Phenolics bioactivity

Finally, a new water-soluble polyphosphazene was recently synthesized that has the structure shown in 36 (46). This polymer has two attributes as a biomedical macromolecule. First, the pendent carboxylic acid groups are potential sites for condensation reactions with amines, alcohols, phenols, or other carboxylic acid units to generate amide, ester, or anhydride links to polypeptides or bioactive small molecules. Second, polymer forms ionic crosslinks when brought into contact with di- or trivalent cations such as Ca or Ai3+. The crosslinking process converts the water-soluble polymer to a hydrogel, a process that can be reversed when the system... 

Carmen Socaciu was bom in Cluj-Napoca, Romania and earned a BSc in chemistry in 1976, an MSc in 1977, and a PhD in 1986 from the University Babes-Bolyai in Cluj-Napoca, an important academic centre located in the Transylvania region. Dr. Socaciu worked as a researcher in medical and cellular biochemistry for more than 10 years, and became a lecturer in 1990 and full professor in 1998 in the Department of Chemistry and Biochemistry of the University of Agricultural Sciences and Veterinary Medicine (USAMV) in Cluj-Napoca. She extended her academic background in pure chemistry (synthesis and instrumental analysis) to the life sciences (agrifood chemistry and cellular biochemistry). Her fields of competence are directed especially toward natural bioactive phytochemicals (carotenoids, phenolics, flavonoids), looking to advanced methods of extraction and analysis and to their in vitro actions on cellular metabolism, their effects as functional food ingredients, and their impacts on health. 

Some non-silica sol-gel materials have also been developed to immobilize bioactive molecules for the construction of biosensors and to synthesize new catalysts for the functional devices. Liu et al. [33] proved that alumina sol-gel was a suitable matrix to improve the immobilization of tyrosinase for detection of trace phenols. Titania is another kind of non-silica material easily obtained from the sol-gel process [34, 35], Luckarift et al. [36] introduced a new method for enzyme immobilization in a bio-mimetic silica support. In this biosilicification process precipitation was catalyzed by the R5 peptide, the repeat unit of the silaffin, which was identified from the diatom Cylindrotheca fusiformis. During the enzyme immobilization in biosilicification the reaction mixture consisted of silicic acid (hydrolyzed tetramethyl orthosilicate) and R5 peptide and enzyme. In the process of precipitation the reaction enzyme was entrapped and nm-sized biosilica-immobilized spheres were formed. Carturan et al. [11] developed a biosil method for the encapsulation of plant and animal cells. 

Huck WC, Stecher G, Scherz H and Bonn G. 2005. Analysis of drugs, natural and bioactive compounds containing phenolic groups by capillary electrophoresis coupled to mass spectrometry. Electrophoresis 26(7-8) 1319-1333. 

Phytochemicals or phytonutrients are bioactive substances that can be found in foods derived from plants and are not essential for life the human body is not able to produce them. Recently, some of their characteristics, mainly their antioxidant capacity, have given rise to research related to their protective properties on health and the mechanisms of action involved. Flavonoids are a diverse group of phenolic phytochemicals (Fig. 6.1) that are natural pigments. One function of flavonoids is to protect plants from oxidative stress, such as ultraviolet rays, environmental pollution, and chemical substances. Other relevant biological roles of these pigments are discussed in other chapters of this book. 

Finally, it should also be considered that flavonoid-rich foods contain a great diversity of compounds with bioactive properties (for e.g., carotenoids, other phenolics, fiber, and minerals), and multiple interactions occur among all of them. There is also great diversity in the ingestion, absorption, and metabolism of these compounds in different populations, and all of these circumstances could camouflage any effect of flavonoids on disease prevention or treatment. 

It may be concluded that PEF, HHP, and IR are adequate techniques for the retention of bioactive compounds in fruit and vegetable products and may even enhance bioactivity of juices, purees, and fresh-cut produce. A greater degradation of ascorbic acid in comparison with phenolics and carotenoids is usually observed. 

Subrahmanyam VV, Doane-Setzer P, Steinmetz KL, et al. 1990a. Phenol-induced stimulation of hydroquinone bioactivation in mouse bone marrow in vivo Possible implications in benzene myelotoxicity. Toxicology 62 107-116. 

