Two Novel Potent α ‐Amylase Inhibitors from the Family of Acarviostatins Isolated from the Culture of Streptomyces coelicoflavus ZG0656

Two novel aminooligosaccharides were separated from the culture filtrate of Streptomyces coelicoflavus ZG0656. Their chemical structures were determined by acidic hydrolysis, electrospray‐ionization tandem mass spectrometry (ESI‐MS/MS), and NMR spectroscopy. The compounds were named acarviostatins III0(−1) and III23 according to the nomenclature of this group of metabolites. The two novel acarviostatins were both mixed noncompetitive inhibitors of porcine pancreatic α ‐amylase (PPA). The inhibition constants ( K i ) for acarviostatins III0(−1) and III23 were 0.009 and 0.026 μ M , respectively, 151 and 52 times more potent than acarbose.