Pomegranate Seed Oil Modulates Functions and Survival of BV-2 Microglial Cells in vitro

Abstract

Current evidence has demonstrated the immunomodulatory efficacy of omega-3 polyunsaturated fatty acids (PUFAs) in glial cells, suggesting their therapeutic potential for diseases in the central nervous system (CNS). However, conjugated omega-5 PUFAs have also attracted considerable attention because of their suggested anti-inflammatory effects. In the present study, the effect of pomegranate (Punica granatum L.) seed oil (PSEO) (a rich source of omega-5 PUFAs) on the activation of cultured BV-2 microglia was investigated within a 24-hour incubation period. PSEO (25 μg/ml) showed only a slightly smaller inhibitory effect on LPS-stimulated NO production (243 ± 12.5 % of control, p<0.001 vs. 437 ± 9.2 % in stimulated cells) and TNF-α release (87.1 ± 5.62 pg/ml vs. 229 ± 24.4 pg/ml in stimulated cells), as well as iNOS expression (7.36-fold of control, p < 0.01, vs. 17.5-fold increase in stimulated cells) compared to a standardized omega-3 PUFAs mixture (25 μg/ml) and the flavonoid quercetin (25 μmol/l). Unlike quercetin and stobadine, only the PUFA preparations effectively prevented apoptosis of microglia (as confirmed by the suppression of caspase 3 activation) exposed to the toxic concentration of LPS. The PUFA preparations did not provide a notable suppression of the intracellular oxidant generation and did not influence the intracellular distribution of cholesterol (as confirmed by filipin staining). However, they appeared to affect the morphology of activated cells. In conclusion, our data point to the first evidence of immunomodulation and cytoprotection of BV-2 microglia by the pomegranate seed oil, indicating that it may be (comparably to omega-3 PUFAs) efficient against microglia-mediated neuroinflammation while preventing the premature depletion of these immune effector cells in the brain.

Could Pomegranate Juice Help in the Control of Inflammatory Diseases?

“…However, experimental conditions applied to cell cultures also tend to vary considerably with regards to the concentration of pomegranate extracts and time-points used ( Table 5 ). In vitro, several pomegranate products have been tested including whole juice [ 61 , 63 , 70 ], extracts from the husk [ 29 ], seeds [ 62 ], or pulp [ 61 , 77 ], bioactive compounds present in pomegranate juice (ET [ 29 , 53 , 77 ] and EA [ 30 ]), or POMx TM extract [ 31 ]. Of all the groups working with these compounds, only Giménez-Bastida et al (2012) [ 28 ] decided to assess the effects in intestinal cells of EA, which is present at high concentrations in the human colon.…”

“…Throughout our literature review, we found that the concentrations of the compounds applied to cells (mainly ET and EA) ranged from 1 to 100 μM; concentrations like 100 μM are considered high but physiologically attainable in the gut. The duration of supplementation was also variable, as groups used short-term (1–2 h) and long-term exposure to ET, EA, and pomegranate extracts (24–48 h), and were tested prior to exposure or in combination with pro-inflammatory stimuli, such as IL-1β [ 28 , 29 , 63 ], TNF-α [ 28 , 66 ], interferon γ (IFN-γ) [ 29 ], lipopolysaccharide (LPS) [ 29 , 53 , 62 ], phorbol 12-myristate 13-acetate (PMA) [ 31 , 79 ], or glucose deprivation [ 61 ]. In a few cases, pomegranate extracts or bioactive molecules were tested individually [ 30 , 70 ].…”

Punica granatum Leaf Lipophilic Fraction Favours Mortality by Attenuating Inflammation in Mice with Polymicrobial Sepsis

“…In a recent study, the hydroalcoholic extract obtained from the leaves of this plant was found to diminish the levels of peritoneal TNFα and to reduce the accumulation of cells (including neutrophils) in to the peritoneum of mice with LPS-induced peritonitis [21]. Similar effects on TNFα production were also observed in vitro for P. granatum seed oil and methanol extract in microglial cells [32,33] and for its leaf hydroalcoholic extract in LPS-injected rats [21] and in a rat model of CLP-induced sepsis [20].…”

“…Indeed, P. granatum fruit decoction was found to inhibit NO production in RAW 267.4 macrophage cells stimulated with toxins derived from Gambierdicus spp., a pathogen causative of infections in fish [31]. Similarly, in vitro LPS-induced NO production by microglial cells was found to be reduced by incubation with P. granatum seed oil [32].…”

Antiinflammatory and anti‐cancer activities of pomegranate and its constituent, ellagic acid: Evidence from cellular, animal, and clinical studies

“…Additionally, PFE prevented extracellular signalregulated kinases (ERK), p38, JNK phosphorylation as well as nuclear factor kappa B (NF-κB) p65-subunit nuclear translocation in LPSstimulated RAW264.7 cells (Xu et al, 2017). Interestingly, it has been shown that pomegranate seed oil (25 μg/mL) considerably attenuates the levels of NO production, TNF-α, iNOS expression and caspase-3 activity following the LPS-induced inflammation in BV-2 murine microglial cell line (Rackova et al, 2014).…”