FIG. 5.
Isolation by TLC of the inhibitory fatty acids. (A) Macrophages were incubated for 24 h in the presence of Pfα (α) alone or with the eight different fractions (P3/1 to P3/8) obtained after separation of fraction P3 (from 2 × 108 trophozoites) by TLC. (B) Macrophages were incubated for 24 h in the presence of Pfα alone or with the eight fractions (P3/2/1 to P3/2/8 added 30 min before Pfα was added) obtained after separation of fraction 3/2 by TLC. Medium alone was used as a negative control (lanes M). The values are means ± standard deviations of triplicate samples in a representative experiment. (C) Negative-ion mass spectrum of P. falciparum inhibitory fraction P3/2/8. The annotated ions correspond to [M-H]− fatty acid carboxylate ions with the numbers of carbon atoms and numbers of C=C double bonds indicated. The y axis shows the relative ion intensities. Nominal mass values are indicated on the spectrum, but the accurate mass values were all within 3 ppm of the theoretical masses for the corresponding fatty acid carboxylate ions.