Diosmin

Diosmin is a flavone, a member of the flavonoid family. Diosmin aglycone is diosmetin. It can be found in Teucrium gnaphalodes, a plant endemic to the Iberian Peninsula.

Drug
Diosmin is semisynthetic drug (modified hesperidin). It is an oral phlebotropic drug used in the treatment of venous disease, i.e., chronic venous insufficiency (CVI) and hemorrhoidal disease (HD), in acute or chronic hemorrhoids, in place of rubber-band ligation, in combination with fiber supplement, or as an adjuvant therapy to hemorrhoidectomy, in order to reduce secondary bleeding. To control internal symptoms of hemorrhoids (piles), it is used with hesperidin.

Clinical studies have been inconclusive and no review articles on its use in vascular disease have been published.

Diosmin is currently a prescription medication in some European countries, and is sold as a nutritional supplement in the United States and the rest of Europe.

Diosmin has been found to be effective in mitigating hyperglycemia in diabetic rats. It is also speculated that diosmin might have potential in the treatment of neurodegenerative diseases, such as Alzheimer's disease, and its anti-inflammatory and anti-apoptotic activity has been demonstrated in neuronal cells, in vitro.

Mechanisms
Diosmin prolongs the vasoconstrictor effect of norepinephrine on the vein wall, increasing venous tone, and therefore reducing venous capacitance, distensibility, and stasis. This increases the venous return and reduces venous hyperpressure present in patients suffering from CVI.

Diosmin improves lymphatic drainage by increasing the frequency and intensity of lymphatic contractions, and by increasing the total number of functional lymphatic capillaries. Furthermore, diosmin with hesperidine decreases the diameter of lymphatic capillaries and the intralymphatic pressure.

At the microcirculation level, diosmin reduces capillary hyperpermeability and increases capillary resistance by protecting the microcirculation from damaging processes.

Diosmin reduces the expression of endothelial adhesion molecules (ICAM1, VCAM1), and inhibits the adhesion, migration, and activation of leukocytes at the capillary level. This leads to a reduction in the release of inflammatory mediators, principally oxygen free radicals and prostaglandins (PGE2, PGF2a).

Regulatory status
Diosmin is distributed in the U.S. as a dietary supplement. The FDA concluded that there was inadequate evidence on which to base an expectation of safety. One company that markets diosmin supplements, Nutratech, has responded that diosmin can reasonably be expected to be safe on the basis of clinical trials, and has a long history of use in Europe. In the U.S., dietary supplements are regulated under Dietary Supplement Health and Education Act of 1994, which does not require proof of efficacy so long as no specific health claims are made.