It is produced by the strain of Streptomyces sp. C39. Gibbestatin B inhibits the expression of α-amylase induced by gibberellin in De-embryoned rice and barley (IC50 is 25-50 ppm, IC100 is 100-200 ppm), and has no anti-bacterial, anti-yeast and anti-fungal effects at 100 ppm (MIC, agar dilution method using bouillon agar for bacteria and Sabouraud agar for yeast and fungi).