Nootkatone improves anxiety- and depression-like behavior by targeting hyperammonemia-induced oxidative stress in D-galactosamine model of liver injury

Nootkatone Counteracts Melamine-Mediated Nephrotoxicity via Modulation of Intermediate Filament Proteins, Oxidative, Inflammatory, and Apoptotic Events

Background

Nootkatone (NK), a bioactive sesquiterpene ketone, is a major ingredient in grapefruit that has distinguished biological activities. Melamine (MM), a food adulterant, was reported to induce toxic effects including renal disorders. Hence, this protocol was devoted to evaluate the renoprotective impact of NK toward MM-evoked renal damage.

Methods

Rats were either exposed to MM (700 mg/kg) or a combination of MM and two doses of NK (5 and 10 mg/kg).

Results

The results showed that NK therapy notably decreased the kidney functional parameters, along with KIM-1 and NGAL expressions of MM group. Furthermore, a decrease in MDA and NO levels as well as an elevation in SOD, CAT, GSH, and SOD and NRF2 mRNA expression in the NK group demonstrated NK's ability to enhance the renal antioxidant defense of the MM group. Significant suppression in renal inflammatory markers was achieved by NK via lessening of IL-1β and TNF-α, besides downregulation of NF-κB and IL-1β expressions. NK also downregulated vimentin, nestin, and desmin in the MM group. Additionally, in response to the MM exposure, NK hindered renal apoptosis by decreasing caspase-3 expression and restoring renal histopathological features.

Conclusion

These outcomes suggest that NK can be considered as a prospective candidate to guard against MM exposure-mediated renal toxic effects.

Novel Sesquiterpenoids with Renoprotective Activities from the Fruits of Alpinae oxyphylla as Potent TGF-β1/Smads Phosphorylation Inhibitors

The fruit of Alpinia oxyphylla Miq is an important food spice in southern China and has been used in the treatment of kidney disorders for centuries. In order to discover the natural products with potent renoprotective activities in A. oxyphylla and provide some references for its usage, systematic phytochemical studies were carried out and 24 new diverse sesquiterpenoids, including seven guaiane sesquiterpenoids (1-7), 10 eudesmane sesquiterpenoids (9-13, 18, 19, and 21-23), six cadinane sesquiterpenoids (31-35 and 38), and an eremophilane sesquiterpenoid (40), along with 24 known analogues were isolated and elucidated by analysis of spectroscopic data and quantum-chemical calculations. Biological evaluation showed that 6 sesquiterpenoids could significantly inhibit the expression of extracellular matrix components, α-SMA in TGF-β1 induced kidney proximal tubular cells (NRK-52e) at low concentrations, and 9 sesquiterpenoids could also downregulate fibronectin and collagen I in a concentration-dependent manner, showing their potential in renal fibrosis. Further action mechanism study displayed that TGF-β1/Smads pathway might be involved in the antifibrotic effects of active sesquiterpenoids 15 and 43. These studies suggest that A. oxyphylla may have a potential to serve as a functional food in preventing renal fibrosis-associated diseases.

Causal relationship between depression and metabolic dysfunction-associated steatotic liver disease: a bidirectional Mendelian randomized study

Background

With the global rise in obesity, metabolic dysfunction-associated steatotic liver disease (MASLD) has emerged as the most common chronic liver disease. Concurrently, depression is a highly prevalent mental disorder. As the incidence of MASLD and depression continues to increase, a growing body of research indicates a potential association between the two conditions. However, the direction of causality between depression and MASLD remains uncertain. To address this gap, our study utilizes a two-sample Mendelian randomization (MR) approach to explore the bidirectional causal relationship between depression and MASLD.

Methods

We extracted single nucleotide polymorphisms (SNPs) associated with depression and MASLD from pooled data of genome-wide association studies (GWAS). A comprehensive assessment of possible causality was also performed. Possible mediating effects of liver enzymes on MASLD were also assessed.

Results

A total of three GWAS pooled data on depression as well as GWAS data related to MASLD and GWAS data on four liver enzymes were used in this study. Our findings indicated a strong causal relationship between depression and MASLD (OR, 1.557; 95% CI, 1.097-2.211; P = 0.016). And we found a mediating effect of gamma-glutamyl transferase (GGT), alanine aminotransferase (ALT) and aspartate aminotransferase (AST). ALT 10% (95% CI: 7% - 13%, P< 0.0002). AST, 4.14% (95% CI: 2.34% - 5.94%, P < 0.05). GGT 0.19% (95% CI: 0.15% - 0.22%, P< 0.000000002). However, we did not find a mediating effect of alkaline phosphatase (ALP). Our inverse MR analysis did not reveal any causal relationship between MASLD and depression.

