Enhancement of Anti-Herpetic Activity of Glycyrrhizic Acid by Physiological Proteins

Abstract

Some enzymes present in biological fluids, such as lysozyme (LYS) and lactoferrin (LAC), are known to possess antibacterial and antiviral activity, against herpesviruses in particular. It will be shown in this paper that their combination with a natural triterpene, namely glycyrrhizic acid (GLA), gives significant results in enhancing the antagonistic activity on HSV1 in in vitro assays. Data elaboration was carried out by calculation of the FIC index (fractional inhibitory concentration) for each combination of the three compounds and by a three-dimensional evaluation of the inhibiting combinatory effects, which indicated the percentage of the synergistic action. A FIC index equal to or below 0.5 demonstrated a significant synergistic effect between two substances. Considering each single compound, the 50% inhibiting doses on viral replication (ID50) were 252±53 μg/ml for LAC, 497±165 μg/ml for LYS and 740±125 μg/ml for GLA. The combination of LAC and GLA showed a clear synergistic effect, with a FIC index of 0.08 and a potentiating activity which, for some doses, was up to 1.5 log10 of difference (from about 5.5×106 to 105 pfu/ml). The combinations of GLA and LYS, and LYS and LAC showed a less significant synergistic activity. These findings led to the conclusion that some physiological proteins, even at concentrations usually present in some body fluids, may enhance the anti-herpetic activity of a natural compound such as GLA.

Covalent attachment of lysozyme to cotton/cellulose materials: protein verses solid support activation

“…The mechanism of action of lysozyme is probably the best studied of any enzyme reported to date. In addition the recent demonstration of potentiated antiviral, anti-HIV, and antifungal activity of lysozyme suggests that lysozyme-cellulose conjugates may have potential use for a broader spectrum of antimicrobial applications, and despite lysozyme's antibacterial and antiviral activity little has been reported on developing a cotton-based antimicrobial fabric using this enzyme (Branen and Davidson 2004;Cisani et al 1989;Samaranayake et al 2001;Lee-Huang et al 2005;Lampis et al 2001). The zeta potential titration curves of the lysozyme-cellulose conjugates are shown in Fig.…”

Antiviral effects of Glycyrrhiza species

“…In studies demonstrating the inhibition of HSV-1 by glycyrrhizic acid in vitro a synergism of the inhibitory effect with the endogenous antiviral substance lactoferrin was found (Lampi et al, 2001). …”

Immobilization of lysozyme-cellulose amide-linked conjugates on cellulose I and II cotton nanocrystalline preparations

“…Lysozyme is also a model of hydrolytic enzymes (Strynadka and James 1996) that displays a broad range of antimicrobial properties (Salton 1957;Cisani et al 1989;Samaranayake et al 2001;LeeHuang et al 2005;Lampis et al 2001). Previously the attachment of lysozyme to cotton (Edwards et al 2000) and wool (Wang et al 2009;Hu et al 2008) fabrics has been presented as a model for developing antimicrobial textile materials with selective activity.…”