LOX Activity Research Articles

Chitosan, Methyl Jasmonate, and Silicon Induce Resistance to Angular Leaf Spot in Common Bean, Caused by Pseudocercospora griseola, with Expression of Defense-Related Genes and Enzyme Activities

This study assessed the efficacy of chitosan, methyl jasmonate, and silicon in the reduction of disease severity and the induction of defense responses in common bean plants against angular leaf spot caused by Pseudocercospora griseola. The expression level of several pathogenesis-related (PR) proteins, PR1, PR2 (β-1,3-glucanase), and PR3 (chitinase), and defense-related enzymes, phenylalanine ammonia-lyase, peroxidase, and lipoxygenase, was analyzed at different time points in common bean plants after different treatments. Elicitor treatments significantly reduced disease severity 21 days after inoculation, with silicon at a 2 mM concentration proving most effective with 38.93% disease control, followed by 1 mM MeJA and 2% chitosan, respectively. Treatments with chitosan, methyl jasmonate, and silicon, regardless of pathogen infection, significantly elevated PR1, PR2, and PR3 gene expressions at 48 h after inoculation (hpi). PAL and POD activities were similarly increased following elicitor treatments and pathogen infection, especially at 48 hpi. Chemical elicitors applied post-inoculation induced PR proteins, PAL, and POD enzyme activities at 48 hpi, while LOX activity exhibited a variable fluctuation with treatments. These findings suggested that chemical elicitors, especially silicon, were effective in reducing ALS disease severity in common beans, with improved resistance associated with the expression of pathogen-responsive genes. This study is the first to analyze the expression profiles of defense-related genes in common beans treated with chemical elicitors prior to P. griseola infection.

Gene inactivation of lysyl oxidase in smooth muscle cells reduces atherosclerosis burden and plaque calcification in hyperlipidemic mice

Background and aimsLysyl oxidase (LOX) catalyzes the crosslinking of collagen and elastin to maintain tensile strength and structural integrity of the vasculature. Excessive LOX activity increases vascular stiffness and the severity of occlusive diseases. Herein, we investigated the mechanisms by which LOX controls atherogenesis and osteogenic differentiation of vascular smooth muscle cells (SMC) in hyperlipidemic mice. MethodsGene inactivation of Lox in SMC was achieved in conditional knockout mice after tamoxifen injections. Atherosclerosis burden and vascular calcification were assessed in hyperlipidemic conditional [Loxf/fMyh11-CreERT2ApoE−/−] and sibling control mice [Loxwt/wtMyh11-CreERT2ApoE−/−]. Mechanistic studies were performed with primary aortic SMC from Lox mutant and wild type mice. ResultsInactivation of Lox in SMCs decreased > 70 % its RNA expression and protein level in the aortic wall and significantly reduced LOX activity without compromising vascular structure and function. Moreover, LOX deficiency protected mice against atherosclerotic burden (13 ± 2 versus 23 ± 1 %, p < 0.01) and plaque calcification (5 ± 0.4 versus 11.8 ± 3 %, p < 0.05) compared to sibling controls. Interestingly, gene inactivation of Lox in SMCs preserved the contractile phenotype of vascular SMC under hyperlipidemic conditions as demonstrated by single-cell RNA sequencing and immunofluorescence. Mechanistically, the absence of LOX in SMC prevented excessive collagen crosslinking and the subsequent activation of the pro-osteogenic FAK/β-catenin signaling axis. ConclusionsLox inactivation in SMC protects mice against atherosclerosis and plaque calcification by reducing SMC modulation and FAK/β-catenin signaling.

Localization and activity of lipoxygenase in the ovule of Larix kaempferi (Lamb.) Carr. during female gametophyte maturation

