Method for extracting alpha-glucosidase inhibitor from averrhoa carambola root

The invention discloses a method for extracting an alpha-glucosidase inhibitor from averrhoa carambola root. The method comprises the following steps: (1) airing the averrhoa carambola root and smashing; (2) taking averrhoa carambola root coarse powder, putting into water, soaking, decocting and filtering, and repeating for three times, thus obtaining aqueous extract; concentrating; then adding ethanol, precipitating and staying overnight, carrying out suction filtration, taking supernatant, and concentrating, thus obtaining concentrated supernatant; (3) carrying out chromatographic column rough separation on the concentrated supernatant, and sequentially obtaining flow components 1-5; (4) taking a No.3 flow component, carrying out secondary chromatographic column separation, and sequentially obtaining flow components 6-12; (5) carrying out tertiary chromatographic column separation on the flow component 10, and sequentially obtaining flow components 13-21; (6) carrying out quaternary chromatographic column s