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Faure L, Cavazos R, Khan BR, Petros RA, Koulen P, Blancaflor EB, Chapman KD. Effects of synthetic alkamides on Arabidopsis fatty acid amide hydrolase activity and plant development. PHYTOCHEMISTRY 2015; 110:58-71. [PMID: 25491532 DOI: 10.1016/j.phytochem.2014.11.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 10/28/2014] [Accepted: 11/06/2014] [Indexed: 05/25/2023]
Abstract
Alkamides and N-acylethanolamines (NAEs) are bioactive, amide-linked lipids that influence plant development. Alkamides are restricted to several families of higher plants and some fungi, whereas NAEs are widespread signaling molecules in both plants and animals. Fatty acid amide hydrolase (FAAH) has been described as a key contributor to NAE hydrolysis; however, no enzyme has been associated with alkamide degradation in plants. Herein reported is synthesis of 12 compounds structurally similar to a naturally occurring alkamide (N-isobutyl-(2E,6Z,8E)decatrienamide or affinin) with different acyl compositions more similar to plant NAEs and various amino alkyl head groups. These "hybrid" synthetic alkamides were tested for activity toward recombinant Arabidopsis FAAH and for their effects on plant development (i.e., cotyledon expansion and primary root length). A substantial increase in FAAH activity was discovered toward NAEs in vitro in the presence of some of these synthetic alkamides, such as N-ethyllauroylamide (4). This "enhancement" effect was found to be due, at least in part, to relief from product inhibition of FAAH by ethanolamine, and not due to an alteration in the oligomerization state of the FAAH enzyme. For several of these alkamides, an inhibition of seedling growth was observed with greater results in FAAH knockouts and less in FAAH over-expressing plants, suggesting that these alkamides could be hydrolyzed by FAAH in planta. The tight regulation of NAE levels in vivo appears to be important for proper seedling establishment, and as such, some of these synthetic alkamides may be useful pharmacological tools to manipulate the effects of NAEs in situ.
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Affiliation(s)
- Lionel Faure
- Center for Plant Lipid Research, Department of Biological Sciences, University of North Texas, Denton, TX 76203, USA
| | - Ronaldo Cavazos
- Department of Chemistry, University of North Texas, Denton, TX 76203, USA
| | - Bibi Rafeiza Khan
- The Samuel Roberts Noble Foundation, Plant Biology Division, Ardmore, OK 73401, USA
| | - Robby A Petros
- Department of Chemistry, University of North Texas, Denton, TX 76203, USA.
| | - Peter Koulen
- Center for Plant Lipid Research, Department of Biological Sciences, University of North Texas, Denton, TX 76203, USA; Vision Research Center, Department of Ophthalmology, School of Medicine, University of Missouri - Kansas City, Kansas City, MO, USA; Department of Basic Medical Science, School of Medicine, University of Missouri - Kansas City, Kansas City, MO, USA
| | - Elison B Blancaflor
- Center for Plant Lipid Research, Department of Biological Sciences, University of North Texas, Denton, TX 76203, USA; The Samuel Roberts Noble Foundation, Plant Biology Division, Ardmore, OK 73401, USA
| | - Kent D Chapman
- Center for Plant Lipid Research, Department of Biological Sciences, University of North Texas, Denton, TX 76203, USA.
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Zhao Y, Zhou J, Xing D. Phytochrome B-mediated activation of lipoxygenase modulates an excess red light-induced defence response in Arabidopsis. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:4907-18. [PMID: 24916071 PMCID: PMC4144769 DOI: 10.1093/jxb/eru247] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Lipoxygenase (LOX), a non-haem-iron-containing dioxygenase, is activated under various biotic or abiotic stresses to trigger a series resistance response, but the molecular mechanism of LOX activation remains unclear. This work investigated the activation of LOX during the plant defence response induced by excess red light (RL). In conditions of RL-induced defence, Arabidopsis LOX activity and transcription levels of LOX2, LOX3, and LOX4 were both upregulated. Under RL, phytochrome B promoted the degradation of phytochrome-interacting factor 3 (PIF3), a factor that inhibited the expression levels of LOXs, and thus the transcription levels of LOX2, LOX3, and LOX4 were increased. Upon pathogen infection, the activity of mitogen-activated protein kinase 3 (MPK3) and MPK6 was increased in plants pre-treated with RL. Moreover, experiments with the inhibitor PD98059 and mutants mpk3 and mpk6-2 demonstrated that MPK3 and MPK6 were both responsible for LOX activation. Further results showed that, in response to RL, an increase in cytoplasmic calcium concentration and upregulation of calmodulin 3 (CaM3) transcript level occurred upstream of MPK3 and MPK6 activation. Collectively, these results suggested that activation of LOX both at the transcript level and in terms of activity modulates the defence response induced by RL, providing a new insight into the mechanistic study of LOX during plant defences.
