Yellow tea is harvested earlier in the year, while the leaves are still buds. That means that the tea leaves still contain all the antioxidants that have been produced throughout the growth process. On the other hand, yellow tea is oxidized for longer than green tea.
If we conservatively assume that yellow tea has about the same antioxidant content as green tea, their health benefits would be similar.
The main antioxidants in green tea & yellow tea is a polyphenol catechin known as epigallocatechin gallate, or EGCG. As a chemical substance, it is a strong antioxidant. That means that is absorbs & neutralizes other substances known as free radicals, which are harmful products of the metabolism in the cells. The EGCG in the human diet only comes from tea.
The free radicals, which antioxidants fight, are closely linked to cell damage and cell death, which appear to be the cause of why we age physically.