1) Choose an effective method to kill enzyme bacteria in plants, or choose an appropriate method to inhibit their biological activity;
2) pulverizing plants into powder or cutting them into appropriate blocks by mechanical method, and extracting with water at a temperature lower than the boiling point of water;
3) The effective components are separated by concentration, alcohol precipitation, precipitation, adsorption, ion exchange, extraction or membrane separation. Can avoid extracting a plurality of different substances at the same time, and has the advantages of simple process, low energy consumption, high extract purity and full utilization of resources.