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The synthetic n-alkyl esters of gallic acid (GA), also known as gallates, especially propyl, octyl and dodecyl gallates, are widely employed as antioxidants by food and pharmaceutical industries. The inhibitory effects of GA and 15 gallates on Herpes Simplex Virus type 1 (HSV-1) and Human Immunodeficiency Virus (HIV-1) replication were investigated here. After a preliminary screening of these compounds, GA and pentyl gallate (PG) seemed to be the most active compounds against HSV-1 replication and their mode of action was characterized through a set of assays, which attempted to localize the step of the viral multiplication cycle where impairment occurred. The detected anti-HSV-1 activity was mediated by the inhibition of virus attachment to and penetration into cells, and by virucidal properties. Furthermore, an anti-HIV-1 activity was also found, to different degrees. In summary, our results suggest that both compounds could be regarded as promising candidates for the development of topical anti-HSV-1 agents, and further studies concerning the anti-HIV-1 activity of this group of molecules are merited.Key words: antiviral -HSV-1 -HIV-1 -gallic acid -pentyl gallate Herpes Simplex Virus type 1 (HSV-1) is an enveloped DNA virus that causes one of the most common viral infections in humans, leading to a variety of diseases ranging from mild to severe and sometimes life-threatening (White & Fenner 1994, Whitley & Rozman 2001. Although several nucleoside analogues have been approved for clinical use, such as acyclovir, immunocompromised patients are at increased risk of severity and recurrent infections, since resistant strains have recently been observed (Brady & Bernstein 2004). Therefore, it is desirable to develop new antiviral agents in order to substitute or complement currently available drugs.The synthetic n-alkyl esters of gallic acid (GA), also known as gallates, especially propyl, octyl and dodecyl gallates, are widely employed as antioxidants by the food and pharmaceutical industries (van der Heijden et al. 1986, Kubo et al. 2002a. Besides the antioxidant activity, other biological activities have been described for this group of molecules, mainly anticancer mechanisms (Fiuza et al. 2004, Kitagawa et al. 2005, Frey et al. 2006, Veluri et al. 2006 as well as antibacterial and antifungal properties (Fujita & Kubo 2002, Kubo et al. 2002b, c, 2003, Stapleton et al. 2004). However, there are few reports about the antiviral activity of these compounds. In 1988, a study described the inhibition of HSV-1 and HSV-2 replication by methyl gallate (Kane et al. 1988). In 2002, as part of the screening of phenolic compounds against HIV-1 integrase, GA was found to be active (Ahn et al. 2002). More recently, several biological activities of a group of gallates were described by our research group, and various structure-activity relationships regarding their anti-HSV-1, antioxidant and genotoxic effects were proposed (Savi et al. 2005). Furthermore, the pronounced anti-HSV-1 activity of octyl gallate, and its inhibitory...

Tuberculosis (TB) is a major cause of morbidity and mortality throughout the world, and it is estimated that one-third of the world's population is infected with Mycobacterium tuberculosis. Among a series of tested compounds, we have recently identified five synthetic chalcones which inhibit the activity of M. tuberculosis protein tyrosine phosphatase A (PtpA), an enzyme associated with M. tuberculosis infectivity. Kinetic studies demonstrated that these compounds are reversible competitive inhibitors. In this work we also carried out the analysis of the molecular recognition of these inhibitors on their macromolecular target, PtpA, through molecular modeling. We observed that the predominant determinants responsible for the inhibitory activity of the chalcones are the positions of the two methoxyl groups at the A-ring, that establish hydrogen bonds with the amino acid residues Arg17, His49, and Thr12 in the active site of PtpA, and the substitution of the phenyl ring for a 2-naphthyl group as B-ring, that undergoes pi stacking hydrophobic interaction with the Trp48 residue from PtpA. Interestingly, reduction of mycobacterial survival in human macrophages upon inhibitor treatment suggests their potential use as novel therapeutics. The biological activity, synthetic versatility, and low cost are clear advantages of this new class of potential tuberculostatic agents.

Herpes simplex virus (HSV) is a DNA-containing enveloped virus that causes common viral infections in humans worldwide leading to a variety of diseases. HSV-1 and HSV-2 can be distinguished on the basis of clinical manifestations (the former is more frequently associated with oral cold sores, while the later causes genital ulcers) and biochemical and serological examinations. In most cases, HSV infection is usually benign or asymptomatic in immunocompetent individuals; however, in patients with an immature or compromised immune system, the infection can be serious and sometimes life-threatening. 1,2) Several nucleoside analogues have been approved for clinical use. Among those, acyclovir is widely used for the systemic treatment of HSV infections. It is a highly selective antiviral agent because it is specifically phosphorylated by viral thymidine kinase in infected cells. However, acyclovir-resistant HSV infection in immunocompromised patients such as transplanted patients and patients with AIDS has recently been observed. Therefore, it is desirable to develop new anti-HSV agents in order to substitute or complement the antiviral drugs available. 3,4)The synthetic n-alkyl esters of gallic acid (GA), also known as gallates, especially propyl, octyl and dodecyl gallates, are widely employed as antioxidants by food and pharmaceutical industries. 5,6) Besides the antioxidant activity, other biological activities have been described for this group of molecules, mainly anticancer, 7-10) antibacterial and antifungal properties. [11][12][13][14][15][16] There are few reports about the antiviral activity of these compounds. In 1988, the potent inhibition of HSV-1 and HSV-2 by methyl gallate was described. 17) In 2000, as part of the screening of phenolic compounds against HIV-1 integrase, gallic acid was found to be active. 18)More recently, the anti-HSV activity of several gallates was described by our research group, which proposed various structure-activity relationships regarding the antiviral, antioxidant and genotoxic effects.19) Furthermore, the pronounced anti-HSV-1 activity of octyl gallate, and its inhibitory effect against RNA viruses were also recently described. 20,21) In the present study, the anti-HSV-2 activity of gallic acid and pentyl gallate was evaluated followed by the determination of the site of antiviral activity of these compounds. MATERIALS AND METHODSCompounds GA and pentyl gallate (PG) (Fig. 1) were synthesized as previously described.19) The compounds (50 mM) were dissolved in dimethyl sulfoxide, stored at Ϫ20°C protected from light, and further diluted in culture medium prior to use.Cells and Virus African green monkey kidney cells (GMK AH1) were grown in Eagle's minimum essential medium (EMEM, Gibco BRL, Grand Island, NY, U.S.A.) supplemented with 2% fetal calf serum (FSC), 0.05% primaton substance (Kraft Inc., Norwich, CT, U.S.A.), 100 U/ml Göteborg, Sweden. Received November 23, 2007; accepted February 5, 2008; published online February 20, 2008 The synthetic n-alkyl esters of galli...

Tuberculosis (TB) is a major infectious disease caused by Mycobacterium tuberculosis (Mtb). According to the World Health Organization (WHO), about 1.8 million people die from TB and 10 million new cases are recorded each year. Recently, a new series of naphthylchalcones has been identified as inhibitors of Mtb protein tyrosine phosphatases (PTPs). In this work, 100 chalcones were designed, synthesized, and investigated for their inhibitory properties against MtbPtps. Structure-activity relationships (SAR) were developed, leading to the discovery of new potent inhibitors with IC(50) values in the low-micromolar range. Kinetic studies revealed competitive inhibition and high selectivity toward the Mtb enzymes. Molecular modeling investigations were carried out with the aim of revealing the most relevant structural requirements underlying the binding affinity and selectivity of this series of inhibitors as potential anti-TB drugs.