Antinociceptive and anti-inflammatory effects of the citrus flavanone naringenin

Impact of Eucalyptus maculata Hook resin exudate constituents on reducing COX-2 gene expression: In-vivo anti-inflammatory, molecular docking and dynamics studies

ETHNOPHARMACOLOGICAL RELEVANCE

Eucalyptus maculata Hook from the Myrtaceae family is a native Australian plant that is frequently cultivated in Egypt. Many Eucalyptus species, including E. maculata, were widely used by the Dharawal, the indigenous Australian people, for their anti-inflammatory properties.

AIM OF THE STUDY

The purpose of this study was to determine the anti-inflammatory activity of the ethanol extract of E. maculata resin exudate, its methylene chloride and n-butanol fractions, as well as the isolated compounds.

MATERIALS AND METHODS

the ethanol extract was partitioned by methylene chloride, and n-butanol saturated with water. The fractions were chromatographed to isolate pure compounds. In-vivo anti-inflammatory activity of the ethanol extract, the fractions at a dose of 200 mg/Kg, and the isolated compounds (20 mg/Kg) was estimated using carrageenan-induced rat paws edema method against indomethacin (20 mg/Kg). The activity was supported by histopathological and biochemical parameters.

RESULTS

Three isolated compounds were identified as aromadendrin (C1), 7-O-methyl aromadendrin (C2), and naringenin (C3). Our findings demonstrated that the tested fractions significantly reduced the paw edema starting from the 3rd to the 5th hour as compared to the positive control, compounds C2 and C3 showed the greatest significant reduction in paw edema. The ethanol extract, fractions, C2, and C3 demonstrated an anti-inflammatory potential through reducing the levels of TNF-α, IL-6, and PGE2, as well as COX-2 protein expression compared to the negative control. These results were supported by molecular docking, which revealed that the isolated compounds had high affinity to target COX-1 and COX-2 active sites with docking scores ranging from -7.3 to -9.6 kcal mol^-1 when compared to ibubrofen (-7.8 and -7.4 kcal mol^-1, respectively). Molecular dynamics simulations were also performed and confirmed the docking results.

CONCLUSION

The results supported the traditional anti-inflammatory potency of E. maculata Hook, and the biochemical mechanisms underlying this activity were highlighted, opening up new paths for the development of potent herbal anti-inflammatory medicine. Finally, our findings revealed that E. maculata resin constituents could be considered as promising anti-inflammatory drug candidates.

Naringin attenuates fructose-induced NAFLD progression in rats through reducing endogenous triglyceride synthesis and activating the Nrf2/HO-1 pathway

Background: Excessive fructose consumption causes hepatic lipid accumulation via increased triglyceride (TG) synthesis, leading to the development and progression of non-alcoholic fatty liver disease (NALFD). Naringin, a flavanone glycoside found in citrus fruit, has antioxidant and hypolipidemic properties. Therefore, the aim of this study was to investigate the effect of naringin on fructose-induced NAFLD in rats and the possible underlying mechanism. Methods: Male Sprague Dawley rats were given 10% (w/v) fructose in drinking water for 12 weeks. Naringin (100 mg/kg/day) was administered orally to rats for the last 4 weeks of fructose overload. After 12 weeks of treatment, the hepatic lipid content was determined. In addition, the expression of proteins involved in de novo lipogenesis (DNL) and TG synthesis as well as antioxidant and inflammatory mediators in the liver were examined by western blot analysis. Results: Treatment of fructose-fed rats with naringin significantly decreased the hepatic TG and cholesterol content as well as serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities. Naringin treatment also decreased the hepatic expression of carbohydrate response element binding protein (ChREBP), sterol regulatory element-binding protein-1c (SREBP-1c) and nuclear SREBP-1c (nSREBP-1c) as well as enzymes involved in DNL (acetyl CoA carboxylase [ACC] and fatty acid synthase [FAS]) and an enzyme involved in TG synthesis (glycerol-3-phosphate acyltransferase 1 [GPAT-1] and diacylglycerol acyltransferase2 [DGAT2]) in fructose-fed rats. In addition, naringin induced a significant decrease in the hepatic expression of nuclear factor kappa B (NF-κB) and tumor necrosis factor α (TNF-α). Furthermore, naringin administration restored the expression of the antioxidant mediators nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and heme oxygenase-1 (HO-1) in the liver of fructose-fed rats. Conclusion: These results demonstrate that oral administration of naringin protects against fructose-induced hepatic steatosis by decreasing DNL and TG synthesis. In addition, naringin could prevent NAFLD progression via targeting the Nrf2/HO-1 and the NF-κB/TNF-α pathways.

