Protective effect of geraniin against carbon tetrachloride induced acute hepatotoxicity in Swiss albino mice

Wnt/β-catenin signaling pathway: proteins' roles in osteoporosis and cancer diseases and the regulatory effects of natural compounds on osteoporosis

Osteoblasts are mainly derived from mesenchymal stem cells in the bone marrow. These stem cells can differentiate into osteoblasts, which have the functions of secreting bone matrix, promoting bone formation, and participating in bone remodeling. The abnormality of osteoblasts can cause a variety of bone-related diseases, including osteoporosis, delayed fracture healing, and skeletal deformities. In recent years, with the side effects caused by the application of PTH drugs, biphosphonate drugs, and calmodulin drugs, people have carried out more in-depth research on the mechanism of osteoblast differentiation, and are actively looking for natural compounds for the treatment of osteoporosis. The Wnt/β-catenin signaling pathway is considered to be one of the important pathways of osteoblast differentiation, and has become an important target for the treatment of osteoporosis. The Wnt/β-catenin signaling pathway, whether its activation is enhanced or its expression is weakened, will cause a variety of diseases including tumors. This review will summarize the effect of Wnt/β-catenin signaling pathway on osteoblast differentiation and the correlation between the related proteins in the pathway and human diseases. At the same time, the latest research progress of natural compounds targeting Wnt/β-catenin signaling pathway against osteoporosis is summarized.

Stress and Liver Fibrogenesis: Understanding the Role and Regulation of Stress Response Pathways in Hepatic Stellate Cells

Stress response pathways are crucial for cells to adapt to physiological and pathologic conditions. Increased transcription and translation in response to stimuli place a strain on the cell, necessitating increased amino acid supply, protein production and folding, and disposal of misfolded proteins. Stress response pathways, such as the unfolded protein response (UPR) and the integrated stress response (ISR), allow cells to adapt to stress and restore homeostasis; however, their role and regulation in pathologic conditions, such as hepatic fibrogenesis, are unclear. Liver injury promotes fibrogenesis through activation of hepatic stellate cells (HSCs), which produce and secrete fibrogenic proteins to promote tissue repair. This process is exacerbated in chronic liver disease, leading to fibrosis and, if unchecked, cirrhosis. Fibrogenic HSCs exhibit activation of both the UPR and ISR, due in part to increased transcriptional and translational demands, and these stress responses play important roles in fibrogenesis. Targeting these pathways to limit fibrogenesis or promote HSC apoptosis is a potential antifibrotic strategy, but it is limited by our lack of mechanistic understanding of how the UPR and ISR regulate HSC activation and fibrogenesis. This article explores the role of the UPR and ISR in the progression of fibrogenesis, and highlights areas that require further investigation to better understand how the UPR and ISR can be targeted to limit hepatic fibrosis progression.

Mechanistic Insights into the Pharmacological Significance of Silymarin

Medicinal plants are considered the reservoir of diverse therapeutic agents and have been traditionally employed worldwide to heal various ailments for several decades. Silymarin is a plant-derived mixture of polyphenolic flavonoids originating from the fruits and akenes of Silybum marianum and contains three flavonolignans, silibinins (silybins), silychristin and silydianin, along with taxifolin. Silybins are the major constituents in silymarin with almost 70–80% abundance and are accountable for most of the observed therapeutic activity. Silymarin has also been acknowledged from the ancient period and is utilized in European and Asian systems of traditional medicine for treating various liver disorders. The contemporary literature reveals that silymarin is employed significantly as a neuroprotective, hepatoprotective, cardioprotective, antioxidant, anti-cancer, anti-diabetic, anti-viral, anti-hypertensive, immunomodulator, anti-inflammatory, photoprotective and detoxification agent by targeting various cellular and molecular pathways, including MAPK, mTOR, β-catenin and Akt, different receptors and growth factors, as well as inhibiting numerous enzymes and the gene expression of several apoptotic proteins and inflammatory cytokines. Therefore, the current review aims to recapitulate and update the existing knowledge regarding the pharmacological potential of silymarin as evidenced by vast cellular, animal, and clinical studies, with a particular emphasis on its mechanisms of action.

