Leishmaniasis and trypanosomiasis are serious and neglected tropical diseases (NTDs) caused by the group parasites Leishmania and Trypanosoma, respectively. These infections remain a major public health problem and cause high morbidity and mortality especially in developing countries [1]. Current available drugs for the treatment of these infections suffer from high toxicities which may cause serious side effects.

The chloroform, ethyl acetate and n-butanol extracts of the aerial parts of Hypericum afrum and Cytisus villosus were screened in in vitro assays for their antiprotozoal activity against L. donovani (promastigotes, axenic amastigotes and intracellular amastigotes in THP1 cells) and T. brucei brucei using standard procedures [2,3]. Both plant extracts revealed significant trypanosomicidal activity with IC₅₀ values ranges of 7.99-19.48 µg/mL. The n-butanol extract of C. villosus showed good antitrypanosomal activity against T. brucei. brucei with IC₅₀ value of 7.99 and IC₉₀ value of 12.61 µg/mL. The chloroform, ethyl acetate and n-butanol extracts of H. afrum showed trypanosomicidal activity against T. brucei. brucei culture with IC₅₀ values of 12.35, 13.53, 12.93 µg/mL and with IC₉₀ values of 14.94, 19.31, 18.67 µg/mL, respectively. The extracts did not show leishmanicidal activity.

This is the first report of in vitro antitrypanosomal activity of these plants. The potent activities of the n-butanol extract of C. villosus and the chloroform extract of H. afrum make them promising candidates for the isolation of compounds that could develop into new leads for drugs against human African trypanosomiasis.

References

[1] World Health Organization (2018) global helath observatory data, Neglegted triopical Diseases (NTDs), WHO, Geneva, Switzerland http://www.who.int/gho/neglected_diseases/en/ Accessed March 2018

[2] Jain SK, Jacob MR, Walker LA, Tekwani BL. BMC Complementary Altern Med. 2016; 16:131.

[3] Jain SK, Sahu R, Walker LA, Tekwani BL. J Visualized Exp. 2012; 70:40-54