Conclusions

The MR analysis revealed a positive causal relationship between depression and MASLD, while no reverse causal relationship was identified. Liver enzymes may mediate the role between depression and MASLD.

Potential antidepressant effects of Traditional Chinese botanical drug formula Chaihu-Shugan-San and its active ingredients

Background: Depression is a severe mental disorder that poses a significant threat to both the physical and mental wellbeing of individuals. Currently, there are various methods for treating depression, including traditional Chinese herbal formulations like Chaihu-Shugan-San (CSS), which have shown effective antidepressant effects in both clinical and animal research. Objective: This review aims to provide a comprehensive synthesis of evidence related to CSS, considering both preclinical and clinical studies, to uncover its potential multi-level, multi-pathway, and multi-target mechanisms for treating depression and identify its active ingredients. Methods: A thorough search was conducted in electronic databases, including PubMed, MEDLINE, Web of Science, Google Scholar, CNKI, and Wanfang, using keywords such as "Chaihu Shugan" and "depression" to retrieve relevant literature on CSS and its active ingredients. The review process adhered to the PRISMA guidelines. Results: This review consolidates the mechanisms underlying antidepressant effects of CSS and its active ingredients. It emphasizes its involvement in the regulation of monoaminergic neurotransmitter systems, synaptic plasticity, and the hypothalamic-pituitary-adrenal axis, among other aspects. Conclusion: CSS exerts a pivotal role in treating depression through various pathways, including the monoaminergic neurotransmitter system, the hypothalamic-pituitary-adrenal axis, synaptic plasticity, inflammation, brain-derived neurotrophic factor levels, and the brain-gut axis. This review facilitates a comprehensive understanding of the current state of CSS research, fostering an in-depth exploration of the etiological mechanisms of depression and the potential discovery of novel antidepressant drugs.

Solid-Phase Microextraction/Gas Chromatography-Time-of-Flight Mass Spectrometry Approach Combined with Network Pharmacology Analysis to Evaluate the Quality of Agarwood from Different Regions against Anxiety Disorder

Agarwood (Aquilaria malaccensis Lam.) is a resinous material from different geographical locations. The current evaluation of agarwood quality is usually based on its physical properties and chemical compounds, yet only a few studies have linked agarwood quality with its anxiolytic effect, as indicated by characteristic compounds. In this study, using solid-phase microextraction/gas chromatography-time-of-flight mass spectrometry (SPME/GC-TOFMS) and multivariate analysis, we found 116 significantly different compounds in agarwood samples from four locations in Southeast Asia with regard to their quality. Brunei and Nha Trang agarwood had abundant sesquiterpenoids, exhibiting notable pharmacological efficacy in relieving anxiety. Malaysian and Irian agarwood had abundant alcohols and aldehydes, qualifying them as high-quality spices. Compound-target-disease network and pathway enrichment analysis were further employed to predict 79 gene targets and 20 pathways associated with the anxiolytic effects based on the 62 sesquiterpenoids. The correlated relationships among the sesquiterpenoids and targets suggest that agarwood treats anxiety via multiple compounds acting on multiple targets. Varying levels of sesquiterpenes across agarwood groups might lead to differences in the anxiolytic effects via signaling pathways, such as neurotransmitter- and hormone-regulated pathways. Our study originally evaluates agarwood quality and its anxiolytic effect by linking the characteristic compounds to potential gene targets and pathways.

Nootkatone attenuates airway inflammation in asthmatic mice through repressing ROS-induced NLRP3 inflammasome activation

Nootkatone (NKT) exhibits potential pharmacological activities including anti-oxidation and anti-inflammation. Nevertheless, little is known about the roles of NKT in asthmatic airway inflammation. In the study, mice were sensitized and challenged with ovalbumin (OVA) to establish experimental allergic asthma model. After treatment with NKT, lung tissues, peripheral blood, and bronchoalveolar lavage fluid (BALF) were collected to assess inflammatory cytokines, oxidative stress, and pathological alternations. The effects of NKT on regulating reactive oxygen species (ROS)-induced NLR family pyrin domain containing 3 (NLRP3) inflammasome activation was assessed in IL-13-treated BEAS-2B cell model. We found that NKT treatment decreased the production of Th2 inflammatory cytokines (IL-4, IL-5, and IL-13) in BALF and IgE levels in serum, and alleviated inflammatory cell penetration, goblet cell proliferation, collagen accumulation, and mucus hypersecretion in lung tissues. NKT treatment mitigated oxidative stress and NLRP3 inflammasome activation in asthmatic mice. IL-13 treatment induced oxidative stress and NLRP3-mediated pyroptosis in BEAS-2B bronchial epithelial cells, whereas these effects were blocked by NKT. NKT protected against airway remodeling, as indicated by decreased epithelial-mesenchymal transition. Taken together, these results demonstrate that NKT mitigates asthmatic airway inflammation by inhibiting ROS-triggered NLRP3 activation and may be a potential agent for treating asthma.