Chemical characterization and evaluation of the nephroprotective potential of Parrotiopsis jacquemontiana (Decne) Rehder and Periploca hydaspidis Falc crude extract in CCl4-induced Male Sprague-Dawley Rats

Biochemical, antioxidant, serum, and urine profiles together with physical examination can deliver important information regarding animal health status, and are vital in the diagnosis and treatment of patients. CCl4, a potent nephrotoxin, was used for causing toxicity in rat kidneys. The present study aimed at exploring the nephroprotective potential of P. jacquemontiana leaves methanol extract (PJM) and P. hydaspidis whole-plant methanol extract (PHM) on kidney cells of male rats after oxidative stress and DNA damage was instigated by CCl4. Various parameters including enzymatic levels, serum profiles, urine profiles, genotoxicity, and histological studies were conducted. In renal samples of rats treated with CCl4, the antioxidant enzymes (POD, SOD, CAT), PH level, protein level, and glutathione contents were significantly (p < 0.05) declined whereas renal biochemicals (H2O2, TBARS, and nitrite), specific gravity, level of urea, urobilinogen, serum BUN and creatinine were markedly (p < 0.05) increased relative to control group. Co-administration of PJM and PHM with CCl4 displayed protective ability against CCl4 intoxication by restoring activities of antioxidant enzymes, urine profile, biochemical parameters, and serum profile in rats. CCl4 also induced prominent DNA damages and glomerular atrophy with abnormal appearance of glomerulus and Bowman's capsule. These damages results in impaired corticular sections, edema in Bowman's capsule, accumulation of necrotic cells, dilation of convoluted tubules, and narrowing of space between Bowman's capsule, which were successfully ameliorated after co-administration of PJM and PHM fractions in a dose-dependent manner (200 and 400 mg/kg b.w.). The results obtained suggest the therapeutic role of PJM and PHM in oxidative-stress related disorders of kidney and may be helpful in kidney trauma.

Cliv-92-Loaded Glycyrrhetinic Acid-Modified Chitosan Nanoparticles for Enhanced Hepatoprotection-Preparation, Characterization, and In Vivo Evaluation

Cliv-92 is a mixture of three structurally similar coumarinolignoids and a proven hepatoprotective agent. Low aqueous solubility and poor bioavailability are notable hindrances for its further use. Therefore, glycyrrhetinic acid-linked chitosan nanoparticles loaded with Cliv-92 were prepared for active targeting to the liver. The nanoparticles were prepared by the ionic gelation method to avoid the use of toxic solvents/rigorous agitation. The method of preparation was optimized using a central composite design with independent variables, namely polymer: drug ratio (3:1, w/w), crosslinker concentration (0.5%), and stirring speed (750 rpm). The optimized nanoparticles had a mean particle size of 185.17 nm, a polydispersity index of 0.41, a zeta potential of 30.93 mV, and a drug loading of 16.30%. The prepared formulation showed sustained release of approximately 63% of loaded Cliv-92 over 72 h. The nanoparticles were freeze-dried for long-term storage and further characterized. The formulation was found to be biocompatible for parenteral delivery. In vivo imaging study showed that optimized nanoparticles were preferentially accumulated in the liver and successfully targeting the liver. The present study successfully demonstrated the improved pharmacokinetic properties (≈12% relative bioavailability) and efficacy profile (evidenced by in vivo and histopathological studies) of fabricated Cliv-92 nanoparticles.

Antiosteoporosis effect of geraniin on ovariectomy-induced osteoporosis in experimental rats

Osteoporosis is a skeletal condition that is characterized by decreasing bone density and deteriorating bone mass. The plant-based phytoconstituent such as geraniin possesses better therapeutic potentials in biomedical field. In the current experimental study, we planned to scrutinize the therapeutic potential of geraniin against ovariectomy (OVX)-induced osteoporosis in rats and find the possible mechanism. Healthy Sprague Dawley rats were randomized into six groups and subjected to geraniin and alendronate (ALN) treatment for 10 weeks. Body weight, uterus, femur weight, bone biochemical, bone turnover markers, inflammatory cytokine, calcium, phosphorus, vitamin D (Vit D), urine, hormones, and antioxidant level were estimated. Geraniin significantly (p < .001) reduced the level of bone turnover markers including beta-CrossLaps (β-CTx), ALN, osteocalcin (OC), alkaline phosphatase (ALP), and bone Gla protein (BGP); reduced the biomechanical parameters including maximum load, energy, stiffness, maximum stress, and Young's modulus; reduced the level of calcium (Ca) and phosphorus (P); and increased the level of vitamin D (Vit D) as compared with OVX-induced osteoporosis rats. Geraniin increased the level of bone structure parameters, namely bone mineral density, bone mineral content, tissue mineral density, bone volume fraction, and trabecular number; increased the level of osteoprotegerin (OPG) and OPG/RANKL; and reduced the level of receptor activator of nuclear factor kappa-Β ligand (RANKL). Geraniin significantly (p < .001) increased the level of glutathione (GSH) and reduced the level of malonaldehyde (MDA) in the liver, intestine, and bone of OVX-induced osteoporosis rats. Geraniin significantly (p < .001) decreased the level of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) pro-inflammatory cytokines. We also argue that geraniin could be an excellent candidate to treat and control bone-related disease or disorders.

