The formation of gossypol occurs through an isoprenoid pathway.
The terpenoids are Isoprenoids derived from five carbon isoprene units.
In people, perhaps the most well-known isoprenoid is cholesterol,
with statin drugs famously inhibiting that manufacturing pathway.
In other words, when present,
PfHAD1 is doing the same job as the drug, slowing isoprenoid manufacturing.
Since Isoprenoids are necessary for life,
it's not clear why the organism would purposefully slow down isoprenoid production.
Inhibiting isoprenoid manufacturing in malaria, bacteria or tuberculosis, for
example, would in theory leave the human pathways safely alone.
While people make Isoprenoids, these vital compounds are manufactured entirely
differently in animals compared with many infectious pathogens likely to cause disease.
Terpenes and Isoprenoids are a large class of lipids that include the carotenoids
and form the largest class of plant natural products.