Mechanism of Action of Diosmin
Diosmin acts primarily by enhancing venous tone through prolongation of norepinephrine's post-synaptic effects and inhibition of catechol-O-methyltransferase (COMT), while simultaneously reducing inflammation and oxidative stress, restoring endothelial glycocalyx integrity, and improving lymphatic drainage. 1
Vascular Tone Enhancement
Diosmin increases smooth muscle contractility by prolonging the post-synaptic response to norepinephrine and increasing vascular smooth muscle sensitivity to both norepinephrine and calcium, even under acidotic conditions. 1
The drug inhibits COMT, the enzyme responsible for norepinephrine degradation, thereby extending norepinephrine's vasoconstrictive effects on venous smooth muscle. 1
Lymphatic and Microcirculatory Effects
Diosmin decreases edema by increasing both the frequency and amplitude of lymphatic vessel contractions, thereby enhancing lymphatic drainage. 1
The compound restores metabolic aspects of chronic venous insufficiency by modulating capillary resistance and managing inflammation in the microcirculation. 1
Anti-inflammatory and Antioxidant Mechanisms
Diosmin functions as a reactive oxygen species (ROS) scavenger and inhibits 5-lipoxygenase, reducing production of prostaglandin E2 and thromboxane B2. 1
This protects endothelial cells from damage associated with inflammation and acute oxidative stress induced by venous hypertension. 1
The drug downregulates adhesion molecule expression and decreases inflammatory cell uptake into vessel walls. 2
Endothelial Glycocalyx Restoration
Diosmin preserves and restores endothelial glycocalyx integrity, which is critical for maintaining vascular permeability and endothelial function. 2
By reducing glycocalyx shedding (evidenced by decreased plasma hyaluronan concentrations), diosmin maintains the protective polysaccharide covering of endothelial cells. 2
This glycocalyx restoration upregulates activated endothelial nitric oxide synthase levels, improving vessel tone and diameter. 2
Metabolic Pathway Modulation
Diosmin activates the AMPK pathway, which plays a critical role in both glucose and lipid metabolism. 3
The compound inhibits lipogenesis and demonstrates effects on metabolic dysfunction-associated conditions. 3
Diosmin modulates the renin-angiotensin system by decreasing classical RAS indicators (AT1R) while augmenting non-classical RAS components (MasR). 4
Central Nervous System Effects
At the central level, diosmin produces effects through opioid and D2 dopaminergic receptor participation. 5
The compound crosses the blood-brain barrier, as confirmed by chromatographic detection in cerebral samples. 5
Peripherally, it reduces proinflammatory cytokines (TNF-α, IL-1β, IL-6) in both spinal cord and sciatic nerve tissues. 5
Molecular Targets
Key therapeutic targets include CASP3, ANXA5, MMP9, and HSP90AA1, with molecular docking studies confirming stable binding between diosmin and these proteins. 6
Diosmin treatment decreases expression of these targets, contributing to antifibrotic effects through multiple signaling pathways including MAPK, PI3K-Akt, and HIF-1. 6