The α-Glucosidase Inhibition Activities of Phaeochromycins D and E Isolated from Marine sp. FJ0218.

Marine are an important source of naturally occurring active compounds. Out of 23 marine strains, 1 strain of sp. FJ0218 was selected for its high activity in inhibiting α-glucosidase. Two polyketides, phaeochromycins D () and E (), were isolated from the fermentation broth of this strain using bioactivity-guided column chromatography over RP-18, Sephadex LH-20, and silica gel. Their structures were determined using NMR data, HR-EI-MS, and single-crystal X-ray crystallography. Phaeochromycins D () and E () exhibited inhibitory activity against α-glucosidase, with IC values of 10 mM and 25 mM, respectively. Lineweaver-Burk plots revealed that phaeochromycin E () acts as an uncompetitive inhibitor, while phaeochromycin D () acts as a non-competitive inhibitor. These findings suggest that there is potential for the pharmacological regulation of glucose levels through the use of polyketide phaeochromycins, emphasizing their significant impact on glucose management.