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Affiliation(s)
- Yuanyuan Zhao
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, PR China
| | - Jun Zhou
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, PR China
| | - Da Xing
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, PR China
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Blancaflor EB, Kilaru A, Keereetaweep J, Khan BR, Faure L, Chapman KD. N-Acylethanolamines: lipid metabolites with functions in plant growth and development. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2014; 79:568-583. [PMID: 24397856 DOI: 10.1111/tpj.12427] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Revised: 12/18/2013] [Accepted: 12/23/2013] [Indexed: 06/03/2023]
Abstract
Twenty years ago, N-acylethanolamines (NAEs) were considered by many lipid chemists to be biological 'artifacts' of tissue damage, and were, at best, thought to be minor lipohilic constituents of various organisms. However, that changed dramatically in 1993, when anandamide, an NAE of arachidonic acid (N-arachidonylethanolamine), was shown to bind to the human cannabinoid receptor (CB1) and activate intracellular signal cascades in mammalian neurons. Now NAEs of various types have been identified in diverse multicellular organisms, in which they display profound biological effects. Although targets of NAEs are still being uncovered, and probably vary among eukaryotic species, there appears to be remarkable conservation of the machinery that metabolizes these bioactive fatty acid conjugates of ethanolamine. This review focuses on the metabolism and functions of NAEs in higher plants, with specific reference to the formation, hydrolysis and oxidation of these potent lipid mediators. The discussion centers mostly on early seedling growth and development, for which NAE metabolism has received the most attention, but also considers other areas of plant development in which NAE metabolism has been implicated. Where appropriate, we indicate cross-kingdom conservation in NAE metabolic pathways and metabolites, and suggest areas where opportunities for further investigation appear most pressing.
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Affiliation(s)
- Elison B Blancaflor
- Plant Biology Division, The Samuel Roberts Noble Foundation Inc., 2510 Sam Noble Parkway, Ardmore, OK, 73401, USA
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Keereetaweep J, Blancaflor EB, Hornung E, Feussner I, Chapman KD. Ethanolamide oxylipins of linolenic acid can negatively regulate Arabidopsis seedling development. THE PLANT CELL 2013; 25:3824-40. [PMID: 24151297 PMCID: PMC3877782 DOI: 10.1105/tpc.113.119024] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 09/24/2013] [Accepted: 10/08/2013] [Indexed: 05/20/2023]
Abstract
N-Acylethanolamines (NAEs) are fatty-acid derivatives with potent biological activities in a wide range of eukaryotic organisms. Polyunsaturated NAEs are among the most abundant NAE types in seeds of Arabidopsis thaliana, and they can be metabolized by either fatty acid amide hydrolase (FAAH) or by lipoxygenase (LOX) to low levels during seedling establishment. Here, we identify and quantify endogenous oxylipin metabolites of N-linolenoylethanolamine (NAE 18:3) in Arabidopsis seedlings and show that their levels were higher in faah knockout seedlings. Quantification of oxylipin metabolites in lox mutants demonstrated altered partitioning of NAE 18:3 into 9- or 13-LOX pathways, and this was especially exaggerated when exogenous NAE was added to seedlings. When maintained at micromolar concentrations, NAE 18:3 specifically induced cotyledon bleaching of light-grown seedlings within a restricted stage of development. Comprehensive oxylipin profiling together with genetic and pharmacological interference with LOX activity suggested that both 9-hydroxy and 13-hydroxy linolenoylethanolamides, but not corresponding free fatty-acid metabolites, contributed to the reversible disruption of thylakoid membranes in chloroplasts of seedling cotyledons. We suggest that NAE oxylipins of linolenic acid represent a newly identified, endogenous set of bioactive compounds that may act in opposition to progression of normal seedling development and must be depleted for successful establishment.
