hypericum and Pleurisy

We previously showed that, in vitro, hyperforin from St. John's wort (Hypericum perforatum) inhibits 5-lipoxygenase (5-LO), the key enzyme in leukotriene biosynthesis. Here, we demonstrate that hyperforin possesses a novel and unique molecular pharmacological profile as a 5-LO inhibitor with remarkable efficacy in vivo. Hyperforin (4 mg/kg, i.p.) significantly suppressed leukotriene B(4) formation in pleural exudates of carrageenan-treated rats associated with potent anti-inflammatory effectiveness. Inhibition of 5-LO by hyperforin, but not by the iron-ligand type 5-LO inhibitor BWA4C or the nonredox-type inhibitor ZM230487, was abolished in the presence of phosphatidylcholine and strongly reduced by mutation (W13A-W75A-W102A) of the 5-LO C2-like domain. Moreover, hyperforin impaired the interaction of 5-LO with coactosin-like protein and abrogated 5-LO nuclear membrane translocation in ionomycin-stimulated neutrophils, processes that are typically mediated via the regulatory 5-LO C2-like domain. Together, hyperforin is a novel type of 5-LO inhibitor apparently acting by interference with the C2-like domain, with high effectiveness in vivo.

Topics: Animals; Arachidonate 5-Lipoxygenase; Binding Sites; Bridged Bicyclo Compounds; Carrageenan; Cells, Cultured; Diglycerides; Humans; Hypericum; Leukotriene B4; Lipoxygenase Inhibitors; Male; MAP Kinase Signaling System; Microfilament Proteins; Neutrophils; Oxidation-Reduction; Phloroglucinol; Phospholipids; Pleurisy; Protein Structure, Tertiary; Protein Transport; Rats; Rats, Wistar; Terpenes; Tryptophan

Hypericum perforatum is a medicinal plant species containing many polyphenolic compounds, namely flavonoids and phenolic acids. Since polyphenolic compounds have a high antioxidant potential, in this study we evaluated the effect of H. perforatum in an animal model of acute inflammation, carrageenan-induced pleurisy. We report here that H. perforatum extract (given at 30 mg/kg orally, bolus prior to carrageenan) exerts potent anti-inflammatory effects in an animal model of acute inflammation. Injection of carrageenan into the pleural cavity of mice elicited an acute inflammatory response characterized by fluid accumulation in the pleural cavity which contained a large number of neutrophils (PMNs) as well as an infiltration of PMNs in lung tissues and subsequent lipid peroxidation (as determined by thiobarbituric acid-reactant substance measurement) and increased production of tumor necrosis factor-alpha, (TNF-alpha) and interleukin-1beta (IL-1 beta). All parameters of inflammation were attenuated by H. perforatum extract. Furthermore, carrageenan induced an upregulation of the expression of adhesion molecules ICAM-1, as well as an increase in the amounts of nitrotyrosine and poly(ADP-ribose) (PAR), as determined by immunohistochemical analysis of lung tissues. The degree of staining for the ICAM-1, nitrotyrosine, and PAR was significantly reduced by H. perforatum extract. Additionally, we demonstrate that these inflammatory events were associated with the activation of nuclear factor-kappaB (NF-kappaB) and signal transducer and activator transcription-3 (STAT-31) activation in the lung. NF-kappaB and STAT-3 activation were significantly inhibited by H. perforatum extract treatment. Taken together, our results indicate that prevention of the activation of NF-kappaB and STAT-3 by H. perforatum extract reduces the development of acute inflammation.

Topics: Animals; Carrageenan; Hypericum; Interleukin-1; Lipid Peroxidation; Lung; Male; Mice; Neutrophils; NF-kappa B; Peroxidase; Plant Extracts; Pleurisy; Pneumonia; Poly Adenosine Diphosphate Ribose; STAT3 Transcription Factor