As predicted and verified, Ranasampel treatment improved diabetes mellitus-associated cognitive impairment behaviors and pathological changes in db/db mice and regulated many biological processes (response to oxidative stress, autophagy, learning or memory, cognition, neuron death, etc.)and pathways (VEGF signaling pathway, AGE-RAGE signaling pathway in diabetic complications, HIF-1 signaling pathway, Insulin resistance, TNF signaling pathway, etc.). This evidence concerns the gene HIF1A and diabetes mellitus.