Chemoprotective Effects of Geraniin against Azoxymethane Induced Colorectal Cancer by Reduction of Inflammatory Reaction

The leading cause of cancer-related death is colorectal cancer, and inflammatory bowel disease is a risk factor for this disease. Azoxymethane (AOM) is a potent cancer inducer widely used in rats for colon cancer. The current study was scrutinizing the chemo-protective effect of geraniin against AOM induced colorectal cancer via alteration of oxidative stress and inflammatory cytokines. The rats were divided into different groups such as Group I: normal control, Group II geraniin (20 mg/kg), Group III: received AOM, Group IV-VI: AOM + geraniin (5, 10 and 20 mg/kg), respectively. All group of rats were received treatment for 16 weeks. At the end of the experimental study, the hepatic, biochemical, phase II antioxidant, antioxidant enzymes, cytokines, apoptosis and inflammatory mediators were estimated. Geraniin treatment significantly reduced tumor weight and enhanced body weight. Geraniin administration also altered the level of antioxidant parameters-superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR); phase I enzymes - cytochrome B5, cytochrome P450; phase II enzymes - Glutathione-S-Transferase (GST), UDP-Glucuronyl transferase (UDP-GT) respectively. Obtained results also demonstrate that geraniin treatment reduced the level of pro-inflammatory cytokines such as IL-2, IL-1α, IL-10, IL-1β, IL-4, IL-6, IL-12, IL-17A, IFN-γ, tumor necrosis factor-α, G-CSF, and GM-CSF. Geraniin also reduced the expression of IL-1α, IL-1β, IL-6, IFN-γ, G-CSF, and GM-CSF. On the basis of result we can conclude that geraniin reduced the colorectal cancer via inflammatory pathway.

Geraniin Protects PC12 Cells Against Aβ25-35-Mediated Neuronal Damage: Involvement of NF-κB and MAPK Signaling Pathways

β-amyloid peptide (Aβ) has been considered a critical factor that is associated with the development of oxidative stress and neuroinflammation in the pathogenesis of Alzheimer's disease. This study was performed to evaluate the effect of geraniin on Aβ_25-35-caused oxidative damage and neuroinflammatory response, and its underlying mechanism. Geraniin protected pheochromocytoma12 (PC12) cells from Aβ_25-35-mediated cell death by reducing oxidative stress and restoring cell cycle dysregulation. Moreover, geraniin markedly attenuated Aβ-triggered DNA injury that was partially associated with decreases in caspase-3 activity. Moreover, the compound significantly downregulated the release of neuroinflammatory factors. Upregulation of nuclear factor-κB activity was suppressed by geraniin, which was due to suppression of JNK, ERK1/2, and the p38 mitogen-activated protein kinase (MAPK) pathway. This was the first study to support further understanding of geraniin as a promising agent against neurotoxicity in the reduction of oxidative stress and neuroinflammation.

Silymarin antiproliferative and apoptotic effects: Insights into its clinical impact in various types of cancer

Silymarin is a complex extract isolated from the plant Silybum marianum, widely known for its prominent antioxidant and hepatoprotective effects, although increasing evidences have reported extraordinary antiproliferative and apoptotic abilities. As a result, several signaling pathways involved in cell cycle control, cell proliferation, and cell death have been deconvoluted as critical mechanisms. In this regard, cyclin and cyclin-dependent pathways have been the most studied ones. Following that, apoptotic pathways, such as p53, Akt, STAT-3, Ras, and caspases pathways, have been extensively studied, although other mechanisms involved in inflammation and angiogenesis have also been highlighted as silymarin-likely targets in cancer therapy. Therefore, the main challenge of this review is to discuss the diverse molecular mechanisms for silymarin antiproliferative and apoptotic effects; most of them largely studied in various types of cancers so far. Clinical trials and combination therapies related to silymarin application in cancer prevention and treatment are presented as well.

