FR901464 (WB 2663B) is potent cytotoxic natural products that share an amine-containing tetrahydropyran ring.

Polyporusterone B is a triterpene carboxylic acid isolated from Polyporus umbellatus Fries known as pentahydroxy bile acids, alcohols, and derivatives. Polyporusterone B Polyporusterone B has an inhibitory effect on free radical-induced lysis of red blood cells (hemolysis).

P-gb-IN-1 is a potent P-glycoprotein (P-gp) inhibitor that exhibits reverse activity by inhibiting P-gp outflow. P-gb-IN-1 has been shown to inhibit P-gp by hydrogen bonding with residues Asn 721 and Met 986. P-gb-IN-1 showed low toxicity in MCF-7/ADR cells.