A polysaccharide extract from the medicinal plant Maidong inhibits the IKK–NF-κB pathway and IL-1β–induced islet inflammation and increases insulin secretion — MPE reduces islet inflammation — A polysaccharide extract from the medicinal plant Maidong inhibits the IKK–NF-κB pathway and IL-1β–induced islet inflammation and increases insulin secretion — MPE reduces islet inflammation