Description: |
Naringenin is a weak estrogen that also exhibits partial antiestrogenic activity in the female rat uterus and MCF-7 human breast cancer cells. Naringenin is also a agent for the treatment of hepatitis C virus (HCV) infection. Naringenin has hypocholesterolemic, antioxidant, free radical scavenger, anti-cancer, anti-inflammatory, neuroprotective, carbohydrate metabolism promoter, and immune system modulator properties. Naringenin possesses potent antidepressant-like property via the central serotonergic and noradrenergic systems. |
Targets: |
NOS | COX | TNF-α | PGE | IL Receptor | PI3K | Akt | Caspase | NF-kB | NO | p65 | LDL |
In vitro: |
Int J Mol Med. 2012 Jul;30(1):204-10. | Naringenin attenuates the release of pro-inflammatory mediators from lipopolysaccharide-stimulated BV2 microglia by inactivating nuclear factor-κB and inhibiting mitogen-activated protein kinases.[Pubmed: 22552813 ] | Naringenin, one of the most abundant flavonoids in citrus fruits and grapefruits, has been reported to exhibit anti-inflammatory and antitumor activities. However, the cellular and molecular mechanisms underlying the naringenin anti-inflammatory activity are poorly understood.
METHODS AND RESULTS:
In this study, we conducted an investigation of the inhibitory effects of naringenin on the production of lipopolysaccharide (LPS)-induced pro-inflammatory mediators in BV2 microglial cells. We found that pre-treatment with naringenin prior to treatment with LPS significantly inhibited excessive production of nitric oxide (NO) and prostaglandin E2 (PGE2) in a dose-dependent manner. The inhibition was associated with downregulation of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression. Naringenin also attenuated the production of pro-inflammatory cytokines and chemokines, including interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) and monocyte chemoattractant protein-1 (MCP-1) by suppressing expression of mRNAs for these proteins. In addition, the molecular mechanism underlying naringenin-mediated attenuation in BV2 cells has a close relationship to suppressing translocation of the nuclear factor-κB (NF-κB) p65 subunit into the nucleus and the phosphorylation of Akt and mitogen-activated protein kinases (MAPKs).
CONCLUSIONS:
These findings suggest that naringenin may provide neuroprotection through suppression of pro-inflammatory pathways in activated BV2 microglial cells. | J Lipid Res. 2001 May;42(5):725-34. | Secretion of hepatocyte apoB is inhibited by the flavonoids, naringenin and hesperetin, via reduced activity and expression of ACAT2 and MTP.[Pubmed: 11352979] | The citrus flavonoids, naringenin and hesperetin, lower plasma cholesterol in vivo. However, the underlying mechanisms are not fully understood.
METHODS AND RESULTS:
The ability of these flavonoids to modulate apolipoprotein B (apoB) secretion and cellular cholesterol homeostasis was determined in the human hepatoma cell line, HepG2. apoB accumulation in the media decreased in a dose-dependent manner following 24-h incubations with naringenin (up to 82%, P < 0.00001) or hesperetin (up to 74%, P < 0.002). Decreased apoB secretion was associated with reduced cellular cholesteryl ester mass. Cholesterol esterification was decreased, dose-dependently, up to 84% (P < 0.0001) at flavonoid concentrations of 200 microM. Neither flavonoid demonstrated selective inhibition of either form of acyl CoA:cholesterol acyltransferase (ACAT) as determined using CHO cells stably transfected with either ACAT1 or ACAT2. However, in HepG2 cells, ACAT2 mRNA was selectively decreased (- 50%, P < 0.001) by both flavonoids, whereas ACAT1 mRNA was unaffected. In addition, naringenin and hesperetin decreased both the activity (- 20% to - 40%, P < 0.00004) and expression (- 30% to - 40%, P < 0.02) of microsomal triglyceride transfer protein (MTP). Both flavonoids caused a 5- to 7-fold increase (P < 0.02) in low density lipoprotein (LDL) receptor mRNA, which resulted in a 1.5- to 2-fold increase in uptake and degradation of (125)I-LDL.
