In vitro Anti-Herpes simplex Type-1 Virus Evaluation of Extracts from Kenya Grown Pyrethrum (Chrysanthemum cinerariaefolium)
Simon Alem *
Institute of Tropical Medicine and Infectious Diseases, Jomo Kenyatta University of Agriculture and Technology, P.O.Box 62000-00200, Nairobi, Kenya and Center for Traditional Medicine Drug Research, Kenya Medical Research Institute, P.O.Box 54840-00200, Nairobi, Kenya
Festus M. Tolo
Center for Traditional Medicine Drug Research, Kenya Medical Research Institute, P.O.Box 54840-00200, Nairobi, Kenya
Nicholas Adipo
Center for Traditional Medicine Drug Research, Kenya Medical Research Institute, P.O.Box 54840-00200, Nairobi, Kenya
Peter G. Mwitari
Center for Traditional Medicine Drug Research, Kenya Medical Research Institute, P.O.Box 54840-00200, Nairobi, Kenya
Ngetich K. Japheth
Center for Traditional Medicine Drug Research, Kenya Medical Research Institute, P.O.Box 54840-00200, Nairobi, Kenya
Anselimo O. Makokha
Department of Food Science, Jomo Kenyatta University of Agriculture and Technology, P.O.Box 62000-00200, Nairobi, Kenya
*Author to whom correspondence should be addressed.
Abstract
Objective: To evaluate in vitro anti-Herpes simplex type 1 activity of methanol and aqueous crude extracts of pyrethrum (Chrysanthemum cinerariaefolium) plant grown in Kenya.
Methods: Cytotoxic effect of methanol and aqueous extracts was determined on vero cells (African green monkey kidney cells) by MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-DiphenylTetrazolium Bromide) reduction colorimetric assay. Antiviral effect of pyrethrum extracts was evaluated; before (post-treatment infection) virus infection to the cells and after (pre-treatment infection) virus infection to cells.
Results: Methanol extract exhibited higher cytotoxicity of CC50 = 42.23 ± 0.320 µg/ml compared to aqueous extract of CC50 = 249 ± 8.4 µg/ml. Methanol extract exhibited a higher anti HSV-1 potency of IC50 = 1.69 µg/ml (TI = 24.99) than the aqueous extract of IC50 = 38.13 µg/ml (TI = 6.53) in the post-treatment infection evaluations. This might be due to its effect on cellular receptors preventing virus entry, while the aqueous extract exhibited higher virus inhibitory potency in the pre-treatment infection, of IC50 = 23.21 µg/ml (TI=10.73) compared to the methanol extract of IC50 = 11.18 µg/ml (TI =3.78), this effect could be due to its effect on some stage during HSV virus replication process.
Conclusions: Crude methanol and aqueous extracts from Kenyan grown pyrethrum exhibited inhibition potency against HSV-1 in vitro on Vero cells.
Keywords: Chrysanthemum cinerariaefolium, anti HSV-1, cytotoxicity, in vitro, vero cells