Bergamottin and 5-Geranyloxy-7-methoxycoumarin Cooperate in the Cytotoxic Effect of Citrus bergamia (Bergamot) Essential Oil in Human Neuroblastoma SH-SY5Y Cell Line.

The plant kingdom has always been a treasure trove for valuable bioactive compounds, and Citrus fruits stand out among the others. Bergamottin (BRG) and 5-geranyloxy-7-methoxycoumarin (5-G-7-MOC) are two coumarins found in different Citrus species with well-acknowledged pharmacological properties. Previously, they have been claimed to be relevant in the anti-proliferative effects exerted by bergamot essential oil (BEO) in the SH-SY5Y human neuroblastoma cells. This study was designed to verify this assumption and to assess the mechanisms underlying the anti-proliferative effect of both compounds. Our results demonstrate that BRG and 5-G-7-MOC are able to reduce the proliferation of SH-SY5Y cells, inducing apoptosis and increasing cell population in sub-G0/G1 phase. Moreover, we demonstrated the pro-oxidant activity of the two coumarins that increased reactive oxygen species and impaired mitochondrial membrane potential. From a molecular point of view, BRG and 5-G-7-MOC were able to modulate apoptosis related factors at both protein and gene levels. Lastly, we evaluated the synergistic effect of their combination, finding that the highest synergy was observed at a concentration ratio similar to that occurring in the BEO, supporting our initial hypothesis. Taken together, our results deepen the knowledge regarding the effect of BRG and 5-G-7-MOC in SH-SY5Y cells, emphasizing the relevance of their cooperation in achieving this effect.

Anti-inflammatory effect of a flavonoid-rich extract of orange juice in adult zebrafish subjected to Vibrio anguillarum-induced enteritis.

Inflammation-related pathologies remain a serious health problem with high costs for the community. Citrus flavonoids are known to possess important pharmacological properties, including anti-inflammatory activity. In this study we evaluated the effects of a flavonoid-rich extract of orange juice (OJe) in an experimental model of enteritis induced by Vibrio anguillarum in adult zebrafish (Danio rerio). Administration of V. anguillarum through live feed (Artemia nauplii) for three consecutive days caused evident signs of enteritis in zebrafish. Three days of treatment with OJe before the pathogenic insult resulted in a remarkable reduction of tissue inflammatory events as well as a molecular down-regulation of the inflammatory genes such as IL-1ß, IL-6 and TNFα. Our data suggest that OJe counteracts the inflammation of zebrafish intestinal mucosa, indicating that the pool of flavonoids present in orange juice could be useful for the prevention of enteritis.

Citrus fruits and their flavonoids in inflammatory bowel disease: an overview.

Inflammatory bowel disease (IBD), with its major manifestations being Crohn's disease and ulcerative colitis, belongs to the gastrointestinal inflammatory disorders, whose main therapeutic approach is represented by synthetic anti-inflammatory drugs. However, they are often accompanied by many side effects that shifted the interest of the scientific community towards natural products. In this context, several studies asserted the anti-IBD effects of Citrus fruits and their flavonoids, thus the aim of the present review is to provide robust evidence favouring their role in the prevention and treatment of IBD. Key mechanisms relate to their anti-inflammatory and antioxidant properties, as well as their ability to modulate gut microbiota. All the findings collected in this review, lay the foundations for further studies in human with the aim of evaluating the concrete applicability as a novel preventive and therapeutic approach of Citrus fruits and their flavonoids.[Figure: see text].

Natural iron chelators: Protective role in A549 cells of flavonoids-rich extracts of Citrus juices in Fe(3+)-induced oxidative stress.

