Structure-dependent phytotoxicity of catechins and other flavonoids: flavonoid conversions by cell-free protein extracts of Centaurea maculosa (spotted knapweed) roots.
J Agric Food Chem
; 51(4): 897-901, 2003 Feb 12.
Article
in En
| MEDLINE
| ID: mdl-12568546
ABSTRACT
Invasive plants are believed to succeed in part by secretion of allelochemicals, thus displacing competing plant species. Centaurea maculosa (spotted knapweed) provides a classic example of this process. We have previously reported that spotted knapweed roots secrete (+/-)-catechin and that (-)-catechin, but not (+)-catechin, is phytotoxic and hence may be a major contributor to C. maculosa's invasive behavior in the rhizosphere. In this communication, we explore both structure/activity relationships for flavonoid phytotoxicity and possible biosynthetic pathways for root production of (+/-)-catechin. Kaempferol and dihydroquercetin were shown to be phytotoxic, while quercetin was not. Kaempferol was converted to dihydroquercetin and (+/-)-catechin when treated with total root protein extracts from C. maculosa, but quercetin was not. This finding suggests an alteration in the standard flavonoid biosynthetic pathway in C. maculosa roots, whereby kaempferol is not a dead-end product but serves as a precursor to dihydroquercetin, which in turn leads to (+/-)-catechin production.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Plant Proteins
/
Quercetin
/
Flavonoids
/
Plant Extracts
/
Catechin
/
Plant Roots
/
Centaurea
/
Kaempferols
Language:
En
Journal:
J Agric Food Chem
Year:
2003
Document type:
Article
Affiliation country:
United States