Abstract The seasonal variation in essential oil yield and composition from naturalized Thymus vulgaris L. Central Otago, New Zealand, is reported. Essential (l/ha), replicated, pilot‐scale distillations, was influenced by both the field production of herb content herb. peaked at 22.8 l/ha December, after flowering had finished. also varied significantly during 13‐month sampling period. Levels phenolic components, thymol carvacrol, a total 37% summer (December January). p ‐Cymene an...

• Red-pigmented leaf margins are common, but their functional significance is unknown. We hypothesized that red reduce herbivory by signalling to herbivorous insects the presence of increased chemical defences. Leaves were collected from a natural population Pseudowintera colorata. Margin size, damage, anthocyanin content and concentrations polygodial, sesquiterpene dialdehyde with antifeedant properties, quantified. Feeding trials involving larvae Ctenopseustis obliquana, generalist...

Summary Whether plants use leaf colour to deter herbivores remains controversial. The warning signal hypothesis predicts that red pigmentation is adaptive by reducing herbivory; with predominantly foliage should have higher fitness than those green leaves. Despite many discussions, this prediction has rarely been tested, and alternative, non‐exclusive hypotheses cannot be ruled out. We exploited polymorphism in P seudowintera colorata test the address possible alternative explanations....

Fast MS techniques have been applied to the analysis of sulfur volatiles in Allium species and varieties distinguish phenotypes. Headspace sampling by proton transfer reaction (PTR) surface desorption electrospray ionization (DESI) were used lachrymatory factor synthase (LFS)-silenced (tearless; LFS-) onions from normal, LFS-active (tear-inducing; LFS+), onions. PTR-MS showed lower concentrations (LF, 3) dipropyl disulfide 12 tearless DESI-MS confirmed decreased LF 3 revealed much higher...

A rapid extraction, clean-up, and RPLC procedure suitable for routine quantitative analyses of alkamide levels in Echinacea purpurea extracts is described. The 13C-NMR spectra the main diene-diyne alkamides E. are reported. Alkamide differed significantly among roots, rhizomes, stems, leaves, flowers purpurea. Roots were distinguished from other plant parts by higher C12 alkamides, whereas tetraene C11 diene-diynes highest vegetative stems. ratio two stereoisomeric between all parts. These...

Naturally occurring β-triketones, isoleptospermone [3, 5-hydroxy-4-(2-methyl-1-oxopentyl)-2,2,6,6-tetramethyl-4-cyclohexene-1,3-dione) from Leptospermum scoparium] and papuanone [6, 5-hydroxy-4-(1-oxohexyl)-2,2,6,6-tetramethyl-4-cyclohexene-1,3-dione Corymbia dallachiana], have been synthesized. Full spectral data are reported for the first time. The 13C NMR spectra of 3, 6, other triketones flavesone (2), leptospermone (4), grandiflorone (5) found in Myrtaceous plants fully assigned.

Crushing intensity and distillation time were evaluated for their effects on the oil yield composition of steam-distilled essential from fruits Coriandrum sativum var. microcarpum L. A comparison oils produced by laboratory- pilot-scale stills showed that two still types gave comparable yields composition. The laboratory was then used to compare compositions crushed at three different intensities, intervals during a period 60 min. Both crushing had significant (P < 0.05) oil. maximum less...

p-Hydroxyphenylpyruvate dioxygenase (HPPD) is the target site of β-triketone herbicides in current use. Nineteen β-triketones and analogues, including naturally occurring leptospermone grandiflorone, were synthesized tested as inhibitors purified Arabidopsis thaliana HPPD. The most active compound was a with C9 alkyl side chain, not reported natural, which inhibited HPPD an I50 19 ± 1 nM. This significantly more than sulcotrione, had 250 21 nM this assay system. 750 70 potential interest...

Four trimethylated acylphloroglucinols (5–8) have been isolated from ma̅nuka (Leptospermum scoparium) foliage. Apart myrigalone A (8), which has previously European bog myrtle (Myrica gale), these compounds not characterized before. The nortriketones are structurally similar to the bioactive tetramethylated β-triketones ma̅nuka, but one less ring methyl group. Two oxidized compounds, 9 and 10, were also isolated, likely isolation artifacts. When evaluated for antibacterial activity against...