Key messageLipoxygenase activity and localization vary throughout the development of Larix kaempferi ovules, with the highest enzyme activity observed in ovules at the cellular stage and the most intense immunogold reaction noted at the mature archegonium stage of gametophyte development.Lipoxygenases are a family of oxidoreductases with a significant role in biological systems, widespread in living organisms e.g. mammals, fish, corals, plants, mosses, algae, fungi, yeasts, and bacteria. Lipoxygenase activity in plants leads to the formation of phytooxylipins, i.e. signaling molecules, which play a crucial role in many significant physiological processes such as male and female gametophyte maturation, germination and seedling growth, pathogen resistance, abiotic stress response, fruit ripening, and senescence. The activity and localization of lipoxygenase change during plant growth and development. The localization of lipoxygenase in a developing ovule of Larix kaempferi was analyzed using the immunogold labeling method, and the activity was determined spectrophotometrically with linolenic acid as a substrate. Among the investigated stages, the immunogold reaction was the most intense at the mature archegonium stage in the ovule. Lipoxygenase was found in all parts of the L. kaempferi ovule. The largest number of immunogold particles was detected in the integument cells of all the analyzed stages of ovule development. Only one isoform of lipoxygenase with an optimum at pH 8 was active in the ovules during female gametophyte maturation. The highest enzyme activity was determined at the cellular stage, whereas the mature archegonium stage was characterized by its lowest level, which means that LOX activity in developing ovules of the Japanese larch is not correlated with the number of antibody-labeled molecules of the enzyme.

Phytochemical Constituents and Evaluation of Lipoxygenase Activity of Tetracera Macrophylla Twigs Wall.Ex Hook.f.&amp; Thoms

Lipoxygenase is an enzyme that catalyzes the formation of leukotriene, which is involved in various diseases such as asthma, osteoporosis and atherosclerosis. Inhibition of this enzyme can overcome inflammatory diseases. Tetracera macrophylla Wall.ex Hook. f.&amp; Thoms plant has shown various biological activities, especially as an anti-inflammatory. This study aims to analyze phytochemical constituents and evaluate the lipoxygenase activity of Tetracera macrophylla twig extract. The sample was gradually macerated using n-hexane, ethyl acetate, and methanol. Phytochemical analysis of the extract was carried out using the LC-MS/MS method. Lipoxygenase assay was carried out in vitro using RAW 264.7 macrophage cells induced with lipopolysaccharide using spectrofluorometry. As a comparison, zileuton, which has been established as a 5-LOX inhibitor and quercetin, which has the potential as a 5-LOX inhibitor. The results showed that methanol extract of Tetracera macrophylla twigs had lower specific LOX activity than standard zileuton and quercetin. This plant contains phenol and flavonoid compounds, which can be developed as lipoxygenase inhibitors to prevent inflammation.

Exploring breast cancer treatment paradigms: innovative design, molecular docking and dynamic simulation of LOXL2 inhibitors

ABSTRACT The impact of the LOXL2 enzyme on cell invasion and metastasis is significantly notable in breast cancer (BC), making it a promising therapeutic target in cancer drug discovery. Considering the diverse functions of lysyl oxidase both extracellularly and intracellularly, inhibiting LOX activity emerges as a strategic approach to impede cancer progression and invasion. This study is uniquely designed to identify potential small molecules targeting LOXL2 in BC. Initially, we designed small molecuels and conducted docking studies using ChemDraw and AutoDock Vina, respectively. Assessment of ADME, drug-likeness and toxicological properties was carried out using online tools such as SwissADME, admetSAR, pkCSM and ProTox-II. The best docked candidates underwent further evaluation through 100 ns molecular dynamics simulations. Compound H.2.9 scored of −8.4 kcal/mol in docking, surpassing the control's (US10717733) −5.0 kcal/mol, indicating its potential as an LOXL2 inhibitor. ADME predictions indicated that all screened compounds adhere to Lipinski's rule of five. Additionally, toxicological predictions confirmed that these compounds are non-cytotoxic, non-hepatotoxic and non-carcinogenic. The RMSD, RMSF and MM-GBSA analyses affirmed the stability of the H.2.9 compound. The development of LOXL2 inhibitors instils optimism for effective therapies against both primary and metastatic cancers in the foreseeable future, contributing to advancements in cancer research. Abbreviations: 2D, Two-dimensional; 3D, Three-dimensional; ADMET, Absorption, distribution, metabolism, excretion and toxicity; CADD, Computer-aided drug design; MD, Molecular dynamics; MMFF, Merck molecular force field; MOL, Molecular structure file; PDB, Protein data bank; PK, Pharmacokinetics; OPLS, Optimised potentials for liquid simulations; RMSD, Root mean square deviation; RMSF, Root mean square fluctuation; SASA, Solvent-accessible surface area; SDF, Structure data file; SMILES, Simplified molecular input line entry system; SPC, Simple-point charge