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Affiliation(s)
- Jantana Keereetaweep
- Department of Biological Sciences, University of North Texas, Center for Plant Lipid Research, Denton, Texas 76203
| | - Elison B. Blancaflor
- Samuel Roberts Noble Foundation, Plant Biology Division, Ardmore, Oklahoma 73401
| | - Ellen Hornung
- Department of Plant Biochemistry, Georg-August-University, Albrecht-von-Haller-Institute for Plant Sciences, D-37077 Gottingen, Germany
| | - Ivo Feussner
- Department of Plant Biochemistry, Georg-August-University, Albrecht-von-Haller-Institute for Plant Sciences, D-37077 Gottingen, Germany
| | - Kent D. Chapman
- Department of Biological Sciences, University of North Texas, Center for Plant Lipid Research, Denton, Texas 76203
- Address correspondence to
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Hayes AC, Stupak J, Li J, Cox AD. Identification of N-acylethanolamines in Dictyostelium discoideum and confirmation of their hydrolysis by fatty acid amide hydrolase. J Lipid Res 2013; 54:457-66. [PMID: 23187822 PMCID: PMC3588872 DOI: 10.1194/jlr.m032219] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Revised: 11/26/2012] [Indexed: 11/20/2022] Open
Abstract
N-acylethanolamines (NAEs) are endogenous lipid-based signaling molecules best known for their role in the endocannabinoid system in mammals, but they are also known to play roles in signaling pathways in plants. The regulation of NAEs in vivo is partly accomplished by the enzyme fatty acid amide hydrolase (FAAH), which hydrolyses NAEs to ethanolamine and their corresponding fatty acid. Inhibition of FAAH has been shown to increase the levels of NAEs in vivo and to produce desirable phenotypes. This has led to the development of pharmaceutical-based therapies for a variety of conditions targeting FAAH. Recently, our group identified a functional FAAH homolog in Dictyostelium discoideum, leading to our hypothesis that D. discoideum also possesses NAEs. In this study, we provide a further characterization of FAAH and identify NAEs in D. discoideum for the first time. We also demonstrate the ability to modulate their levels in vivo through the use of a semispecific FAAH inhibitor and confirm that these NAEs are FAAH substrates through in vitro studies. We believe the demonstration of the in vivo modulation of NAE levels suggests that D. discoideum could be a good simple model organism in which to study NAE-mediated signaling.
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Affiliation(s)
- Alexander C Hayes
- Human Health Therapeutics Portfolio, National Research Council Canada, Ottawa, ON, Canada.
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Kilaru A, Tamura P, Isaac G, Welti R, Venables BJ, Seier E, Chapman KD. Lipidomic analysis of N-acylphosphatidylethanolamine molecular species in Arabidopsis suggests feedback regulation by N-acylethanolamines. PLANTA 2012; 236:809-24. [PMID: 22673881 PMCID: PMC3579225 DOI: 10.1007/s00425-012-1669-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2012] [Accepted: 05/20/2012] [Indexed: 05/25/2023]
Abstract
N-Acylphosphatidylethanolamine (NAPE) and its hydrolysis product, N-acylethanolamine (NAE), are minor but ubiquitous lipids in multicellular eukaryotes. Various physiological processes are severely affected by altering the expression of fatty acid amide hydrolase (FAAH), an NAE-hydrolyzing enzyme. To determine the effect of altered FAAH activity on NAPE molecular species composition, NAE metabolism, and general membrane lipid metabolism, quantitative profiles of NAPEs, NAEs, galactolipids, and major and minor phospholipids for FAAH mutants of Arabidopsis were determined. The NAPE molecular species content was dramatically affected by reduced FAAH activity and elevated NAE content in faah knockouts, increasing by as much as 36-fold, far more than the NAE content, suggesting negative feedback regulation of phospholipase D-mediated NAPE hydrolysis by NAE. The N-acyl composition of NAPE remained similar to that of NAE, suggesting that the NAPE precursor pool largely determines NAE composition. Exogenous NAE 12:0 treatment elevated endogenous polyunsaturated NAE and NAPE levels in seedlings; NAE levels were increased more in faah knockouts than in wild-type or FAAH overexpressors. Treated seedlings with elevated NAE and NAPE levels showed impaired growth and reduced galactolipid synthesis by the "prokaryotic" (i.e., plastidic), but not the "eukaryotic" (i.e., extraplastidic), pathway. Overall, our data provide new insights into the regulation of NAPE-NAE metabolism and coordination of membrane lipid metabolism and seedling development.
