The first statin drug was isolated from which kind of organism?

A fungus. Akira Endo, working in Tokyo in the 1970s, reasoned that moulds compete with bacteria by attacking cholesterol synthesis - since microbes need sterols for their membranes - and so screened thousands of fungal cultures looking for one that blocked the pathway. He found it in a Penicillium, the same genus as penicillin.

Statins block HMG-CoA reductase, the rate-limiting step in the body's own cholesterol production, which matters because most circulating cholesterol is manufactured rather than eaten. The liver responds by pulling more LDL out of the blood, and the effect on heart attacks and strokes turned out to be large enough that statins became among the most prescribed drugs on Earth.

Endo's first compound never reached market, and the credit and the money went largely elsewhere - Merck's lovastatin, approved in 1987, came from a related mould. He held no patent that paid him and has said he is content with the outcome; he received a Lasker Award in 2008, and the citation credits him with the discovery. Red yeast rice, a traditional Chinese food colouring, turns out to contain the same molecule, which is why it lowers cholesterol and why regulators treat it awkwardly.