The predominant polyphenol in the leaves of the resurrection plant Myrothamnus flabellifolius, 3,4,5 tri-O-galloylquinic acid, protects membranes against desiccation and free radical-induced oxidation.
The predominant (>90%) low-molecular-mass polyphenol was isolated from the leaves of the resurrection plant Myrothamnus flabellifolius and identified to be 3,4,5 tri-O-galloylquinic acid using 1H and 13C one- and two-dimensional NMR spectroscopy. The structure was confirmed by mass spectrometric analysis. This compound was present at high concentrations, 44% (by weight) in hydrated leaves and 74% (by weight) in dehydrated leaves. Electron microscopy of leaf material fixed with glutaraldehyde and caffeine demonstrated that the polyphenols were localized in large vacuoles in both hydrated and dehydrated leaves. 3,4,5 Tri-O-galloylquinic acid was shown to stabilize an artificial membrane system, liposomes, against desiccation if the polyphenol concentration was between 1 and 2 microg/mug phospholipid. The phase transition of these liposomes observed at 46 degrees C was markedly diminished by the presence of 3,4,5 tri-O-galloylquinic acid, suggesting that the presence of the polyphenol maintained the membranes in the liquid crystalline phase at physiological temperatures. 3,4,5 Tri-O-galloylquinic acid was also shown to protect linoleic acid against free radical-induced oxidation.
Moore
John P
JP
Department of Molecular and Cellular Biology, University of Cape Town, Private Bag, Rondebosch 7701, South Africa.
Westall
Kim L
KL
Ravenscroft
Neil
N
Farrant
Jill M
JM
Lindsey
George G
GG
Brandt
Wolf F
WF
D002152:Calorimetry, Differential Scanning; D002851:Chromatography, High Pressure Liquid; D003890:Desiccation; D005419:Flavonoids / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D005452:Fluoresceins / Q000378:metabolism; D005609:Free Radicals / Q000737:chemistry / Q000378:metabolism; D005707:Gallic Acid / Q000031:analogs & derivatives* / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D019787:Linoleic Acid / Q000737:chemistry / Q000378:metabolism; D008081:Liposomes / Q000737:chemistry / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D019684:Magnoliopsida / Q000737:chemistry* / Q000166:cytology; D015394:Molecular Structure; D010084:Oxidation-Reduction / Q000187:drug effects; D044367:Phase Transition; D010636:Phenols / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry* / Q000166:cytology; D059808:Polyphenols; D011801:Quinic Acid / Q000031:analogs & derivatives* / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D014617:Vacuoles / Q000737:chemistry
D005419:Flavonoids; D005452:Fluoresceins; D005609:Free Radicals; D008081:Liposomes; D010636:Phenols; D059808:Polyphenols; D011801:Quinic Acid; D005707:Gallic Acid; C061995:3,4,5-tri-O-galloylquinic acid; D019787:Linoleic Acid; C007740:fluorexon