A methodology based on density functional theory calculations for the design of molecularly imprinted polymers (MIPs) is described. The method allows the rational choice of the most suitable monomer and polymerization solvent among a set of chemicals traditionally used in MIP formulations for the molecular imprinting of a given template. It is based on the comparison of the stabilization energies of the prepolymerization adducts between the template and different functional monomers. The effect of the polymerization solvent is included using the polarizable continuum model. A voltammetric sensor for homovanillic acid was constructed using different MIPs as recognition element, confirming that the solvent (toluene) and functional monomer (methacrylic acid) selected according to the theoretical predictions lead to the most efficient molecular recognition sensing phase. With the voltammetric sensor prepared using the MIP designed according to the theoretical predictions, a linear response for concentrations of homovanillic acid between 5 x 10(-8) and 1 x 10(-5) M can be obtained. The limit of detection is 7 x 10(-9) M. The selectivity obtained for homovanillic acid over other structurally related compounds buttresses the validity of this strategy of design.

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The antiherpes virus properties of Phyllanthus orbicularis Kunth, a Cuban-endemic medicinal plant, have been reported previously but data on its phytochemical profile and identification of antiviral metabolites as well as their mechanisms of action are still lacking. In this work, a bioactivity-guided phytochemical analysis was performed in order to isolate anti HSV-2 compounds. P. orbicularis contained mainly phenolic acids derivatives and flavonoids. The antiviral effects were attributed to (-)-epicatechin-3-O-gallate (EC(50) = 11.7 µg/mL), procyanidins B1 and B2 (EC(50) = 32.8 µg/mL and 24.2 µg/mL, respectively) as well as oligomeric and polymeric procyanidins and their gallate derivatives. The antiviral mechanisms of the active P. orbicularis extracts and fractions were also investigated and the inhibition of several HSV-2 early replication events and DNA synthesis were observed. This is the first study of extensive fractionation and phytochemical characterization of phenolic compounds from this species.

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