Novel mechanisms underlying bioactivities of polyphenols via hormesis

Individual and combined walnut oil and blueberry attenuate lipopolysaccharide-induced neuroinflammation in rat microglia

OBJECTIVES

Chronic microglial activation drives neuroinflammation, contributing to neurodegenerative diseases and cognitive decline. Walnuts and blueberries (BB) have been demonstrated to reduce neuroinflammation, but it is unknown whether they act synergistically to enhance the effects seen with individual treatment. This study examined the individual and synergistic effects of walnut oil (WO) and BB on lipopolysaccharide (LPS)-induced neuroinflammation in rat microglial cells. The effects of pretreatment duration and concentration were also explored.

METHODS

Rat microglial cells were pretreated for 48 hours, one, two, or four weeks with 0.05, 0.1, 0.2, 0.5 and 1.0 mg/mL BB extract, WO or WOBB, followed by exposure to LPS (100 ng/mL). Cell viability was assessed and standard immunochemical techniques were used to measure levels of the inflammatory biomarkers: nitrite, inducible nitrous oxide synthase (iNOS), and cyclooxygenase-2 (COX-2).

RESULTS

BB, WO, and WOBB reduced LPS-induced nitrite, COX-2 and iNOS relative to control, with higher concentrations and longer treatment durations typically being most beneficial. All treatments showed similar ability to reduce iNOS expression, while BB had a stronger effect on reducing nitrite production than WO and WOBB. There were no significant differences between treatment effects on COX-2 expression.

CONCLUSION

BB and WO each reduced LPS-induced inflammation in microglia, but their combination was not more effective, suggesting no synergistic effect. This result suggests that they may work through similar mechanisms to attenuate inflammation in microglia. Overall, the reduction in neuroinflammation shows that the addition of BBs or walnuts to the diet may attenuate neuroinflammation linked to neurodegeneration.

Caffeic acid stimulates migration and invasion of human trophoblast HTR-8/SVneo cells

The placenta is a transient organ essential for development of the fetus. Adequate invasion of trophoblast cells, specialized cells of the placenta, is of utmost importance for the establishment and maintenance of healthy pregnancy. Caffeic acid (CA), one of the most abundantly present hydroxycynamic acids in everyday human diet, exhibits various physiological effects such as antioxidant, anti-inflammatory and anticancer activities including an inhibitory effect on migration and invasion of different cancer cell types. There are not many studies on CA safety in human pregnancy. Therefore, the aim of this research was to investigate the potential of CA to affect trophoblast cell function. We evaluated adhesion, migration and invasion of human trophoblast HTR-8/SVneo cells following CA treatment by functional assays. Furthermore, expression of molecular mediators of these processes such as integrin α1, α5 and β1 subunits and matrix metalloproteinase (MMP)-2 and MMP-9 was evaluated at the mRNA level by qPCR and the protein level by cell-based ELISA assay or zymography. Our results showed that 24 h treatment with 10 μM CA stimulated migration and invasion of HTR-8/SVneo cells as well as expression of the integrin α1 subunit. Furthermore, treatment with 100 μM CA stimulated expression of MMP2 and MMP9 mRNA in the treated HTR-8/SVneo cells as well as secretion of MMP-9. According to obtained results, we can conclude that CA could have the potential to affect processes important for placentation. However, further research is needed to elucidate all aspects of potential CA effects on placental function and pregnancy as a whole.

A novel black poplar propolis extract with promising health-promoting properties: focus on its chemical composition, antioxidant, anti-inflammatory, and anti-genotoxic activities

Propolis is a resinous mixture produced by honeybees which has been used since ancient times for its useful properties. However, its chemical composition and bioactivity may vary, depending on the geographical area of origin and the type of tree bees use for collecting pollen. In this context, this research aimed to investigate the total phenolic content (using the Folin-Ciocalteu assay) and the total antioxidant capacity (using the FRAP, DPPH, and ABTS assays) of three black poplar (Populus nigra L.) propolis (BPP) solutions (S1, S2, and S3), as well as the chemical composition (HPLC-ESI-MSn) and biological activities (effect on cell viability, genotoxic/antigenotoxic properties, and anti-inflammatory activity, and effect on ROS production) of the one which showed the highest antioxidant activity (S1). The hydroalcoholic BPP solution S1 was a prototype of an innovative, research-type product by an Italian nutraceutical manufacturer. In contrast, hydroalcoholic BPP solutions S2 and S3 were conventional products purchased from local pharmacy stores. For the three extracts, 50 phenolic compounds, encompassing phenolic acids and flavonoids, were identified. In summary, the results showed an interesting chemical profile and the remarkable antioxidant, antigenotoxic, anti-inflammatory and ROS-modulating activities of the innovative BPP extract S1, paving the way for future research. In vivo investigations will be a possible line to take, which may help corroborate the hypothesis of the potential health benefits of this product, and even stimulate further ameliorations of the new prototype.

Prosopis africana exerts neuroprotective activity against quaternary metal mixture-induced memory impairment mediated by oxido-inflammatory response via Nrf2 pathway

The beneficial effects of Prosopis africana (PA) on human health have been demonstrated; however, its protective effects against heavy metals (HM) are not yet understood. This study evaluated the potential neuroprotective effects of PA in the cerebral cortex and cerebellum. To accomplish this, we divided 35 albino Sprague Dawley rats into five groups. Group I did not receive either heavy metal mixture (HMM) or PA. Group II received a HMM of PbCl2 (20 mg/kg), CdCl2 (1.61 mg/kg), HgCl2 (0.40 mg/kg), and NaAsO3 (10 mg/kg) orally for a period of two months. Groups III, IV, and V received HMM along with PA at doses of 500, 1000, and 1500 mg/kg, respectively. PA caused decreased levels of HM accumulation in the cerebral cortex and cerebellum and improved performance in the Barnes maze and rotarod tests. PA significantly reduced levels of IL-6 and TNF-α. PA increased concentrations of SOD, CAT, GSH, and Hmox-1 and decreased the activities of AChE and Nrf2. In addition, levels of MDA and NO decreased in groups III, IV, and V, along with an increase in the number of live neurons. In conclusion, PA demonstrates a complex neuroprotective effect with the potential to alleviate various aspects of HM-induced neurotoxicity.