The Protective Roles and Molecular Mechanisms of Troxerutin (vitamin P4) for Treatment of Chronic Diseases: A Mechanistic Review
Troxerutin (TRX), a semi-synthetic bioflavonoid derived from rutin, has been reported to exert several pharmacological effects including antioxidant, anti-inflammatory, antihyperlipidemic, and nephroprotective. However, the related molecular details and its mechanisms remain poorly understood. In the present review, we presented evidences from the diversity in vitro and in vivo studies on the therapeutic potential of TRX against neurodegenerative, diabetes, cancer and cardiovascular diseases with the purpose to find molecular pathways related to the treatment efficacy. TRX has a beneficial role in many diseases through multiple mechanisms including, increasing antioxidant enzymes and reducing oxidative damage, decreasing in proapoptotic proteins (APAF-1, BAX, caspases-9 and-3) and increasing the antiapoptotic BCL-2, increasing nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) and downregulating the nuclear factor κB (NFκ). TRX also reduces acetylcholinesterase activity and upregulates phosphoinositide 3-kinase/Akt signaling pathway in Alzheimer's disease models. Natural products such as TRX may develop numerous and intracellular pathways at several steps in the treatment of many diseases. Molecular mechanisms of action are revealing novel, possible combinational beneficial approaches to treat multiple pathological conditions.
Oxidative Stress Modulation by Cameroonian Spice Extracts in HepG2 Cells: Involvement of Nrf2 and Improvement of Glucose Uptake
Oxidative stress plays a relevant role in the progression of chronic conditions, including cardiometabolic diseases. Several Cameroonian plants, including spices, are traditionally used as herbal medicines for the treatment of diseases where oxidative stress contributes to insulin resistance, like type 2 diabetes mellitus. This study evaluated the antioxidant capacity and the effects on oxidative-stress-induced impairment of glucose uptake of 11 Cameroonian spice extracts. HO-induced reactive oxygen species (ROS) production by human HepG2 cells was significantly reduced by 8/11 extracts. The most effective extracts, , , and , showed a concentration-dependent ROS-scavenging activity, which involved Nrf2 translocation into the nucleus. , , , , and extracts showed the highest antioxidant capacity, according to oxygen radical absorbance capacity (ORAC) (2.52-88 μM Trolox Eq/g of extract), ferric-reducing antioxidant power (FRAP) (40.23-233.84 mg gallic acid Eq/g of extract), and total phenol (8.96-32.96% mg gallic acid Eq/g of extract) assays. In HepG2 cells, glucose uptake was stimulated by 4/11 extracts, similarly to insulin and metformin. HO-induced oxidative stress reduced glucose uptake, which was rescued by pretreatment with , , , , and extracts. The ROS-scavenging ability of the spice extracts may reside in some secondary metabolites observed by phytochemical profiling (reverse-phase high-performance liquid chromatography coupled to a diode array detector (HPLC-UV-DAD)). Further studies are needed to better clarify their biological activities and potential use to control oxidative stress and promote insulin sensitivity.
The role of natural products in revealing NRF2 function
Covering: up to 2020The transcription factor NRF2 is one of the body's major defense mechanisms, driving transcription of >300 antioxidant response element (ARE)-regulated genes that are involved in many critical cellular processes including redox regulation, proteostasis, xenobiotic detoxification, and primary metabolism. The transcription factor NRF2 and natural products have an intimately entwined history, as the discovery of NRF2 and much of its rich biology were revealed using natural products both intentionally and unintentionally. In addition, in the last decade a more sinister aspect of NRF2 biology has been revealed. NRF2 is normally present at very low cellular levels and only activated when needed, however, it has been recently revealed that chronic, high levels of NRF2 can lead to diseases such as diabetes and cancer, and may play a role in other diseases. Again, this "dark side" of NRF2 was revealed and studied largely using a natural product, the quassinoid, brusatol. In the present review, we provide an overview of NRF2 structure and function to orient the general reader, we will discuss the history of NRF2 and NRF2-activating compounds and the biology these have revealed, and we will delve into the dark side of NRF2 and contemporary issues related to the dark side biology and the role of natural products in dissecting this biology.
