Phlorotannins from the genus kombu exhibit anti-diabetic activity mainly through the inhibition of α-amylase, α-glucosidase, pancreatic lipase and aldose reductase (AR), which can promote the delay of carbohydrate and lipid digestion, followed by reducing postprandial plasma glucose levels and overall body weight, thereby helping to prevent and improve metabolic disorders such as diabetes mellitus type 2 (T2DM) and obesity [124]. This evidence concerns the gene AR and type 2 diabetes mellitus.