In vitro antiviral effect of meroditerpenes isolated from the Brazilian seaweed Stypopodium zonale (Dictyotales)

The meroditerpenoids atomaric acid (1), epitaondiol (2) and the peroxylactone of 5'a-desmethyl-5'-acetylatomaric acid (3) were isolated from the Brazilian brown alga Stypopodium zonale collected in two localities (Buzios and Marataizes, RJ and ES States). These compounds showed strong anti-HSV-1 activity in vitro but neither of them inhibited the transcriptase reverse enzyme of HIV-1.