In vitro and in vivo effects of Ranunculus peltatus subsp. baudotii methanol extract on models of eicosanoid production and contact dermatitis

• Published in: Phytotherapy research 2008-03, Vol.22 (3), p.297-302
• Main Authors: Prieto, J.M, Recio, M.C, Giner, R.M, Schinella, G.R, Máñez, S, Ríos, J.L
• Format: Article
• Language: English
• Subjects: Animals; antiinflammatory activity; Biological and medical sciences; Cell Survival - drug effects; contact dermatitis; cyclooxygenase; Cyclooxygenase 1 - drug effects; Cyclooxygenase 1 - metabolism; Dermatitis, Allergic Contact - drug therapy; Eicosanoids - biosynthesis; Enzyme Inhibitors - pharmacology; Enzymes - analysis; Enzymes - drug effects; Female; General pharmacology; Humans; lipoxygenase; Medical sciences; Methanol - chemistry; Mice; Models, Animal; Neutrophils - drug effects; Pharmacognosy. Homeopathy. Health food; Pharmacology. Drug treatments; Phytotherapy; Plant Extracts - pharmacology; Ranunculus - chemistry; Ranunculus peltatus subsp. baudotii; Rats; Rats, Wistar; Time Factors
• ISSN: 0951-418X; 1099-1573
• DOI: 10.1002/ptr.2309

Ranunculus (Crowfoot) species are numerous and they are all reputed to be counter-irritants and are used in several topical conditions. In order to study the pharmacological mechanisms of action underlying this popular use, a methanol extract of Ranunculus peltatus was tested in vitro in various assays involving eicosanoid and human elastase release by intact cells as well as in vivo, with models of delayed-type hypersensitivity (DTH) contact dermatitis. The extract proved to be a selective inhibitor of the cyclooxygenase-1 pathway, producing the total inhibition of 12-(S)-HHTrE release at 200 μg/mL, while leaving both 5-lipoxygenase and 12-lipoxygenase activities unaffected at the same dose. The n-hexane, chloroform and ethyl acetate fractions of the crude methanol extract inhibited LTB₄ release by intact rat peritoneal neutrophils, but more polar fractions were inactive and did not increase the 5-LOX activity as seen previously for extracts of other Ranunculus species. In the in vivo models, the methanol extract reduced the dinitrofluorobenzene (DNFB)-induced oedema by 40%, but failed to inhibit the oedema brought on by oxazolone. The results agree with the age-old assertion that Water Crowfoot species can be used as a topical antiinflammatory remedy without the prominent irritant action that accompanies the application of non-aquatic Ranunculus species. Copyright © 2007 John Wiley & Sons, Ltd.