Protective effects of an extract from Citrus bergamia against inflammatory injury in interferon-γ and histamine exposed human keratinocytes.
OBJECTIVE
The present work evaluated the anti-inflammatory/antioxidant activity of a well characterized extract from Citrus bergamia Risso and Poiteau (CBE), containing neoeriocitrin, naringin, neohesperidin and other flavonoids, on human NCTC 2544 keratinocytes treated with interferon-gamma (IFN-γ) and histamine (H).


METHODS
High performance liquid chromatography (HPLC) coupled with diode array detectors was used to characterize and quantify phenolic compounds in CBE. Anti-inflammatory/antioxidant ability on keratinocytes was determined through evaluation of inter-cellular adhesion molecule-1 (ICAM-1) and inducible nitric oxide synthase (iNOS) expression by Western blot, production of nitric oxide (NO) with Griess reagent and concentration of reactive oxygen species (ROS) by fluorescent quantitative analysis with 2',7'-dichlorfluorescein-diacetate (DCFH-DA). Cell viability was assessed using 3-(4,5-dimethyl-2 thiazoyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. Antioxidant activity was also measured by oxygen radical absorbance capacity (ORAC) assay. Glycosaminoglycans (GAGs) were quantified using 1.9-dimethyl methylene blue (DMB).


RESULTS
CBE exhibited high antioxidant activity confirmed by elevated ORAC values related to high capacity in oxygen radical scavenging. The assays on keratinocytes demonstrated that CBE does not inhibit cell proliferation and is shown to significantly reduce dose-dependently ICAM-1, iNOS, NO, ROS and GAG production in cells exposed to IFN-γ and H.


CONCLUSIONS
Our study demonstrates that the pools of compounds of an extract from C. bergamia efficiently block the proinflammatory actions induced by IFN-γ and H on human keratinocytes. CBE may be used for topic employment in some inflammatory diseases of the skin and to represent an important opportunity for the essential oil processing industries.
Department of Bio-medical Sciences, University of Catania, Viale A. Doria, 6, 95125 Catania, Italy.
Adriana C E
AC
Graziano
Venera
V
Cardile
Lucia
L
Crascì
Sivia
S
Caggia
Paola
P
Dugo
Francesco
F
Bonina
Annamaria
A
Panico
D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D002957:Citrus / Q000502:physiology*; D019610:Cytoprotection / Q000187:drug effects* / Q000502:physiology; D006632:Histamine / Q000633:toxicity*; D006801:Humans; D007249:Inflammation / Q000139:chemically induced / Q000378:metabolism / Q000517:prevention & control; D007371:Interferon-gamma / Q000187:drug effects / Q000633:toxicity*; D015603:Keratinocytes / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology* / Q000627:therapeutic use
D010936:Plant Extracts; D006632:Histamine; D007371:Interferon-gamma