Rutin ameliorates free radical mediated cataract by enhancing the chaperone activity of α-crystallin

Natural Antioxidant Activities of Plants in Preventing Cataractogenesis

A cataract is a condition that causes 17 million people to experience blindness and is the most significant cause of vision loss, around 47.9%. The formation of cataracts is linked to both the production of reactive oxygen species (ROS) and the reduction of endogenous antioxidants. ROS are highly reactive molecules produced by oxygen. Examples of ROS include peroxides, super-oxides, and hydroxyl radicals. ROS are produced in cellular responses to xenobiotics and bacterial invasion and during mitochondrial oxidative metabolism. Excessive ROS can trigger oxidative stress that initiates the progression of eye lens opacities. ROS and other free radicals are highly reactive molecules because their outer orbitals have one or more unpaired electrons and can be neutralized by electron-donating compounds, such as antioxidants. Examples of natural antioxidant compounds are vitamin C, vitamin E, and beta-carotene. Numerous studies have demonstrated that plants contain numerous antioxidant compounds that can be used as cataract preventatives or inhibitors. Natural antioxidant extracts for cataract therapy may be investigated further in light of these findings, which show that consuming a sufficient amount of antioxidant-rich plants is an excellent approach to cataract prevention. Several other natural compounds also prevent cataracts by inhibiting aldose reductase and preventing apoptosis of the eye lens.

Gelatin hydrogel/contact lens composites as rutin delivery systems for promoting corneal wound healing

Corneal wound healing is a highly regulated biological process that is of importance for reducing the risk of blinding corneal infections and inflammations. Traditional eye drop was the main approach for promoting corneal wound healing. However, its low bioavailability required a high therapeutic concentration, which can lead to ocular or even systemic side effects. To develop a safe and effective method for treating corneal injury, we fabricated rutin-encapsulated gelatin hydrogel/contact lens composites by dual crosslinking reactions including in situ free radical polymerization and carboxymethyl cellulose/N-hydroxysulfosuccinimide crosslinking. In vitro drug release results evidenced that rutin in the composites could be sustainedly released for up to 14 days. In addition, biocompatibility assay indicated nontoxicity of the composites. Finally, the effect of rutin-encapsulated composites on the healing of the corneal injury in rabbits was investigated. The injury was basically cured in corneas using rutin-encapsulated composites (healing rate, 98.3% ± 0.7%) at 48 h post-operation, while the damage was still present in corneas using the composite (healing rate, 87.0% ± 4.5%). Further proteomics analysis revealed that corneal wound healing may be promoted by the ERK/MAPK and PI3K/AKT signal pathways. These results inform a potential intervention strategy to facilitate corneal wound healing in humans.

Preventive effect of insect tea primary leaf (Malus sieboldii (Regal) Rehd.) extract on D-galactose-induced oxidative damage in mice

Insect tea is consumed as a health beverage in China. The insect tea primary leaf (ITPL) is rich in bioactive substances, which are also used as traditional Chinese medicine. This study investigated the role of ITPL in reducing the oxidative response induced by D-galactose in mice. Mice were intraperitoneally injected with D-galactose to induce oxidative damage. The effect of ITPL was tested by pathological observation, serum detection with kits, quantitative polymerase chain reaction, and Western blot. The experimental results show that ITPL increased the thymus, brain, heart, liver, spleen, and kidney indices of oxidized mice. ITPL increased superoxide dismutase, glutathione peroxidase, and glutathione levels and reduced nitric oxide and malondialdehyde levels in the serum, liver, and spleen in oxidative damaged mice. The pathological observations show that ITPL reduced the oxidative damage of the liver and spleen in mice induced with D-galactose. Simultaneously, ITPL upregulated mRNA expression of neuronal nitric oxide synthase, endothelial nitric oxide synthase, cuprozinc-superoxide dismutase, manganese superoxide dismutase, catalase, heme oxygenase-1, nuclear factor-erythroid 2 related factor 2, γ-glutamylcysteine synthetase, and NAD(P)H dehydrogenase [quinone] 1, and downregulated the expression of inducible nitric oxide synthase in the liver and spleen of oxidized mice. ITPL had beneficial preventive effects on the oxidative damage caused by D-galactose in mice and was more effective as an antioxidant than vitamin C. The component analysis test by high-performance liquid chromatography indicated that ITPL contained the following seven compounds: neochlorogenic acid, cryptochlorogenic acid, rutin, kaempferin, isochlorogenic acid B, isochlorogenic acid A, and hesperidin. ITPL is a plant with excellent antioxidant activities derived from its bioactive substances.

