INS and diabetic retinopathy: The hyperglycemia associated with diabetes mellitus and its associated diseases can be controlled with oral hypoglycemic agents, insulin, diet, and physical activity, but this review showed the therapeutics potential of monoterpenes with a wealth of specific effects and important markers that were able to act in blood glucose control and action to treat diabetic neuropathy, diabetic retinopathy, and possible liver damage associated with the evolution of this pathology.