Carotenoids are widespread lipophilic pigments synthesized by all
photosynthetic organisms and some nonphotosynthetic fungi and bacteria. All
carotenoids are derived from the C40 isoprenoid precursor geranylgeranyl
pyrophosphate, and their chemical and physical properties are associated with
light absorption, free radical scavenging, and antioxidant activity.
Carotenoids are generally synthesized in well defined subcellular organelles,
the plastids, which are also present in the phylum Apicomplexa, which
comprises a number of important human parasites, such as Plasmodium
and Toxoplasma. Recently, it was demonstrated that Toxoplasma
gondii synthesizes abscisic acid. We therefore asked if Plasmodium
falciparum is also capable of synthesizing carotenoids. Herein,
biochemical findings demonstrated the presence of carotenoid biosynthesis in
the intraerythrocytic stages of the apicomplexan parasite P.
falciparum. Using metabolic labeling with radioisotopes, in
vitro inhibition tests with norflurazon, a specific inhibitor of plant
carotenoid biosynthesis, the results showed that intraerythrocytic stages of
P. falciparum synthesize carotenoid compounds. A plasmodial enzyme
that presented phytoene synthase activity was also identified and
characterized. These findings not only contribute to the current understanding
of P. falciparum evolution but shed light on a pathway that could
serve as a chemotherapeutic target