,M. BAMUWAMYE 1

Naphthoquinones are common compounds found in several species of Bignoniaceae and exhibit anti plasmodial activity hence providing leads for discovery and development of anti theilerial drugs. This study has established the presence of naphthoquinones in the leaf, stem bark and root bark of S. kunthianum for both the hydrophilic and lipophilic extracts and established the anti theilerial activity of the lipophilic root bark extract. Sixteen unknown naphthoquinones in both the lipophilic and hydrophilic extracts of the leaf; stem bark and root bark of S. kunthianum were screened by Thin layer chromatographic technique. The lipophilic root bark extract of S.kunthianum caused death of macroschizonts of T.parva with 18 % mean percentage activity at a start experimental dose of 1 µg/L. The mean percentage activity against macroschizonts of T. parva increased with increase in the concentration of the lipophilic root bark extract of S. kunthianum. The in vitro Median Effective Concentration, EC50 of 1.585µg/L as compared to the reported EC50 of 0.3 µg/L for Buparvaquone, a known hydroxy naphthoquinone used in the treatment of ECF, was obtained for the lipophilic root bark extrac