Isolation and Structure Determination of PTP1B Inhibitor from Streptomyces sp. Strain TD-X10

In the course of bioassay-guided study for natural antidiabetic compounds from microorganisms, two steroids, i.e. compounds 1 and 2 , were isolated in vitro from biomass of antidiabetic Streptomyces sp. strain TD-X10. Structures of the compounds 1 and 2 were elucidated on the basis of spectroscopic analysis of nuclear magnetic resonance and mass spectral data and comparison with reported literature data as β-sitosterol and β-sitosteryl ferulate, respectively. While compound 1 exhibited faintly inhibitory activity against protein tyrosine phosphatase 1B, a highly validated therapeutic target for diabetes mellitus, compound 2 displayed a moderate inhibitory effect to the enzyme with IC 50 value of 40.05 ± 2.46 µM. The results highlight the antidiabetic potential of natural products from actinobacteria, particularly Streptomyces species.