Ferrulic acid

As can be seen, all the water-soluble compounds are capable of quenching CAR + efficiently, with rate constants of the order of 106,107, and 108 M 1 s 1 for ferrulic acid, both ascorbic and uric acids, and Trolox, respectively. 

CAR + max(nm) Ascorbic Acid Trolox Ferrulic Acid Uric Acid... 

The 4-coumarate CoA ligase (4CL EC 6.2.1.12) enzyme activates 4-coumaric acid, caffeic acid, ferrulic acid, and (in some cases) sinapic acid by the formation of CoA esters that serve as branch-point metabolites between the phenylpropanoid pathway and the synthesis of secondary metabolites [46, 47]. The reaction has an absolute requirement for Mg " and ATP as cofactors. Multiple isozymes are present in all plants where it has been studied, some of which have variable substrate specificities consistent with a potential role in controlling accumulation of secondary metabolite end-products. Examination of a navel orange EST database (CitEST) for flavonoid biosynthetic genes resulted in the identification of 10 tentative consensus sequences that potentially represent a multi-enzyme family [29]. Eurther biochemical characterization will be necessary to establish whether these genes have 4CL activity and, if so, whether preferential substrate usage is observed. 

R1=R2=H coumaric acid Rl=OH, R2=H caffeic acid R1=0CH3, R2=H ferrulic acid R1=R2 CH3, sinapic acid... 

An intriguing route to materials with built-in anti-oxidant capability was demonstrated through the addition of ferrulic acid. The strategy for attaching the acid included initial protection of the acidic moeity. 

The bimolecular rate constants were determined (Burke 2001) for the repair of carotenoid radical cations by trolox, ascorbic, ferrulic, and uric acids from the pulse radiolysis studies of carotenoids in aqueous micellar solutions (see Table 14.10). 

Figure F1.3.6 HPLC chromatograms of radish anthocyanin extract before (solid line) and after (dashed line) saponification. Peak 1 pelargonidin-3-sophoroside-5-g ucoside Peaks 2, 3, 4, 5 pelargonidin-3-sophoroside-5-glucoside acylated with />coumaric (2), ferrulic (3), p-couniaric and malonic (4), or ferrulic and malonic acid (5), respectively. Note that the saponified sample has only pelargonidin-3-sophoroside-5-glucoside.

Acid resistant ferrules are provided at the gas entry points of the tubes to minimize corrosion of welded joints with tube sheets. Provision was made of expansion bellows for the shell to minimize stress due to thermal expansion. 

Ceramic/stainless steel AISI-304/stainless steel AISI-316 ferrules may be put in tubes and fixed by fire- /acid-resistant cement. 

The compound at a retention index (RI) of 897 is tentatively identified as a methoxy-phenyl oxime and possesses a base peak at m/z 133 and a molecular ion of m/z 151. This compound is believed to originate from the glue that is used to attach the fiber to the syringe plunger. A series of compounds are observed that have a base peak of m/z 100. These compounds may be associated with the action of moisture with the Vespel ferrules. Other contaminants include the ubiquitous phthalic acid esters and antioxidants, butylated hydroxy toluene and butylated hydroxy anisole. Sources of these compounds are the packaging used for vials. 

Optical fibers were provided by NRL and all fiber tapering was conducted at the laboratory in Washington, DC. Fibers were made from step-index plastic clad silica optical fiber (200 m core, Quartz et Silica, Quartz Products) with a black plastic ferrule on the proximal end. The proximal face of the fiber is polished after insertion into the ferrule. The total length of the fiber is approximately 1 meter with only 10 centimeters of the entire fiber being used for assay purposes. At the distal end of the fiber (last 12 cm), the cladding was stripped with a razor blade and the fiber core was tapered by computer-controlled immersion into hydrofluoric acid. 

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