K. Robards Strategies for the determination of bioactive phenols in plants, fruit and vegetables. 

Thus, a synthetic source of promising allelochemicals is essential if we are to comprehensively study the agent s mode of activity and establish its basic structure-activity profile. The proposed work addresses this need. We will synthesize alleopathic natural products isolated from the sunflower (the heliannuols), and structurally related compounds, in optically pure form based on biomimetic phenol-epoxide cyclizations. The bioactivity of the targets and intermediates will be evaluated through laboratory tests on plant germination and growth. Bioassays will be performed on the synthetic intermediates to allow for the development of a preliminary structure-activity profile for these novel natural herbicides. 

Phenolic acids have already been discussed as inhibitory compounds. But inhibition of germination requires a concentration of 10 to 10 M phenolic acids. (j ). Such high concentration may locally be achieved if oat straw is accumulated in the fields (4). This could sometimes be a reason for poor plant growth on fields after harvest of oats without removal of straw. We did not find such concentrations in our husk extracts, however they were 100 - 1000 fold smaller than expected from bioactivity. Phenolic acids are therefore not the active compounds in our inhibitory extracts. 

The behavior of phenolic compounds derived from decaying plant residues, or released from degrading humic substances, is dictated by the physico-chemical processes of adsorption and desorption. Equilibria between these processes determine the concentration of phenolic compounds in the soil solution and consequently the bioactivity, movement, and persistence of these substances in the soil. Surface interactions between phenolic compounds and colloidal matrices may promote their polymerization (25, 26) or protect them from microbial degradation and mineralization. 

Phenolic and antioxidant substances have usually studied in red wines, however, recently, interest has increased in the study of bioactive phenolics in white wines Frega et al. [374] isolated and measured concentration of ethyl caffeoate in Verdicchio white wine by HPLC-tandem-mass spectrometry (HPLC-ESI-MS/MS) and they also determined its effects on hepatic stellate cells and intracellular peroxidation. The resnlts were interesting in the light of other studies demonstrating the relationship between reactive oxygen species, chronic liver injury, and hepatic fibrosis. 

Diarylheptanoids are characteristic phenolics found in the family Zingiberaceae, e.g., curcu-min, the bioactive yellow pigment from the spice turmeric (roots of Curcuma longa) and similar compounds from ginger Zingiber officinalis). A series of novel diarylheptanoids... 

Macias, F.A. et al., Natural products as allelochemicals. Bioactive phenolics and polar compounds from Melilotus messanensis, Phytochemistry, 50, 35, 1999. 

CasteUari, M., Matricardi, L., Arfelli, G., Galassi, S., and Amati, A. (2000). Level of single bioactive phenolics in red wine as a function of the oxygen supplied during storage. Food Chem. 69, 61-67. 

Physical properties depend upon the same types of steric effects as chemical reactivities. In both types of data the measurable phenomenon is occurring at a clearly defined active site. Thus, for the ionization of a set of phenols the active site is the OH group, while for the stretching frequency in the infrared spectrum of the acetyl group in a set of acetophenones the active site is the carbonyl group. In the case of bioactivities, steric effects in the formation of the bioactive substance-receptor site complex are frequently of great importance. In this case the entire bioactive... 

Catechol may be oxidized by peroxidases to the reactive intennediate benzo-1,2-quinone, which readily binds to proteins (Bhat et al., 1988) this process, catalysed by rat or human bone-marrow cells in the presence of H2O2 (0.1 mM), is stimulated by phenol (0.1-10 mM), and decreased by hydroquinone and by glutathione, which conjugates with benzo-l,2-quinone. These phenols (phenol, catechol and hydroquinone) may play a role in benzene toxicity to bone marrow all three are formed as benzene metabolites (Smith et al., 1989) and they interact in several ways as far as their bioactivation by (myelo)peroxidases is concerned (Smith et al., 1989 Subrahmanyam et al., 1990). 

There is a huge variety of plant defensive secondary metabolites that has been the subject of major phytochemical [1-6] or pharmacological and toxicological [7-12] compilations. This structural complexity is very briefly reviewed below before considering those plant bioactives with signal transduction targets. The major groups are the phenolics, the terpenoids and the alkaloids as well as bioactives structurally related to... 

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