Antiviral of selected medical plants extracts as compared to acyclovir against herpes simplex virus
Omondi, Antony Radol
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Herpes simplex vines (HSV) is among the most common opportunistic infections in immunocompromised individuals. The available drugs, mainly the nucleoside analogs such as acyclovir are losing efficacy due to development of resistance by some HSV strains. Alternative drugs are too expensive for many resource poor patients to access and therefore, there is need for a drug which will control HSV infections at affordable cost. The concept of using a locally available plant virucide seem to be an obvious alternative. For such purpose, the objective of this study was to determine the in vitro antiviral activity and therapeutic efficacy of selected medicinal plants: Latex of Plumeria alba, leaves from melia azedarach, Vinca rosea and Warbugia ugandensis. Acyclovir was used as a reference drug for antiviral activity and for comparison with antiviral effects of the medicinal plants. The activity and efficacy were based on reduction of HSV - 1 titer in infected Vero cells and prevention of symptoms and death of infected 6 weeks old male mice. Leave extracts from Melia azedarach, Warbugia ugandensis and Vinca rosea did not reduce virus infectivity at concentration tolerated by the Vero cells. Hexane, dichloromethane and ethylacetate extracts from latex of Plumeria alba reduced virus infectivity by 0.25, 0.75 and 1.5 log1o of reference vinusTCID50 respectively. Whole latex reduced infectivity by 0.25 and 1.25 log,10 of reference virusTCID1o at 5% and 10% (v/v) of latex in maintenance media respectively. Although whole latex did not significantly prevent mortality of infected mice, prevention of skin lesions was significant at P< 05 compared to untreated infected mice. Acyclovir cream was superior in efficacy compared to the latex of Plumeria when used in traditional form. Thus all the mice treated with acyclovir cream survived. Prevention of skin lesions with acyclovir was however similar to latex. The cream containing 5% latex in petroleum jelly did not reduce virus infectivity in our in vivo assay using the animal model. Maximum amount of latex with zero toxicity to Vero cells was observed at 2.5% (v/v) of latex in maintenance media, but no virus inhibition was detected at same concentration. In vivo toxicity was assessed on skin tissues of mice after mice treatment with whole latex and processing for histology. F ibrocyte cell counts in the dermal layer of treated mice were increased by 32%, giving significant statistical difference of p< 05 compared to untreated ones. There were cell debris and thick network of tissue fibers in tissues of treated mice compared to untreated ones. The findings show that latex of Plumeria alba can be exploited for its antiviral properties for the treatement of HSV but there is need to isolate the active ingredient for further antiviral testing and toxicity studies.