Astrocytic Nrf2 Mediates the Neuroprotective and Anti-Inflammatory Effects of Nootkatone in an MPTP-Induced Parkinson's Disease Mouse Model

This study aims to investigate the neuroprotective effects of nootkatone (NKT), a sesquiterpenoid compound isolated from grapefruit, in an MPTP-induced Parkinson's disease (PD) mouse model. NKT restored MPTP-induced motor impairment and dopaminergic neuronal loss and increased the expression of neurotrophic factors like BDNF, GDNF, and PGC-1α. In addition, NKT inhibited microglial and astrocyte activation and the expression of pro-inflammatory markers like iNOS, TNF-α, and IL-1β and oxidative stress markers like 4-HNE and 8-OHdG. NKT increased the expression of nuclear factor erythroid 2-related factor 2 (Nrf2)-driven antioxidant enzymes like HO-1 and NQO-1 in astrocytes, but not in neurons or microglia in MPTP-treated mice. To investigate whether Nrf2 mediates the anti-inflammatory, antioxidant, or neuroprotective effects of NKT, mice were pretreated with Nrf2-specific inhibitor brusatol (BT) prior to NKT treatment. BT attenuated the NKT-mediated inhibition of 4-HNE and 8-OHdG and the number of Nrf2+/HO-1+/NQO1+ cells co-localized with GFAP+ astrocytes in the substantia nigra of MPTP-treated mice. In addition, BT reversed the effects of NKT on dopaminergic neuronal cell death, neurotrophic factors, and pro-/anti-inflammatory cytokines in MPTP-treated mice. Collectively, these data suggest that astrocytic Nrf2 and its downstream antioxidant molecules play pivotal roles in mediating the neuroprotective and anti-inflammatory effects of NKT in an MPTP-induced PD mouse model.

From Tea to Health: Exploring Abrus mollis for Liver Protection and Unraveling Its Potential Mechanisms

Abrus mollis Hance is a characteristic medicinal herb which is used in Guangdong and Guangxi provinces of China for making soup, medicinal meals, and herbal tea to treat dampheat jaundice and rib discomfort. Current phytochemical study on A. mollis led to the isolation of four new flavones, mollisone A-D (1-4), and thirty two known compounds (5-36). Their structures were characterized by an extensive analysis of spectroscopic data including IR, UV, HR-ESI-MS, and 1D and 2D NMR, as well as electronic circular dichroism calculation. In addition, in order to initially understand their biological activities for traditional applications, in vitro antioxidant and hepatoprotective tests were carried out, whose results illustrated that 25 compounds had significant free radical scavenging ability, and compounds 13 and 16 exhibited protective activities on D-GalN-induced LO2 cell damage than the positive control. Moreover, network pharmacological analysis revealed that the hepatoprotective activity of A. mollis involved multitargets and multipathways such as PI3K/Akt, MAPK, and JAK-STAT pathways and various biological processes such as positive regulation of phosphorylation and regulation of kinase activity. These results suggested that this species could serve as a potential hepatoprotective agent for functional food or medicinal use.

Nootkatone Mitigated Melamine-Evoked Hepatotoxicity by Featuring Oxidative Stress and Inflammation Interconnected Mechanisms: In Vivo and In Silico Approaches

Melamine (ML) is a common environmental contaminant, commonly used in food fraud, representing a serious health hazard and jeopardizing human and animal health. Recently, nootkatone (NK), a naturally occurring sesquiterpenoid, has garnered considerable attention due to its potential therapeutic advantages. We investigated the potential mechanisms underlying the protective effects of NK against ML-induced liver injury in rats. Five groups were utilized: control, ML, NK10, ML-NK5, and ML-NK10. ML induced substantial hepatotoxicity, including considerable alterations in biochemical parameters and histology. The oxidative distress triggered by ML increased the generation of malondialdehyde (MDA) and nitric oxide (NO) and decreased levels of reduced glutathione (GSH), catalase (CAT), and superoxide dismutase (SOD) activities. In addition, decreased expression of nuclear factor-erythroid 2-related factor 2 (Nrf2) and increased nuclear factor kappa beta (NF-κB) expression levels were observed in hepatocytes, which indicated the occurrence of inflammatory changes following ML exposure. These alterations were alleviated by NK supplementation in a dose-dependent manner. The data revealed that the favorable effects of NK were attributed, at least in part, to its antioxidant and anti-inflammatory properties. Moreover, our results were supported by molecular docking studies that revealed a good fit and interactions between NK and antioxidant enzymes. Thus, the current study demonstrated that NK is a potential new food additive for the prevention or treatment of ML-induced toxicity.

