Glycosylated and Succinylated Macrocyclic Lactones with Amyloid-β-Aggregation-Regulating Activity from a Marine Bacillus sp.

Two new glycosylated and succinylated macrocyclic lactones, succinyl glyco-oxydifficidin ( 1 ) and succinyl macrolactin O ( 2 ), were isolated from a Bacillus strain collected from an intertidal mudflat on Anmyeon Island in Korea. The planar structures of 1 and 2 were proposed using mass spectrometric analysis and NMR spectroscopic data. The absolute configurations of 1 and 2 were determined by optical rotation, J -based configuration analysis, chemical derivatizations, including the modified Mosher's method, and quantum-mechanics-based calculation. Biological evaluation of 1 and 2 revealed that succinyl glyco-oxydifficidin ( 1 ) inhibited/dissociated amyloid β (Aβ) aggregation, whereas succinyl macrolactin O ( 2 ) inhibited Aβ aggregation, indicating their therapeutic potential for disassembling and removing Aβ aggregation.