antidepressant- and anxiolytic-like effects of huauzontle fermented by Lactiplantibacillus plantarum Lp22. The possible association between oxidative stress/inflammation biomarkers and unconditional behavioural tests was also evaluated. Red light-induced stress mice C57Bl/6 (n = 5 per group) received orally either fermented or unfermented huauzontle, diazepam or fluoxetine. A non-stressed group which received saline solution was also included. Then, anxiety-related and depression-related behaviour tests were performed; after that, blood and tissues samples were collected to determine oxidative stress/inflammation biomarkers. The mice receiving both fermented and unfermented huauzontle spent more time (94 s) in open arms in the elevated plus maze test p < 0.05; besides, travelled longer distance (p < 0.05) and increased by more than 50% the exploration time for the open field, as well as the time spent in the illuminated zone (197 s) in the light/dark test. Furthermore, reduced immobility time in the tail suspension and forced swim tests (23.1 and 15.85, respectively), and anhedonia was no detected in the sucrose preference test. The oxidative stress index was lower in the liver of fermented huauzontle-treated mice, while enhanced levels of IL-10, MCP-1 and BDNF in plasma, and lipoxygenase (LOX) activity in the hippocampus were found. Finally, PCA revealed a positive correlation among LOX and BDNF and parameters determined in the anxiety tests, as between catalase activity and immobility time in the depression test. These findings indicate the novel potential therapeutic applications of fermented huauzontle on depression and anxiety-like behaviours possibly mediated by antioxidant and anti-inflammatory mechanisms.

Chemical profile, anti 5-lipoxygenase and cyclooxegenase inhibitory effects of ginger (Zingiber officinale) rhizome, callus and callus treated with elicitors / Perfil químico, anti-5-lipoxigenase e efeitos inibitórios da ciclooxegenase do rizoma de gengibre (Zingiber officinale), do calo e calos tratados com elicitores

The present study investigated the chemical profiles and evaluated the inhibitory effect against 5-Lipoxygenase (5-Lox) activity for extracts of ginger rhizome, callus, and callus treated with the elicitors; yeast extract (100, 300 and 500 mg/L), glycine (100, 200 and 300 mg/L) and salicylic acid (100 and 200 mg/L). Oils and chloroform: methanol (CM) extracts were prepared by maceration in petroleum ether and CM (1:1, v/v), respectively. Chemical profiles were determined by gas chromatography/mass spectrometry (GC/MS) analysis. Oil of the callus recorded higher 5-Lox inhibitory effect (IC50 58.33±4.66 µg/mL) than the oil of rhizome (IC50168.34±15.64 µg/mL) and comparable to that of the positive control; Nordihydroguaiaretic acid (IC50 61.25±1.02 µg/mL). The chemical profile of the callus oil contained large amounts of fatty acids, mainly the unsaturated fatty acid oleic acid (31.11%) and saturated fatty acid palmitic acid (28.56%). Elicitors modified the chemical profile of the callus and ameliorated the anti-5-Lox activity of CM extract of the callus. CM extracts of callus treated with 100 and 300 mg/L yeast extract and 50 mg/L salicylic acid significantly suppressed (P ≤ 0.05) the 5-Lox activity by 33.16%, 25.46% and 16%, respectively as compared to the CM extract of untreated callus. In conclusion, ginger callus could be considered as a valuable dietary supplement in the treatment of various inflammatory disorders.

