New dinapinone derivatives, potent inhibitors of triacylglycerol synthesis in mammalian cells, produced by Talaromyces pinophilus FKI-3864.

Eight new dinapinones, AB1, AB2, AC1, AC2, AD1, AD2, AE1 and AE2, were isolated from the culture broth of Talaromyces pinophilus FKI-3864. The structures of these dinapinones were elucidated by various NMR experiments. All these dinapinones possessed the same biaryl dihydronaphthopyranone skeleton consisting of a heterodimer with one monapinone A and one different monapinone. Dinapinones AB1 and AB2, consisting of monapinones A and B, were atropisomers. Similarly, dinapinones AC1 and AC2, consisting of monapinones A and C, dinapinones AD1 and AD2, consisting of monapinones A and D, and dinapinones AE1 and AE2, consisting of monapinones A and E, were atropisomers. Dinapinone AB2 showed potent inhibition of triacylglycerol (TG) synthesis in intact mammalian cells with an IC50 value of 1.17 μM, whereas the other dinapinones showed weak inhibition of TG synthesis.