CONCLUSIONS:
We conclude that both naringenin and hesperetin decrease the availability of lipids for assembly of apoB-containing lipoproteins, an effect mediated by 1) reduced activities of ACAT1 and ACAT2, 2) a selective decrease in ACAT2 expression, and 3) reduced MTP activity. Together with an enhanced expression of the LDL receptor, these mechanisms may explain the hypocholesterolemic properties of the citrus flavonoids. |
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In vivo: |
Life Sci. 2005 Mar 18;76(18):2125-35. | Naringenin attenuates cisplatin nephrotoxicity in rats.[Pubmed: 15826879 ] | METHODS AND RESULTS:
The effect of naringenin (NAR), a naturally occurring citrus flavanone, on the acute nephrotoxicity produced by cisplatin (7 mg/kg, i.v.) was investigated in the rat. Oral administration of NAR (20 mg/kg/day) for 10 days, starting 5 days before cisplatin single i.v. injection, produced significant protection of renal function. NAR reduced the extent of cisplatin-induced nephrotoxicity, as evidenced by significant reduction in serum urea and creatinine concentrations, decreased polyuria, reduction in body weight loss, marked reduction in urinary fractional sodium excretion and glutathione S-transferase (GST) activity, and increased creatinine clearance. Cisplatin-induced alterations in renal cortex lipid peroxides and GST activity were markedly improved by NAR. Cisplatin-induced alterations in renal cortex antioxidant defense system were greatly prevented by NAR. In cisplatin-NAR combined treatment group, antioxidant enzymes namely superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) were significantly increased to 54.5, 30.3 and 35.6%, respectively compared to cisplatin treated group. Platinum renal content was not affected by NAR treatment.
CONCLUSIONS:
The results provide further insight into the mechanisms of cisplatin-induced nephrotoxicity and confirm the antioxidant potential of NAR. | Exp Toxicol Pathol. 2010 Mar;62(2):171-81. | Cadmium-induced hepatotoxicity in rats and the protective effect of naringenin.[Pubmed: 19409769] | This experiment pertains to the protective role of naringenin against cadmium (Cd)-induced oxidative stress in the liver of rats. Cadmium is a major environmental pollutant and is known for its wide toxic manifestations. Naringenin is a naturally occurring citrus flavonone which has been reported to have a wide range of pharmacological properties.
METHODS AND RESULTS:
In the present investigation cadmium (5mg/kg) was administered orally for 4 weeks to induce hepatotoxicity. Liver damage induced by cadmium was clearly shown by the increased activities of serum hepatic marker enzymes namely aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), gamma glutamyl transferase (GGT) and serum total bilirubin (TB) along with the increased level of lipid peroxidation indices (thiobarbituric acid reactive substances (TBARS) and lipid hydroperoxides) and protein carbonyl contents in liver. The toxic effect of cadmium was also indicated by significantly decreased levels of enzymatic antioxidants (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione S-transferase (GST)) and non-enzymatic antioxidants (reduced glutathione (GSH), vitamin C and vitamin E). Administration of naringenin at a dose of (50mg/kg) significantly reversed the activities of serum hepatic marker enzymes to their near-normal levels when compared to Cd-treated rats. In addition, naringenin significantly reduced lipid peroxidation and restored the levels of antioxidant defense in the liver. The histopathological studies in the liver of rats also showed that naringenin (50mg/kg) markedly reduced the toxicity of cadmium and preserved the normal histological architecture of the tissue.
CONCLUSIONS:
The present study suggested that naringenin may be beneficial in ameliorating the cadmium-induced oxidative damage in the liver of rats. | Free Radic Res. 2005 Oct;39(10):1119-25. | Neuroprotective properties of the natural phenolic antioxidants curcumin and naringenin but not quercetin and fisetin in a 6-OHDA model of Parkinson's disease.[Pubmed: 16298737 ] |
Although the cause of dopaminergic cell death in Parkinson's disease (PD) remains unknown, oxidative stress has been strongly implicated. Because of their ability to combat oxidative stress, diet derived phenolic compounds continue to be considered as potential agents for long-term use in PD.
This study was aimed at investigating whether the natural phenolic compounds curcumin, naringenin, quercetin, fisetin can be neuroprotective in the 6-OHDA model of PD.
METHODS AND RESULTS:
Unilateral infusion of 6-OHDA into the medial forebrain bundle produced a significant loss of tyrosine hydroxylase (TH)-positive cells in the substantia nigra (SN) as well as a decreased of dopamine (DA) content in the striata in the vehicle-treated animals. Rats pretreated with curcumin or naringenin showed a clear protection of the number of TH-positive cells in the SN and DA levels in the striata. However, neither pretreatment with quercetin nor fisetin had any effects on TH-positive cells or DA levels.
CONCLUSIONS:
The ability of curcumin and naringenin to exhibit neuroprotection in the 6-OHDA model of PD may be related to their antioxidant capabilities and their capability to penetrate into the brain.
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