Anti-viral activity of the extracts of a Kenyan medicinal plant Carissa edulis against herpes simplex virus

• Published in: Journal of ethnopharmacology 2006-03, Vol.104 (1-2), p.92-99
• Main Authors: Tolo, Festus M., Rukunga, Geoffrey M., Muli, Faith W., Njagi, Eliud N.M., Njue, Wilson, Kumon, Kazuko, Mungai, Geoffrey M., Muthaura, Charles N., Muli, Joseph M., Keter, Lucia K., Oishi, Esau, Kofi-Tsekpo, Mawuli W.
• Format: Article
• Language: English
• Subjects: Animals; Anti-viral activity; Antiviral Agents - isolation & purification; Antiviral Agents - pharmacology; Antiviral Agents - therapeutic use; antiviral properties; Apocynaceae; Biological and medical sciences; Carissa; Carissa edulis; Carrisa edulis; Cercopithecus aethiops; chemical constituents of plants; ethnobotany; Female; General pharmacology; herpes simplex; Herpes Simplex - drug therapy; Herpes Simplex - virology; Herpes simplex virus; Kenya; Male; Medical sciences; medicinal plants; medicinal properties; Mice; Mice, Inbred BALB C; Pharmacognosy. Homeopathy. Health food; Pharmacology. Drug treatments; Plant Bark; plant extracts; Plant Extracts - isolation & purification; Plant Extracts - pharmacology; Plant Extracts - therapeutic use; Plant Roots; Plants, Medicinal; roots; Simplexvirus - drug effects; traditional medicine; Vero Cells
• ISSN: 0378-8741; 1872-7573
• DOI: 10.1016/j.jep.2005.08.053

Herpes simplex virus (HSV) infection is a major opportunistic infection in immunosuppressed persons. It is therefore a serious disease in high HIV/AIDS prevalence areas as in sub-Saharan Africa where infections due to HSV have risen significantly. The development of resistant strains of HSV to the available drugs for infection management, as is evident in the first drug of choice acyclovir, has further compounded this situation. There is therefore an urgent need to identify and develop new alternative agents for management of HSV infections, more so, for those due to resistant strains. We report here on an aqueous total extract preparation from the roots of Carissa edulis (Forssk.) Vahl (Apocynaceae), a medicinal plant locally growing in Kenya that has exhibited remarkable anti-HSV activity in vitro and in vivo for both wild type and resistant strains of HSV. The extract significantly inhibited formation of plaques in Vero E6 cells infected with 100PFU of wild type strains of HSV (7401H HSV-1 & Ito-1262 HSV-2) or resistant strains of HSV (TK− 7401H HSV-1 & APr 7401H HSV-1) by 100% at 50μg/ml in vitro with minimal cell cytotoxicity (CC50=480μg/ml). When the extract was examined for in vivo efficacy in a murine model using Balb/C mice cutaneously infected with wild type or resistant strains of HSV, the extract at an oral dose of 250mg/kg significantly delayed the onset of HSV infections by over 50%. It also increased the mean survival time of treated infected mice by between 28 and 35% relative to the infected untreated mice (p