Antiviral compounds phenolics

Odabasoglu F, Aslan A, Cakir A et al (2004) Comparison of antioxidant activity and phenolic content of three lichen species. Phytother Res 18 938-941 Omarsdottir S, Oladottir AK, Amadottir T et al (2006) Antiviral compounds from Icelandic lichens. Planta Med 72 - S 009... 

These compounds contain the fragment R as an alkyl or aryl moiety. In other words, they result from the esterification of an alcohol or a phenol with nitrous acid, nitric acid, phosphoric acid, sulfuric acid, or sulfamic acid, respectively. Many of the esters to be examined in this chapter must be activated prior to eliciting their effects, e.g., the organic nitrites and nitrates, which act as donors of nitric oxide or an analogous molecule, and phosphates, which are activated by hydrolysis or even by phosphorylation (antiviral agents). Sulfates are very seldom active or used as prodrugs, but they have significance as metabolites and as industrial xenobiotics. 

Lin CW, Tsai FJ, Tsai CH, Lai CC, Wan L, Ho TY, Hsieh CC, Chao PD. (2005) Anti-SARS coronavirus 3C-like protease effects of Isatis indigotica root and plant-derived phenolic compounds. Antiviral Res 68 36-42. 

Lignans are a well-known class of widespread natural phenolic compounds that exhibit great structural and biological diversity and are commonly found in vascular plants from various families [1]. They are present at different levels of abundance in all plant parts, including roots, rhizomes, hardwood, bark, stems, leaves, flowers, fruits and seeds [2]. Lignans are of considerable pharmacological and clinical interest and are used in the treatment of cancer and other diseases [3]. The extensive pharmaceutical use of lignans is due to their antitumor, antiviral and hepatoprotective properties as well as many other beneficial activities. 

There have been remarkably few new applications of compounds in this class, but aromatic sultones of general structure (107) related to phenol red have been patented for use as heat-sensitive recording materials <93JAP0509187>, and the spiro adamantane sultones (108) and (109) have been evaluated as antiviral agents, although they proved to have disappointing activity <92BMC647>. 

Polyphenolic compounds occur widely distributed in nature and may possess a variety of interesting biological properties, e. g. antibiotic, antiviral and antitumor activity. The synthesis and further elaboration of these compounds often requires the selective protection or deprotection of specific phenolic hydroxy groups. To achieve this goal, the methods highlighted above for the various aliphatic polyols can also be applied successfully. 

In order to explain and confirm the biological activities claimed by the traditional medicine, and to search for new biologically active compounds we studied the antimicrobial, antioxidative, immunomodulatory, antiinflammatory, skin-regenerating and antiviral properties of Fraxinus ornus bark extract and its components. In a parallel detailed phytochemical investigation of the extract we isolated and determined the structures of many hydroxycoumarins, secoiridoid glucosides, caffeoyl esters of phenylethanoid glycosides, lignans and other phenolic compounds. 

Caffeic Acid Phenethyl Ester (CAPE). CAPE, a phenolic compound with antioxidant properties, is an active ingredient derived from honeybee propolis (52). CAPE has antiviral, anti-inflammatory and antiproliferative properties. The compound differentially suppresses the growth of numerous human cancer cells and also inhibits tumor promoter-mediated processes in transformed cells (53,54). In transformed cells, CAPE induces apoptosis and inhibits the expression of the malignant phenotype (55,56). In addition, CAPE treatment attenuates the formation of azoxymethane-induced aberrant crypts and the activities of ornithine decarboxylase (ODC), tyrosin protein kinase, and lipoxygenase activity (57). Although the molecular basis for these multiple chemopreventive effects of CAPE is not clear, recent studies have demonstrated that CAPE is a potent and specific inhibitor of the transcription factor NF-kB (58). CAPE inhibited the activity and expression of COX-2 in the carrageenan air pouch model of inflammation as well as in TPA-treated human oral epithelial cells (59). CAPE was able to reduce neointimal formation by inhibiting NF-kB activation in a model of endothelial injury of rat carotid artery (60). 

Toxicity seems to be an important attribute of phenols in plants. Essentially, every phenolic compound has some antimicrobial and antifungal activity (Jenkins et al., 1957 Walker, 1975). Antibiotic, antiviral, anticellular, antineoplastic, and related effects of tannins, mostly in vitroy have been reported by several researchers (Alexander, 1965 Herz and Kaplan, 1968 Kreber and Einhellig, 1972 Konowalchuk and Speirs, 1976 Chan et al., 1978 Loub et al., 1973 DeOliveira et al., 1972). 

Okuda T, Yoshida T, Hatano T (1992) Polyphenols from Asian plants - structural diversity and antitumor and antiviral activities. In Huang M-T, Ho C-T, Lee CY (eds) Phenolic compounds in food and their effects on health, voi II, ACS symposium series 507. American Chemical Society, Washington, DC... 

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