A method of isolating an extract of Urtica dioica is described herein. The method includes drying a raw material comprising Urtica dioica； grinding the raw material to form a ground raw material having a particle size in a range of about 0.5 to 1 mm； mixing the ground raw material with water to form a mixed raw material solution； and heating the mixed raw material solution to a temperature of about 100° C. and maintaining the temperature of about 100° C. for a period of time to form an extracted liquid solution.
