Human antiviral activity

Antiviral Agents. Although a number of antibiotics have been shown to have some sort of antiviral activity, only vidarabine [5536-17-4] (adenine arabinoside) is used clinically against viral infections at this time. As the need for new antiviral agents (qv) increases and new screening procedures are developed, one would expect the discovery of other new effective antiviral antibiotics that could be used safely in human therapy. 

Matthews DA, Dragovich PS, Webber SE, Fuhrman SA, Patick AK, Zalman LS, Hendrickson TF, Love RA, Prins TJ, Marakovits JT, Zhou R, Tikhe J, Ford CE, Meador JW, Ferre RA, Brown EL, Binford SL, Brothers MA, DeLisle DM, Worland ST (1999) Structure-assisted design of mechanism-based irreversible inhibitors of human rhinovirus 3C protease with potent antiviral activity against multiple rhinovirus serotypes. Proc Natl Acad Sci USA 96 11000-11007... 

In this chapter, we have described the spectrum of antiviral activities that have been discovered beyond the world of nucleoside analogues, protease and fusion inhibitors. The compounds and mechanisms described here may one day add significantly to the armamentarium of antiviral agents, not only against Herpes Simplex, Hepatitis B and Human Immunodeficiency Virus, but also against Hepatitis C and Human Cytomegalovirus. 

Gibson W (1996) Structure and assembly of the virion. Intervirology 39 389 00 Goldman ME, Nunberg JH, O Brien JA, Quintero JC, Schleif WA, Freund KF, Gaul SL, Saari WS, Wai IS, Hoffman JM et al. (1991) Pyridinone derivatives specific human immunodeficiency virus type 1 reverse transcriptase inhibitors with antiviral activity. Proc Natl Acad Sci USA... 

Townsend L, Devivar R, Turk S, Nassiri M, Drach J (1995) Design, synthesis, and antiviral activity of certain 2,5,6-trihalo-l-(beta-d-ribofuranosyl)benzimidazoles. J Med Chem 38 4098 105 Turlure F, Devroe E, Silver PA, Engelman A (2004) Human cell proteins and human immunodeficiency virus DNA integration. Front Biosd 9 3187-3208 Umehara T, Fukuda K, Nishikawa F, Kohara M, Hasegawa T, NisUkawa S (2005) Rational design of dual-functional aptamers that inhibit the protease and helicase activities of HCV NS3. J Biochem 137 339-347... 

Jacobson JM, Lowy 1, Fletcher CV, O NeUl TJ, Tran DN, Ketas TJ, Trkola A, Klotman ME, Maddon PJ, Olson WC, Israel RJ (2000) Single-dose safety, pharmacology, and antiviral activity of the human immunodeficiency virus (HIV) type 1 entry inhibitor PRO 542 in HIV-infected adults. J Infect Dis 182 326-329... 

Bain VG, Kaita KD, Yoshida EM, Swain MG, Heathcote EJ, Neumann AU, FisceUa M, Yu R, Osborn BE, Cronin PW, Ereimuth WW, McHutchison JG, Subramanian GM (2006) A phase 2 study to evaluate the antiviral activity, safety, and pharmacokinetics of recombinant human albumin-interferon alfa fusion protein in genotype 1 chronic hepatitis C patients. J Hepatol 44 671-678... 

Buckwold VE, Wei J, Huang Z, Huang C, Nalca A, Wells J, Russell J, Collins B, Ptak R, Lang W, Scribner C, Blanchett D, Alessi T, Langecker P (2007) Antiviral activity of CHO-SS cell-derived human omega interferon and other human interferons against HCV RNA repUcons and... 

Hewson CA, Jardine A. Edwards MR. Laza-Stanca V, Johnston SL Toll-like receptor 3 is induced by and mediates antiviral activity against rhinovirus infection of human bronchial epithelial cells. J Virol 2005 79 12273-12279. 

The 2 -chloro and 2 -bromo congeners of either 748 (FIAC) or 758 (FMAU) are more cytotoxic than FIAC and FMAU, suggesting that these chloro and bromo nucleosides, in contrast to the 2 -fluoro compounds, are comparatively better substrates for deoxycytidine kinase of human lymphocytes than the substrates for viral-specific thymidine kinase. The disposition of the 2 -fluoro group may also be important from the biological viewpoint. It should be noted that the structural difference between RNA and DNA is at the 2 -position. The ribo type of analog (738) of FIAC is 10 times less effective in suppression of HSV replication than is FIAC. Thus Fox, and Watanabe and coworkers concluded that the 2 - up fluorine disposition and the species of the substituent at C-5 are the two important factors influencing antiviral activity. Nevertheless, the mechanism of action of 2 -deoxy-2 -fluorocytidine (737) on certain herpes viruses, including HSV-1... 

Catechins and proanthocyanidins have a documented antiviral activity. Catechins from an extract of Cocos nucifera husk fibre exhibited a strong inhibitory activity against acyclovir-resistant herpes simplex virus type 1 (HSV-l-ACVr) [62]. The use of 10 to 20ngml of ECG and EGCG has been reported to cause 50% inhibition of human immunodeficiency virus reverse transcriptase [89], while Kara and Nakayama [90] reported that a patented chewing gum containing tea catechins is claimed to prevent viral infections against influenza and to inhibit dissemination of this virus. 