Protective Effects of Trimetazidine in Retarding Selenite-Induced Lens Opacification

Purpose: Cataracts are the leading cause of vision loss worldwide, and the over-production of reactive oxygen species (ROS) is the foremost underlying cause of cataracts. Reducing ROS levels can efficiently prevent lens opacification, as evidenced by many studies. Here, we inhibited ROS overproduction with trimetazidine (TMZ), which is an antioxidant, to explore the therapeutic effects of TMZ and the mechanism of lens opacification.Materials and methods: Sodium selenite-induced cataract formation resulted in a significant loss of lens transparency. This effect could be efficiently rescued by TMZ, which was further found to be an inhibitor of ROS production, as determined by assaying oxidative stress-related parameters (SOD activity, MDA, ·OH and H₂O₂ levels) during cataract formation. The experimental protocols involving animal research were approved by the Animal Care and Ethics Committee of Wenzhou Medical University and conducted according to the Association for Research in Vision and Ophthalmology under the guidelines of the Animal Welfare Act (SYXK 2015-0009).Results: Our study found that TMZ can retard the onset and progression of lens opacification in vivo in experiments using Sprague-Dawley (SD) suckling rats and can rescue the morphology of HLEB₃ cells in vitro. The flow cytometry and DNA fragmentation assays showed that TMZ could prevent sodium selenite-induced apoptosis. The western blot analysing showed that the levels of apoptosis-associated Bcl-2 and Nrf2 were dramatically decreased following the sodium selenite treatment. In addition, the bisulfate DNA sequencing revealed that the demethylation of CpGs in the promoter region of Keap1 was stimulated, and that this demethylation could be inhibited by TMZ by rescuing the Nrf2 expression level.Conclusions: Our findings indicate that the antioxidant TMZ strongly reduces ROS production, which ultimately delays the progression of cataract formation, suggesting that treatment with TMZ represents a novel, promising antioxidant protection to retard cataract formation.

Medicinal Plants and Natural Products Used in Cataract Management

Cataract is the leading reason of blindness worldwide and is defined by the presence of any lens opacities or loss of transparency. The most common symptoms of cataract are impaired vision, decreased contrast sensitivity, color disturbance, and glare. Oxidative stress is among the main mechanisms involved in the development of age-related cataract. Surgery through phacoemulsification and intraocular lens implantation is the most effective method for cataract treatment, however, there are chances of serious complications and irreversible loss of vision associated with the surgery. Natural compounds consisting of antioxidant or anti-inflammatory secondary metabolites can serve as potential leads for anticataract agents. In this review, we tried to document medicinal plants and plant-based natural products used for cataract treatment worldwide, which are gathered from available ethnopharmacological/ethnobotanical data. We have extensively explored a number of recognized databases like Scifinder, PubMed, Science Direct, Google Scholar, and Scopus by using keywords and phrases such as “cataract”, “blindness”, “traditional medicine”, “ethnopharmacology”, “ethnobotany”, “herbs”, “medicinal plants”, or other relevant terms, and summarized the plants/phytoconstituents that are evaluated in different models of cataract and also tabulated 44 plants that are traditionally used in cataract in various folklore medical practices. Moreover, we also categorized the plants according to scientific studies carried out in different cataract models with their mechanisms of action.