Sesquiterpene nootkatone counteracted the melamine-induced neurotoxicity via repressing of oxidative stress, inflammatory, and apoptotic trajectories

Melamine (ML), a chemical substance of high nitrogen content, is used as a food adulterant. Former evidences implied that ML could induce a variety of toxic effects including neurotoxicity and cognitive impairment. Therefore, the aim of this study was to delineate the protective effect of the nootkatone (NK) against ML-induced neural adverse effects. Rats were orally pretreated with NK (5 and 10 mg/kg) prior to the oral administration of ML (700 mg/kg) for a period of 28 days. Our findings unveiled remarkable alleviating effect of NK on MK-induced neurobehavioral disturbance in open field test. Furthermore, NK lessened ML-caused increases in the acetylcholine esterase level in the brain tissue of exposed rats. NK also decreased the neural oxidative stress as represented by elevated levels of SOD, CAT, and GSH along with decreased MDA and NO levels. Upregulated mRNA expression levels of neural NRF-2 and HO-1 were noticed after NK administration. Remarkable anti-inflammatory impact was prominent by decreased neural IL-1β, and TNF-α along with downregulated NF-κB and TLR-4 gene expression levels in NK-treated rats. Noteworthily, pre-treatment with NK decreased the immune reaction of RAGE and HMGB-1 induced by oral ML exposure. Brain histological examination validated the obtained biochemical and molecular results. To sum up, these outcomes reveal that NK successfully alleviated the neural damage induced by ML via blocking of oxidative stress, and inflammatory signaling pathways. Consequently, our study may suggest NK as a new effective therapeutic supplement for treatment of ML-mediated neurotoxicity in rats via inhibition of HMGB-1-RAGE/TLR-4/NF-κB.

Could the Urease of the Gut Bacterium Proteus mirabilis Play a Role in the Altered Gut-Brain Talk Associated with Parkinson's Disease?

Intestinal dysbiosis seems to play a role in neurodegenerative pathologies. Parkinson's disease (PD) patients have an altered gut microbiota. Moreover, mice treated orally with the gut microbe Proteus mirabilis developed Parkinson's-like symptoms. Here, the possible involvement of P. mirabilis urease (PMU) and its B subunit (PmUreβ) in the pathogenesis of PD was assessed. Purified proteins were given to mice intraperitoneally (20 μg/animal/day) for one week. Behavioral tests were conducted, and brain homogenates of the treated animals were subjected to immunoassays. After treatment with PMU, the levels of TNF-α and IL-1β were measured in Caco2 cells and cellular permeability was assayed in Hek 293. The proteins were incubated in vitro with α-synuclein and examined via transmission electron microscopy. Our results showed that PMU treatment induced depressive-like behavior in mice. No motor deficits were observed. The brain homogenates had an increased content of caspase-9, while the levels of α-synuclein and tyrosine hydroxylase decreased. PMU increased the pro-inflammatory cytokines and altered the cellular permeability in cultured cells. The urease, but not the PmUreβ, altered the morphology of α-synuclein aggregates in vitro, forming fragmented aggregates. We concluded that PMU promotes pro-inflammatory effects in cultured cells. In vivo, PMU induces neuroinflammation and a depressive-like phenotype compatible with the first stages of PD development.

The Nrf2 Pathway in Depressive Disorders: A Systematic Review of Animal and Human Studies

