Cytotoxicity and Anti - Herpes Activity of Selected Medicinal Plants Cited for Management of HIV Conditions in Kakamega County – Kenya

Aim: To determine safety and anti-herpes activity of selected medicinal plants cited by Community Health Workers in Mukhwa sub-location, Bukaya location in Kakamega County, Kenya.

Study Design: Ethno-medical interview for selection of medicinal plants and In-vitro experiment for determination of safety and anti-herpes activity.

Methodology: Eight medicinal plants were selected for safety and determination of anti-herpes activity of water extracts using Vero cell and Human herpes Virus type 1. The metabolism of 3 – (4, 5-Dimethylthiazole -2-y) -2, 5-diphenyltetra-zolium bromide (MTT) was used for cytotoxicity and different levels of extract antiviral experiments. End point titration technique (EPTT) was used for virus quantification and antiviral screening test.

Place and Duration of the Study: Plant samples were collected in September 2013 in Mukhwa sub-location, the processing and biological experiments were carried out between March 2014 and October 2015 at the center of traditional medicine and drug research of Kenya Medical Research Institute, Nairobi.

Results: Safety profile: Tithonia diversifolia (Whole root) gave maximum nontoxic extract concentration (MNC) at 20 µg/mL, extract concentration killing 50% of cells (CC50) was 460 µg/mL. Schkuhria pinnata (Leaves); MNC ˂20 µg/mL, CC50 90 µg/mL. Entada abyssinica (Stem bark); MNC 20 µg/mL, CC50 > 500 µg/mL. Garcinia buchanii (Stem bark); MNC 40 µg/mL, CC50 >500 µg/mL. Croton macrostachyus (Stem bark); MNC 40 µg/mL, CC50 >500 µg/mL. Vernonia adoensis (Whole root); MNC 20 µg/mL, CC50 470 µg/mL. Plumeria alba (Leaves); MNC ˂20 µg/mL, CC50 120 µg/mL. Caesalpinia decapetala (Whole root); MNC 20 µg/mL, CC50 500 µg/mL. Anti-herpes activity: The best anti-herpes activity was obtained from G. buchanii (Stem bark), giving an extract concentration inhibiting 50% of virus activity (IC50) at 20 µg/mL) and C. decapetala (Whole root) giving IC50 at 80 µg/mL. Therapeutic index of G. buchanii was ˃ 25 and that of C. decapetala was ˃ 6.

Conclusion: Majority of the medicinal plants selected for anti-herpes activity have narrow none-toxic limits. Of all the selected medicinal plants, G. buchananii and C. decapetala are the most promising for selective anti-herpes activity.