Dietary flavonoids inhibit the glycation of lens proteins: implications in the management of diabetic cataract

The intervention of functional foods as complementary therapeutic approach for the amelioration of diabetes and sugar induced cataractogenesis is more appreciated over the present day chemotherapy agents owing to their nontoxic and increased bioavailability concerns. Dietary flavonoids, a class of bioactive phytochemicals is known to have wide range of biological activities against variety of human ailments. In the present study, we demonstrate anti-cataract effect of eight dietary flavonoids in sugar induced lens organ culture study. We present data on processes like inhibition of glycation-induced lens cloudiness, lens protein aggregation, glycation reaction and advanced glycation end products formation that can act as biochemical markers for this disease. The selected flavonoids were also tested for their aldose reductase (AR) inhibition (experimental and in silico). The molecular dynamics simulation results shed light on mechanistic details of flavonoid induced AR inhibition. The outcome of the present study clearly focuses the significance of kaempferol, taxifolin and quercetin as potential candidates for controlling diabetic cataract.

Rosmarinic Acid Restores Complete Transparency of Sonicated Human Cataract Ex Vivo and Delays Cataract Formation In Vivo

Cataract, the leading cause of vision impairment worldwide, arises from abnormal aggregation of crystallin lens proteins. Presently, surgical removal is the only therapeutic approach. Recent findings have triggered renewed interest in development of non-surgical treatment alternatives. However, emerging treatments are yet to achieve full and consistent lens clearance. Here, the first ex vivo assay to screen for drug candidates that reduce human lenticular protein aggregation was developed. This assay allowed the identification of two leading compounds as facilitating the restoration of nearly-complete transparency of phacoemulsified cataractous preparation ex vivo. Mechanistic studies demonstrated that both compounds reduce cataract microparticle size and modify their amyloid-like features. In vivo studies confirmed that the lead compound, rosmarinic acid, delays cataract formation and reduces the severity of lens opacification in model rats. Thus, the ex vivo assay may provide an initial platform for broad screening of potential novel therapeutic agents towards pharmacological treatment of cataract.

Quantification of rutin in rat's brain by UHPLC/ESI-Q-TOF-MS/MS after intranasal administration of rutin loaded chitosan nanoparticles

Rutin (RT), an antioxidant drug, has been utilized to treat cerebral ischemia hence a sensitive quantification method for estimation of RT in brain homogenate is necessary to develop. This study aims to prepare RT loaded Chitosan Nanoparticles (RT-CS-NPs) develop and validate ultra-high performance liquid chromatography-electrospray ionization-synapt mass spectrometric method Synapt Mass Spectrometry (Synapt MS) (UHPLC/ESI-QTOF-MS/MS) for quantification of RT in brain homogenate from Wistar rat. The process of chromatographic separation was carried out on Waters ACQUITY UPLC™ with the components of separation in detail as; column: BEH C-18 with dimension as 2.1 mm×100 mm and particle size 1.7 µm, mobile phase: acetonitrile (85 % v/v/v): 2 mM ammonium formate (15 % v/v/v): formic acid (0.1 % v/v/v) and flow rate: 0.25 mL/min. Liquid-liquid extraction method (LLE), in mixture, i.e. ethyl acetate:acetonitrile, was considered to optimize the recovery of analyte from the brain homogenate of Wistar rat. Over a total run time of 5 minutes, the elution time for RT and internal standard (IS), i.e. Tolbutamide, observed was 2.67 and 2.82 min respectively whereas the transition observed for RT and IS was at m/z 611.1023/303.1071 and 271.1263/155.1073, respectively. Results, regarding various processes and parameters studied for RT as summarized, established a linear dynamic range over a concentration range of 1.00 ng/mL - 1000.0 ng/mL with r²; 0.9991±0.0010. Accuracy for intra and inter-assay in terms of % CV revealed a range of 0.45- 2.11 whereas lower limit of detection (LOD) and quantitation (LOQ) observed was 0.09 ng/mL and 0.142 ng/mL, respectively. The analyte stability as well as method specificity and accuracy, i.e. recovery > 86 %, supports the idea for application of current developed method in order to quantify and evaluate the RT-loaded-CS-NPs for RT determination in brain homogenate after intranasal drug delivery.