O presente estudo teve como objetivo investigar os perfis químicos e avaliar o efeito inibitório da atividade da 5-Lipoxigenase (5-Lox) em extratos de rizoma, calo e calo de gengibre tratados com os eliciadores; extrato de levedura (100, 300 e 500 mg / L), glicina (100, 200 e 300 mg / L) e ácido salicílico (100 e 200 mg / L). Extratos de óleos e clorofórmio: metanol (CM) foram preparados por maceração em éter e CM (1: 1, v / v), respectivamente. Os perfis químicos foram determinados por análise de cromatografia gasosa / espectrometria de massa (GC / MS). O óleo do calo registrou maior efeito inibitório de 5-Lox (IC50 58,33 ± 4,66 µg / mL) do que o óleo de rizoma (IC50168,34 ± 15,64 µg / mL) e comparável ao do controle positivo; Ácido nordi-hidroguaiarético (IC50 61,25 ± 1,02 µg / mL). O perfil químico do óleo de calo continha grandes quantidades de ácidos graxos, principalmente o ácido graxo insaturado ácido oleico (31,11%) e ácido graxo saturado palmítico (28,56%). Os elicitores modificaram o perfil químico do calo e melhoraram a atividade anti-5-Lox do extrato de CM do calo. Extratos de CM de calos tratados com 100 e 300 mg / L de extrato de levedura e 50 mg / L de ácido salicílico suprimiram significativamente (P ≤ 0,05) a atividade de 5-Lox em 33,16%, 25,46% e 16%, respectivamente, em comparação com o extrato de CM de calo não tratado. Em conclusão, o calo de gengibre pode ser considerado um suplemento dietético valioso no tratamento de vários distúrbios inflamatórios.

Sprouting improves the flavour quality of faba bean flours.

Flours were made from the sprouted seeds of the low- and high-tannin faba bean cultivars Fabelle, FB9-4, Snowbird, and Snowdrop. Headspace measurements on sprouted flours found the most favourable aroma profiles following 48 h sprouting and 24 h drying at 60 °C. Lipoxygenase activity, and the tannin, protein, and moisture contents were determined for unsprouted and sprouted faba bean flours. Lipoxygenase activity was higher in sprouted seeds before drying. Protein content increased after sprouting, whereas the tannin content decreased, especially for high-tannin varieties. Key volatile flavour compounds of faba bean flours included pentanal, hexanal, heptanal, octanal, nonanal, decanal, 1-hexanol, 1-octen-3-ol, 3-methylbutanal, phenyl acetaldehyde, 3-methylbutyric acid, d-limonene, ß-linalool, menthol, and estragole; these include oxidative degradation products of oleic, linoleic, and some amino acids. An overall flavour improvement was achieved after germination, as indicated by a decrease in bitter compounds (tannins) and beany flavours (hexanal, nonanal, 2-heptanone, and 2-pentylfuran).

Lipoxygenase and Its Relationship with Ethylene During Ripening of Genetically Modified Tomato (Solanum lycopersicum).

RESEARCH BACKGROUND: TomloxB is the main isoform of lipoxygenase associated with ripening and senescence of fruits. On the other hand, ethylene, a gaseous hormone, is essential for the regulation of ripening in climacteric fruits like tomatoes. However, the relationship between TomloxB and ethylene production has not been thoroughly studied. Therefore, we aim to assess the effect of exogenous ethylene in transgenic tomatoes that contain a silenced TomloxB gene, and subsequently evaluate lipoxygenase activity, 1-aminocyclopropane-1-carboxylic acid oxidase and ethylene production; as well as to quantify the expression of the genes encoding 1-aminocyclopropane-1-carboxylic acid oxidase and TomloxB. EXPERIMENTAL APPROACH: To investigate the effect of lipoxygenase and 1-aminocyclopropane-1-carboxylic acid oxidase activity, fruits harvested at the stages of break, turning and pink were used. Tomatoes at break stage collected from transgenic and wild type plants were used to determine ethylene production and gene expression. Genetically modified and wild type tomato fruits were exposed to 100 µL/L exogenous ethylene. Lipoxygenase activity was measured spectrophotometrically. Activity of 1-aminocyclopropane-1-carboxylic acid oxidase and ethylene production were determined by gas chromatography. Oligonucleotides for differentially expressed genes: 1-aminocyclopropane-1-carboxylic acid oxidase and TomloxB were used to determine gene expression by real-time PCR. RESULTS AND CONCLUSIONS: The data showed that silencing of TomloxB caused a reduction in lipoxygenase activity and ethylene production in tomato fruits, and also reduced 1-aminocyclopropane-1-carboxylic acid oxidase activity. Hence, the addition of exogenous ethylene increased lipoxygenase activity in all treatments and 1-aminocyclopropane-1-carboxylic acid oxidase activity only in transgenic lines at break stage, consequently there was a positive regulation between TomloxB and ethylene, as increasing the amount of ethylene increased the activity of lipoxygenase. The results suggest that lipoxygenase may be a regulator of 1-aminocyclopropane-1-carboxylic acid oxidase and production of ethylene at break stage. NOVELTY AND SCIENTIFIC CONTRIBUTION: These results lead to a better understanding of the metabolic contribution of TomloxB in fruit ripening and how it is linked to the senescence-related process, which can lead to a longer shelf life of fruits. Understanding this relationship between lipoxygenase and ethylene can be useful for better post-harvest handling of tomatoes.