Acute oral toxicity of the ellagitannin geraniin and a geraniin-enriched extract from Nephelium lappaceum L rind in Sprague Dawley rats

Despite the lack of its toxicity evaluation, traditional herbal products are being widely used for various health indications. Geraniin, an ellagitannin, is a bioactive compound found in many traditional herbal medicines. In spite its numerous health benefits ranging from anti-inflammatory, anti-hyperglycaemic, hepatoprotective, anti-cancer and anti-microbial, no toxicity data on geraniin is available. The objective of this study is to evaluate the acute oral toxicity of geraniin and an enriched geraniin-extract of Nephelium lappaceum L rind. This study followed the guidelines of the OECD 423 acute oral toxicity test. Subsequent to a single oral administration of the test compounds, the rats were observed for 14 days for signs of toxicity and mortality. Following euthanasia, full blood count, biochemistry of blood and histopathology assessment of organs were carried out. All parameters analysed indicated insignificant difference compared to control. The LD₅₀ cut-off values for both geraniin and geraniin-enriched extract was established to be 2000 mg/kg b. w., following a single oral dose. It was however observed that the hepatocytes of three geraniin-administered rats exhibited a ‘foamy appearance’. As such, the no-observed-adverse-effect level of geraniin is below 2000 mg/kg, while that of geraniin-enriched extract is up to 2000 mg/kg. Further detailed toxicity studies are required to establish geraniin or its enriched extract from Nephelium lappaceum L rind safe for human consumption.

Efficacy of geraniin on dengue virus type-2 infected BALB/c mice

BACKGROUND

Dengue continues to be a major international public health concern. Despite that, there is no clinically approved antiviral for treatment of dengue virus (DENV) infections. In this study, geraniin extracted from the rind of Nephelium lappaceum was shown to inhibit the replication of DENV-2 in both in vitro and in vivo experiments.

METHODS

The effect of geraniin on DENV-2 RNA synthesis in infected Vero cells was tested using quantitative RT-PCR. The in vivo efficacy of geraniin in inhibiting DENV-2 infection was then tested using BALB/c mice with geraniin administered at three different times. The differences in spleen to body weight ratio, DENV-2 RNA load and liver damage between the three treatment groups as compared to DENV-2 infected mice without geraniin administration were determined on day eight post-infection.

RESULTS

Quantitative RT-PCR confirmed the decrease in viral RNA synthesis of infected Vero cells when treated with geraniin. Geraniin seemed to provide a protective effect on infected BALB/c mice liver when given at 24 h pre- and 24 h post-infection as liver damage was observed to be very mild even though a significant reduction of DENV-2 RNA load in serum was not observed in these two treatment groups. However, when administered at 72 h post-infection, severe liver damage in the form of necrosis and haemorrhage had prevailed despite a substantial reduction of DENV-2 RNA load in serum.

CONCLUSIONS

Geraniin was found to be effective in reducing DENV-2 RNA load when administered at 72 h post-infection while earlier administration could prevent severe liver damage caused by DENV-2 infection. These results provide evidence that geraniin is a potential candidate for the development of anti-dengue drug.

Anti-Inflammatory Effect of a Polyphenol-Enriched Fraction from Acalypha wilkesiana on Lipopolysaccharide-Stimulated RAW 264.7 Macrophages and Acetaminophen-Induced Liver Injury in Mice