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Affiliation(s)
- Aruna Kilaru
- East Tennessee State University, Department of Biological Sciences, Johnson City, TN 37614, USA
- University of North Texas, Center for Plant Lipid Research, Department of Biological Sciences, Denton, TX 76203, USA
| | - Pamela Tamura
- Kansas State University, Kansas Lipidomics Research Center, Division of Biology, Manhattan, KS 66506, USA
| | - Giorgis Isaac
- Kansas State University, Kansas Lipidomics Research Center, Division of Biology, Manhattan, KS 66506, USA
| | - Ruth Welti
- Kansas State University, Kansas Lipidomics Research Center, Division of Biology, Manhattan, KS 66506, USA
| | - Barney J. Venables
- University of North Texas, Center for Plant Lipid Research, Department of Biological Sciences, Denton, TX 76203, USA
| | - Edith Seier
- East Tennessee State University, Department of Mathematics and Statistics, Johnson City, TN 37614, USA
| | - Kent D. Chapman
- University of North Texas, Center for Plant Lipid Research, Department of Biological Sciences, Denton, TX 76203, USA
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Coulon D, Faure L, Salmon M, Wattelet V, Bessoule JJ. N-Acylethanolamines and related compounds: aspects of metabolism and functions. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2012; 184:129-140. [PMID: 22284717 DOI: 10.1016/j.plantsci.2011.12.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Revised: 12/16/2011] [Accepted: 12/16/2011] [Indexed: 05/31/2023]
Abstract
N-Acylethanolamines (NAE) are fatty acid derivates that are linked with an ethanolamine group via an amide bond. NAE can be characterized as lipid mediators in the plant and animal kingdoms owing to the diverse functions throughout the eukaryotic domain. The functions of NAE have been widely investigated in animal tissues in part due to their abilities to interact with the cannabinoid receptors, vanilloid receptors or peroxisome proliferator activated receptors. However, the interest of studying the functions of these lipids in plants is progressively becoming more apparent. The number of publications about the functions related to NAE and to structural analogs (homoserine lactone and alkamides) is greatly increasing, showing the importance of these lipids in various plant physiological processes. This review sheds light on their role in different processes such as seedling development, plant pathogen interaction, phospholipase D alpha inhibition and senescence of cut flowers, and underlines the interaction between NAE and NAE-related molecules with plant hormone signaling. The different metabolic pathways promoting the synthesis and degradation of NAE are also discussed, in particular the oxygenation of polyunsaturated N-acylethanolamines, which leads to NAE-oxylipins, a new family of bioactive lipids.
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Affiliation(s)
- Denis Coulon
- Laboratoire de Biogenèse Membranaire, Univ. de Bordeaux, UMR 5200, F-33000 Bordeaux, France.
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Coulon D, Faure L, Salmon M, Wattelet V, Bessoule JJ. Occurrence, biosynthesis and functions of N-acylphosphatidylethanolamines (NAPE): Not just precursors of N-acylethanolamines (NAE). Biochimie 2012; 94:75-85. [DOI: 10.1016/j.biochi.2011.04.023] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Accepted: 04/29/2011] [Indexed: 01/19/2023]
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Méndez-Bravo A, Calderón-Vázquez C, Ibarra-Laclette E, Raya-González J, Ramírez-Chávez E, Molina-Torres J, Guevara-García AA, López-Bucio J, Herrera-Estrella L. Alkamides activate jasmonic acid biosynthesis and signaling pathways and confer resistance to Botrytis cinerea in Arabidopsis thaliana. PLoS One 2011; 6:e27251. [PMID: 22076141 PMCID: PMC3208606 DOI: 10.1371/journal.pone.0027251] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Accepted: 10/12/2011] [Indexed: 11/18/2022] Open
Abstract
Alkamides are fatty acid amides of wide distribution in plants, structurally related to N-acyl-L-homoserine lactones (AHLs) from Gram-negative bacteria and to N- acylethanolamines (NAEs) from plants and mammals. Global analysis of gene expression changes in Arabidopsis thaliana in response to N-isobutyl decanamide, the most highly active alkamide identified to date, revealed an overrepresentation of defense-responsive transcriptional networks. In particular, genes encoding enzymes for jasmonic acid (JA) biosynthesis increased their expression, which occurred in parallel with JA, nitric oxide (NO) and H₂O₂ accumulation. The activity of the alkamide to confer resistance against the necrotizing fungus Botrytis cinerea was tested by inoculating Arabidopsis detached leaves with conidiospores and evaluating disease symptoms and fungal proliferation. N-isobutyl decanamide application significantly reduced necrosis caused by the pathogen and inhibited fungal proliferation. Arabidopsis mutants jar1 and coi1 altered in JA signaling and a MAP kinase mutant (mpk6), unlike salicylic acid- (SA) related mutant eds16/sid2-1, were unable to defend from fungal attack even when N-isobutyl decanamide was supplied, indicating that alkamides could modulate some necrotrophic-associated defense responses through JA-dependent and MPK6-regulated signaling pathways. Our results suggest a role of alkamides in plant immunity induction.
