Antimutagenic and antiherpetic activities of different preparations from Uncaria tomentosa (cat's claw)

- Hydroethanolic extracts from UT may be considered promising for antiherpetic therapy.
- Higher antimutagenic activity was observed in pre- and simultaneous treatment.
- Purified fractions showed lower antiherpetic activity than hydroethanolic extracts.
- Inhibition of viral attachment to cell was the main mechanism of antiherpetic action.
- Antiherpetic activity seems be associated with the polyphenols.

Uncaria tomentosa have been used to treat viral diseases such as herpes due to multiple pharmacological effects, but its therapeutic efficacy against this virus have not been reported yet. Thus, in vitro antiherpetic activity of hydroethanolic extract from barks, purified fractions of quinovic acid glycosides and oxindole alkaloids was evaluated by plaque reduction assay, including mechanistic studies (virucidal, attachment and penetration action). Once exposure to physical agents might lead to reactivation of the herpetic infection, antimutagenic effect (pre-, simultaneous and post-treatment protocols) was also evaluated by Comet assay. The antiherpetic activity from the samples under investigation seemed to be associated with the presence of polyphenols or their synergistic effect with oxindole alkaloids or quinovic acid glycosides, once both purified fractions did not present activity when evaluated alone. Inhibition of viral attachment in the host cells was the main mechanism of antiviral activity. Although both purified fractions displayed the lowest antimutagenic activity in pre and simultaneous treatment, they provided a similar effect to that of cat's claw hydroethanolic extract in post-treatment. Given that purified fractions may result in a reduced antiherpetic activity, the use of cat's claw hydroethanolic extract from barks should be prioritized in order to obtain a synergistic effect.