Effect of hesperetin on chaperone activity in selenite-induced cataract

BACKGROUND

Chaperone activity of α-crystallin in the lens works to prevent protein aggregation and is important to maintain the lens transparency. This study evaluated the effect of hesperetin on lens chaperone activity in selenite-induced cataracts.

METHODOLOGY

Thirteen-day-old rats were divided into four groups. Animals were given hesperetin (groups G2 and G4) or vehicle (G1 and G3) on Days 0, 1, and 2. Rats in G3 and G4 were administered selenite subcutaneously 4 hours after the first hesperetin injection. On Days 2, 4, and 6, cataract grades were evaluated using slit-lamp biomicroscopy. The amount of a-crystallin and chaperone activity in water-soluble fraction were measured after animals sacrificed.

RESULTS

G3 on day 4 had developed significant cataract, as an average cataract grading of 4.6 ± 0.2. In contrast, G4 had less severe central opacities and lower stage cataracts than G3, as an average cataract grading of 2.4 ± 0.4. The a-crystallin levels in G3 lenses were lower than in G1, but the same as G4. Additionally, chaperone activity was weaker in G3 lenses than G1, but the same as in G4.

CONCLUSIONS

Our results suggest that hesperetin can prevent the decreasing lens chaperone activity and a-crystallin water solubility by administered of selenite.

Rutin-encapsulated chitosan nanoparticles targeted to the brain in the treatment of Cerebral Ischemia

OBJECTIVE

Rutin, a potent antioxidant, has been reported to reduce the risk of ischemic disease. Our study aims to prepare rutin-encapsulated-chitosan nanoparticles (RUT-CS-NPs) via ionic gelation method and determine its results, based on different parameters i.e. surface morphology characterization, in-vitro or ex-vivo release, dynamic light scattering and differential scanning calorimetry (DSC), for treating cerebral ischemia.

METHODS

UPLC-ESI-Q-TOF-MS/MS was used to evaluate the optimized RT-CS-NPs1 for brain-drug uptake as well as to follow-up the pharmacokinetics, bio-distrbution, brain-targeting efficiency and potential after intranasal administration (i.n.).

KEY FINDINGS

A particle size of <100nm for the formulation, significantly affected by drug:CS ratio, and entrapment efficiency and loading capacity of 84.98%±4.18% and 39.48%±3.16%, respectively were observed for RUT. Pharmacokinetics, bio-distribution, brain-targeting efficiency (1443.48±39.39%) and brain drug-targeting potential (93.00±5.69%) showed enhanced bioavailability for RUT in brain as compared to intravenous administration. In addition; improved neurobehavioral activity, histopathology and reduced infarction volume effects were observed in middle cerebral artery occlusion (MCAO) induced cerebral ischemic rats model after i.n. administration of RUT-CS-NPs.

CONCLUSION

A significant role of mucoadhesive-RT-CS-NPs1 as observed after high targeting potential and efficiency of the formulation prove; RUT-CS-NPs are more effectively accessed and target easily the brain.

Quercetin glycosides and chlorogenic acid in highbush blueberry leaf decoction prevent cataractogenesis in vivo and in vitro: Investigation of the effect on calpains, antioxidant and metal chelating properties

