Drug combination studies of curcumin and genistein against rhodesain of <i>Trypanosoma brucei rhodesiense</i>

<p>Curcumin and genistein are two natural products obtained from <i>Curcuma longa</i> L. and soybeans, endowed with many biological properties. Within the last years they were shown to possess also a promising antitrypanosomal activity. In the present paper, we investigated the activity of both curcumin and genistein against rhodesain, the main cysteine protease of <i>Trypanosoma brucei rhodesiense</i>; drug combination studies, according to Chou and Talalay method, allowed us to demonstrate a potent synergistic effect for the combination curcumin-genistein. As a matter of fact, with our experiments we observed that the combination index of curcumin-genistein is < 1 for the reduction from 10 to 90% of rhodesain activity.</p>