Acidic electrolyzed-oxidizing water treatment mitigated the disease progression in Phomopsis longanae Chi-infected longans by modulating ROS and membrane lipid metabolism

Postharvest harmful pathogenic infestation leads to rapid decay in longan fruit. Compared with P. longanae-infected longans, AEOW alleviated fruit disease severity and diminished the O2-. production rate and MDA content. It also increased APX, CAT, and SOD activities, delayed the decrease in the levels of GSH and AsA, as well as the reducing power and DPPH radical scavenging ability, which resulted in a decline in membrane lipid peroxidation in P. longanae-infected longans. Additionally, AEOW reduced LOX, lipase, PI-PLC, PC-PLC, and PLD activities, maintained higher levels of PC, PI, IUFA, USFAs, and U/S, while reducing levels of PA, DAG, SFAs, and CMP. These effects alleviated membrane lipid degradation and peroxidation in P. longanae-infected longans. Consequently, AEOW effectively maintained membrane integrity via improving antioxidant capacity and suppressing membrane lipid peroxidation. This comprehensive coordination of ROS and membrane lipid metabolisms improved fruit resistance and delayed disease development in longans.

Anti-Inflammatory Activity of Cyanobacteria Pigment Extracts: Physiological Free Radical Scavenging and Modulation of iNOS and LOX Activity.

Cyanobacteria are among the oldest organisms colonizing Earth. Their great biodiversity and ability to biosynthesize secondary metabolites through a variety of routes makes them attractive resources for biotechnological applications and drug discovery. In this pioneer study, four filamentous cyanobacteria (Cephalothrix lacustris LEGE 15493, Leptolyngbya boryana LEGE 15486, Nodosilinea nodulosa LEGE 06104 and Leptothoe sp. LEGE 11479) were explored for their anti-inflammatory potential in cell and cell-free in vitro bioassays, involving different inflammatory mediators and enzymes. Extracts of different polarities were sequentially prepared and chemically characterized for their content of phycobiliproteins (PBPs) and carotenoids. HPLC-PDA analysis of the acetone extracts revealed β-carotene to be the dominant carotenoid (18.4-44.3 mg/g) and zeaxanthin as the dominant xanthophyll (52.7-192.9 mg/g), with Leptothoe sp. LEGE 11479 and Nodosilinea nodulosa LEGE 06104, respectively, being the richest strains. The PBP profile was in accordance with the color presented by the aqueous extracts, with Leptolyngbya boryana LEGE 15486 being the richest in phycocyanin (204.5 μg/mg) and Leptothoe sp. LEGE 11479 the richest in phycoerythrin (78.5 μg/mg). Aqueous extracts were more effective in superoxide anion radical scavenging, while acetone ones were more effective in scavenging nitric oxide radical (●NO) and in inhibiting lipoxygenase. Acetone extracts also reduced ●NO production in lipopolysaccharide-stimulated RAW 264.7 macrophages, with the mechanistic study suggesting a downregulation of the inducible nitric oxide synthase expression. Nodosilinea nodulosa LEGE 06104 and Leptothoe sp. LEGE 11479 acetone extracts presented the lowest IC50 values for the mentioned assays, pointing them out as promising resources for the development of new multi-target anti-inflammatory therapies.

Development of defense system and secondary metabolites of Korla fragrant pear during Alternaria alternata infection

Blackhead disease causes serious postharvest loss of fragrant pear (Pyrus brestschneideri Rehd), with Alternaria alternata being the main pathogen. Herein, the changes in defense responses of fragrant pear to A. alternata were explored. The results showed that compared to sterile distilled water treatment, A. alternata inoculation promoted MDA and H2O2 accumulation, and increased LOX activity. Moreover, it decreased the activity of SOD, POD, PAL, LAC, CAD, and 4CL, and repressed the expression of PbPOD, PbLAC, Pb4CL, and PbCAD, and reduced the accumulation of defense-related substances (total phenols, total flavonoids, and lignin). In addition, compared with the control group, the activity of pathogenesis-related proteins (GLU, CHT) and the overall gene expression level increased significantly in pear inoculated with A. alternata. A. alternata infection also affected endogenous hormones in pear, especially the contents of salicylic acid and abscisic acid. Overall, the defense of pears after infection with A. alternata is lower than that of pears inoculated with sterile water.

