Complex sentence: As an alkaloid it is accumulated in the food vacuoles of the plasmodium, especially "P. falciparum" and acts by inhibiting the heme polymerase enzyme thus facilitating an aggregation of the cytotoxic heme.
Split into simpler sentences: As an alkaloid, it is accumulated in the food vacuoles of plasmodium species, especially "P. falciparum". It acts by inhibiting the heme polymerase enzyme, thus facilitating an aggregation of cytotoxic heme.