3-Hydroxy-4-Methyldecanoic Acid-Containing Cyclotetradepsipeptides From An Endolichenic Beauveria Sp.

An investigation of an endolichenic Beauveria sp. led to the discovery of seven new cyclotetradepsipeptides, beauveamides A-G (2-8), along with the known beauverolide Ka (1). All incorporate a 3-hydroxy-4-methyldecanoic acid (HMDA) moiety in their structures. Their configuration was determined through Marfey's, J-based configuration analysis, and NMR computational methods, representing the first time that the stereostructures of HMDA-moiety-containing cyclotetradepsipeptides have been established. Compounds 1 and 2 exhibited protecting effects on HEI-OC1 cells at 10 mu M, while 1, 4, and 5 could stimulate glucose uptake in cultured rat L6 myoblasts at 50 mu M. Compound 1 showed dose-dependent activity in both L6 myoblasts and myotubes.