Metabolomics: an unexplored tool for allelopathy studies

Allelopathy is a very complex phenomenon, influenced by many inherent and environmental factors. Due to this complexity, its elucidation is a challenging task, requiring expertises from several fields. A valuable approach to study these interactions is systems biology, a holistic approach giving a broad view of biological systems and relying on omics technologies. Among omics sciences, metabolomics could be very powerful, but despite its potential it has been seldom applied to allelopathy studies. This review aims to introduce metabolomics approach to researchers involved in the study of allelopathy: to this end, an overview of this approach is given along with examples of application of metabolomics to other ecological issues (effects of abiotic and biotic stresses). Furthermore, the scarce examples of application of metabolomics or metabolomics-related approaches to allelopathy studies are reported

Comment on the paper: “Spectroscopic and computational study of the major oxidation products formed during the reaction of two quercetin conformers with a free radical

the title paper reports a study on the structural elucidation by spectroscopic and computational methods of the products obtained from the reaction of two conformers of quercetin with the 2,2-diphenyl-1- picrylhydrazyl radical (DPPH•). Many points of criticism, concerning both theoretical principles and experimental data, are highlighted in the present communication. © 2013 Elsevier B.V. All rights reserved

Tocopherols, tocotrienols, and their bioactive analogs

Vitamin E is a lipid-soluble vitamin naturally synthesized by photosynthetic organisms (Yerin et al., 1984). The term “vitamin E” refers to a group of chemical compounds, tocols, and tocotrienols that act as antioxidant compounds and maintain the stability of cell membranes against oxidative stress. The antioxidant activity of vitamin E seems to be correlated with their capacity to quench free radicals and, in particular, reactive oxygen species produced by the cell metabolism. Vitamin E was discovered by Evans and Bishop (1922) and called “substance X” because it was essential to maintain rat fertility. The most active vitamer of vitamin E is α-tocopherol (from the Greek tokos = child, phero = to bear, and -ol indicating that the substance is an alcohol), isolated for the ‚rst time from wheat germ oil (Evans et al., 1936). © 2012 by Taylor & Francis Group, LLC

Low molecular weight phenols from the bioactive aqueous fraction of Cestrum parqui.

The aqueous fraction of fresh leaves of Cestrum parqui and its organic fractions have been assayed for their phytotoxicity on Lactuca sativa, Lycopersicon esculentum, and Allium cepa. The tests showed that the bioactivity was retained in the organic fractions. Chromatographic processes led to isolation and characterization of the N-(p-carboxymethylphenyl)-p-hydroxybenzamide together with 17 low molecular weight phenols and 2 flavones. The phytotoxicity tests showed a good activity of these compounds on the target species. Comparison of some metabolites with commercial herbicides revealed a major activity of the natural compounds at lower concentrations

Isolation and phytotoxicity of apocarotenoids from Chenopodium album. Journal of Natural Products

Two new compounds (1, 2) and 16 apocarotenoids (3-18) were isolated from the weed Chenopodium album. The structures of new apocarotenoids were determined to be (3R,6R,7E,9E,11E)-3-hydroxy-13- apo-R-caroten-13-one (1) and (6S,7E,9E,11E)-3-oxo-13-apo-R-caroten-13-one (2) by spectroscopic, NMR, and MS analysis. Five of the known compounds (5, 6, 13, 15, and 17) were previously reported only as synthetic compounds. Effects of these compounds on germination and growth of Lactuca sativa (lettuce) were studied in the 10-4-10-7 M concentration range

Lignans and neolignans from Brassica fruticulosa: Effects on seed germination and plant growth

Five lignans, five neolignans, two sesquilignans, and a dilignan were identified from a phytotoxic extract of Brassica fruticulosa L. Compounds 8, 9, 12, and 13 have been isolated for the first time. Structures were determined on the basis of their spectroscopic features. Their effects on the germination and growth of two dicotyledons, Lactuca sativa (lettuce) and Lycopersicon esculentum (tomato), and a monocotyledon, Allium cepa (onion), as standard target species have been studied

Antioxidant iridoid and phenylethanoid glycosides from Teucrium chamaedrys (L.)

Wall Germander (Teucrium chamaedrys) is a Mediterranean species used as medicinal herb. A previous screening turned to the radical scavenging efficacy determination was carried out on crude extracts from T. chamaedrys ipogeal and epigeal components undergoing each one to DPPH radical antioxidative HAT assay. Leaf and root methanolic extracts are responsive of a peculiar DPPH radical scavenging efficacy. The methanolic crude extracts were object of extractive and chromatographic analyses to yield twelve compounds: seven iridoid and five phenylethanoid glycosides, four of them isolated and characterized for the first time on the basis of their spectroscopic features. The DPPH radical scavenging and antioxidant capabilities of the purified metabolites were assessed. The antioxidant capability in cell-free systems of the isolated metabolites was carried out by measuring their capabilities to inhibit the synthesis of thiobarbituric acid reactive in assay media using as oxydable substrates a vegetable fat and the pentose sugar 2-deoxyribose. The inhibiting capacity of isolated metabolites the protein oxidation, defined as the covalent modification of a protein induced either directly by reactive oxygen species or indirectly by reaction with secondary by-products of oxidative stress, was also measured. Compounds from T. chamaedrys were tested in increasing concentration (5.0µM, 10.0µM and 20.0µM) in triplicate analysis. The detected activities were compared to those exercised from Trolox®. When DPPH radical scavenging was tested, phenylethanoid glycosides highly reduced the oxidant probe employing an activity strongly dose-dependent. Iridoid glycosides prevent massively the 2-deoxyribose and BSA oxidations in assay media. The results show that oxidation and radical processes are highly complex and involve various mechanisms and targets. In particular the ability to scavenge free radical does not necessarily confer antioxidant properties