A Scoping Review of the Skeletal Effects of Naringenin

BACKGROUND

Osteoporosis is caused by the deterioration of bone density and microstructure, resulting in increased fracture risk. It transpires due to an imbalanced skeletal remodelling process favouring bone resorption. Various natural compounds can positively influence the skeletal remodelling process, of which naringenin is a candidate. Naringenin is an anti-inflammatory and antioxidant compound found in citrus fruits and grapefruit. This systematic review aims to present an overview of the available evidence on the skeletal protective effects of naringenin.

METHOD

A systematic literature search was conducted using the PubMed and Scopus databases in August 2022. Original research articles using cells, animals, or humans to investigate the bone protective effects of naringenin were included.

RESULTS

Sixteen eligible articles were included in this review. The existing evidence suggested that naringenin enhanced osteoblastogenesis and bone formation through BMP-2/p38MAPK/Runx2/Osx, SDF-1/CXCR4, and PI3K/Akt/c-Fos/c-Jun/AP-1 signalling pathways. Naringenin also inhibited osteoclastogenesis and bone resorption by inhibiting inflammation and the RANKL pathway.

CONCLUSIONS

Naringenin enhances bone formation while suppressing bone resorption, thus achieving its skeletal protective effects. It could be incorporated into the diet through fruit intake or supplements to prevent bone loss.

Naringenin and Its Derivatives-Health-Promoting Phytobiotic against Resistant Bacteria and Fungi in Humans

Naringenin is a trihydroxyflavanone present in large amount in different citrus fruits, e.g., oranges, pomelos, grapefruits, but also in tomatoes, fenugreek and coffee. It has a wide range of pharmacological and biological effects beneficial to human health. Its antioxidant, anti-cancer, anti-inflammatory, antifungal and antimicrobial activity is frequently reported in scientific literature. In this review we presented the current state of knowledge on the antimicrobial activity of naringenin and its natural and synthetic derivatives as a phytobiotic against resistant Gram-positive and Gram-negative bacteria as well as fungi in humans. Most of the data reported here have been obtained from in vitro or in vivo studies. Over the past few years, due to the overuse of antibiotics, the occurrence of bacteria resistant to all available antibiotics has been growing. Therefore, the main focus here is on antibiotic resistant strains, which are a significant, worldwide problem in the treatment of infectious diseases. The situation is so alarming that the WHO has listed microbial resistance to drugs on the list of the 10 most important health problems facing humanity. In addition, based on scientific reports from recent years, we described the potential molecular mechanism of action of these bioflavonoids against pathogenic strains of microorganisms. As plant-derived substances have been pushed out of use with the beginning of the antibiotic era, we hope that this review will contribute to their return as alternative methods of preventing and treating infections in the epoch of drug resistance.

Protective Effects of Naringenin from Citrus sinensis (var. Valencia) Peels against CCl4-Induced Hepatic and Renal Injuries in Rats Assessed by Metabolomics, Histological and Biochemical Analyses

Citrus fruits are grown worldwide for their special nutritive and several health benefits. Among citrus bioactives, naringenin, a major flavanone, exhibits a potential hepatoprotective effect that is not fully elucidated. Herein, serum biochemical parameters and histopathological assays were used to estimate the hepatoprotective activity of naringenin, isolated from Citrus sinensis (var. Valencia) peels, in CCl4-induced injury in a rat model. Further, GC-MS-based untargeted metabolomics was used to characterize the potential metabolite biomarkers associated with its activity. Present results revealed that naringenin could ameliorate the increases in liver enzymes (ALT and AST) induced by CCl4 and attenuate the pathological changes in liver tissue. Naringenin decreased urea, creatinine and uric acid levels and improved the kidney tissue architecture, suggesting its role in treating renal disorders. In addition, naringenin increased the expression of the antiapoptoic cell marker, Bcl-2. Significant changes in serum metabolic profiling were noticed in the naringenin-treated group compared to the CCl4 group, exemplified by increases in palmitic acid, stearic acid, myristic acid and lauric acids and decrease levels of alanine, tryptophan, lactic acid, glucosamine and glucose in CCl4 model rats. The results suggested that naringenin's potential hepato- and renoprotective effects could be related to its ability to regulate fatty acids (FAs), amino acids and energy metabolism, which may become effective targets for liver and kidney toxicity management. In conclusion, the current study presents new insights into the hepato- and renoprotective mechanisms of naringenin against CCl4-induced toxicity.

