Caffeic acid is a selective inhibitor for leukotriene biosynthesis

Inhibitory effect of esculetin on 5-lipoxygenase and leukotriene biosynthesis.

https://febs.onlinelibrary.wiley.com/doi/pdf/10.1016/0014-5793%2883%2980672-3

Selective inhibition of 5-lipoxygenase by natural compounds isolated from Chinese plants, Artemisia rubripes Nakai

Human chorionic gonadotropin stimulation of immunoreactive prostaglandin synthase in the rat ovary

The effects of short-chain fatty acids (SCFA) produced by anaerobic bacteria, namely propionic, butyric and iso-butyric on T-cell proliferation was investigated. A dose-dependent inhibition of both phytohemagglutinin-induced blastogenesis and mixed lymphocyte culture was observed in the millimolar range of SCFA concentrations. The tested SCFA displayed different levels of suppression. The degree of activity was in the following order: butyrate greater than propionate greater than isobutyrate. T-cell inhibition was partially reversed, at least for propionic and isobutyric acids, by increasing the concentration of macrophages in the assay system. Furthermore, butyric acid displayed an interesting biphasic stimulation of monocyte interleukin-1 beta production, a cytokine with a powerful bone-resorbing activity. Since millimolar concentrations of SCFA are present in gingival fluid from periodontal pockets, the observed results support the role of these by-products of anaerobic metabolism in the pathogenesis of periodontal diseases.

Divergent effect of the anaerobic bacteria by-product butyric acid on the immune response: suppression of T-lymphocyte proliferation and stimulation of interleukin-1 beta production.

Treatment of a cloned mastocytoma P-815 cell line (2-E-6) with 1 mM-sodium n-butyrate for 40h induced prostaglandin synthase activity and arrested cell growth. The induction of enzyme activity by n-butyrate was not associated with suppression of DNA synthesis, since hydroxyurea had no effect on prostaglandin synthase induction. The effect of sodium n-butyrate was reversible. Experiments with cycloheximide and actinomycin D showed that the induction of prostaglandin synthase activity involved synthesis de novo of protein and RNA. The time of half-maximal induction of the newly synthesized RNA for prostaglandin synthase activity was estimated as about 15h, which is similar to the generation time of the cells. Selective induction of fatty acid cyclo-oxygenase activity by sodium n-butyrate was suggested by the following two pieces of experimental evidence. (1) There was no significant difference between treated and untreated cells in the activities of radioactive prostaglandin H2 conversion into individual prostaglandins. (2) The incorporation of [3H]acetylsalicylic acid into the fraction equivalent to protein of mol.wt. approx. 75000 of sodium n-butyrate-treated cells was higher than that of untreated cells, on analysis of cell particulate fraction by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. A high concentration (5 mM) of sodium propionate also induced prostaglandin synthesis, but other short-chain fatty acids, such as isobutyrate and sodium acetate, had no effect.

Senshu T

Papers

Effect of sodium n-butyrate on induction of prostaglandin synthase activity in cloned mastocytoma P-815 2-E-6 cells.