Antitrypanosomal and Antileishmanial Activities of Tubers and Stem Bark.

The phytochemical screening of extracts of tubers has afforded the isolation of two novel chalcones, tarkalynins A and B, along with taccalonolide A and its 12-propanoate. The screening of stem bark yielded taraxerol acetate, dihydrochelerythrin and fagaramide. These compounds were obtained through column and thin-layer chromatography and identified using NMR and LC-HRMS. The compounds were tested against s427 and its multi-drug-resistant clone B48, against , and , and against . Cytotoxicity was tested against the human HEK293 cell line. The highest activities were observed with dihydrochelerythrin and fagaramide against s427 and B48, , and , with EC values of 1.37, 2.559, 1.09, and 5.44 µM and 17.8, 10.9, 10.9, and 13.3 µM, respectively. In addition, tarkalynin A and taraxerol acetate displayed promising activity against (EC = 21.4 and 21.3 µM, respectively). None of these compounds showed significant cross-resistance with existing trypanocides (RF ≈ 1; > 0.05). The compounds displayed low toxicity to human cells, with most exhibiting no growth inhibition at concentrations of 100, or even 300 µM. This report provides further evidence of the potential use of natural products for combating parasitic diseases.