Aesculus hippocastanum is a high, columnar tree native of northern and central Asia but also of Greece, but generally a recent arrival in the rest of Europe. It is not even distantly related to sweet chestnut, an old native of Europe. The parts used are the bark and fruit. The bark, which has no smell but an astringent taste, possesses tonic, narcotic and febrifuge properties. The principal active ingredients of the extract are escin, esculin and esculentin.
- Anti-asthmatic. Horse chestnut extract improves asthmatic conditions, apparently through the actions of esculentin and esculin in inhibiting lipoxygenase or lipoxydase, an enzyme that catalyzes the double bonds of unsaturated fatty acids.
- Anti-cellulitic. The herb has been used for the treatment of cellulite. The principal active agent is escin, which may be given orally, or alternatively, applied topically as an escin/cholesterol complex.
- Capillary tonic. Horse chestnut lowers the fragility of capillaries by reducing both the number and size of the small pores in the capillary wall. This reduction appears to be due to the inhibition of lysosomal enzymes that normally break down glycoproteins, glycolipids etc, and in this case of proteoglycans. This also accounts for the large reduction of edema in the lower limbs.
- Vein tonic. Escin also improves the ability of the elastic fibers of vein walls to contract, as proven in clinical treatment of varicose veins and thrombophlebitis, and the popular use of the herb against hemorrhoids.