Synthesis of Tyrosol 1,2,3-Triazole Derivatives and Their Phytotoxic Activity against Euphorbia heterophylla.

The synthesis and phytotoxic activity of a series of tyrosol 1,2,3-triazole derivatives are reported herein. Target compounds were synthesized through the copper(I)-catalyzed azide-alkyne cycloaddition reaction (CuAAC), known as click reaction, and these were tested for phytotoxic activity on leaves of wild poinsettia (Euphorbia heterophylla), fleabane (Conyza sumatrensis), and tropical spiderwort (Commelina benghalensis). These are three highly noxious agricultural weeds that challenge available weed control methods, including the use of chemical herbicides. Twenty-five compounds were synthesized and tested. None of the compounds showed phytotoxic activity against C. benghalensis and C. sumatrensis, but almost all of them produced yellowing, bleaching, and necrosis on leaves of E. heterophylla. Two of the tyrosol 1,2,3-triazole derivatives produced more extensive lesions than those produced by the commercial herbicide diquat, used as a positive control (p ≤ 0.05). When applied on leaves of E. heterophylla, these compounds interfered with the stomatal conductance, net photosynthesis, internal carbon concentration, transpiration rate, water-use efficiency, and chlorophyll A and B contents. The interference of such compounds on such photosynthesis-related variables indicates that tyrosol 1,2,3-triazole derivatives may be capable of lowering the competitiveness of E. heterophylla and acting as additional tools for managing this competitive weed in agricultural lands.

Spray-dried olive mill wastewater reduces Maillard reaction in cookies model system.

The network of the Maillard reaction can be influenced by the presence of polyphenols. In this paper, we evaluated the ability of secoiridoids to interact with asparagine and lysine tuning the formation of dietary advanced glycation end-products (d-AGEs), dicarbonyls and acrylamide. Olive oil mill wastewater polyphenol powders (OMWP) were added to glucose and lysine or asparagine in silica model systems to mimic water activity present in cookies. Results revealed that acrylamide, Amadori compounds and N-ε-carboxyethyllysine (CEL) were reduced to 50%, after 13 min at 180 °C; for the reduction of N-ε-carboxymethyllysine (CML), secoiridoids were effective only in model systems with the addition of acacia fiber and maltodextrin as coating agents. In cookies, OMWP at three different concentrations decreased the concentration of protein bound Amadori compounds, CML, CEL and dicarbonyls. Acrylamide and 5-hydroxymethylfurfural were reduced to 60% and 76% respectively, highlighting the ability of secoiridoids-based functional ingredients in controlling d-AGEs formation.

Engineering Eschericha coli for Enhanced Tyrosol Production.

Tyrosol is a phenolic compound found in olive oil and wines. The health benefits of tyrosol have attracted considerable attention. Because the tyrosol extraction from plants poses a major obstacle, biosynthesizing this compound using microbial hosts is of interest. In this study, the phenylpyruvate decarboxylase gene ARO10 and the aromatic amino acid aminotransferase gene ARO8 were introduced into Escherichia coli to generate two recombinant tyrosol producers. Deleting the prephenate dehydratase gene pheA and the phenylacetaldehyde dehydrogenase gene feaB improved the tyrosol production. Under the optimal fermentation conditions, a recombinant strain overexpressing ARO10 gene produced 4.15 mM tyrosol from 1% (w/v) glucose during a 48 h shake flask cultivation. Furthermore, when tyrosine was used as the substrate, the recombinant strain co-overexpressing ARO8 and ARO10 genes displayed a higher tyrosol yield, in which 8.71 mM tyrosol was produced from 10 mM tyrosine. This investigation suggests that microbial tyrosol production has application potential.

Simultaneous determination of phenolic compounds in sesame oil using LC-MS/MS combined with magnetic carboxylated multi-walled carbon nanotubes.

A novel magnetic carboxylated multi-walled carbon nanotubes (c-MWCNT-MNPs) was proposed for magnetic solid-phase extraction coupled with liquid chromatography-tandem mass spectrometry to determine phenolic compounds in sesame oil. In this study, c-MWCNT-MNPs were acquired by simply dispersing Fe3O4 magnetic nanoparticles into carboxylated multi-walled carbon nanotubes. The major parameters affecting extraction efficiency were optimized, including the type and volume of desorption solvents, extraction and desorption time, washing solution, and sorbent amount. The limit of quantifications and limit of detections were from 0.03µg/kg to 43.00µg/kg and from 0.01µg/kg to 13.60µg/kg, respectively. The recoveries of phenolic compounds in vegetable oils were in the range of 83.8-125.9% with inter-day and intra-day precisions of less than 13.2%. It was confirmed that this method was simple, rapid and reliable with an excellent potential for routine analysis of phenolic compounds in oil samples.