There is increasing interest in the involvement of antioxidative systems in protecting from depression. Among these, Nrf2 occupies a central place. We aimed to review the role of Nrf2 in depression. For this reason, we conducted a PubMed search using as search strategy (psychiatr*[ti] OR schizo*[ti] OR psychot*[ti] OR psychos*[ti] OR depress*[ti] OR MDD[ti] OR BD[ti] OR bipolar[ti] OR Anxiety[ti] OR antidepress*[ti] OR panic[ti] OR obsess*[ti] OR compulsio*[ti] OR “mood disord*”[ti] OR phobi*[ti] OR agoraphob*[ti] OR anorex*[ti] OR anorect*[ti] OR bulimi*[ti] OR “eating disorder*”[ti] OR neurodevelopm*[ti] OR retardation[ti] OR autism[ti] OR autistic[ti] OR ASM[ti] OR adhd[ti] OR “attention-deficit”[ti]) AND nrf2, which on the 9th of March produced 208 results of which 89 were eligible for our purposes. Eligible articles were studies reporting data of Nrf2 manipulations or content by any treatment in human patients or animals with any animal model of depression. Most studies were on mice only (N = 58), 20 on rats only, and three on both rats and mice. There were two studies on cell lines (in vitro) and one each on nematodes and fish. Only four studies were conducted in humans, one of which was post mortem. Most studies were conducted on male animals; however, human studies were carried out on both men and women. The results indicate that Nrf2 is lower in depression and that antidepressant methods (drugs or other methods) increase it. Antioxidant systems and plasticity-promoting molecules, such as those in the Nrf2–HO-1, BDNF–TrkB, and cyclic AMP–CREB pathways, could protect from depression, while glycogen synthase kinase-3β and nuclear factor κB oppose these actions, thus increasing depressive-like behaviours. Since Nrf2 is also endowed with tumorigenic and atherogenic potential, the balance between benefits and harms must be taken into account in designing novel drugs aiming at increasing the intracellular content of Nrf2.

Nootkatone Supplementation Attenuates Carbon Tetrachloride Exposure-Induced Nephrotoxicity in Mice

Nootkatone (NKT), a major ingredient of Alpinia oxyphylla, exhibited potential nephroprotective effects; however, the precise molecular mechanisms remain poorly understood. This study aimed to study the nephroprotective effects of NKT and the underlying mechanisms in a mouse model. Our results showed that NKT pretreatment at the doses of 5, 10, and 20 mg/kg per day for 7 days significantly attenuates carbon tetrachloride (CCl₄)-induced increases of serum BUN and CRE and kidney pathology injury. NKT pretreatment also markedly inhibited oxidative stress, inflammatory response, and the activation of caspases-9 and -3 in kidneys of mice exposed to CCl₄. Meanwhile, NKT pretreatment downregulated the expression of NOX4, IL-1β, IL-6, and TNF-α proteins and NO levels in the kidney tissues. Moreover, NKT pretreatment upregulated the expression of Nrf2 and HO-1 mRNAs, and downregulated the expression of NF-κB, IL-1β, IL-6, TNF-α, and iNOS mRNAs in the kidneys of mice, compared to those in the CCl₄ alone treatment group. In conclusion, our results reveal that NKT supplementation could protect against CCl₄ exposure-induced oxidative stress and inflammatory response in the kidneys by inhibiting NOX4 and NF-κB pathways and activating the Nrf2/HO-1 pathway. Our current study highlights the therapeutic application of NKT for kidney diseases.

Curcumin-resveratrol nano-formulation counteracting hyperammonemia in rats

Malnutrition and low dietary protein intake could be risk factors for developing peripheral and central hyperammonemia, especially in pediatrics. Both curcumin and resveratrol proved to be effective against several hepatic and cerebral injuries. They were reported to be beneficial in lowering circulating ammonia levels, yet both are known for their low bioavailability. The use of pharmaceutical nano-formulations as delivery systems for these two nutraceuticals could solve the aforementioned problem. Hence, the present study aimed to investigate the valuable outcome of using a combination of curcumin and resveratrol in a nanoemulsion formulation, to counteract protein-deficient diet (PDD)-induced hyperammonemia and the consequent complications in male albino rats. Results revealed that using a nanoemulsion containing both curcumin and resveratrol at a dose of (5 + 5 mg/kg) effectively reduced hepatic and brain ammonia levels, serum ALT and AST levels, hepatic and brain nitric oxide levels, oxidative DNA damage as well as disrupted cellular energy performance. In addition, there was a substantial increase in brain levels of monoamines, and a decrease in glutamate content. Therefore, it can be concluded that the use of combined curcumin and resveratrol nanoemulsion is an effective means of ameliorating the hepatic and cerebral adverse effects resulting from PDD-induced hyperammonemia in rats.