Protective effect of diosgenin on LPS/D-Gal-induced acute liver failure in C57BL/6 mice
Acute liver failure (ALF) is a deadly clinical syndrome, which leads to a rapid loss of normal liver function. Diosgenin is a natural steroidal sapogenin found in various plant families. Various studies have shown that diosgenin have therapeutic or preventive effect in various diseases such as cancer, cardiovascular disorders, type 2 diabetes, and neurodegenerative disorders. In this study, we evaluated effects of diosgenin on mice model of ALF. Animal model of ALF was induced by intraperitoneal injection of lipopolysaccharide (LPS)/d-galactosamine (D-Gal). The male C57BL/6 mice were randomly divided into 3 groups: control group, LPS/D-Gal group, and LPS/D-Gal + diosgenin group (50 mg/kg). Mice in the LPS/D-Gal group received a combination of LPS (50 μg/kg) and D-Gal (400 mg/kg) intraperitoneally. LPS/D-Gal + diosgenin group received diosgenin twice orally 24 h and 1 h before receiving LPS/D-Gal. Markers of liver injury including ALT, AST and ALP were measured in blood samples in addition to determination of oxidative stress and inflammatory markers including MDA, nitrite, ROS, catalase, SOD, Nrf2, IL-1β, IL-6, TLR4, TNF-α and NF-κB in hepatic tissue. Administration of diosgenin could greatly reduce serum levels of ALT, AST, and ALP. Besides, hepatic levels of MDA, ROS, IL-1β, IL-6, TLR4, TNF-α, and NF-κB significantly decreased and SOD activity and Nrf2 level increased in comparison with the LPS/D-Gal group. In addition, myeloperoxidase activity as a marker of neutrophil infiltration decreased following diosgenin administration. In summary, diosgenin led to reduction of liver injury indices and oxidative stress and inflammatory events and diosgenin has probably hepatoprotecive effects in ALF.
Costus pictus D. Don leaf extract stimulates GLP-1 secretion from GLUTag L-cells and has cytoprotective effects in BRIN-BD11 β-cells
Costus pictus D. Don, commonly known as insulin plant, is a traditional Indian antidiabetic herbal medicine with glucose-lowering and insulin secretory effects having been reported in animal models and humans with Type 2 diabetes. However, its effects on GLP-1 secretion from intestinal endocrine L-cells and potential metabolic and protective effects in insulin secreting pancreatic β-cells are not yet fully understood.
Role of Silent Information Regulator 1 (SIRT1) in Regulating Oxidative Stress and Inflammation
Silent information regulator 1 (SIRT1) is a ubiquitously expressed protein and has an intricate role in the pathology, progression, and treatment of several diseases. SIRT1 is a NAD+-dependent deacetylase and regulates gene expression by histone deacetylation. Deletion of SIRT1 in the liver, pancreas, and brain significantly increases the reactive oxygen species (ROS) and inflammatory response. Literature survey on SIRT1 shows the evidence for its role in preventing oxidative stress and inflammation. Oxidative stress and inflammation are closely related pathophysiological processes and are involved in the pathogenesis of a number of chronic disorders such as fatty liver diseases, diabetes, and neurodegenerative diseases. Both oxidative stress and inflammation alter the expression of several genes such as nuclear factor E2 related factor (Nrf2), nuclear factor E2 related factor 2 (Nef2), nuclear factor kappa B (NF-kB), pancreatic and duodenal homeobox factor 1 (PDX1), interleukin-1 (IL1), forkhead box class O (FOXO), and tumour necrosis factor alpha (TNF-α). By annotating this knowledge, we can conclude that modulating the expression of SIRT1 might prevent the onset of diseases inexorably linked to the liver, pancreas, and brain. Graphical Abstract Role of silent information regulator 1 (SIRT1) in the pancreas, brain, and liver.
In-vivo antioxidant and anti-inflammatory effects of soluble dietary fiber Konjac glucomannan in type-2 diabetic rats
Although the anti-diabetic properties of Konjac glucomannan (KGM) have been reported previously; however, the molecular pathways of its anti-diabetic properties are not clear. The present study hypothesized that KGM could mitigate oxidative stress and inflammation. Three doses of KGM (40, 80, 120 mg/kg b.w.) decreased the levels of plasma glucose and insulin in type-2 diabetic rats induced by a high-fat diet and streptozotocin (STZ) after administration for 28 days. Besides, the C-reactive protein, antioxidants, and the pathways of the nuclear factor erythroid 2-related factor 2 (Nrf2) and nuclear factor-kappa B (NF-κB) showed amelioration and positively regulation after treated with a medium dose of KGM (80 mg/kg b.w.). The results of the histological study indicated that the medium dose of KGM was able to reverse the structural impairment of kidney and liver caused by type-2 diabetes. In conclusion, our research demonstrated that KGM reduced the hyperglycemia, regulated the Nrf2 pathway and by which it prevented oxidative stress, besides, it reduced the inflammation via regulation of the NF-kB pathway.
