A cold sore is an infection on the lips and face caused by the herpes simplex virus type-1, or HSV-1. An outbreak leaves tiny blisters that can be painful and itchy. The infection lasts about two weeks, but the virus may lie dormant in the nerve cells until the next outbreak. Stress, illness, fatigue and exposure to the sun can trigger an outbreak. Antiviral medications like acyclovir and valacyclovir may have a slight effect on the pain and duration of the outbreak, but the virus is becoming resistant to these drugs. Herbs with antiviral action are effective home remedies for cold sores. It is important to consult a health care specialist before starting herbal treatment.
Simple-spined Carissa
Simple-spined carissa, or Carissa edulis, is a short, spiny evergreen tree with edible berries and tiny reddish-tinged white flowers. Traditional African healers use the bark to treat skin infections, parasites, headache and sexually transmitted diseases. The roots have anti-HSV actions. A study published in the March 2006 issue of the “Journal of Ethnopharmacology” tested a root extract of carissa on wild and acyclovir-resistant strains of HSV-1. The study found that the extract showed antiviral action against both strains: herpes infection took longer to develop and there was a lower mortality rate in the treated animals compared to the untreated ones. Studies and clinical trials on humans are needed to determine the efficacy of carissa on humans infected with HSV-1.
Lemon Balm, Peppermint and Thyme
Lemon balm, or Melissa officinalis; peppermint, or Mentha piperita; and thyme, or Thymus vulgaris, are aromatic herbs with a long history of medicinal use. These herbs belong to the same plant family, Lamiaceae, and they all contain similar potent chemicals with antimicrobial properties. A study published in the December 2006 issue of “Planta Medica” examined extracts of six herbs from the Lamiaceae family. The study found that lemon balm, peppermint and thyme had the most antiviral activity. All three contain rosmarinic acid and caffeic acid, which are potent antiviral constituents. This in vitro study confirmed the antiviral action of these plants. Further studies can determine if they have the same effects in human subjects.
Manuka Oil
Manuka, or Leptospermum scoparium, is an aromatic evergreen with white or scarlet flowers native to Australia and New Zealand. The Maori of New Zealand use the oil from the leaves to treat bronchitis and rheumatism. The oil contains caryophyllene, geraniol, flavesone, leptospermone and humulene, and has antibacterial, antiviral, analgesic and decongestant actions. A study published in the December 2005 issue of “Planta Medica” tested manuka oil on herpes viruses in vitro and found that it significantly inhibited infection by both HSV-1, which causes cold sores, and HSV-2, which causes genital herpes. After cells were infected, manuka significantly inhibited replication only of HSV-1. The researchers state that the topical use of manuka oil for HSV-1 infection would be efficacious for people with frequently recurring infections. Studies on human subjects are needed to confirm these results.
References
- “Journal of Ethnopharmacology”; Anti-viral activity of the extracts of a Kenyan medicinal plant Carissa edulis against herpes simplex virus; Tolo FM, Rukunga GM, Muli FW, Njagi EN, Njue W, Kumon K, Mungai GM, Muthaura CN, Muli JM, Keter LK, Oishi E, Kofi-Tsekpo MW; March 2006
- “Planta Medica”; Antiviral effect of aqueous extracts from species of the Lamiaceae family against Herpes simplex virus type 1 and type 2 in vitro; Nolkemper S, Reichling J, Stintzing FC, Carle R, Schnitzler P; December 2006
- “Planta Medica”; Virucidal activity of a beta-triketone-rich essential oil of Leptospermum scoparium (manuka oil) against HSV-1 and HSV-2 in cell culture; Reichling J, Koch C, Stahl-Biskup E, Sojka C, Schnitzler P; December 2005