Exogenous iron in particulate matter and imbalanced iron homeostasis cause deleterious effects on health. Natural and synthetic iron chelators may be of therapeutic benefit, therefore we evaluated the protective effect of Citrus flavonoids-rich extracts from bergamot and orange juices in iron overloaded human lung epithelial cells. Cytofluorimetric, biochemical and genotoxic analyses were performed in Fe2(SO4)3 exposed A549, pretreated with each extract whose chemical composition was previously detected. Chelating activity was assessed in cells by a calcein ester. Both extracts reduced the generation of reactive oxygen species and membrane lipid peroxidation, improved mitochondrial functionality, and prevented DNA-oxidative damage in iron-exposed cells. Antioxidant effects were attributed to the chelating property, blocking upstream the redox activity of iron. Flavonoid-rich extracts also induced antioxidant catalase. The bergamot and orange juice extracts had a broad-spectrum protective effect. Their use prevents iron oxidative injury and these natural iron chelators could be used as therapeutic agents.

NF-κB mediates the antiproliferative and proapoptotic effects of bergamot juice in HepG2 cells.

AIMS: Among cancers, hepatocellular carcinoma is one of the commonest worldwide, and its incidence is increasing around the world. A lot of evidence underlines that natural substances usually consumed in the diet can have an important role in the prevention of cancer. In this study we investigated the molecular mechanisms underlying the antiproliferative activity of Citrus bergamia (bergamot) juice (BJ) in human hepatocellular carcinoma HepG2 cells. MAIN METHODS: HepG2 cells were exposed to BJ and then cell proliferation, cell cycle progression, apoptosis and NF-κB nuclear translocation were evaluated. KEY FINDINGS: Here we present results demonstrating that BJ reduced the growth rate of human hepatocellular carcinoma HepG2 cells in a time- and concentration-dependent manner, by a mechanism involving the activation of apoptotic machinery via both intrinsic and extrinsic pathways. Moreover, BJ increased expression of P53 and P21 proteins that may be responsible for the HepG2 cell cycle arrest in G2 phase. In addition, BJ reduced NF-κB nuclear translocation. SIGNIFICANCE: Our data demonstrate the ability of BJ in reducing the growth of HepG2 cells, revealing its mechanism of action and suggesting a promising role as anticancer drugs.

Flavonoid Fraction of Orange and Bergamot Juices Protect Human Lung Epithelial Cells from Hydrogen Peroxide-Induced Oxidative Stress.

It has been reported that oxidant/antioxidant imbalance triggers cell damage that in turn causes a number of lung diseases. Flavonoids are known for their health benefits, and Citrus fruits juices are one of the main food sources of these secondary plant metabolites. The present study was designed to evaluate the effect of the flavonoid fraction of bergamot and orange juices, on H2O2-induced oxidative stress in human lung epithelial A549 cells. First we tested the antioxidant properties of both extracts in cell-free experimental models and then we assayed their capability to prevent the cytotoxic effects induced by H2O2. Our results demonstrated that both Citrus juice extracts reduce the generation of reactive oxygen species and membrane lipid peroxidation, improve mitochondrial functionality, and prevent DNA-oxidative damage in A549 cells incubated with H2O2. Our data indicate that the mix of flavonoids present in both bergamot and orange juices may be of use in preventing oxidative cell injury and pave the way for further research into a novel healthy approach to avoid lung disorders.

Neuroprotective effects of a polyphenolic white grape juice extract in a mouse model of experimental autoimmune encephalomyelitis.

