Prevention of selenite induced oxidative stress and cataractogenesis by luteolin isolated from Vitex negundo

Biosynthesis of a water solubility-enhanced succinyl glucoside derivative of luteolin and its neuroprotective effect

The natural flavonoids luteolin and luteoloside have anti-bacterial, anti-inflammatory, anti-oxidant, anti-tumour, hypolipidemic, cholesterol lowering and neuroprotective effects, but their poor water solubility limits their application in industrial production and the pharmaceutical industry. In this study, luteolin-7-O-β-(6″-O-succinyl)-d-glucoside, a new compound that was prepared by succinyl glycosylation of luteolin by the organic solvent tolerant bacterium Bacillus amyloliquefaciens FJ18 in an 8.0% DMSO (v/v) system, was obtained and identified. Its greater water solubility (2293 times that of luteolin and 12 232 times that of luteoloside) provides the solution to the application problems of luteolin and luteoloside. The conversion rate of luteolin (1.0 g l^-1 ) was almost 100% at 24 h, while the yield of luteolin-7-O-β-(6″-O-succinyl)-d-glucoside reached 76.2%. In experiments involving the oxygen glucose deprivation/reoxygenation injury model of mouse hippocampal neuron cells, the cell viability was significantly improved with luteolin-7-O-β-(6″-O-succinyl)-d-glucoside dosing, and the expressions of the anti-oxidant enzyme HO-1 in the nucleus increased, providing a neuroprotective effect for ischemic cerebral cells. The availability of biosynthetic luteolin-7-O-β-(6″-O-succinyl)-d-glucoside, which is expected to replace luteolin and luteoloside, would effectively expand the clinical application value of luteolin derivatives.

Natural Products for the Prevention and Control of the COVID-19 Pandemic: Sustainable Bioresources

Background: The world has been unprecedentedly hit by a global pandemic which broke the record of deadly pandemics that faced humanity ever since its existence. Even kids are well-versed in the terminologies and basics of the SARS-CoV-2 virus and COVID-19 now. The vaccination program has been successfully launched in various countries, given that the huge global population of concern is still far behind to be vaccinated. Furthermore, the scarcity of any potential drug against the COVID-19-causing virus forces scientists and clinicians to search for alternative and complementary medicines on a war-footing basis. Aims and Objectives: The present review aims to cover and analyze the etiology and epidemiology of COVID-19, the role of intestinal microbiota and pro-inflammatory markers, and most importantly, the natural products to combat this deadly SARS-CoV-2 virus. Methods: A primary literature search was conducted through PubMed and Google Scholar using relevant keywords. Natural products were searched from January 2020 to November 2020. No timeline limit has been imposed on the search for the biological sources of those phytochemicals. Interactive mapping has been done to analyze the multi-modal and multi-target sources. Results and Discussion: The intestinal microbiota and the pro-inflammatory markers that can serve the prognosis, diagnosis, and treatment of COVID-19 were discussed. The literature search resulted in yielding 70 phytochemicals and ten polyherbal formulations which were scientifically analyzed against the SARS-CoV-2 virus and its targets and found significant. Retrospective analyses led to provide information about 165 biological sources that can also be screened if not done earlier. Conclusion: The interactive analysis mapping of biological sources with phytochemicals and targets as well as that of phytochemical class with phytochemicals and COVID-19 targets yielded insights into the multitarget and multimodal evidence-based complementary medicines.

Effects of Binahong (Anredera cordifolia (Tenore) