In recent years, there has been an increasing volume of evidence to suggest that many age-related
human diseases such as heart disease, cancer, arthritis, immune system decline, brain dysfunction, and
cataracts are the results of cellular damage by free radicals, and that antioxidants in our diet could play
an important role in the prevention of such diseases [1,2]. This has attracted much public interest in
natural antioxidants and has led to an extensive search for effective antioxidants in nature [3-7]. At the
same time, numerous crude extracts and pure natural compounds from natural plants have been