An extract from the common herb known as 'self-heal' may prove to be a powerful new herpes treatment, researchers reported at the annual American Society of Microbiology meeting in Washington last week.
Researchers from Canada and Hong Kong have discovered that the plant, prunella vulgaris, contains a lignin-carbohydrate complex with potent activity against herpes viruses responsible for cold sores and genital herpes. The lignin-carbohydrate was effective in treating herpes skin lesions in guinea pigs and protecting mice from genital herpes infection, they reported.
And the lignin-carbohydrate has a different anti-herpes mechanism than acyclovir, the current clinical anti-herpes drug, which is encountering acyclovir-resistant strains of herpes viruses.
Prunella vulgaris is a perennial plant commonly found in China, the British Isles, Europe, and North America. It is known to treat sores in the mouth and throat, as an astringent for internal and external purposes and as a herbal remedy to lower high blood pressure.
Drs Song Lee and Spencer Lee at the Dalhousie University, Halifax, Nova Scotia, Canada and Drs Paul But and Vincent Ooi at the Chinese University of Hong Kong, Shatin, Hong Kong isolated the lignin-carbohydrate complex from the spike of P. vulgaris. Two surface-localised herpes virus proteins, gC and gD, were identified as potential targets for the lignin-carbohydrate complex, the researchers told the ASM meeting.
The anti-herpes efficacy of the lignin-carbohydrate complex was assessed in a HSV-1 skin lesion model in guinea pigs and a HSV-2 genital infection model in BALB/c mice. Guinea pigs that received the lignin-carbohydrate complex cream treatment showed a significant reduction in skin lesions than those which received no treatment, while mice receiving the lignin-carbohydrate complex cream treatment also showed a significant increase in survival rate than the control group.
The researchers concluded that the anti-HSV compound from P. vulgaris is a novel lignin-carbohydrate complex with potent activity against HSV-1 and HSV-2. "The mode of action of this lignin-carbohydrate appears to be inhibiting viral binding and penetration into host cell with the potential viral targets being gC and gD," they said.
The researchers noted that given the high incidence of herpes infection and the emergence of acyclovir-resistant strains of herpes viruses, the Prunella lignin-carbohydrate complex may prove to be a useful new anti-herpes drug.