SAR studies were carried out by de Bruyne et al. [92] on a series of dimeric procyanidins, considered as model compounds for antiviral therapies. On the whole, proanthocyanidins containing EC dimers exhibited more pronounced activity against herpes simplex virus (HSV) and human immunodeficiency virus (HIV), while the presence of ortho-trihydroxyl groups in the B-ring appeared to be essential in all proanthocyanidins exhibiting anti-HSV effects. Galloylation and polymerization reinforced the antiviral activities markedly. 

Lin T-S, Luo M-Z, Liu M-C, Pai SB, Dutschman GE, Cheng Y-C. Antiviral activity of 2, 3 -dideoxy-(l-L-5-fluorocytidine ((i-L-FddC) and 2, 3 -dideoxy-(1-L-cytidine ((1-L-ddC) against hepatitis B virus and human immunodeficiency virus type 1 in vitro. Biochem Pharmacol 1994 47 171-174. 

Heijtink RA, De Wilde GA, Kruining J, Berk L, Balzarini J, De Clercq E, Holy A, Schalm SW. Antiviral activity of 9-(2-phosphonylmethoxyethyl) adenine (PMEA) on human and duck hepatitis B virus infection. Antiviral Res 1993 21 141-153. 

Elvitegravir (18, GS-9137, JTK-303, EVG) is the second IN strand transfer inhibitor to advance into phase III clinical trials (Figure 7). EVG was derived from the quinolone antibiotics which do not show IN activity [39-41]. Through careful optimization, this work resulted in EVG displaying enzyme and antiviral activity of 7.2 and 0.9 nM, respectively. EVG has moderate bioavailability in preclinical species (29 and 34%), low clearance (Qp 0.5 and l.OL/h/kg) and a moderate half-life of 2.3 and 5.2h in rats and dogs, respectively [42]. It is primarily metabolized via CYP450 oxidation and shows a marked increase in human exposure with RTV boosting. 

Examples of the early application of recombinant DNA technology in medicine are the development of recombinant human growth hormone human insulin human interferons, thought to have anticancer activity in addition to antiviral activity interleukins (regulatory proteins from lymphocytes that are believed to be important in the treatment of immunodeficiency diseases and cancer) tumor necrosis factor epidermal and bone marrow progenitor cell growth factors and the production of vaccines (Table 12.1). 

Methyl oxetane-2-carboxylate derivatives (e.g., 284), obtained by ring contraction of aldonolactones, have been employed for the synthesis (279) of the nucleoside / -noroxetanocin [9-(/ -D-eryt/iro-oxetanosyl)adenine, 304] and its a-anomer via an a-chloride obtained by a modified Hunsdiecker reaction. Displacement of chloride by adenine and debenzylation gave 304. The threo isomer of304, /J-epinoroxetanocin (305), was likewise synthesized from D-lyxono-1,4-lactone. The oxetane nucleosides display potent antiviral activity against the human immunodeficiency virus (HIV). 

Dideoxyuridine (ddU) is an antiviral agent that proved ineffective at controlling human immunodeficiency virus type 1 (HIV-1) infection in human T-cells. This ineffectiveness was ascribed to a lack of substrate affinity of ddU for cellular nucleoside kinases, which prevent it from being metabolized to the active 5 -triphosphate. To overcome this problem, bis[(pivaloyloxy)methyl] 2, 3 -dideoxyuridine 5 -monophosphate (9.41) was prepared and shown to be a membrane-permeable prodrug of 2, 3 -di-deoxyuridine 5 -monophosphate (ddUMP, 9.42) [93]. Indeed, human T-cell lines exposed to 9.41 rapidly formed the mono-, di-, and triphosphate of ddU, and antiviral activity was observed. This example again documents... 

High temperatures can break native S-S bonds and form new S-S bonds which can lock the protein into a denatured eonfiguration [89]. Low pH, sodium dodecyl sulfate. Tween 80, chaotropie salts, and exogenous proteins have been used to protect proteins from thermal inaetivation [90]. Ethylene glycol at 30-50% was used to protect the antiviral activity of P-interferon preparations [91]. Human serum albumin was used in recombinant human interferon-Psei-n which resulted in increased thermal stability [62]. Water-soluble polysaeeharides sueh as dextrans and amylose [92], as well as point-specific (site-directed) mutagenesis [93] have also been used to increase thermal stability of therapeutie proteins and peptides. 

However, the nucleoside analogue 164 was found to be devoid of activity against HSV-1, HSV-2, VZV and the cytomegalovirus (CMV) in human fibroblast (MRC-5) cells. In this case the decreased conformational flexibility resulting from the introduction of the cyclopropyl group into 164 appeared to be unfavourable for interaction with the enzymes involved (vide supra. Sect. 2.9) [222]. Likewise, the cyclopropylpyrimidine 166c-f and 167, the cyclopropyl-purine nucleosides 168 showed no antiviral activity against HSV-1, HSV-2, HCMV and HIV-1 in cell culture, Eq. (66) [223]. 

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