Klotho ameliorates the onset and progression of cataract via suppressing oxidative stress and inflammation in the lens in streptozotocin-induced diabetic rats
Increased oxidative stress and inflammation play an important role in the pathogenesis of diabetic cataract. Klotho, known as an anti-ageing protein, has antioxidative and anti-inflammatory properties. Klotho is expressed in limited tissues including the lens. Here we examined whether klotho expression is decreased in diabetic lens and, if so, whether klotho treatment can prevent diabetic cataract formation. Streptozotocin (STZ)-induced diabetic rats and age-matched control rats were treated with vehicle or klotho protein, starting at 1 week after STZ injection. Twelve weeks after treatment, cataract formation was observed in diabetic rats but not control rats. Cataract formation and scores were significantly less in klotho-treated diabetic rats than vehicle-treated diabetic rats. Levels of klotho in plasma, aqueous humor and lens were significantly decreased in vehicle-treated diabetic rats, compared with control rats, but were restored in klotho-treated diabetic rats. Additionally, vehicle-treated diabetic rats had increased oxidative stress and inflammation in the lens, which were associated with decreased antioxidant transcriptional master regulator Nrf2 activity and increased transcription factor NF-κB activity. All of these findings were ameliorated in klotho-treated diabetic rats. Notably, klotho treatment did not alter blood glucose in diabetic rats. These results indicate that klotho reduction may increase susceptibility of the lens to oxidative and inflammatory insults, promoting cataract formation under diabetic conditions. Klotho treatment can ameliorate the onset and progression of diabetic cataract via enhancing Nrf2-mediated antioxidant defense and suppressing NF-κB-mediated inflammatory responses. Klotho in the lens may be a novel therapeutic target for prevention of cataract formation in diabetes.
Neuroprotective effect of diosgenin in a mouse model of diabetic peripheral neuropathy involves the Nrf2/HO-1 pathway
Diabetic peripheral neuropathy (DPN) is one of the most common chronic complications of diabetes. Diosgenin is a natural steroidal saponin with a variety of beneficial effects, including antidiabetic effects, and is a raw material for the synthesis of carrier hormones. In our study, we aimed to assess the antioxidant effects of diosgenin in diabetic mice.
Akebia Saponin D ameliorated kidney injury and exerted anti-inflammatory and anti-apoptotic effects in diabetic nephropathy by activation of NRF2/HO-1 and inhibition of NF-KB pathway
Diabetic nephropathy (DN), a common microvascular complication of type 2 diabetes mellitus (T2DM), causes increasing mortality and morbidity due to its high prevalence and severe consequences. Hence, it is urgent to search for effective agents that provide new insights into novel molecular therapeutic targets for DN. This study was designed to investigate the critical role of Akebia saponin D (ASD) in kidney damage, inflammation and apoptosis of renal tubular cells in DN. To probe the protective effects of ASD on DN in vivo, diabetes mellitus model was established by intraperitoneal (ip) injection of STZ (60 mg/kg) for 5 days consecutively. Besides, HG-induced human renal tubular cells (HK-2) were used to analyze the defined effects and underlying mechanism of ASD on DN in vitro. Blood glucose, insulin, serum creatinine (Scr), blood urea nitrogen (BUN), renal injury, inflammation, oxidative stress and apoptosis of renal tubular cells were respectively measured and evaluated. ASD prevented kidney damage, improved renal function and inflammatory reaction, ameliorated oxidative stress and inhibited apoptosis of renal tubular cells in DN mice via activation of NRF2/HO-1 pathway and inhibition of NF-KB pathway.
The protective effect of recombinant globular adiponectin on testis by modulating autophagy, endoplasmic reticulum stress and oxidative stress in streptozotocin-induced diabetic mice
This study was to investigate whether recombinant globular adiponectin produced its protective effect on the testis of diabetic mice by modulating autophagy, endoplasmic reticulum stress and oxidative stress. Male mice were randomly divided into control, diabetic, diabetic treated with low and high dose of adiponectin. Mice were killed at the termination after 4 weeks and 8 weeks of adiponectin treatment. Serum levels of glucose, lipids, testosterone, insulin, LH and FSH were measured. The protein expression of glucose-regulated protein 78 (GRP78), C/EBP homologous protein (CHOP), Caspase12, Beclin1, microtubule-associated protein light chain 3 (LC3) and p62 was determined by western blotting. The mRNA expression of adiponectin receptor 1 (AdipoR1), p22phox, p47phox, nuclear factor erythroid2-related factor 2 (Nrf2), NAD(P)H-quinone oxidoreductase 1(NQO1), heme oxygenase-1 (HO-1) and superoxide dismutase (SOD) were determined by real-time fluorescence quantitative PCR. The testicular weight, the sperm number and motility, and the serum levels of testosterone and insulin were significantly decreased in diabetic mice (P < 0.05). The expression of Beclin1, LC3, Nrf2, NQO1, HO-1, SOD and AdipoR1 were significantly decreased (P < 0.05), while the expression of GRP78, CHOP, Caspase12, p62, p22phox and p47phox were notably increased in the testes of diabetic mice (P < 0.05). Adiponectin treatment significantly reversed the above-mentioned changes in the testes of diabetic mice, some of which were dose- and time-dependent (P < 0.05). These data suggested that recombinant globular adiponectin may produce the protective effect on the testes of diabetic mice by inducing autophagy and inhibiting ER stress and oxidative stress.
