A plant extract obtained from the plant leaves of mulberry. It is extracted from Morus plant leaves, and has an IC50 value, to inhibit α-glucosidaseⅠ, at a concentration of less than 90 μg/ml. The extract preferably comprises 5-40%(w/w) total imino sugars and 20-70%(w/w) total amino acids. The extract is obtained by a three-step extraction and purification process and may be used to reduce the production of melanin for the treatment of such ailments or diseases caused by pigmentation as freckle, chloasma, striae gravidarum, sensile plaque and melanoma. It can also be used to control blood glucose level.
