Abstract: The present invention encompasses a method of preparing a pharmaceutically active extract of D. Antarctica comprising the steps of: a. Collecting and disinfecting D. Antarctica plants; b. Exposing the D. Antarctica plants to ultra pure water at a temperature of from 95° to 100° C. for a period of about 5 hours to yield a liquid extract of the plant; and c. Lyophilizing the liquid extract yielding a dry homogeneous product. In another embodiment, the present invention provides an anti-aging pharmaceutical composition useful in slowing down or reversing the aging process in human beings said composition comprising an aqueous extract of D. Antarctica. In a particular embodiment the aqueous extract comprises a polyphenolic free-radical scavenger present in the amount of at least 4.0% (w/w) and preferably at least 5.