Antinociceptive and Anti-Inflammatory Effects of Recombinant Crotamine in Mouse Models of Pain

Crotamine, a toxin found in the venom of the South American rattlesnake Crotalus durissus terrificus, has been reported to have antinociceptive effects. We purified recombinant crotamine expressed in Escherichia coli and investigated its antinociceptive and anti-inflammatory effects using the hot-plate test, acetic-acid-induced writhing method, and formalin test in mice. Recombinant crotamine was administered intraperitoneally (0.04–1.2 mg kg⁻¹) or intraplantarly (0.9–7.5 μg 10 μL⁻¹) before the tests. The paw volume was measured with a plethysmometer. To evaluate the antagonistic and anti-inflammatory effects of naloxone, subcutaneous naloxone (4 mg kg⁻¹) or intraplantar naloxone (5 μg 10 μL⁻¹) was administered before recombinant crotamine. For tumor necrosis factor (TNF)-α assays, blood was drawn 3 h after formalin injection and measured using enzyme-linked immunosorbent assay. Intraperitoneal and intraplantar recombinant crotamine had antinociceptive and anti-inflammatory effects, neither of which were affected by pre-treatment with naloxone. The mean serum TNF-α levels were significantly lower in the intraperitoneal recombinant crotamine (0.4 and 1.2 mg kg⁻¹) or intraplantar (2.5 and 7.5 μg 10 μL⁻¹) recombinant crotamine groups than in the saline group and were not affected by naloxone pre-treatment. In conclusion, recombinant crotamine possesses significant antinociceptive and anti-inflammatory effects that do not appear to be related to the opioid receptor. The antinociceptive and anti-inflammatory effects of intraperitoneal or intraplantar recombinant crotamine are related to TNF-α.

Antioxidant-rich fraction of Amomum subulatum fruits mitigates experimental methotrexate-induced oxidative stress by regulating TNF-α, IL-1β, and IL-6 proinflammatory cytokines

The culinary spice Amomum subulatum was assessed for its phytochemical composition, in vitro antioxidant potential, and in vivo ameliorating effect against methotrexate (MTX)-induced toxicities. Phytochemical analysis of methanolic extract of A. subulatum dry fruits (MEAS) confirmed the presence of different bioactive secondary metabolites. MEAS scavenged reactive free radicals and inhibited lipid peroxidation in vitro. To confirm the antioxidant efficiency of MEAS, in vivo experiment was carried out in which MTX was administered to induce oxidative stress. Co-administration of MEAS reduced MTX-induced hepatic, renal, and pulmonary toxicities via significantly (p < .01) enhancing antioxidant status and reducing oxidative stress. MTX treatment significantly (p < .01) increased liver and kidney toxicity markers and increased proinflammatory cytokine (TNF-α, IL-1β, and IL-6) levels. However, co-administration of MEAS significantly (p < .01) reduced their levels, and tissue histopathology confirmed the protective effect of MEAS in maintaining normal tissue architecture following MTX treatment. Protective effect of MEAS is accredited to the antioxidant and anti-inflammatory properties exhibited by bioactive compounds in MEAS. PRACTICAL APPLICATIONS: Amomum subulatum (Black cardamom) is a folkloric and culinary spice used for its organoleptic, nutritional, and medicinal properties. This study demonstrated the phytochemical composition and antioxidant potential of methanolic extract of A. subulatum dry fruits (MEAS). Toxicities associated with MTX therapy limit its clinical application. MEAS attenuated methotrexate-induced oxidative stress, inflammation, and associated organ damages, suggesting the possible therapeutic application of A. subulatum in reducing oxidative stress and associated diseases. Our results showed that A. subulatum is a potential functional food, which may be used for the betterment of health due to its richness in antioxidant and anti-inflammatory phytochemicals.

Wnt/β-catenin Antagonists: Exploring New Avenues to Trigger Old Drugs in Alleviating Glioblastoma Multiforme

BACKGROUND

Glioblastoma multiforme is one of the most heterogenous primary brain tumor with high mortality. Nevertheless, of the current therapeutic approaches, survival rate remains poor with 12 to 15 months following preliminary diagnosis, this warrants the need for effective treatment modality. Wnt/β-catenin pathway is presumably the most noteworthy pathway up-regulated in almost 80% GBM cases contributing to tumor-initiation, progression and survival. Therefore, therapeutic strategies targeting key components of Wnt/β-catenin cascade using established genotoxic agents like temozolomide and pharmacological inhibitors would be an effective approach to modulate Wnt/β-catenin pathway. Recently, drug repurposing by means of effective combination therapy has gained importance in various solid tumors including GBM, by targeting two or more proteins in a single pathway, thereby possessing the ability to overcome the hurdle implicated by chemo-resistance in GBM.

OBJECTIVE

In this context, by employing computational tools, an attempt has been carried out to speculate the novel combinations against Wnt/β-catenin signaling pathway.

METHODS

We have explored the binding interactions of three conventional drugs namely temozolomide, metformin, chloroquine along with three natural compounds viz., epigallocatechin gallate, naringenin and phloroglucinol on the major receptors of Wnt/β-catenin signaling.