Purification of Soluble Membrane-Bound Ambystoma mexicanum Epidermal Lipoxygenase from E. coli and Its Growth Effect on Human Fetal Foreskin Fibroblast.

Lipoxygenases are non-heme iron-containing lipid dioxygenases enzymes that catalyze the hydroperoxidation of lipids. The Mexican axolotl (Ambystoma mexicanum) is a prominent source of the enzyme with a regeneration capacity in limbs. It has been shown that transfected human osteosarcoma and keratinocyte cells with epidermal lipoxygenase (LOXe) have an increased rate of cell migration. In the present study, LOXe, a peripheral membrane protein, was produced in Escherichia coli. The enzyme was purified using different detergents, anionic solutions, and gel filtration chromatography. Kinetic assay of the enzyme activity was carried out by the spectroscopy method using arachidonic acid as a substrate. Finally, the enzyme was characterized and its growth effect on human fibroblast cells was examined by MTT viability assay. Enzyme kinetic parameters including Km of 90.4 µM and Vmax of 2.63 IU were determined for LOXe. The enzyme with 0.1 nM end concentration promoted the growth of 5000 cells/well human fibroblast cells up to 11% (P < 0.01). In the present study, we introduce an E. coli expression system to produce an excessive amount of soluble LOXe and the efficient purification method to provide a soluble and active form of LOXe that is effective in stimulating human fibroblast cell proliferation.

The hidden mechanism beyond ginger (Zingiber officinale Rosc.) potent in vivo and in vitro anti-inflammatory activity.

ETHNOPHARMACOLOGICAL RELEVANCE: Ginger (Zingiber officinale Roscoe) is a well known anti-inflammatory drug in the Egyptian, Indian and Chinese folk medicines, yet its mechanism of action is unclear. AIM OF THE STUDY: To explore its mechanism of action and to correlate it to its biophytochemicals. MATERIALS AND METHODS: Various extracts viz. water, 50%, 70%, 80%, and 90% ethanol were prepared from ginger rhizomes. Fractionation of the aqueous extract (AE) was accomplished using Diaion HP-20. In vitro anti-inflammatory activity of the different extracts and isolated compounds was evaluated using protein denaturation inhibition, membrane stabilization, protease inhibition, and anti-lipoxygenase assays. In vivo anti-inflammatory activity of AE was estimated using carrageenan-induced rat paw edema in rats at doses 25, 50, 100 and 200mg/kg b.wt. RESULTS: All the tested extracts showed significant (p< 0.1) in vitro anti-inflammatory activities. The strongest anti-lipoxygenase activity was observed for AE that was more significant than that of diclofenac (58% and 52%, respectively) at the same concentration (125µg/ml). Purification of AE led to the isolation of 6-poradol (G1), 6-shogaol (G2); methyl 6- gingerol (G3), 5-gingerol (G4), 6-gingerol (G5), 8-gingerol (G6), 10-gingerol (G7), and 1-dehydro-6-gingerol (G8). G1, G2 and G8 exhibited potent activity in all the studied assays, while G4 and G5 exhibited moderate activity. In vivo administration of AE ameliorated rat paw edema in a dose-dependent manner. AE (at 200mg/kg) showed significant reduction in production of PGE2, TNF-α, IL-6, monocyte chemoattractant protein-1 (MCP-1), regulated upon activation, normal T-cell expressed and secreted (RANTES), myeloperoxidase (MPO) activity by 60%, 57%, 60%, 41%, 32% and 67%, respectively. AE at 100 and 200mg/kg was equipotent to indomethacin in reduction of NOx level and in increasing the total antioxidant capacity (TAC). Histopathological examination revealed very few inflammatory cells infiltration and edema after administration of AE (200mg/kg) prior to carrageenan. CONCLUSIONS: Ginger anti-inflammatory activity is mediated by inhibiting macrophage and neutrophils activation as well as negatively affecting monocyte and leukocyte migration. This was evidenced by the dose-dependent decrease in pro-inflammatory cytokines and chemokines and replenishment the total antioxidant capacity.

