In vitro activity evaluation of Parkia pendula seed lectin against human cytomegalovirus and herpes virus 6.

Human cytomegalovirus (HCMV) in vitro infectivity was inhibited by Parkia pendula seed lectin (PpeL) in contrast to human herpes virus 6 (HHV-6) which was not affected. The antiviral activity was detected for HCMV in human embryo lung (HEL) cells using a microtechnique in culture plates. The assay showed a reduction of cellular infectivity from approximately 95%, at a concentration of 150microg/mL with minimal cytotoxicity (25%). Also, a reduction of 75% was observed in HEL cells at a concentration of 75microg/mL without toxic effect. The reduction on infectivity was observed even after virus pre-adsorption to cells suggesting that this action should occur after virus penetration, in the intracellular replication phase. MT4 lymphocytes and cord blood mononuclear cells (CBMC) were used to evaluate the lectin effect on HHV-6 following the same technique. Lectin concentrations with few or no toxic effects on lymphocytes did not show inhibitory action of HHV-6 cytopathic effect. The results obtained with PpeL demonstrate that it may have an impact in the design of pharmacological strategies to infection of cytomegalovirus.