Horse chestnut bark extract (Aesculus hippocastanum) improves blood flow and stabilizes blood vessels. The aesculin contained in horse chestnut bark absorbs ultraviolet radiation and aids in sun protection. It is also anti-inflammatory and inhibits enzymes that catalyze structural break down resulting in beneficial effects on the appearance and texture of the skin.
Int J Cosmet Sci. 1999 Dec; 21(6):437-47 doi: 10.1046/j.1467-2494.1999.234192.x.