Protoanemonin

Protoanemonin is found in the fresh leaves of the plants from the Ranunculaceae family and leads to contact dermatitis. In this publication, the authors present three cases that developed phytocontact dermatitis caused by the topical use of R. arvensis as an alternative treatment method for arthralgia and palmoplantar psoriasis.

Ranunculus arvensis is used for the local treatment of joint pain, muscle pain, burns, lacerations, edema, abscess drainage, hemorrhoids, and warts among the population. The authors of this case report present three patients who developed chemical skin burns after using R. arvensis plant locally for knee pain, and noted that the skin-related toxic effects of this plant have been reported to be more in fresh plants than in dried plants. Although protoanemonin, considered as the main toxic substance, was reported to be absent in dried or boiled plants, the plant was boiled, cooled, and wrapped over the region with pain in these cases. Thus, the authors think that protoanemonin might be heat resistant.

Anemone pulsatilla and other related species of Pulsatilla contain protoanemonin, ranunculin, and anemonin. They also contain triterpene saponins and flavonoids. The fresh plant is extremely irritating to the skin, gastrointestinal tract and mucous membranes. Allergic reactions have been reported. Homeopathic preparations of pulsatilla are reportedly used for sore nipples and mastitis, to reduce an overabundant milk supply, or to increase milk supply; however, no scientifically valid clinical trials support these uses.

Ranunculin, a glucoside, serves as a chemotaxonomic marker in Ranunculaceae plants. When these plants are damaged, β-glucosidase triggers the conversion of ranunculin into protoanemonin through hydrolysis. Subsequently, protoanemonin undergoes cyclodimerization to form anemonin. The inherent instability of ranunculin and the rapid dimerization of protoanemonin make them unsuitable for use in biological assays. Anemonin stands out as the optimal molecule for bioassays and demonstrates diverse biological properties, including anti-inflammatory, anti-infective, and anti-oxidant effects. Anemonin's potential medical uses are enhanced by the capacity to inhibit nitric oxide synthesis and successfully counteract lipopolysaccharide-induced inflammation.