Document Detail

Xanthone biosynthesis in Hypericum perforatum cells provides antioxidant and antimicrobial protection upon biotic stress.
MedLine Citation:
PMID:  19062051     Owner:  NLM     Status:  MEDLINE    
Xanthone production in Hypericum perforatum (HP) suspension cultures in response to elicitation by Agrobacterium tumefaciens co-cultivation has been studied. RNA blot analyses of HP cells co-cultivated with A. tumefaciens have shown a rapid up-regulation of genes encoding important enzymes of the general phenylpropanoid pathway (PAL, phenylalanine ammonia lyase and 4CL, 4-coumarate:CoA ligase) and xanthone biosynthesis (BPS, benzophenone synthase). Analyses of HPLC chromatograms of methanolic extracts of control and elicited cells (HP cells that were co-cultivated for 24h with A. tumefaciens) have revealed a 12-fold increase in total xanthone concentration and also the emergence of many xanthones after elicitation. Methanolic extract of elicited cells exhibited significantly higher antioxidant and antimicrobial competence than the equivalent extract of control HP cells indicating that these properties have been significantly increased in HP cells after elicitation. Four major de novo synthesized xanthones have been identified as 1,3,6,7-tetrahydroxy-8-prenyl xanthone, 1,3,6,7-tetrahydroxy-2-prenyl xanthone, 1,3,7-trihydroxy-6-methoxy-8-prenyl xanthone and paxanthone. Antioxidant and antimicrobial characterization of these de novo xanthones have revealed that xanthones play dual function in plant cells during biotic stress: (1) as antioxidants to protect the cells from oxidative damage and (2) as phytoalexins to impair the pathogen growth.
Gregory Franklin; Luis F R Conceição; Erich Kombrink; Alberto C P Dias
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2008-12-04
Journal Detail:
Title:  Phytochemistry     Volume:  70     ISSN:  0031-9422     ISO Abbreviation:  Phytochemistry     Publication Date:  2009 Jan 
Date Detail:
Created Date:  2009-02-09     Completed Date:  2009-05-13     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0151434     Medline TA:  Phytochemistry     Country:  United States    
Other Details:
Languages:  eng     Pagination:  60-8     Citation Subset:  IM    
Departamento de Biologia, Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
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MeSH Terms
Anti-Bacterial Agents / metabolism*
Antioxidants / metabolism*
Hypericum / cytology*,  metabolism*
Molecular Structure
Oxidative Stress
Reactive Oxygen Species
Rhizobium radiobacter / drug effects
Xanthones / metabolism*
Reg. No./Substance:
0/Anti-Bacterial Agents; 0/Antioxidants; 0/Reactive Oxygen Species; 0/Xanthones

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