Two new structurally related metabolites, novae-zelandin A (1) and B (2), as well the novel metabolite 4Z-infectopyrone (3) were purified from extracts of filamentous fungi belonging to Alternaria infectoria species-group. The structures elucidated by a combination 1D 2D NMR spectroscopic data MS data. 1-3 are important chemotaxonomic markers A. species-group exhibit similar those known biologically active compounds, suggesting that they could be potential phytotoxins.

Summary The N ew Z ealand mānuka shrub, L eptospermum scoparium , and the Australian . morrisonii produce herbicidal β‐triketones in their leaves. localization of these potential self‐toxicants has not been proven. We investigated compounds leaves using R aman microscopy. results are presented as heat maps derived from principal component analysis ( PCA ) spectra sampling grids leaf sections. This approach used undirected, data‐driven to qualitatively distinguish localized plant chemistry....

Apples (Malus spp.) accumulate significant quantities of the dihydrochalcone glycoside, phloridzin, whilst pears (Pyrus do not. To explain this difference, we hypothesized that a metabolic bottleneck in phenylpropanoid pathway might exist apple. Expression analysis indicated transcript levels early genes apple and pear leaves were similar, except for chalcone isomerase (CHI), which was much lower also showed very low CHI activity compared with pear. relieve at CHI, transgenic plants...

The effects of processing, drying, and storage time temperature on alkamide levels in Echinacea purpurea roots are described. Chopping altered the some alkamides slightly, whereas drying had no effect. Levels all fell by over 80 % during at 24 °C for 64 weeks. Alkamide also dropped significantly − 18 °C.

Retrobiosynthetic analysis of the allergenic sesquiterpene lactone, anthecotuloide, suggested that this natural product could be formed either by head to condensation geranyl diphosphate with dimethylallyl diphosphate, or from farnesyl (FPP), accepted regular precursor via rearrangement a germacranolide precursor. Isotopic labelling anthecotuloide has now been achieved feeding [1-13C]-glucose, [U-13C6]-glucose and [6,6-2H2]-glucose aseptically grown plantlets Anthemis cotula(family...

Mānuka (Leptospermum scoparium) is valued for its unique bioactive honey, but relatively little known about mānuka nectar and the factors modulating production. In this study compositional variability of collected throughout floral development was measured in glasshouse-cultivated plants. The total yield estimated by rinsing flowers with water measuring sugars (°Brix). concentration dihydroxyacetone (DHA), precursor to methylglyoxal key honey bioactive, increased through maximised just prior...

Abstract Essential oil composition and plant morphology were observed over four years in individual plants raised from seed of a wild population Leptospermum scoparium (Myrtaceae) collected at single site New Zealand. Principal component analyses data young mature showed no significant grouping on the basis composition, but identified differences between essential components contributing most to variation both plants. The dominant variables six sesquiterpene plants, three monoterpenes two...

The traditionally consumed New Zealand native plant nau, Cook's scurvy grass, Lepidium oleraceum, has a pungent wasabi-like taste, with potential for development as flavor ingredient. main glucosinolate in this Brassicaceae was identified by LC-MS and NMR spectroscopy 3-butenyl (gluconapin, 7-22 mg/g DM leaves). leaves were treated to mimic chewing, the headspace analyzed solid-phase microextraction GC-MS. This showed that isothiocyanate, flavor, produced endogenous myrosinase. Different...

Abstract Several Anisotome diterpene derivatives were synthesized in an attempt to obtain a crystalline compound for X‐ray analysis. Although we unable suitable crystal, the absolute configuration of irregular skeleton was determined using two other techniques: circular dichroism (CD) protocol based on tetraarylporphyrin molecular tweezer that allowed prediction stereochemistry microscale level, and method employing differences NMR shifts from derivatization naturally occurring acid 1 with...