A polyphenol-enriched fraction (PEF) from Acalypha wilkesiana, whose leaves have been traditionally utilized for the treatment of diverse medical ailments, was investigated for the anti-inflammatory effect and molecular mechanisms by using lipopolysaccharide- (LPS-) stimulated RAW 264.7 macrophages and acetaminophen- (APAP-) induced liver injury mouse model. Results showed that PEF significantly attenuated LPS-induced nitric oxide (NO) and prostaglandin E₂ (PGE₂) production and suppressed the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX-2) in RAW 264.7 macrophages. PEF also reduced the secretion of proinflammatory cytokines including tumor necrosis factor-α (TNF-α), interleukin- (IL-) 1β, and IL-6 in LPS-stimulated RAW 264.7 macrophages. Moreover, PEF potently inhibited LPS-induced phosphorylation of mitogen-activated protein kinases (MAPKs) as well as the activation of nuclear factor-κB (NF-κB) by preventing the degradation of inhibitor κB-α (IκB-α). In vivo, PEF pretreatment ameliorated APAP-induced liver injury and hepatic inflammation, as presented by decreased hepatic damage indicators and proinflammatory factors at both plasma and gene levels. Additionally, PEF pretreatment remarkably diminished Toll-like receptor 3 (TLR3) and TLR4 expression and the subsequent MAPKs and NF-κB activation. HPLC analysis revealed that two predominantly polyphenolic compounds present in PEF were geraniin and corilagin. These results indicated that PEF has an anti-inflammatory effect, and its molecular mechanisms may be involved in the inactivation of the TLR/MAPK/NF-κB signaling pathway, suggesting the therapeutic potential of PEF for inflammatory diseases.

Geraniin Protects High-Fat Diet-Induced Oxidative Stress in Sprague Dawley Rats

Geraniin, a hydrolysable polyphenol derived from Nephelium lappaceum L. fruit rind, has been shown to possess significant antioxidant activity in vitro and recently been recognized for its therapeutic potential in metabolic syndrome. This study investigated its antioxidative strength and protective effects on organs in high-fat diet (HFD)-induced rodents. Rats were fed HFD for 6 weeks to induce obesity, followed by 10 and 50 mg/kg of geraniin supplementation for 4 weeks to assess its protective potential. The control groups were maintained on standard rat chows and HFD for the same period. At the 10th week, oxidative status was assessed and the pancreas, liver, heart and aorta, kidney, and brain of the Sprague Dawley rats were harvested and subjected to pathological studies. HFD rats demonstrated changes in redox balance; increased protein carbonyl content, decreased levels of superoxide dismutase, glutathione peroxidase, and glutathione reductase with a reduction in the non-enzymatic antioxidant mechanisms and total antioxidant capacity, indicating a higher oxidative stress (OS) index. In addition, HFD rats demonstrated significant diet-induced changes particularly in the pancreas. Four-week oral geraniin supplementation, restored the OS observed in the HFD rats. It was able to restore OS biomarkers, serum antioxidants, and the glutathione redox balance (reduced glutathione/oxidized glutathione ratio) to levels comparable with that of the control group, particularly at dosage of 50 mg geraniin. Geraniin was not toxic to the HFD rats but exhibited protection against glucotoxicity and lipotoxicity particularly in the pancreas of the obese rodents. It is suggested that geraniin has the pharmaceutical potential to be developed as a supplement to primary drugs in the treatment of obesity and its pathophysiological sequels.

An increased autophagic flux contributes to the anti-inflammatory potential of urolithin A in macrophages

BACKGROUND

An extract of Phyllanthus muellerianus and its constituent geraniin have been reported to exert anti-inflammatory activity in vivo. However, orally consumed geraniin, an ellagitannin, shows low bioavailability and undergoes metabolization to urolithins by gut microbiota. This study aimed at comparing geraniin and urolithin A with respect to inhibition of M1 (LPS) polarization of murine J774.1 macrophages and shedding more light on possible underlying mechanisms.

METHODS

Photometric, fluorimetric as well as luminescence-based assays monitored production of reactive oxygen species (ROS) and nitric oxide (NO), cell viability or reporter gene expression. Western blot analyses and confocal microscopy showed abundance and localization of target proteins, respectively.

RESULTS

Urolithin A is a stronger inhibitor of M1 (LPS) macrophage polarization (production of NO, ROS and pro-inflammatory proteins) than geraniin. Urolithin A leads to an elevated autophagic flux in macrophages. Inhibition of autophagy in M1 (LPS) macrophages overcomes the suppressed nuclear translocation of p65 (NF-kB; nuclear factor kB), the reduced expression of pro-inflammatory genes as well as the diminished NO production brought about by urolithin A. The increased autophagic flux is furthermore associated with impaired Akt/mTOR (mammalian target of rapamycin) signaling in urolithin A-treated macrophages.

CONCLUSIONS AND GENERAL SIGNIFICANCE

Intestinal metabolization may boost the potential health benefit of widely consumed dietary ellagitannins, as suggested by side by side comparison of geraniin and urolithin A in M1(LPS) macrophages. Increased activity of the autophagic cellular recycling machinery aids the anti-inflammatory bioactivity of urolithin A.