Horse Chestnut Seed Extract (Aesculus hippocastanum Seed Extract)

The horse chestnut, also known as the conket tree, is a large tree native to southeast Europe around Balkan Mountains. The horse chestnut tree, including the seeds, leaves, and bark, have been traditionally utilized in folk medical as early as the 1500s, with the nuts being often used to treat persistent fever, hemorrhoids, and phlebitis . Modern analysis of the seed shows that it contains hydroxycoumarins, flavonoids, tannins, sterols, saponins, and glycosides, all of which have large amounts of research behind them for their positive effects in the body for a variety of conditions.

The extract of the horse chestnut seed has anti-inflammatory and astringent properties and is most widely used in topical formulas for the treatment of varicose veins, cellulite, and dark circles under the eyes because of its circulation stimulating and capillary repairing properties. The ability to heal capillaries and enhance the integrity of the skin's vascular network is due to the escin (also called aescin) compound that is present in high amounts in horse chestnut extract. Several studies have shown that escin is able to inhibit enzymes that degrade the lining of veins and capillaries while reinforcing the integrity of elastic fibers in blood vessel walls (making them more flexible and resistant to degredation).

Research has also shown that escin also is effective at inhibiting elastase and hyaluronidase enzymes, which both have roles in the degradation of proteoglycans, an important element in the extravascular matrix and a component of blood vessel endothelium. It is speculated that escin alters the equilibrium between proteoglycan synthesis and degradation, resulting in the prevention of vascular leakage. Escin is also associated with the release of prostaglandin F2 from veins, an antagonism to histamine and 5-hydroxytryptamine, and a decreased catabolism of tissue mucopolysaccharides. It is believed that escin works synergistically with rutin, another phytonutrient compound in horse chestnut seed extract, to strengthen fragile capillaries. Ultimately, this culminates in horse chestnut seed extract being a powerful weapon against dark circle formation under the eyes.