Nootkatone Supplementation Ameliorates Carbon Tetrachloride-Induced Acute Liver Injury via the Inhibition of Oxidative Stress, NF-κB Pathways, and the Activation of Nrf2/HO-1 Pathway

Acute liver injury is a type of liver diseases, and it has raised concerns worldwide due to the lack of effective therapies. The aim of this study is to investigate the protective effects of nootkatone (NOOT) on carbon tetrachloride (CCl₄)-caused acute liver injury in mice. Mice were randomly divided into control, CCl₄ model, NOOT, and NOOT (5, 10, and 20 mg/kg/day) plus CCl₄ groups, respectively. Mice in the CCl₄ plus NOOT groups were orally administrated with NOOT at 5, 10, and 20 mg/kg/days for seven days prior to 0.3% CCl₄ injection at 10 mL/kg body weight, respectively. Our results showed that NOOT supplementation significantly ameliorated CCl₄-induced increases of serum AST and ALT levels, hepatocyte necrosis, inflammatory response, oxidative stress, and caspases-9 and -3 activities in the livers of mice. Moreover, NOOT supplementation significantly upregulated the expression of Nrf2 and HO-1 mRNAs but downregulated the expression of NF-κB mRNAs and the levels of IL-1β, IL-6, and TNF-α proteins in the liver tissues, compared to those in the CCl₄ model group. In conclusion, for the first time, our results reveal that NOOT could offer protective effects against CCl₄-caused oxidative stress and inflammatory response via the opposite regulation of Nrf2/HO-1 pathway and NF-κB pathway.

Production, Function, and Applications of the Sesquiterpenes Valencene and Nootkatone: a Comprehensive Review

Valencene and nootkatone, two sesquiterpenes, extracted from natural sources, have great market potential with diverse applications. This paper aims to comprehensively review the recent advances in valencene and nootkatone, including source, production, physicochemical and biological properties, safety and pharmacokinetics evaluation, potential uses, and their industrial applications as well as future research directions. Microbial biosynthesis offers a promising alternative approach for sustainable production of valencene and nootkatone. Both compounds exert various beneficial activities, including antimicrobial, insecticidal, antioxidant, anti-inflammatory, anticancer, cardioprotective, neuroprotective, hepatoprotective, and nephroprotective and other activities. However, most of the studies are performed in animals and in vitro, making it difficult to give a conclusive description about their health benefits and extend their application. Hence, more attention should be paid to in vivo and long-term clinical studies in the future. Moreover, valencene and nootkatone are considered safe for consumption and show great promise in the applications of food, cosmetic, pharmaceutical, chemical, and agricultural industries.

Nootkatone Improves Chronic Unpredictable Mild Stress-Induced Depressive-Like Behaviors by Repressing NF-κB/NLRP3-Mediated Neuroinflammation

OBJECTIVE

To explore the effect of nootkatone (NKT) on chronic unpredictable mild stress (CUMS)-induced depressive-like behaviors and the mechanism underlying NKT improving the depressive-like behaviors.

METHODS

The CUMS-induced depression model was established in mice. Fifty mice were randomized into 5 groups (n=10) in accordance with a random number table: control group, CUMS group, CUMS + NKT (6 mg/kg) group, CUMS + NKT (12 mg/kg) group, and CUMS + ketamine group. From the 22th day, NKT (6 or 12 mg/kg) or ketamine (0.5 mg/kg) was given with intragastric administration every day for 21 days. Behavioral tests including forced swimming test (FST), tail suspension test (TST), sucrose preference test (SPT) and open-field test (OFT) were carried out. The mRNA and protein expressions of interleukin (IL)-1β, IL-18, IL-6, and tumor necrosis factor (TNF)-α in hippocampus were assessed using quantitative realtime polymerase chain reaction (PCR), Western blot analysis, and enzyme linked immunosorbent assay. The nuclear factor-κB (NF-κB)/NOD-like receptor 3 (NLRP3) inflammasome pathway was analyzed using Western blot and immunofluorescence analysis.

RESULTS

NKT treatment improved CUMS-induced depressive-like behaviors in mice (P<0.05 or P<0.01). NKT significantly decreased the mRNA and protein levels of IL-1β, IL-18, IL-6, and TNF-α in hippocampus of CUMS mice (P<0.05 or P<0.01). Furthermore, NKT repressed CUMS-induced activation of NF-κB signaling and NLRP3 inflammasome (P<0.01). More important, Nigericin, a NLRP3 activator, destroyed the effect of NKT on repressing neuroinflammation and improving depressive-like behaviors (P<0.05 or P<0.01).

CONCLUSION

NKT ameliorates the depressive-like symptoms, in part by repressing NF-κB/NLRP3-mediated neuroinflammation.

