Extraction, structural characterisation and evaluation of hydroxycinnamate esters of orchard grass (Dactylis glomerata) as substrates for polyphonel oxidase

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dc.contributor.author Parveen, Ifat
dc.contributor.author Morris, Phillip
dc.contributor.author Winters, Ana L.
dc.contributor.author Hauck, Barbara D.
dc.contributor.author Threadgill, Michael D.
dc.date.accessioned 2009-06-04T10:28:36Z
dc.date.available 2009-06-04T10:28:36Z
dc.date.issued 2008-07
dc.identifier.citation Parveen , I , Morris , P , Winters , A L , Hauck , B D & Threadgill , M D 2008 , ' Extraction, structural characterisation and evaluation of hydroxycinnamate esters of orchard grass (Dactylis glomerata) as substrates for polyphonel oxidase ' Planta Medica , vol 74 , pp. T1.51 . en
dc.identifier.issn 1439-0221
dc.identifier.other PURE: 912945
dc.identifier.other dspace: 2160/2450
dc.identifier.uri http://hdl.handle.net/2160/2450
dc.description Parveen, I., Winters, A. L., Threadgill, M. D., Hauck, B. D., Morris, P. (2008). Extraction, structural characterisation and evaluation of hydroxycinnamate esters of orchard grass (Dactylis glomerata) as substrates for polyphonel oxidase.  Planta Medica, 74(9),1054-1055. Natural products with Pharmaceutical, Nutraceutical, Cosmetic and Agrochemical interest. 7th Joint meeting of AFERP/ASP/GA/PSE/SIF, Athens, Greece, August 2008, RONO: 1910 3007 Joint meeting of AFERP/ASP/GA/PSE/SIF on Natural products with Pharmaceutical, Nutraceutical, Cosmetic and Agrochemical interest, Athens, Greece, August 2008 journalsupplement: Natural products with Pharmaceutical, Nutraceutical, Cosmetic and Agrochemical interest. Joint Meeting of AFERP/ASP/GA/PSE/SIF, Athens, Greece, August 2008 1 T1.51 24th International Conference on Polyphenols, Salamanca, 8-11 July 2008 en
dc.description.abstract Orchard grass (Dactylis glomerata) is a common perennial grass that is frequently found in woodland edges, rough grassland, meadows and permanent pastures. In the UK and continental Europe, orchard grass, together with other native species, including fescues, occupies around 30% of pastoral land. Polyphenol oxidases are enzymes that cause enzymatic browning by conversion of natural phenolic compounds, such as monophenols to o-dihydroxyaryl compounds and subsequent oxidation to o-quinones [1]. These highly electrophilic species bind rapidly to nucleophilic sites on other compounds (e.g. phenols, amino-acids and proteins) and condense with phenols to form brown-, black- or red-colored polymers, associated with the undesired discoloration of fruit and vegetables. Recently, high levels of PPO activity have been reported in orchard grass [2]; however, to date, no endogenous substrates have been identified. In the present study, we report the isolation and structural elucidation of PPO substrates in this species. The free phenol fraction was extracted, separated by reverse-phase chromatography and six potential substrates, including two novel hydroxycinnamate esters (2-O-caffeoylisocitric acid 6-methyl ester and 2-O-caffeoylthreonic acid), were identified by UV spectrometry, electrospray ionisation-tandem mass spectrometry (LC-ESI-MSn) and 1D and 2D NMR analyses (1H NMR, 13C NMR, DEPT, COSY, HMQC and HMBC). Furthermore, three caffeoylquinic acids (3-CQA, 4-CQA and 5-CQA) were identified by comparison of their spectral data (ESI-MS) with those of known compounds and literature data. Five of the isolated compounds (i.e. chlorogenic acid, 2-O-caffeoylisocitric acid, 2-O-caffeoylisocitric acid 6-methyl ester, 2-O-caffeoylthreonic acid and 2-O-caffeoylhydroxycitric acid) were demonstrated to be substrates for orchard grass PPO. en
dc.format.extent 2 en
dc.language.iso eng
dc.relation.ispartof Planta Medica en
dc.title Extraction, structural characterisation and evaluation of hydroxycinnamate esters of orchard grass (Dactylis glomerata) as substrates for polyphonel oxidase en
dc.type Text en
dc.type.publicationtype Article (Journal) en
dc.identifier.doi http://dx.doi.org/10.1055/s-0028-1084432
dc.contributor.institution Institute of Biological, Environmental and Rural Sciences en
dc.description.status Non peer reviewed en


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