Dielectric barrier discharge cold plasma collaborated with coconut exocarp flavonoids: A promising technology for oyster preservation under refrigerated storage

The effect of coconut exocarp flavonoids (CF) combined with cold plasma (CP) treatment on oyster preservation during refrigerated storage was investigated. It was observed oyster without preservation suffered the most serious microbial spoilage and chemical changes during storage. CP significantly inhibited spoilage bacteria, inactivated endogenous lipid hydrolases and LOX activities (P < 0.05). Simultaneously, it caused undesirable polyunsaturated fatty acid (PUFA) oxidation and glycerophospholipid species depletion, while extended CP processing aggravated them. CF marinating collaborated with 10 min CP exposure exhibited least bacterial count, total volatile base nitrogen, peroxide and thiobarbituric acid values with 5.16 logCFU/g, 19.62 mg/100 g, 22.05 meq/kg and 801.8 μg MDAeq/kg, respectively, thus extending the shelf-life. Moreover, it enhanced the inhibition ability toward LOX activity and alleviated PUFA oxidation triggered by CP. Therefore, the collaboration of CF and CP serve as effective technology for oyster preservation, while the CP processing time should be optimized from the nutritional value perspective.

Nanoselenium inhibits chromium toxicity in wheat plants by modifying the antioxidant defense system, ascorbate glutathione cycle, and glyoxalase system

Chromium (Cr) stress negatively impacts plant growth and physiological processes, making it a significant environmental concern. This study investigates the effectiveness of selenium nanoparticles (Se-NPs) in mitigating Cr stress on plants, comparing its efficacy with traditional selenium (Se). Nevertheless, research on using soil-applied Se-NP to lessen Cr buildup in plants has not been widely documented as of now. Here, we investigate the effectiveness of Se-NPs in mitigating Cr stress on plants, comparing their efficacy with traditional Se and control. Under the pervasive influence of Cr stress, Se-NPs exhibit remarkable superiority over conventional Se, significantly enhancing growth parameters (fresh weight, dry weight, shoot length, and root length), respectively, compared to the Cr-stressed plants. Physiologically, Se-NPs outperform Se by substantially improving the net photosynthesis rate (+32%), transpiration (+147%), and stomatal conductance (+64%), indicating its exceptional contribution to fortifying plant resilience under Cr stress. In mitigating oxidative stress, Se-NPs surpass Se, demonstrating a more pronounced reduction in LOX activity (−35%), MDA levels (−34%), H2O2 (−37%), and MG (−47%), showcasing heightened protection against Cr induced oxidative damage. Antioxidant defense systems also witness greater activation under Se-NPs, with higher increases in SOD (+27%), CAT (+54%), GPX (+7%), and GST (+37%) activities. Moreover, under Cr stress Se-NPs induce a more profound upregulation of antioxidant genes and the production of secondary metabolites, emphasizing its superior impact on the plant's defense mechanisms. The modulation of the ASA-GSH cycle by Se-NPs is more robust, with increased levels of ASA (+69%) and GSH (+33%), and decreased DHA (−28%) and GSSG (−29%), suggesting a more effective antioxidant network. Moreover, Se-NPs demonstrate heightened interference in Cr uptake in both root (−30%) and shoot tissues (−23%), indicating its potential to disrupt the Cr-induced ASA-GSH cycle. The study highlights the potential of Se-NPs as a more effective and sustainable approach to mitigate Cr-induced stress in plants, emphasizing the importance of understanding the underlying mechanisms and optimizing application strategies for improved agricultural sustainability and productivity in Cr-contaminated environments. Furthermore, it is necessary to conduct economic feasibility studies and assessments of the effects of Se-NP on soil microbiota in order to promote the widespread application in agricultural activities.

Green-synthesized silver nanoparticles from Zingiber officinale extract: antioxidant potential, biocompatibility, anti-LOX properties, and in silico analysis

IntroductionZingiber officinale extract has emerged as a compelling candidate for green synthesis of nanoparticles, offering diverse applications across medicine, cosmetics, and nutrition. This study delves into the investigation of in vitro toxicity and explores the biomedical utility of green-synthesized silver nanoparticles derived from ginger extract (GE-AgNPs).MethodsWe employed established protocols to evaluate in vitro aspects such as antioxidant capacity, anti-inflammatory potential, and biocompatibility of GE-AgNPs. Additionally, molecular docking was employed to assess their anti-lipoxygenase (anti-LOX) activity.ResultsOur findings highlight that the extraction of ginger extract at a pH of 6, utilizing a cosolvent blend of ethanol and ethyl acetate in a 1:1 ratio, yields heightened antioxidant capacity attributed to its rich phenolic and flavonoid content. In the context of silver nanoparticle synthesis, pH 6 extraction yields the highest quantity of nanoparticles, characterized by an average size of 32.64 ± 1.65 nm. Of particular significance, GE-AgNPs (at pH 6) demonstrated remarkable efficacy in scavenging free radicals, as evidenced by an IC50 value of 6.83 ± 0.47 µg/mL. The results from the anti-LOX experiment indicate that GE-AgNPs, at a concentration of 10 µg/mL, can inhibit LOX activity by 25%, outperforming ginger extract which inhibits LOX by 17–18%. Notably, clionasterol exhibited higher binding energy and enhanced stability (-8.9 kcal/mol) compared to nordihydroguaiaretic acid. Furthermore, a cell viability study confirmed the safety of GE-AgNPs at a concentration of 17.52 ± 7.00 µg/mL against the L929 cell line.ConclusionThese comprehensive findings underscore the significant biomedical advantages of GE-AgNPs and emphasize their potential incorporation into cosmetic products at a maximum concentration of 10 µg/mL.

Novel 1-H Phenyl Benzimidazole Derivatives for IBD Therapy - An in-vitro and in-silico Approach to Evaluate its Effects on the IL-23 Mediated Inflammatory Pathway.

IBD is a chronic idiopathic gut condition characterised by recurring and remitting inflammation of the colonic mucosal epithelium. Benzimidazole is a prominent and attractive heterocyclic compound with diverse actions. Although seven locations in the benzimidazole nucleus can be changed with a number of chemical entities for biological activity, benzimidazole fused with a phenyl ring has caught our interest. To find and optimize novel 1-H phenyl benzimidazole compounds with favorable physicochemical features and drug-like characteristics for the treatment of IBD, in-silico studies and in-vitro approach were being used to identify and optimize these derivatives as potent inhibitors of IL-23 mediated inflammatory signaling pathway. All six compounds exhibit favorable drug-like properties with good intestinal absorption properties. Its high affinity for the target JAK and TYK, which is thought to be a key immunological signaling cascade in the pathophysiology of IBD, is revealed by docking studies. Because of their effects on decreasing iNOS-derived NO release and IL-23-mediated immune signaling by decreasing COX-2 and LOX activity, it's conceivable that the compounds CS3 and CS6 are better options for the treatment of IBD based on in-vitro cell line investigations.

Exploring Swedish pea varieties suitable for protein isolation, focusing on antinutrients and off-flavors

Six different pea (Pisum sativum) varieties and their proteins isolated via wet fractionation were screened to find varieties with outstanding protein functionality but minimum contents of antinutrients and off-flavor volatiles. A broad difference in emulsion activity (44.7–74.2 m2/g) and foaming capacity (163–210%) were detected between the varieties. Pea variety significantly affected LOX activity of the sample, yielding outstanding decreases (1.6–28.6 times) for all varieties following protein isolation. Variety Eso had the highest hexanal increase ratio (820 times) while variety Balder had the lowest (32 times) after the protein isolation. The total concentration of volatile off-flavors, phytate, and saponin increased during the protein isolation with distinctive degrees for each variety. The content of the antinutrients in the proteins was substantially affected by the variety. Altogether, purpose-specific selection of pea varieties based on their desired potential could enable pea proteins with fewer antinutrients and off-flavors.

Nitric oxide fumigation can affect the metabolism of volatile compounds derived from analyses of fatty acids and amino acids in post-harvest flat peach during cold storage

The loss of aroma volatiles can significantly reduce the economic value of postharvest flat peach during cold storage. In this study, the mechanism of NO fumigation regulating the aroma volatiles during cold storage at 1 ± 0.5 °C was investigated. The possible effects of NO on storage quality, VOCs, enzyme activity related to the fatty acid metabolism pathway, and the level of fatty acids and amino acids in fruit were analyzed. The results indicated that treatment with 10 μL L−1 NO maintained higher VC, firmness, SSC, TA, and restrained increase of MDA as well as the rotting rate. 10 μL L−1 NO treatment significantly supported a higher abundance of aldehydes before day 18 and encouraged the production of esters after day 18 of fruit under cold storage, which was associated with higher activity of ADH, AAT, HPL and LOX after day 18.10 μL L−1 NO treatment led to higher content of unsaturated acids, including OA, LA before day 18 and maintained higher content of LeA during the whole cold storage. According to these findings, 10 μL L−1 NO treatment may be a viable strategy to preserve the main aromatic volatiles and extend the shelf life of flat peaches.

Rapid Screening of Phenolic Compounds with Anti-Enteritis Activity from Camellia oleifera Oil Using a Smurf Drosophila Model and Molecular Docking Methods.

Screening and identifying the active compounds in foods are important for the development and utilization of functional foods. In this study, the anti-enteritis activity of ethanol extract from Camellia oleifera oil (PECS) was quickly evaluated using a Smurf Drosophila model and the metabolomics approach, combined with molecular docking techniques, were performed to rapidly screen and identify compounds with potential anti-enteritis activity in PECS. PECS showed good anti-enteritis activity and inhibited the activity of 5-lipoxygenase (LOX), cyclooxygenase 2 (COX-2) and inducible nitric oxide synthase (iNOS). In particular, wighteone and p-octopamine were newly identified in C. oleifera oil and were proven to have good anti-enteritis activity. The inhibitory activity of kaempferitrin (IC50 = 0.365 mmol L-1) was higher than that of wighteone (IC50 = 0.424 mmol L-1) and p-octopamine (IC50 = 0.402 mmol L-1). Of note, the IC50 value of salazosulfapyridine was 0.810 mmol L-1. Inhibition of LOX activity is likely one of the anti-enteritis mechanisms of PECS. These new findings lay the foundation for further investigations into the underlying mechanisms of anti-enteritis activity in C. oleifera oil.

Development of Novel Pyrrole Derivatives and Their Cinnamic Hybrids as Dual COX-2/LOX Inhibitors.

Molecular hybridization has emerged as a promising approach in the treatment of diseases exhibiting multifactorial etiology. With regard to this, dual cyclooxygenase-2/lipoxygenase (COX-2/LOX) inhibitors could be considered a safe alternative to traditional non-steroidal anti-inflammatory drugs (tNSAIDs) and selective COX-2 inhibitors (coxibs) for the treatment of inflammatory conditions. Taking this into account, six novel pyrrole derivatives and pyrrole-cinnamate hybrids were developed as potential COX-2 and soybean LOX (sLOX) inhibitors with antioxidant activity. In silico calculations were performed to predict their ADMET (absorption, distribution, metabolism, excretion, toxicity) properties and drug-likeness, while lipophilicity was experimentally determined as RM values. All synthesized compounds (1-4, 5-8) could be described as drug-like. The results from the docking studies on COX-2 were in accordance with the in vitro studies. According to molecular docking studies on soybean LOX, the compounds displayed allosteric interactions with the enzyme. Pyrrole 2 appeared to be the most potent s-LOX inhibitor (IC50 = 7.5 μM). Hybrids 5 and 6 presented a promising combination of in vitro LOX (IC50 for 5 = 30 μM, IC50 for 6 = 27.5 μM) and COX-2 (IC50 for 5 = 0.55 μM, IC50 for 6 = 7.0 μM) inhibitory activities, and therefore could be used as the lead compounds for the synthesis of more effective multi-target agents.

Effect of oxyresveratrol on the quality and membrane lipid metabolism of shiitake mushroom (Lentinus edodes) during storage.

The effect of oxyresveratrol on postharvest quality and membrane lipid metabolism of shiitake mushroom was investigated. The result exhibited that oxyresveratrol retarded browning, maintained firmness and alleviated occurrence of decay of shiitake mushroom. The oxidation and hydrolysis of membrane phospholipids were suppressed by oxyresveratrol treatment, which was associated with reduced LOX and PLD activities and increased SOD and CAT activities. The membrane lipidomics of shiitake mushroom was determined by LC-MS. 385 lipid species and 13 fatty acids in membrane lipids were identified by multiple reaction monitoring method. Compared with control group, the phospholipic acid and lysophospholipid reduced by 29.24% and 21.29% in oxyresveratrol-treated group, respectively, which alleviated hydrolysis of phospholipid. Meanwhile, oxyresveratrol maintained the unsaturation of fatty acids and alleviated oxidation of phospholipid. These results demonstrated that oxyresveratrol could play a dual role of inhibiting the oxidation and hydrolysis of phospholipids to mitigate cellular damage of shiitake mushroom.

