Metabolic modifications of birch leaf phenolics by an herbivorous insect: detoxification of flavonoid aglycones via glycosylation.

The metabolic modifications of birch (Betula pubescens Ehrh.) leaf phenolics in the digestive tract of its major defoliator, larvae of the autumnal moth Epirrita autumnata, were studied. The main phenolic acids of birch, i.

HPLC analysis of leaf surface flavonoids for the preliminary classification of birch species.

Flavonoid aglycones found on the surfaces of birch (Betula spp.) leaves may constitute up to 10% of the dry weight of the leaf. A facile extraction and HPLC procedure has been developed that can be used for the preliminary classification of birch species according to the patterns of their leaf surface flavonoids.

Characterisation of proanthocyanidin aglycones and glycosides from rose hips by high-performance liquid chromatography-mass spectrometry, and their rapid quantification together with vitamin C.

Fifteen individual proanthocyanidin aglycones and 19 glycosides, together with a complex mixture of chromatographically non-separated tetra- to octameric proanthocyanidin glycosides were detected--the non-separated glycosides being novel natural products--and characterised from dog rose hips using high-performance liquid chromatography-electrospray ionisation mass spectrometry (HPLC-ESI-MS). Along with these phenolics, a 50% aqueous ethanol extract of rose hips was found to contain high levels of Vitamin C. A simple and rapid HPLC method assisted by diode array detection for the estimation of the total concentration of proanthocyanidin aglycones and glycosides, as well as Vitamin C, in rose hip extracts was developed.

Defensive effect of surface flavonoid aglycones of Betula pubescens leaves against first instar Epirrita autumnata larvae.

The surface of birch leaves contains glandular trichomes that secrete exudates containing flavonoid aglycones. We investigated the biological activities of white birch (Betula pubescens) leaf surface exudates against larvae of the autumnal moth, Epirrita autumnata, a common insect pest of birch. We found that tree-specific mortality (up to 100%) of first instar larvae correlated strongly with the tree-specific contents of surface flavonoid aglycones (r(s) = 0.

Rapid herbivore-induced changes in mountain birch phenolics and nutritive compounds and their effects on performance of the major defoliator, Epirrita autumnata.

Insect damage changes plant physiology and chemistry, and such changes may influence the performance of herbivores. We introduced larvae of the autumnal moth (Epirrita autumnata Borkh.) on individual branches of its main host plant.