Lipoxygenase Activity Accelerates Programmed Spore Germination in Aspergillus fumigatus.

The opportunistic human pathogen Aspergillus fumigatus initiates invasive growth through a programmed germination process that progresses from dormant spore to swollen spore (SS) to germling (GL) and ultimately invasive hyphal growth. We find a lipoxygenase with considerable homology to human Alox5 and Alox15, LoxB, that impacts the transitions of programmed spore germination. Overexpression of loxB (OE::loxB) increases germination with rapid advance to the GL stage. However, deletion of loxB (ΔloxB) or its signal peptide only delays progression to the SS stage in the presence of arachidonic acid (AA); no delay is observed in minimal media. This delay is remediated by the addition of the oxygenated AA oxylipin 5-hydroxyeicosatetraenoic acid (5-HETE) that is a product of human Alox5. We propose that A. fumigatus acquisition of LoxB (found in few fungi) enhances germination rates in polyunsaturated fatty acid-rich environments.

Suppression Substractive Hybridization and NGS Reveal Differential Transcriptome Expression Profiles in Wayfaring Tree (Viburnum lantana L.) Treated with Ozone.

Tropospheric ozone (O3) is a global air pollutant that causes high economic damages by decreasing plant productivity. It enters the leaves through the stomata, generates reactive oxygen species, which subsequent decrease in photosynthesis, plant growth, and biomass accumulation. In order to identify genes that are important for conferring O3 tolerance or sensitivity to plants, a suppression subtractive hybridization analysis was performed on the very sensitive woody shrub, Viburnum lantana, exposed to chronic O3 treatment (60 ppb, 5 h d(-1) for 45 consecutive days). Transcript profiling and relative expression assessment were carried out in asymptomatic leaves, after 15 days of O3 exposure. At the end of the experiment symptoms were observed on all treated leaves and plants, with an injured leaf area per plant accounting for 16.7% of the total surface. Cloned genes were sequenced by 454-pyrosequencing and transcript profiling and relative expression assessment were carried out on sequenced reads. A total of 38,800 and 12,495 high quality reads obtained in control and O3-treated libraries, respectively (average length of 319 ± 156.7 and 255 ± 107.4 bp). The Ensembl transcriptome yielded a total of 1241 unigenes with a total sequence length of 389,126 bp and an average length size of 389 bp (guanine-cytosine content = 49.9%). mRNA abundance was measured by reads per kilobase per million and 41 and 37 ensembl unigenes showed up- and down-regulation respectively. Unigenes functionally associated to photosynthesis and carbon utilization were repressed, demonstrating the deleterious effect of O3 exposure. Unigenes functionally associated to heat-shock proteins and glutathione were concurrently induced, suggesting the role of thylakoid-localized proteins and antioxidant-detoxification pathways as an effective strategy for responding to O3. Gene Ontology analysis documented a differential expression of co-regulated transcripts for several functional categories, including specific transcription factors (MYB and WRKY). This study demonstrates that a complex sequence of events takes place in the cells at intracellular and membrane level following O3 exposure and elucidates the effects of this oxidative stress on the transcriptional machinery of the non-model plant species V. lantana, with the final aim to provide the molecular supportive knowledge for the use of this plant as O3-bioindicator.

