Anti-Herpes Effects of Echinacea
Echinacea's effects against herpes are not as well-studied as against flu and cold viruses. They also appear to depend on the species and type of herpes.
The most exciting news about echinacea and herpes may be that its compounds could prevent it from recurring if taken before infection. Although results are quite preliminary, echinacea's immune boosting effects may be its most powerful antiviral benefit.(114)
Herpes Simplex Virus-1
Lab studies have shown that Echinacea purpurea inhibits the inflammatory proteins triggered by herpes simplex virus type-1. HSV-1 is the type of herpes that causes cold sores. Though it is less common, HSV-1 can also cause eye or genital infections or life-threatening encephalitis.(114)
Like all herpes viruses, HSV-1 establishes latent infections. This means that even though the symptoms may go away for long periods of time, the virus can reactivate and cause symptoms to recur at any time.(115)
Active herpes infections are treated with antiviral drugs. There are no conventional treatments to prevent latency.(115)
In eye infections, herpes resides in the cluster of nerves behind the eye. Multiple recurrences of latent HSV-1 are a major cause of blindness.(114, 115)
Research shows E. purpurea reduces the severity of herpes eye infections. Importantly, it may also prevent herpes from establishing latency.(114)
In an animal study, mice were injected with polysaccharide compounds from E. purpurea before infected with HSV-1 in the eyes. The echinacea compounds boosted production of proteins and immune system cells linked to preventing latency. In fact, they prevented the virus from establishing itself in the eye nerves in over half the mice.(114)
Herpes Simplex Virus-2 (Genital Herpes)
Although HSV-1 can cause genital lesions, HSV-2 is the most common cause of genital herpes. Results of a 12 month controlled clinical trial were not so promising for E. purpurea in treating HSV-2.(115, 116)
The study involved 50 patients with frequently recurrent genital herpes. Patients were assigned to take an E. purpurea formula or placebo for alternating 6-month periods. The echinacea treatment did not significantly reduce either symptoms or rate of recurrence.(116)
More encouraging results against HSV-2 come from lab studies of the pressed juice and alcohol extracts from E. pallida. This echinacea species showed dramatic antiviral activity against both HSV-1 and HSV-2 — blocking 99-100% of the virus' ability to infect cells.(106)
The pressed E. pallida juice showed antiviral activity during all phases of viral replication, even when highly diluted. These results suggest that E. pallida may be a potent antiviral agent against both types of herpes in a clinical setting.(106)