chlorophyll-a and ethyl-acetate

The aim of the study was to evaluate an elevated (3.0 °C) and low (1.0 °C) storage temperature combined with dynamic controlled atmosphere monitored by respiratory quotient (DCA-RQ) and chlorophyll fluorescence (DCA-CF) on anaerobic metabolism, physiological storage disorders and overall quality of 'Nicoter' ('Kanzi®') apples after 5.5 and 8.0 months of storage plus 7d shelf-life. Fruit stored under DCA-RQ 2.0 accumulated the highest amounts of anaerobic metabolites (acetaldehyde, ethanol and ethyl acetate), regardless of storage temperature and timing of storage outturn evaluation, but it did not result in higher electrolyte leakage. Flesh breakdown, core breakdown and cavity formation were reduced at 3 °C. Storage at 3 °C combined with DCA maintained higher flesh firmness after 8.0 months storage plus 7d shelf-life. 'Nicoter' apples can be stored at 3 °C using a DCA system, based either on CF or on RQ, to save electrical energy.

Topics: Acetaldehyde; Acetates; Anaerobiosis; Atmosphere; Chlorophyll; Ethanol; Fluorescence; Food Storage; Fruit; Malus; Temperature

As part of our continuing research for anticancer compounds from the Walloon Region forest, EtOAc extract from Carpinus betulus leaves was phytochemically studied, leading to the bioguided isolation of pheophorbide a, which is responsible of anticancer properties of C. betulus young leaves. This compound was identified using nuclear magnetic resonance and mass spectrophotometric data and comparison with a commercial standard. Evaluation of the growth inhibitory activities of pheophorbide a using MTT colorimetric assay and phase-contrast microscopy in various human cancer cell lines confirmed the photoactivable properties of this compound. Our research showed, for the first time, the presence of pheophorbide a, a chlorophyll derived compound, which we quantified in high quantities in young leaves of C. betulus. This is in contrast with the literature which generally describes pheophorbide a as a catabolic product of chlorophyll, then preferentially present in old leaves.

Topics: Acetates; Antineoplastic Agents, Phytogenic; Betulaceae; Cell Line, Tumor; Chemical Fractionation; Chlorophyll; Chromatography, High Pressure Liquid; Humans; Inhibitory Concentration 50; Magnetic Resonance Spectroscopy; Microscopy, Phase-Contrast; Plant Extracts; Plant Leaves

The lower oxygen limit (LOL) in plants may be identified through the measure of respiratory gases [i.e. the anaerobic compensation point (ACP) or the respiratory quotient breakpoint (RQB)], but recent work shows it may also be identified by a sudden rise in dark minimum fluorescence (F(o)). The interrelationship between aerobic respiration and fermentative metabolism, which occur in the mitochondria and cytosol, respectively, and fluorescence, which emanates from the chloroplasts, is not well documented in the literature. Using spinach (Spinacia oleracea), this study showed that F(o) and photochemical quenching (q(P)) remained relatively unchanged until O(2) levels dropped below the LOL. An over-reduction of the plastoquinone (PQ) pool is believed to increase F(o) under dark + anoxic conditions. It is proposed that excess cytosolic reductant due to inhibition of the mitochondria's cytochrome oxidase under low-O(2), may be the primary reductant source. The maximum fluorescence (F(m)) is largely unaffected by low-O(2) in the dark, but was severely quenched, mirroring changes to the xanthophyll de-epoxidation state (DEPS), under even low-intensity light (≈4 μmol m(-2) s(-1)). In low light, the low-O(2)-induced increase in F(o) was also quenched, likely by non-photochemical and photochemical means. The degree of quenching in the light was negatively correlated with the level of ethanol fermentation in the dark. A discussion detailing the possible roles of cyclic electron flow, the xanthophyll cycle, chlororespiration and a pathway we termed 'chlorofermentation' were used to interpret fluorescence phenomena of both spinach and apple (Malus domestica) over a range of atmospheric conditions under both dark and low-light.

Topics: Acetaldehyde; Acetates; Chlorophyll; Dithiothreitol; Electron Transport; Ethanol; Fermentation; Fluorescence; Light; Malus; Mitochondria; Oxidoreductases; Oxygen; Photosynthesis; Spinacia oleracea; Xanthophylls

Our aim was to determine the antimutagenic activity of various solvent extracts from an herb Mesona procumbens Hemsl, normally called Hsian-tsao in China. We also investigated the relationships between the special components in the water extract of Hsian-tsao (WEHT) and the antimutagenic activity. It was found that the extracts at 0-0.6 mg/plate from three solvents (water, methanol, and ethyl acetate) exhibited a dose-dependent antimutagenic effect against benzo[a]pyrene [B(a)P] and 2-amino-3-methylimidazo(4,5-f)quinoline (IQ), both are indirect mutagens in Salmonella tester strains TA98 and TA100. The WEHT from three different plantations revealed a similar inhibitory effect on the mutagenicity of IQ in TA 98 at 2.5-5.0 mg/plate. The inhibitory effect of WEHT on the mutagenicity of IQ correlates with their polyphenol and ascorbic acid contents but not with their chlorophyll contents. These findings suggest that the antimutagenicity activity of WEHT may be attributed mainly to their polyphenolic compounds and ascorbic acid.

Topics: Acetates; Antimutagenic Agents; Ascorbic Acid; Benzo(a)pyrene; Chlorophyll; Flavonoids; Medicine, Chinese Traditional; Methanol; Mutagenicity Tests; Mutagens; Phenols; Plant Extracts; Plants, Medicinal; Polymers; Polyphenols; Quinolines; Solvents; Water

Two methods for analysis of acid-labile sulfide and zero-valence sulfur in plant extracts containing chlorophyll as well as ionic and/or nonionic detergents are presented. Both methods are based on the conversion of sulfide into methylene blue. In the first method an ethyl acetate extraction step is used to remove chlorophyll and its degradation products which otherwise prevent spectrophotometric quantitation of methylene blue. The second assay method employs 35S-labeled plant extracts. This method, which involves thin-layer chromatography and autoradiography, is potentially more sensitive than the spectrophotometric assay in detecting acid-labile sulfide and zero-valence sulfur.

Topics: Acetates; Autoradiography; Chlorophyll; Chromatography, Thin Layer; Detergents; Methylene Blue; Plants; Spectrophotometry; Sulfides; Sulfur