Mallo Seijas, NataliaFelipe González, Ana Paula deFolgueira López, IriaSueiro Benavides, Rosa AnaLamas Fernández, JesúsLeiro Vidal, José Manuel2019-01-302019-01-302017-01-04Mallo, N. , DeFelipe, A. P., Folgueira, I. , Sueiro, R. A., Lamas, J. and Leiro, J. M. (2017), Combined antiparasitic and anti‐inflammatory effects of the natural polyphenol curcumin on turbot scuticociliatosis. J Fish Dis, 40: 205- 217. doi:10.1111/jfd.125031365-2761http://hdl.handle.net/10347/18168This is the peer reviewed version of the following article: Mallo, N. , DeFelipe, A. P., Folgueira, I. , Sueiro, R. A., Lamas, J. and Leiro, J. M. (2017), Combined antiparasitic and anti‐inflammatory effects of the natural polyphenol curcumin on turbot scuticociliatosis. J Fish Dis, 40: 205217. doi:10.1111/jfd.12503, which has been published in final form at https://doi.org/10.1111/jfd.12503. This article may be used for noncommercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived VersionsThe histiophagous scuticociliate Philasterides dicentrarchi is the aetiological agent of scuticociliatosis, a parasitic disease of farmed turbot. Curcumin, a polyphenol from Curcuma longa (turmeric), is known to have antioxidant and anti-inflammatory properties. We investigated the in vitro effects of curcumin on the growth of P. dicentrarchi and on the production of pro-inflammatory cytokines in turbot leucocytes activated by parasite cysteine proteases. At 100 μm, curcumin had a cytotoxic effect and completely inhibited the growth of the parasite. At 50 μm, curcumin inhibited the protease activity of the parasite and expression of genes encoding two virulence-associated proteases: leishmanolysin-like peptidase and cathepsin L-like. At concentrations between 25 and 50 μm, curcumin inhibited the expression of S-adenosyl-L-homocysteine hydrolase, an enzyme involved in the biosynthesis of the amino acids methionine and cysteine. At 100 μm, curcumin inhibited the expression of the cytokines tumour necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β) produced in turbot leucocytes activated by parasite proteases. Results show that curcumin has a dual effect on scuticociliatosis: an antiparasitic effect on the catabolism and anabolism of ciliate proteins, and an anti-inflammatory effect that inhibits the production of proinflammatory cytokines in the host. The present findings suggest the potential usefulness of this polyphenol in treating scuticociliatosiseng© 2016 John Wiley & Sons Ltd. This article may be used for noncommercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived VersionsPhilasterides dicentrarchiCurcuminProteasesS-adenosyl-L-homocysteine hydrolaseCathepsin L-likeLeishmanolysinjournal article10.1111/jfd.12503open access