High-protein diets and testosterone

A recent meta-analysis found low-carbohydrate, high-protein diets (> 3.4 g/kg of bodyweight/day) (g/kg/day) decreased men's total testosterone (∼5.23 nmol/L) [Whittaker and Harris (2022) Low-carbohydrate diets and men's cortisol and testosterone: systematic review and meta-analysis. Nutrition and Health. DOI: 10.1177/02601060221083079]. This finding has generated substantial discussion, however, it has often lacked clarity and context, with the term 'high-protein' being used unqualified. Firstly, diets < 3.4 g/kg/day are not associated with a consistent decrease in testosterone. Secondly, the average protein intake is ∼1.3 g/kg/day, conventional 'high-protein' diets are ∼1.8-3 g/kg/day and the vast majority of athletes are < 3.4 g/kg/day; meaning very few individuals will ever surpass 3.4 g/kg/day. To avoid such confusion in the future, the following definitions are proposed: very high (> 3.4 g/kg/day), high (1.9-3.4 g/kg/day), moderate (1.25-1.9 g/kg/day) and low (<1.25 g/kg/day). Using these, very high-protein diets (> 3.4 g/kg/day) appear to decrease testosterone, however high- and moderate-protein diets (1.25-3.4 g/kg/day) do not.

Nootkatone, a Sesquiterpene Ketone From Alpiniae oxyphyllae Fructus, Ameliorates Metabolic-Associated Fatty Liver by Regulating AMPK and MAPK Signaling

Metabolic-associated fatty liver disease (MAFLD) is becoming more common due to lifestyle changes. A long-term high-fat and high-glucose diet induces glycolipid metabolism disorders in the liver, which results in the development of MAFLD. To date, there is no specific clinically useful therapeutics for this disease. Natural products or synthetic compounds were screened and investigated to find effective agents for treating MAFLD. In this study, nootkatone (Nok), a natural sesquiterpene ketone isolated from Alpiniae oxyphyllae fructus, was explored for its potential to treat MAFLD, and underlying mechanisms were studied. Our results show that Nok dramatically ameliorated the disordered lipid and glucose metabolism in MAFLD mice, decreased fat accumulation in hepatic tissue, and improved liver injury. Inflammation, metabolic disorder, and oxidative stress were ameliorated in liver tissue based on RNA-seq transcriptome comparison between a Nok-treated group and an MAFLD model group. Furthermore, Nok significantly activated AMPK activity and inhibited MAPK activity, especially the p38 and JNK signaling pathways, in vivo based on western blot analysis. The pharmaceutical effects and potential signaling pathways impacted by Nok were also investigated in L02 cells. Nok significantly promoted the consumption of glucose and decreased the deposition of triglycerides in vitro. The p-AMPKα level was notably upregulated by Nok, indicating dramatic AMPK activation. In addition, Nok decreased the levels of p-ERK1/2, p-p38, and p-JNK. Nok also inhibited the activation of MAPK signaling and, thus, alleviated MAFLD development. Our results suggest that Nok may be useful in treating MAFLD. Nok may ameliorate MAFLD by regulating glycolipid metabolism disorders by activating AMPK and inhibiting MAPK activity. Collectively, this study suggests that Nok is an effective compound for the treatment of MAFLD.

Oxidative brain and cerebellum injury induced by d-galactosamine: Protective effect of S-methyl methionine sulfonium chloride

The objective of this study was to examine the protective effects of S-methyl methionine sulfonium chloride (MMSC) against galactosamine (GalN)-induced brain and cerebellum injury in rats. A total of 22 female Sprague-Dawley rats were randomly divided into four groups as follows: Group I (n = 5), intact animals; Group II (n = 6), animals received 50 mg/kg/day of MMSC by gavage technique for 3 consecutive days; Group III (n = 5), animals injected with a single dose of 500 mg/kg of GalN intraperitoneally (ip); and Group IV (n = 6), animals injected with the same dose of GalN 1 h after MMSC treatment. After 6 h of the last GalN treatment (at the end of the experiments), all animals were killed under anesthesia, brain and cerebellum tissues were dissected out. Reduced glutathione, total antioxidant status levels, and antioxidant enzymes (catalase, superoxide dismutase, and glutathione-related enzymes), aryl esterase, and carbonic anhydrase activities remarkably declined whereas advanced oxidized protein products, reactive oxygen species, total oxidant status, oxidative stress index levels, and myeloperoxidase, acetylcholinesterase, lactate dehydrogenase, and xanthine oxidase activities were significantly elevated in the GalN group compared with intact rats. In contrast, the administration of MMSC to GalN groups reversed these alterations. In conclusion, we may suggest that MMSC has protective effects against GalN-induced brain and cerebellar toxicity in rats.

