salicina

Salicina, commonly known as salicin, is a natural glycoside first isolated from willow bark (genus Salix). Chemically, salicina is a β-D-glucoside of salicyl alcohol (saligenin), with the formula C13H18O7. It occurs in several Salix species and other plants, including Populus. In plants, salicina serves as a defensive metabolite and storage form of salicyl alcohol.

Biological activity: In humans, salicina acts as a prodrug for salicylic acid. After ingestion, salicina is hydrolyzed by gastric and intestinal β-glucosidases, or by gut microbiota, to glucose and saligenin, which is oxidized to salicylic acid. The salicylic acid inhibits cyclooxygenase enzymes, reducing prostaglandin synthesis and producing anti-inflammatory, analgesic, and antipyretic effects. Compared with acetylsalicylic acid (aspirin), salicin-derived effects are generally milder.

History and use: Willow bark and willow-derived preparations containing salicina have been used for centuries to treat fever and pain. In the 19th century, salicin was isolated and studied, contributing to the development of aspirin. Modern medicines often use aspirin or other salicylates, but willow bark extracts and salicina remain of interest in pharmacognosy.

Occurrence and safety: Salicina is typically found in the bark and leaves of willow species, with concentrations varying by species, season, and geography. As with other salicylates, it can cause gastrointestinal irritation in some individuals and should be used with caution in those with aspirin sensitivity or ulcers.