RESULTS

It was noted that all the experimental compounds possessed profound interaction with the two major receptors of Wnt/β-catenin pathway.

CONCLUSION

To the best of our knowledge, this study is the first of its kind to characterize the combined interactions of the afore-mentioned drugs on Wnt/β-catenin signaling in silico and this will putatively open up new avenues for combination therapies in GBM treatment.

Naringenin Ameliorates Chronic Sleep Deprivation-Induced Pain via Sirtuin1 Inhibition

Growing experimental evidences have suggested the reciprocal correlation between sleep deprivation and pain. Inflammation and oxidative stress are among the key pathways underlying this correlation. Therefore, the present study was aimed to assess the effect of antioxidant and anti-inflammatory compound naringenin (NGN) against chronic sleep deprivation (CSD)-induced mechanical and thermal hyperalgesia in female Swiss albino mice. In this study, mice were chronically sleep-deprived for 8 h a day for five days a week with the weekend as a free sleep period and continued for nine weeks using a modified multiple platform method. The pain behavioral tests were conducted at the end of the fourth week to assess the development of hyperalgesia followed by the administration of NGN and a combination of NGN with Sirtinol (SIR, a sirtuin1 inhibitor) till the end of the study. After nine weeks, pain behavioral tests, along with oxidative stress and inflammatory parameters in cortex and striatum, were assessed. Results indicated that CSD-induced hyperalgesia in mice accompanied by increased oxidative stress and inflammatory markers in cortex and striatum of the brain. NGN combatted the hyperalgesic response and also decreased levels of oxidative stress and inflammatory markers. Furthermore, the pharmacological effect of NGN was mitigated with SIR. Thus, the findings of the present study reveal that NGN is acting via sirtuin1 to exert its antinociceptive activity against CSD-induced hyperalgesia.

Hydroxypropyl-β-cyclodextrin-complexed naringenin by solvent change precipitation for improving anti-inflammatory effect in vivo

The flavonoid naringenin (NAR) exhibits an outstanding anti-inflammatory potential; however, stability problems and reduced solubility hinder its commercial insertion. This work aimed to obtain solid-state hydroxypropyl-β-cyclodextrin (CD) inclusion complexes with NAR using, for the first time, the solvent change precipitation method. For this, molecular modeling and physicochemical characterizations were conducted, followed by in vitro and in vivo assays. The complexation method showed thermal and spectroscopic evidence of NAR inclusion complexes formation, suggesting an improvement of its stability. Additionally, 30 min-dissolution efficiency of the complex was 57.2 %, whereas NAR, as supplied, showed only 14.3 %, a four-fold enhancement. In vitro and in vivo performance attested the potent anti-inflammatory and antinociceptive profile of NAR with significant suppression of TNF-α production. Moreover, NAR complexation with CD improved its therapeutic effect, which showed similar activity to that achieved with NAR as supplied but employing only 1/5 of its dose.

The Natural Flavonoid Naringenin Elicits Analgesia through Inhibition of NaV1.8 Voltage-Gated Sodium Channels

Naringenin (2S)-5,7-dihydroxy-2-(4-hydroxyphenyl)-3,4-dihydro-2H-1-benzopyran-4-one is a natural flavonoid found in fruits from the citrus family. Because (2S)-naringenin is known to racemize, its bioactivity might be related to one or both enantiomers. Computational studies predicted that (2R)-naringenin may act on voltage-gated ion channels, particularly the N-type calcium channel (CaV2.2) and the NaV1.7 sodium channel-both of which are key for pain signaling. Here we set out to identify the possible mechanism of action of naringenin. Naringenin inhibited depolarization-evoked Ca²⁺ influx in acetylcholine-, ATP-, and capsaicin-responding rat dorsal root ganglion (DRG) neurons. This was corroborated in electrophysiological recordings from DRG neurons. Pharmacological dissection of each of the voltage-gated Ca²⁺ channels subtypes could not pinpoint any selectivity of naringenin. Instead, naringenin inhibited NaV1.8-dependent and tetrodotoxin (TTX)-resistant while sparing tetrodotoxin sensitive (TTX-S) voltage-gated Na⁺ channels as evidenced by the lack of further inhibition by the NaV1.8 blocker A-803467. The effects of the natural flavonoid were validated ex vivo in spinal cord slices where naringenin decreased both the frequency and amplitude of sEPSC recorded in neurons within the substantia gelatinosa. The antinociceptive potential of naringenin was evaluated in male and female mice. Naringenin had no effect on the nociceptive thresholds evoked by heat. Naringenin's reversed allodynia was in mouse models of postsurgical and neuropathic pain. Here, driven by a call by the National Center for Complementary and Integrative Health's strategic plan to advance fundamental research into basic biological mechanisms of the action of natural products, we advance the antinociceptive potential of the flavonoid naringenin.