One of four principal bioactive compounds in the plant extract Centella asiatica. One double-blind study has shown even small amounts of this compound (0.1% in one case) combined with vitamin C have antioxidant benefit when applied to skin.
References for this information:
Biotechnology Letters, June 2008, ePublication
Planta Medica, June 2008, pages 809-815
Experimental Dermatology, May 2008, ePublication