Biological Activities, Pharmacokinetics and Toxicity of Nootkatone: A Review

Abstract:

Plant-based drugs have a significant impact on modern therapeutics due to their vast array of pharmacological activities. The integration of herbal plants in the current healthcare system has emerged as a new field of research. It can be used for the identification of novel lead compound candidates for future drug development. Nootkatone is a sesquiterpene derivative and an isolate of grapefruit. Shreds of evidence illustrate that nootkatone targets few molecular mechanisms to exhibit its pharmacological activity and yet needs more exploration to be established. The current review is related to nootkatone, drafted through a literature search using research articles and books from different sources, including Science Direct, Google Scholar, Elsevier, PubMed, and Scopus. It has been reported to possess a wide range of pharmacological activities such as anti-inflammatory, anticancer, antibacterial, hepatoprotective, neuroprotective, and cardioprotective. Although preclinical studies in experimental animal models suggest that nootkatone has therapeutic potential, it is further warranted to evaluate its toxicity and pharmacokinetic parameters before being applied to humans. Hence in the present review, we have summarized the scientific knowledge on nootkatone with a particular emphasis on its pharmacological properties to encourage researchers for further exploration in preclinical and clinical settings.

Nootkatone protects cartilage against degeneration in mice by inhibiting NF-κB signaling pathway

Osteoarthritis is a common chronic disease associated with chondrocyte inflammation and cartilage matrix hydrolyzation. Studies report that IL-1β plays a critical role in osteoarthritis. Anti-inflammatory effect of nootkatone has been explored in acute and chronic inflammatory disease, thus the current study sought to explore its therapeutic effect in osteoarthritis. Notably, the effect of nootkatone in osteoarthritis has not been elucidated. Therefore, murine primary chondrocytes were extracted and ACLT induced OA mouse model was established in the current study to explore the therapeutic effect of nootkatone in OA both in vitro and in vivo. The findings showed that nootkatone inhibited inflammatory response and protected cartilage balance in murine primary chondrocyte. Further analysis showed that nootkatone suppressed inflammation and protected cartilage against degeneration induced by ACLT surgery in mice. The cellular mechanism of the protective effect of nootkatone in osteoarthritis and associated signaling pathway was identified as the NF-κB signaling pathway. In summary, the findings of the current study indicated that nootkatone is a potential therapeutic agent for OA.

Protective Effects of Nootkatone on Renal Inflammation, Apoptosis, and Fibrosis in a Unilateral Ureteral Obstructive Mouse Model

Nootkatone is one of the major active ingredients of Alpiniae oxyphyllae, which has been used as both food and medicinal plants for the treatment of diarrhea, ulceration, and enuresis. In this study, we aimed to investigate whether nootkatone treatment ameliorated the progression of chronic kidney diseases (CKD) and clarified its underlying mechanisms in an obstructive nephropathy (unilateral ureteral obstructive; UUO) mouse model. Our results revealed that nootkatone treatment preventively decreased the pathological changes and significantly mitigated the collagen deposition as well as the protein expression of fibrotic markers. Nootkatone could also alleviate oxidative stress-induced injury, inflammatory cell infiltration, and renal cell apoptotic death in the kidneys of UUO mice. These results demonstrated for the first time that nootkatone protected against the progression of CKD in a UUO mouse model. It may serve as a potential therapeutic candidate for CKD intervention.

Study of the Neurotransmitter Changes Adjusted by Circadian Rhythm in Depression Based on Liver Transcriptomics and Correlation Analysis

Depression has drawn increasing attention from the public around the world in recent years. Studies have shown that liver injury caused by chronic stress is relevant to depression and neurotransmitter changes. It is essential to clarify the relationship between neurotransmitter changes and hepatic gene expression in depression. In this study, we used the chronic unpredictable mild stress (CUMS) model combined with UHPLC-MS to explore the changes of neurotransmitters in serum and hippocampus and to decipher the differential gene expression in the liver by using the RNA-Seq combined with multivariate statistical analysis. Compared with the control group, the levels of neurotransmitters including 5-hydroxytryptamine (5-HT), acetylcholine, glutamate (Glu), and dopamine (DA) in the hippocampus and 5-HT, norepinephrine, γ-aminobutyric acid (GABA), and 5-hydroxyindoleacetic acid in serum were significantly changed in the CUMS rats. The results of liver transcriptomic analysis and correlation analysis showed that the Glu, DA, 5-HT, and GABA were impacted by 68 liver genes which were mainly enriched in three pathways including circadian rhythm, serotonergic synapse, and p53 signaling pathway. The expressive levels of clock genes and serotonergic synapse genes were validated by using q-PCR, and the diurnal rhythms of neurotransmitters were validated by in vivo hippocampus microdialysis. The CUMS stressors might cause phase advance of Glu and GABA by adjusting clock genes. The transcriptomic technique combined with correlation analysis and in vivo microdialysis could be used to discover comprehensive pathways of depression. It provides a new strategy for the rational assessment of the mechanism of disease.