Magnesium lithospermate B and rosmarinic acid have potent antiviral activity against enterovirus 71


Senior Member
Thanks for alerting me to that study, @pattismith.

Although this study finds rosmarinic acid (which is available as a supplement) and magnesium lithospermate B potent antivirals for enterovirus 71, note that this is an in vitro study.

I've looked at many of these in vitro studies of antiviral compounds, and what you usually find is that the concentrations used in vitro cannot be obtained in vivo, because even at the maximum safe oral dose, the blood and tissue concentration achieved is too low to match the in vitro study. So usually the antiviral is potent in vitro, but not effective in vivo.

In this case, I did a quick calculation on rosmarinic acid, and found that it's in vivo potency is very poor.

Note also that antivirals which are effective against enterovirus 71 will not necessarily work for the enteroviruses found in ME/CFS (coxsackievirus B and echovirus).

I compiled a long list of enterovirus antiviral compounds in this post, but most of these compounds unfortunately suffer from the same problem: they are potent in vitro, but not in vivo, because you cannot achieve high enough concentrations in vivo.