GCG and diabetes mellitus: In order to detect the in vitro anti‐diabetes effect of the polysaccharide extracted from Dendrobium officinale leaf named LDOP‐A, the present study investigated the structure and simulated digestion of LDOP‐A in vitro and then explored secretion of GLP‐1 from endocrine L cells by direct stimulation of digested LDOP‐A.