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Affiliation(s)
- Alfonso Méndez-Bravo
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Michoacán, México
- Laboratorio Nacional de Genómica para la Biodiversidad, Cinvestav Irapuato, Irapuato, Guanajuato, México
| | - Carlos Calderón-Vázquez
- Laboratorio Nacional de Genómica para la Biodiversidad, Cinvestav Irapuato, Irapuato, Guanajuato, México
- Centro Interdisciplinario de Investigación para el Desarrollo Integral Regional-IPN, Guasave, Sinaloa, México
| | - Enrique Ibarra-Laclette
- Laboratorio Nacional de Genómica para la Biodiversidad, Cinvestav Irapuato, Irapuato, Guanajuato, México
| | - Javier Raya-González
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Michoacán, México
| | - Enrique Ramírez-Chávez
- Departamento de Biotecnología y Bioquímica, Unidad Irapuato, Cinvestav, Irapuato, Guanajuato, México
| | - Jorge Molina-Torres
- Departamento de Biotecnología y Bioquímica, Unidad Irapuato, Cinvestav, Irapuato, Guanajuato, México
| | | | - José López-Bucio
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Michoacán, México
| | - Luis Herrera-Estrella
- Laboratorio Nacional de Genómica para la Biodiversidad, Cinvestav Irapuato, Irapuato, Guanajuato, México
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Singh J, Sood S, Muthuraman A. In-vitro evaluation of bioactive compounds, anti-oxidant, lipid peroxidation and lipoxygenase inhibitory potential of Citrus karna L. peel extract. Journal of Food Science and Technology 2011; 51:67-74. [PMID: 24426049 DOI: 10.1007/s13197-011-0479-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Revised: 07/16/2011] [Accepted: 08/01/2011] [Indexed: 02/01/2023]
Abstract
Many medicinal plants have been studied for their antioxidant and their pharmacological activity. Citrus species were well documented as potential antioxidant based therapy for cancer, inflammation, heart disease. Citrus seeds and peels have been shown to possess high antioxidant activity. Therefore, the present study to explore the antioxidant and lipid peroxidation & lipoxygenase inhibitory action of Citrus karna peel extracts were undertaken. Extraction was performed with different solvents of increasing polarity and yield was calculated. Peel extracts were also analyzed for the presence of phenols, flavonoids, vitamin C, and carotenoids. Then the Citrus karna peel extracts were evaluated for the antioxidant and lipid peroxidation & lipoxygenase inhibitory action In-Vitro. In further, the quantification of hesperidin and naringin was carried out by HPLC-DAD method. The results indicated the presence of phenols, flavonoids, vitamin C, carotenoids, hesperidin and naringin in Citrus karna peel extracts with maximum yield of (3.91% w/w). Citrus karna peel extracts were also found to have potential antioxidant and lipid peroxidation & lipoxygenase inhibitory action. Therefore, Citrus karna peel extracts could be used for the future therapeutic medicine due to presence of potential bioactive compounds.