MnTE-2-PyP, a manganese porphyrin, reduces cytotoxicity caused by irradiation in a diabetic environment through the induction of endogenous antioxidant defenses
Radiation is a common anticancer therapy for many cancer patients, including prostate cancer. Diabetic prostate cancer patients suffer from increased lymph node metastasis, tumor recurrence and decreased survival as compared to non-diabetic prostate cancer patients. These patients are also at increased risk for enhanced radiation-induced normal tissue damage such as proctitis. Diabetics are oxidatively stressed and radiation causes additional oxidative damage. We and others have reported that, MnTE-2-PyP, a manganese porphyrin, protects normal prostate tissue from radiation damage. We have also reported that, in an in vivo mouse model of prostate cancer, MnTE-2-PyP decreases tumor volume and increases survival of the mice. In addition, MnTE-2-PyP has also been shown to reduce blood glucose and inhibits pro-fibrotic signaling in a diabetic model. Therefore, to investigate the role of MnTE-2-PyP in normal tissue protection in an irradiated diabetic environment, we have treated human prostate fibroblast cells with MnTE-2-PyP in an irradiated hyperglycemic environment. This study revealed that hyperglycemia causes increased cell death after radiation as compared to normo-glycemia. MnTE-2-PyP protects against hyperglycemia-induced cell death after radiation. MnTE-2-PyP decreases expression of NOX4 and α-SMA, one of the major oxidative enzymes and pro-fibrotic molecules respectively. MnTE-2-PyP obstructs NF-κB activity by decreasing DNA binding of the p50-p50 homodimer in the irradiated hyperglycemic environment. MnTE-2-PyP increases NRF2 mediated cytoprotection by increasing NRF2 protein expression and DNA binding. Therefore, we are proposing that, MnTE-2-PyP protects fibroblasts from irradiation and hyperglycemia damage by enhancing the NRF2- mediated pathway in diabetic prostate cancer patients, undergoing radiotherapy.
Combined treatment with extracorporeal shockwaves therapy and an herbal formulation for activation of penile progenitor cells and antioxidant activity in diabetic erectile dysfunction
A Korean herbal formulation named KH-204 was reported to have an antioxidant effect in our previous study. We hypothesized that Low-intensity extracorporeal shockwave therapy (Li-ESWT) combined with KH-204 would accelerate the treatment of erectile dysfunction (ED) by enhancing antioxidant. We investigated the synergistic effect of Li-ESWT and KH-204 for ED and explored the mechanism.
Polysaccharides from Opuntia milpa alta alleviate alloxan-induced INS-1 cells apoptosis via reducing oxidative stress and upregulating Nrf2 expression
The incidence and progression of type 2 diabetes are closely related to pancreatic β-cell damage. Oxidative stress may be one of the key factors contributing to β-cell apoptosis. Opuntia milpa alta polysaccharides (MAPs) are water-soluble macromolecular polysaccharides that have antidiabetic effects in vivo. Therefore, we hypothesized that MAPs might effectively prevent β-cell apoptosis via the inhibition of oxidative damages. In this study, INS-1 cells were exposed to alloxan with different concentrations of MAPs in vitro, and the cell viability, oxidative enzyme activities, nitric oxide production, reactive oxygen species production, apoptosis, and the expression of proteins in the antioxidant nucleus transcription factor NF-E2-related factor 2 (Nrf2) pathway and proteins related to apoptosis were measured to assess oxidative stress responses and apoptosis. The results indicated that INS-1 cell viabilities and superoxide dismutase and reduced glutathione activities were significantly restored, whereas lactate dehydrogenase releases and reactive oxygen species, nitric oxide, and malondialdehyde levels were greatly decreased after MAPs treatment. We found that MAPs could attenuate alloxan-induced apoptosis by increasing the expression of Bcl-2 and decreasing the expression of Bax and the activities of caspase-3 and caspase-9. The results of Western blot revealed that MAPs suppressed the expression of cleaved caspase-3 and cleaved PARP and upregulated the expression of nucleus Nrf2 and its downstream protein. These findings indicated that MAPs could alleviate alloxan-induced β-cell apoptosis by reducing oxidative stress and upregulating Nrf2 expression.
The Hypoglycemic and Renal Protection Properties of Crocin Oxidative Stress-Regulated NF-κB Signaling in db/db Mice
As the main ingredient of . (Iridaceae) extract, crocin- I (CR) has been reported to show various pharmacological activities. The aim of this study was to investigate the hypoglycemic and renal protection properties of CR in db/db mice.