Impact of embedded endocannabinoids and their oxygenation by lipoxygenase on membrane properties.

N-Arachidonoylethanolamine (anandamide) and 2-arachidonoylglycerol are the best characterized endocannabinoids. Their biological activity is subjected to metabolic control whereby a dynamic equilibrium among biosynthetic, catabolic, and oxidative pathways drives their intracellular concentrations. In particular, lipoxygenases can generate hydroperoxy derivatives of endocannabinoids, endowed with distinct activities within cells. The in vivo interaction between lipoxygenases and endocannabinoids is likely to occur within cell membranes; thus, we sought to ascertain whether a prototypical enzyme like soybean (Glycine max) 15-lipoxygenase-1 is able to oxygenate endocannabinoids embedded in synthetic vesicles and how these substances could affect the binding ability of the enzyme to different lipid bilayers. We show that (i) embedded endocannabinoids increase membrane fluidity; (ii) 15-lipoxygenase-1 preferentially binds to endocannabinoid-containing bilayers; and that (iii) 15-lipoxygenase-1 oxidizes embedded endocannabinoids and thus reduces fluidity and local hydration of membrane lipids. Together, the present findings reveal further complexity in the regulation of endocannabinoid signaling within the central nervous system, disclosing novel control by oxidative pathways.

Chemical composition and antioxidant activities of Jeddah corniche algae, Saudi Arabia.

The increased use of natural product in the pharmaceutical industry has led to an increase in demand for screening for bioactive compounds in marine algae. An important economic algae, through chemical composition analysis and their antioxidant activities were investigated in this study. Chemical composition analysis of three algal samples from the Chlorophyta Ulva lactuca (U), Phaeophyta Sargassum crassifolia (S) and Rhodophyta Digenea simplex (D) was tested. Main components were sugars (57.40-185.13 mg/g dry weight), uronic acids (29.3-45.26 mg/g dry weight), sulfate (94.7-181.2 mg/g dry weight), amino acids (7.6-16.7 mg/g dry weight) and small amounts of betaines (2.38-8.47 mg/g dry weight). Hydrolyzed chemical composition analysis fractions of algal extract was shown a great proportion of sugars plus sulfate (as polysaccharide composed) ranges between 332 and 538.2 mg/g dry weight with trace amounts of uronic acids (⩽9%). All three algal extract showed antioxidant activities on lipoxygenase, DPPH and on Ames test. Two of aqueous extracts (U and D) inhibited lipoxygenase activity by less than 50%, where as the methanolic extract (S) caused 76% inhibition of the control. In all cases, the methanolic extract were more inhibitory than the aqueous extract. The (S) showed the highest antioxidant activity with DPPH (69%) in aqueous extract and in methanol extract with Ames test (85%). Both U and D showed antioxidant activity with DPPH in hexane by less of 25% where as in both aqueous and methanolic extracts by less than 50% of the control. Aqueous and methanolic extracts of U and D showed high inhibition by Ames test which caused 70% and 75% respectively. IR spectra of algal extracts (U; D and S) range from 1450 to 750 cm(-1) were very similar absorption band at 1430, 1370, 1250, 1130, 1110, 1050 and 1020 cm(-1). Absorption bands were due to uronic acids, glucosides and sulfate. The presence of sulfated polysaccharide material in the fractions UF2, DF2 and SF2 were found as cell wall storage of marine algae, confirmed by (13)C NMR spectroscopy. It is concluded that the algal species probably have a different components and can be used in the activities of antioxidant enzymes as reduced the risks of enzymes. But the correlation between the chemical composition and antioxidant activities of algal extracts needs further investigation.