Description

Icariin is a chemical compound classified as a prenylated flavonol glycoside, a type of flavonoid. It is the 8-prenyl derivative of kaempferol 3,7-O-diglucoside. The compound has been isolated from several species of plant belonging to the genus Epimedium which are commonly known as horny goat weed, Yin Yang Huo, and Herba epimedii. Extracts from these plants are reputed to produce aphrodisiac effects, and are used in traditional Chinese medicine to enhance erectile function. However, clinical trial data are lacking to support these claims.

Pharmacological Action

Icariin is a major bioactive pharmaceutical constituent isolated from Chinese medicine Horny Goat Weed (Ying Yang Huo) with potent cardiovascular protective functions. Emerging evidence in the past decade has shown that Icariin possesses multiple atheroprotective functions, through multiple mechanisms, including attenuating DNA damage, correcting endothelial dysfunction, inhibiting the proliferation and migration of smooth muscle cells, repressing macrophage-derived foam cell formation and inflammatory responses, as well as preventing platelet activation. All of these protective effects, combined with its lipid-modulatory effects, contribute to the broad atheroprotective effects of Icariin.

Osteoarthritis (OA) is the common chronic degenerative joint bone disease that is mainly featured by joint stiffness and cartilage degradation. Icariin (ICA), an extract from Epimedium, has been preliminarily proven to show anti-osteoporotic and anti-inflammatory effects in OA. However, the underlying mechanisms of ICA on chondrocytes need to be elucidated.

Health effects

Effects on sexual function: Epimedium extract has a certain effect on promoting gonadal function. Flavonoids such as icariin have the effect of invigorating the kidney and strengthening sexal function. 30-1000μg/l can promote the secretion of estradiol, and at 1000μg/l, it can promote the secretion of corticosterone. At the same time EPS can increase the level of gonadal hormones, mainly to increase the level of FSH.

Improve the body's immune function: Epimedium pilosa 50% methanol extract can inhibit the transformation of lymphocytes. The total flavonoids of Epimedium can make "sexual performance-deficiency" mice form high cell function and antibody, and significantly enhance the immune function of human T cells. Both EPS and EI have immunomodulatory effects.  Antioxidant EPS and EI have antioxidant activity, which can enhance the activity of antioxidant enzymes and reduce the effect of free radical products.

Anti-aging effect: Epimedium extract can resist aging and prolong life by affecting cell passage, prolonging growth period, regulating immune and secretion system, improving body metabolism and various organ functions. 

Cardiovascular effects: The non-amino acid fraction in icariol extract can significantly increase coronary flow in isolated rabbit hearts. Decoction and alcohol infusion have the effect of lowering blood pressure. Icariin can directly relax vascular smooth muscle and dilate coronary, femoral and cerebral arteries. The mechanism of action is to inhibit the influx of extracellular calcium ions in vascular smooth muscle.