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Affiliation(s)
- Jagdeep Singh
- Rayat Institute of Pharmacy, Nawanshahr District Near Ropar, Distt Shaheed Bhagat Singh Nagar, Railmajra, Punjab 144533 India
| | - Shailja Sood
- Rayat Institute of Pharmacy, Nawanshahr District Near Ropar, Distt Shaheed Bhagat Singh Nagar, Railmajra, Punjab 144533 India
| | - Arunachalam Muthuraman
- Rayat Institute of Pharmacy, Nawanshahr District Near Ropar, Distt Shaheed Bhagat Singh Nagar, Railmajra, Punjab 144533 India ; Department of Pharmaceutical Sciences & Drug Research, Punjabi University, Patiala, 147002 Punjab India
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Kilaru A, Herrfurth C, Keereetaweep J, Hornung E, Venables BJ, Feussner I, Chapman KD. Lipoxygenase-mediated oxidation of polyunsaturated N-acylethanolamines in Arabidopsis. J Biol Chem 2011; 286:15205-14. [PMID: 21372125 DOI: 10.1074/jbc.m110.217588] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
N-acylethanolamines (NAEs) are bioactive fatty acid derivatives that occur in all eukaryotes. In plants, NAEs have potent negative growth-regulating properties, and fatty acid amide hydrolase (FAAH)-mediated hydrolysis is a primary catabolic pathway that operates during seedling establishment to deplete these compounds. Alternatively, polyunsaturated (PU)-NAEs may serve as substrates for lipid oxidation. In Arabidopsis, PU-NAEs (NAE 18:2 and NAE 18:3) were the most abundant NAE species in seeds, and their levels were depleted during seedling growth even in FAAH tDNA knock-out plants. Therefore, we hypothesized that lipoxygenase (LOX) participated in the metabolism of PU-NAEs through the formation of NAE-oxylipins. Comprehensive chromatographic and mass spectrometric methods were developed to identify NAE hydroperoxides and -hydroxides. Recombinant Arabidopsis LOX enzymes expressed in Escherichia coli utilized NAE 18:2 and NAE 18:3 as substrates with AtLOX1 and AtLOX5 exhibiting 9-LOX activity and AtLOX2, AtLOX3, AtLOX4, and AtLOX6 showing predominantly 13-LOX activity. Feeding experiments with exogenous PU-NAEs showed they were converted to hydroxide metabolites indicating that indeed Arabidopsis seedlings had the capacity for LOX-mediated metabolism of PU-NAEs in planta. Detectable levels of endogenous NAE-oxylipin metabolites were identified in FAAH fatty acid amide hydrolase seedlings but not in wild-type or FAAH overexpressors, suggesting that NAE hydroxide pools normally do not accumulate unless flux through hydrolysis is substantially reduced. These data suggest that Arabidopsis LOXs indeed compete with FAAH to metabolize PU-NAEs during seedling establishment. Identification of endogenous amide-conjugated oxylipins suggests potential significance of these metabolites in vivo, and FAAH mutants may offer opportunities to address this in the future.
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Affiliation(s)
- Aruna Kilaru
- Center for Plant Lipid Research, Department of Biological Sciences, University of North Texas, Denton, Texas 76203, USA.
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Garg P, Duncan RS, Kaja S, Zabaneh A, Chapman KD, Koulen P. Lauroylethanolamide and linoleoylethanolamide improve functional outcome in a rodent model for stroke. Neurosci Lett 2011; 492:134-8. [PMID: 21296126 DOI: 10.1016/j.neulet.2011.01.073] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Revised: 01/26/2011] [Accepted: 01/28/2011] [Indexed: 11/19/2022]
Abstract
Ischemic stroke is a significant health problem affecting over 6 million people in the United States alone. In addition to surgical and thrombolytic therapeutic strategies for stroke, neuroprotective therapies may offer additional benefit. N-acylethanolamines (NAEs) are signaling lipids whose synthesis is upregulated in response to ischemia, suggesting that they may be neuroprotective. To date only three NAEs, arachidonylethanolamide (NAE 20:4), palmitoylethanolamide (NAE 16:0) and oleoylethanolamide (NAE 18:1) have shown to exert neuroprotective effect in animal models for stroke. Here, we describe neuroprotective effects of the hitherto uncharacterized NAEs, lauroylethanolamide (NAE 12:0) and linoleoylethanolamide (NAE 18:2) in a middle cerebral artery occlusion model of stroke. Pretreatment with NAE 18:2 prior to ischemia/reperfusion (I/R) injury resulted in both significantly reduced cortical infarct volume and improved functional outcome as determined using the neurological deficit score. NAE 12:0 improved neurological deficits without a significant reduction lesion size. Our results suggest that NAEs, as a whole, provide neuroprotection during I/R injury and may have therapeutic benefit when used as complementary treatment with other therapies to improve stroke outcome.
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Affiliation(s)
- Puja Garg
- Vision Research Center and Department of Ophthalmology, School of Medicine, University of Missouri - Kansas City, Kansas City, MO 64108, United States
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