Plant extract more commonly known as the satsuma. This medium-sized citrus fruit is native to Japan. Like all citrus extracts, it contains volatile fragrance chemicals that can be a source of skin aggravation. Of course, it has antioxidant ability as do most plants, but ideally you should be seeking antioxidants that provide benefits rather than a mix of benefits and risks.
References for this information:
Journal of Agriculture and Food Chemistry, July 2008, issue 14, pages 5682-5690