The present study investigates whether highbush blueberry leaf polyphenols prevent cataractogenesis and the underlying mechanisms. Chlorogenic acid, quercetin, rutin, isoquercetin and hyperoside were quantified in Vaccinium corymbosum leaf decoction (BBL) using HPLC-DAD. Wistar rats were injected subcutaneously with 20 μmol selenite (Na2SeO3)/kg body weight on postnatal (PN) day 10 (Se, n = 8-10/group) only or also intraperitoneally with 100 mg dry BBL/kg body weight on PN days 11 and 12 (SeBBL group, n = 10). Control group received only normal saline (C). Cataract evaluation revealed that BBL significantly prevented lens opacification. It, also, protected lens from selenite oxidative attack and prevented calpain activation, as well as protein loss and aggregation. In vitro studies showed that quercetin attenuated porcine lens turbidity caused by [Formula: see text] or Ca(2+) and interacted efficiently with those ions according to UV-Vis titration experiments. Finally, rutin, isoquercetin and hyperoside moderately inhibited pure human μ-calpain. Conclusively, blueberry leaf extract, a rich source of bioactive polyphenols, prevents cataractogenesis by their strong antioxidant, chelating properties and through direct/indirect inhibition of lens calpains.

Association between DNA repair genes (XPD and XRCC1) polymorphisms and susceptibility to age-related cataract (ARC): a meta-analysis

BACKGROUND

DNA repair gene (XPD and XRCC1) polymorphisms have been considered as risk factors for the development of age-related cataract (ARC). To confirm the association between DNA repair gene (XPD and XRCC1) polymorphisms and the risk of ARC, a meta-analysis was conducted.

METHODS

A search was made of published literature from Institute for Scientific Information (ISI) Web of Knowledge, PubMed, Google Scholar, China National Knowledge Infrastructure (CNKI), and Wanfang Data. In addition, all studies evaluating the association between DNA repair genes (XPD and XRCC1) polymorphisms and the risk for ARC were included in our analysis. Pooled odds ratio (OR) and 95 % confidence interval (CI) were calculated by using fixed- or random-effects model. The Egger's test was used to check the publication bias.

RESULTS

Six studies on XRCC1 Arg399Gln (1,300 cases, 1,222 controls) and five studies on XPD Lys751Gln (1,092 cases, 1,061 controls) were included. For the XPD Lys751Gln (A/C) SNP, the overall analysis demonstrated that the CC genotype showed a significant association with a decreased risk for ARC compared with the AA genotype (OR = 0.59, 95 % CI, 0.38-0.92, P = 0.019). Similarly, the CC genotype showed a significant association with a decreased risk for ARC compared with the (AA + AC) genotype (OR = 0.65, 95 % CI, 0.43-0.98, P = 0.040). Subgroup analysis showed that the association between the CC genotype and decreased risk for ARC is statistically significant in Caucasians (OR = 0.41, 95 % CI, 0.24-0.73, P = 0.002) but not in Asians (OR = 1.06, 95 % CI, 0.51-2.19, P = 0.877). For the XRCC1 Arg399Gln (G/A) SNP, the overall analysis demonstrated that the A allele showed a significant association with an increased risk for ARC compared with the G allele (OR = 1.16, 95 % CI, 1.03-1.31, P = 0.015). Subgroup analyses exhibited that the association between the A allele and the risk for ARC was statistically significant in Asians (OR = 1.23, 95 % CI, 1.07-1.41, P = 0.003) but not in Caucasians (OR = 0.94, 95 % CI, 0.73-1.22, P = 0.660). Compared with the GG genotype, the GA genotype showed a significant association with an increased risk for ARC in Asians (OR = 1.32, 95 % CI, 1.08-1.61, P = 0.006) but not in Caucasians (OR = 0.58, 95 % CI, 0.27-1.26, P = 0.171). The Egger's test did not reveal an obvious publication bias among the included studies.

CONCLUSIONS

Our meta-analysis suggested that the CC genotype of XPD Lys751Gln (A/C) SNP seemed to portend a decreased risk for ARC in Caucasian populations but not in Asian populations. The A allele and GA genotype of XRCC1 Arg399Gln (G/A) SNP might increase risk for ARC in Asian populations but not in Caucasian populations. More researches with larger and more different ethnic populations on this issue are therefore necessary.