**Author details**

312 Olive Germplasm – The Olive Cultivation, Table Olive and Olive Oil Industry in Italy

3,4-DHPEA-EA may be useful in the therapy of inflammation.

Oxidative stress is described as an imbalance between ROS synthesis and antioxidant system in the mammal body where the normal production of oxidants is counteracted by several antioxidative mechanisms. Food constituents are the normal substrate for energy generation but a hypercaloric diet may result in higher ROS, thus inducing oxidative stress. Epidemiological studies have shown that populations consuming a predominantly olive oilbased Mediterranean-style diet exhibit lower incidences of breast cancer and other chronic diseases than those eating a northern European or North American diet. Habitual high intakes of olive oil, especially virgin olive oil, provide a continuous supply of antioxidants, which may reduce oxidative stress via inhibition of lipid peroxidation, a factor that is

currently linked to a host of diseases such as cancer, heart disease, and ageing.

**4. Overall conclusion** 

nitration of lipids, DNA disruption, and nitration and deamination of DNA bases (Filippin *et al.*, 2008). In this report, an intense immunostaining of nitrotyrosine formation also suggested that a structural alteration of joint had occurred, most probably due to the formation of highly reactive nitrogen derivatives ROS produce strand breaks in DNA, which triggers energy-consuming DNA repair mechanisms and activates the nuclear enzyme poly(ADP-ribosyl) polymerase (PARP). There is various evidence that the activation of PARP may also play an important role in inflammation (Genovese *et al.*, 2005). Continuous or excessive activation of PARP produces extended chains of ADP-ribose (PAR) on nuclear proteins and results in a substantial depletion of intracellular NAD and subsequently, ATP, leading to cellular dysfunction and, ultimately, cell death (Chiarugi, 2002). We demonstrate here that 3,4-DHPEA-EA treatment reduced the activation of PARP with a decrease in PAR expression in the joint during CIA. In this regard, several studies demonstrated that hydroxytyrosol, a hydrolysis product of 3,4-DHPEA-EA, also exerts an inhibitory effect on peroxynitrite-dependent DNA base modifications and tyrosine nitration (Deiana *et al.*, 1999). Likewise, Salvini *et al.* (2006) showed a 30% reduction of oxidative DNA damage in peripheral blood lymphocytes during intervention in postmenopausal women with virgin olive oil containing high amounts of phenols. Thus, 3,4-DHPEA-EA, given at the onset of the disease, reduced paw swelling, clinical score, and the histological severity of the disease when injected after the onset of clinical arthritis. Amelioration of joint disease was associated with near to full inhibition of cytokines as well as inhibition of neutrophil infiltration, which is a key player in RA. Therefore, 3,4-DHPEA-EA was also administered from day 28 after collagen immunization, targeting this early initiation phase of CIA. Then, with treatment starting at day 28, 3,4-DHPEA-EA post-treatment caused a significant reduction of inflamed joints collected at day 35. In conclusion, RA is a complex chronic inflammatory disease dependent on multiple interacting environmental and genetic factors, making it difficult to understand its pathogenesis and thereby to find effective therapies. Taken together, the results of the present study enhance our understanding of the role of ROS generation in the pathophysiology of CII-induced arthritis, implying that olive oil compounds such as

Domenico Britti and Antonio Procopio *Dept. of Health Sciences, University of Catanzaro, Catanzaro, Italy* 

Daniela Impellizzeri and Salvatore Cuzzocrea *Dept. of Clinical and Experimental Medicine and Pharmacology, University of Messina, Torre Biologica – Policlinico Universitario, Messina, Italy* 
