Abstract
It is known that plant phenolic compounds exert anti-inflammatory activity through both anti-oxidant effects and modulation of pivotal pro-inflammatory factors. Recently, Olea europaea has been studied as a natural source of bioactive molecules; however, few studies have focused on the biological effect of oleacein (OLC), the most abundant secoiridoid. Therefore, the aim of this study was to investigate the potential anti-oxidant activity of OLC, as well as to study its anti-inflammatory effect in lipopolysaccharide (LPS)-stimulated THP-1-derived macrophages. LPS brought a dramatic increase of both release and gene expression of pro-inflammatory cytokines (IL-6, IL-1β and TNF-α), as well as a decrease of anti-inflammatory ones (IL-10), the effects of which are reverted by OLC. Moreover, it reduced the levels of COX-2, NO and PGE2 elicited by LPS exposure in THP-1 macrophages. Interestingly, OLC modulated inflammatory signaling pathways through the inhibition of CD14/TLR4/CD14/MyD88 axis and the activation of NF-κB. Finally, OLC showed relevant anti-oxidant capability, assessed by abiotic assays, and reduced the intracellular amount of ROS generated by LPS exposure in THP-1 macrophages. Overall, these results suggest that the anti-oxidant activity and anti-inflammatory effect of OLC may cooperate in its protective effect against inflammatory stressors, thus being a possible alternative pharmacological strategy aimed at reducing the inflammatory process.
Highlights
Inflammation is an adaptive process of the immune system, prompted by harmful stimuli, which starts in order to initiate the healing process [1,2]
The activated M1 macrophages promote inflammation by producing and releasing cytokines, such as interleukin-1 beta (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α), along with nitric oxide (NO) and prostaglandins (PGE2) [10]. The latter are mediators of inflammatory response synthesized starting from arachidonic acid by both isoforms of cyclooxygenase (COX), COX-1 and COX-2. These can be considered the main targets of antiinflammatory therapy, which are successfully inhibited by nonsteroidal anti-inflammatory drugs (NSAIDs)
Cell viability significantly decreased from 10 to 50 μM. These results indicate that OLC is non-toxic up to 5 μM, and these concentrations were used for further experiments
Summary
Inflammation is an adaptive process of the immune system, prompted by harmful stimuli, which starts in order to initiate the healing process [1,2]. The activated M1 macrophages promote inflammation by producing and releasing cytokines, such as interleukin-1 beta (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α), along with nitric oxide (NO) and prostaglandins (PGE2) [10]. The latter are mediators of inflammatory response synthesized starting from arachidonic acid by both isoforms of cyclooxygenase (COX), COX-1 and COX-2. In the last decades, the use of natural remedies, nutraceuticals and food supplements has increased significantly as an alternative and/or complementary medicine to treat inflammation [11,12] This is because, even if natural products are not risk-free, commonly, they are safer than both synthetic and biologic drugs
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