In the last 20 years, wine phenolic compounds have received increasing interest since several epidemiological studies have suggested associations between regular consumption of moderate amount of wine and prevention of certain chronic pathologies, such as neurodegenerative diseases. This study was aimed to investigate the possible neuroprotective role of a polyphenolic white grape juice extract (WGJe) in an experimental mice model of autoimmune encephalomyelitis (EAE), the most commonly used model for multiple sclerosis (MS) in vivo. EAE mimics the main features of MS, including paralysis, weight loss, demyelination, central nervous system (CNS) inflammation and blood-brain barrier (BBB) breakdown. Our study demonstrated that oral administration of WGJe (20 and 40 mg/kg/day) may exert neuroprotective effects against MS, diminishing both clinical signs and histological score typical of disease (lymphocytic infiltration and demyelination). In particular, by western blot, histological evaluations and immunolocalization of the main markers of inflammation, oxidative stress and apoptosis (TNF-α, iNOS, Nitrotyrosine, PARP, Foxp3, Bcl-2, Caspase 3 and DNA fragmentation), we documented that WGJe counteracts the alteration of all these inflammatory and oxidative pathway, without any apparent sign of toxicity. On these bases, we propose this natural product as putative novel helpful tools for the prevention of autoimmune and neurodegenerative diseases such as MS. WGJe could have considerable implication for future therapies of MS, and this study may represents the starting point for further investigation on the role of WGJe in neuroinflammation.

Effects of bergamot essential oil and its extractive fractions on SH-SY5Y human neuroblastoma cell growth.

OBJECTIVES: The goals were to investigate the mechanisms underlying the antiproliferative effects of bergamot essential oil (BEO) and to identify the compounds mainly responsible for its SH-SY5Y cells growth rate inhibition. METHODS: Five BEO extractive fractions (BEOs) differing in their chemical composition were used. Cell proliferation was determined by 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and cell count assays. Trypan blue exclusion test and Annexin V/PI staining were performed to assess their cytotoxic activity. Genotoxicity was detected by comet assay. The cell cycle was checked cytofluorimetrically. Reactive oxygen species (ROS) and Δψm were measured fluorimetrically. Western blotting analyses for some apoptosis-related proteins were carried out. KEY FINDINGS: Treatment of SH-SY5Y cells with some types of BEOs decreased cell growth rate by a mechanism correlated to both apoptotic and necrotic cell death. Coloured BEOs act by increasing ROS generation, responsible for the drop in Δψm, and modulate p38 and extracellular signal-regulated kinases (ERK ½) mitogen-activated protein kinases, p53, Bcl-2 and Bax signalling pathways. Finally, we identify bergamottin and 5-geranyloxy-7-methoxycoumarin as the bioactive molecules that could play a pivotal role in the antiproliferative effects exerted by coloured BEOs. CONCLUSIONS: Our study provides novel insights into the field of the antiproliferative effects of BEO, which could be exploited in the context of a multitarget pharmacological strategy.

Antiinflammatory activity of glucomoringin isothiocyanate in a mouse model of experimental autoimmune encephalomyelitis.

Glucomoringin (4(α-L-rhamnosyloxy)-benzyl glucosinolate) (GMG) is an uncommon member of glucosinolate group belonging to the Moringaceae family, of which Moringa oleifera Lam. is the most widely distributed. Bioactivation of GMG with the enzyme myrosinase forms the corresponding isothiocyanate (4(α-L-rhamnosyloxy)-benzyl isothiocyanate) (GMG-ITC), which can play a key role in antitumoral activity and counteract the inflammatory response. The aim of this study was to assess the effect of GMG-ITC treatment in an experimental mouse model of multiple sclerosis (MS), an inflammatory demyelinating disease with neurodegeneration characterized by demyelinating plaques, neuronal, and axonal loss. For this reason, C57Bl/6 male mice were injected with myelin oligodendrocyte glycoprotein35-55 which is able to evoke an autoimmune response against myelin fibers miming human multiple sclerosis physiopatogenesis. Results clearly showed that the treatment was able to counteract the inflammatory cascade that underlies the processes leading to severe MS. In particular, GMG-ITC was effective against proinflammatory cytokine TNF-α. Oxidative species generation including the influence of iNOS, nitrotyrosine tissue expression and cell apoptotic death pathway was also evaluated resulting in a lower Bax/Bcl-2 unbalance. Taken together, this work adds new interesting properties and applicability of GMG-ITC and this compound can be suggested as a useful drug for the treatment or prevention of MS, at least in association with current conventional therapy.