The last few decades have provided stunning progresses in the understanding of physiopathology of several diseases. The remarkable progress in research fields, like genetics, immunology, neurobiology, among others, as well as the advent of more powerful tools, have made it possible to characterize, monitor, and understand far more of the basis of physiology and disease. However, for some diseases the treatment remains a problematic issue as the efforts performed so far were not translated into therapeutic solutions. Notwithstanding the steady increase in the total amount of FCUP

Hydroxycinnamic acids (such as ferulic, caffeic, sinapic, and p-coumaric acids) are a group of compounds highly abundant in food that may account for about one-third of the phenolic compounds in our diet. Hydroxycinnamic acids have gained an increasing interest in health because they are known to be potent antioxidants. These compounds have been described as chain-breaking antioxidants acting through radical scavenging activity, that is related to their hydrogen or electron donating capacity and to the ability to delocalize/stabilize the resulting phenoxyl radical within their structure. The free radical scavenger ability of antioxidants can be predicted from standard one-electron potentials. Thus, voltammetric methods have often been applied to characterize a diversity of natural and synthetic antioxidants essentially to get an insight into their mechanism and also as an important tool for the rational design of new and potent antioxidants. The structure-property-activity relationships (SPARs) correlations already established for this type of compounds suggest that redox potentials could be considered a good measure of antioxidant activity and an accurate guideline on the drug discovery and development process. Due to its magnitude in the antioxidant field, the electrochemistry of hydroxycinnamic acid-based antioxidants is reviewed highlighting the structure-property-activity relationships (SPARs) obtained so far.

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a b s t r a c tPhenolic compounds constitute a diverse group of secondary metabolites which are present in both grapes and wine. The phenolic content and composition of grape processed products (wine) are greatly influenced by the technological practice to which grapes are exposed. During the handling and maturation of the grapes several chemical changes may occur with the appearance of new compounds and/or disappearance of others, and consequent modification of the characteristic ratios of the total phenolic content as well as of their qualitative and quantitative profile. The non-volatile phenolic qualitative composition of grapes and wines, the biosynthetic relationships between these compounds, and the most relevant chemical changes occurring during processing and storage will be highlighted in this review.

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a b s t r a c tPhenolic compounds constitute a diverse group of secondary metabolites which are present in both grapes and wine. The phenolic content and composition of grape processed products (wine) are greatly influenced by the technological practice to which grapes are exposed. During the handling and maturation of the grapes several chemical changes may occur with the appearance of new compounds and/or disappearance of others, and consequent modification of the characteristic ratios of the total phenolic content as well as of their qualitative and quantitative profile. The non-volatile phenolic qualitative composition of grapes and wines, the biosynthetic relationships between these compounds, and the most relevant chemical changes occurring during processing and storage will be highlighted in this review.

Hydroxycinnamic acids (HCAs) are important phytochemicals possessing significant biological properties. Several investigators have studied in vitro antioxidant activity of HCAs in detail. In this review, we have gathered the studies focused on the structure-activity relationships (SARs) of these compounds that have used medicinal chemistry to generate more potent antioxidant molecules. Most of the reports indicated that the presence of an unsaturated bond on the side chain of HCAs is vital to their activity. The structural features that were reported to be of importance to the antioxi-dant activity were categorized as follows: modifications of the aromatic ring, which include alterations in the number and position of hydroxy groups and insertion of electron donating or withdrawing moieties as well as modifications of the car-boxylic function that include esterification and amidation process. Furthermore, reports that have addressed the influence of physicochemical properties including redox potential, lipid solubility and dissociation constant on the antioxidant activ-ity were also summarized. Finally, the pro-oxidant effect of HCAs in some test systems was addressed. Most of the investigations concluded that the presence of ortho-dihydroxy phenyl group (catechol moiety) is of significant importance to the antioxidant activity, while, the presence of three hydroxy groups does not necessarily improve the activity. Optimiza-tion of the structure of molecular leads is an important task of modern medicinal chemistry and its accomplishment relies on the careful assessment of SARs. SAR studies on HCAs can identify the most successful antioxidants that could be use-ful for management of oxidative stress-related diseases.Keywords: Antioxidant, hydroxycinnamic acids, in vitro, ROS, structure-activity relationships. OXIDATIVE STRESS AND ANTIOXIDANTSReactive oxygen species (ROS) are oxygen derived molecules that readily react with other compounds and macromolecules and oxidize them. Some representative exam-ples of these species include superoxide (O2•-), hydroxy (HO • ) and peroxy (ROO • ) radicals, hydrogen peroxide (H2O2) and singletROS are involved in important physiological processes such as immune response, gene expression, signal transduc-tion and growth regulation [5,6]; however if they are not kept under tight control by physiological antioxidant systems they will be able to oxidize and damage various biological molecules leading to a condition called oxidative stress [1,7,8]. In this regard, oxidative stress has been reported to be in-volved in the pathogenesis of diseases such as cancer [9], neurodegenerative diseases [10], stroke [11], and others [12,13].Since an important source of ROS comes from environment [14], with the industrial development and the change in life style, oxidative stress related diseases need a special attention [15].Antioxidants operate by preventing or slowing the progression of oxidative damage reactions [16,17]. An antioxidant has been defined as "any substance that delays, p...

Abstract-A multidisciplinary project was developed, combining the synthesis of a series of b-nitrostyrene derivatives and the determination of their physicochemical parameters (redox potentials, partition coefficients), to the evaluation of the corresponding antibacterial activity. A complete conformational analysis was also performed, in order to get relevant structural information. Subsequently, a structure-property-activity (SPAR) approach was applied, through linear regression analysis, aiming at obtaining a putative correlation between the physicochemical parameters of the compounds investigated and their antibacterial activity (both against standard strains and clinical isolates). The b-nitrostyrene compounds displayed a lower activity towards all the tested bacteria relative to the b-methyl-b-nitrostyrene analogues. This was observed particularly for the 3-hydroxy-4-methoxy-b-methyl-bnitrostyrene (IVb) against the Gram-positive bacteria (Staphylococcus aureus, Enterococcus faecalis and Enterococcus faecium). The SPAR results revealed the existence of a clear correlation between the redox potentials and the antibacterial activity of the series of b-nitrostyrene derivatives under study.