Fatty acid metabolism and C9 aldehyde biosynthesis are involved in ε-poly-l-lysine-induced citrus fruit resistance to Penicillium digitatum

Citrus fruit were easily infected by Penicillium digitatum, and caused green mold rapidly, resulting in enormous post-harvest losses. ε-poly-l-lysine (ε-PL) was generally regarded as a safe (GRAS) substance. Besides, it was proved to have a dual effect on harming fungi and triggering fruit defense responses. Fatty acid metabolism is closely related to fruit defense response. However, little is known about how ε-PL affected fatty acid metabolism in citrus fruit. Here, we found that ε-PL increased the expression of CsFATA, CsACSL, CsFAD2, CsFAD3, CsLOX2S, and CsHPL in fatty acid metabolism, decreasing oleic acid levels and enhancing linoleic and linolenic acid levels. Additionally, ε-PL enriched the activities of LOX and HPL during the oxidative decomposition of fatty acids, and activating C9 aldehyde biosynthesis. Interestingly, ε-PL combined with (2E,4E)-nonadienal (C9 aldehyde) would improve the inhibitory effect against Penicillium digitatum. And the combined bio-fungicide significantly delayed the citrus green mold compared to single concentrations of the individual components. These results suggested that ε-PL improved citrus fruit defense responses through fatty acid-mediated defense responses. Combined bio-fungicide consisting of ε-PL and (2E,4E)-nonadienal have an excellent prospect for controlling citrus green mold.

The roles of lipoxygenases and autoxidation during mackerel (Scomberomorus niphonius) dry-cured processing

The roles of enzymatic (Lipoxygenases, LOX) oxidation and autoxidation in the dry-cured processing of mackerel were investigated by adding exogenous substances in this study. Four groups, namely control, chlorogenic acid (inhibiting LOX activity), EDTA-2Na (inhibiting autoxidation), and exogenous LOX (adding eLOX), were assigned. The results showed that lipid oxidation of mackerel was reduced by inhibiting LOX activity and autoxidation, while adding eLOX promoted lipid oxidation. Inhibition of LOX activity and autoxidation suppressed fatty acid accumulation mainly in the air-drying and curing stage, respectively. The total contents of key flavors in the mackerel during dry-cured processing were decreased by inhibiting LOX activity and autoxidation, and the former inhibitory effect was stronger than autoxidation, while it was corresponding increased through adding eLOX, of particular in the later stage of air-drying. Collectively, LOX could promote the flavor formation of the mackerel in the dry-cured processing, which could be applied in the flavor adjustment of aquatic products or some similar fields.

Effect on lipoxygenase pathway and flavor stabilization of postharvest strawberries by intense pulsed light treatment

A non-thermal pretreatment method was developed to improve the flavor stability of strawberries using an intense pulsed light during postharvest storage. The physicochemical properties, volatile organic compounds (free and bound), enzyme activities, and key gene expressions were investigated during 7-day storage. A 23.67% decrease in the decay ratio was obtained in IPL-treated with 2.0 Hz frequency for 60 s compared to the control. A more stable surface color was obtained at the end of the storage period. A total of 21 f-VOCs and 13 b-VOCs were quantitatively identified. IPL treatment promoted the contents of free aldehydes, esters, and ketones. The content of (E)− 2-heptenal in the IPL-treated strawberries was 1.90 times higher than that in control. The variation in the total content of b-VOCs was less than 31.61% that in the control group. Correspondingly, IPL treatment inhibited the activities of fatty acid metabolism enzymes and decreased LOX activity by 26.3% after storage. Aroma-related genes, including FaLOX, FaADH, and FaAAT, were down-regulated in the metabolism of specific VOCs following IPL treatment. This work provided evidence about the practical application of IPL in inhibiting the activity of enzyme in the LOX pathway, thereby improving the flavor stability of strawberries under non-thermal process conditions.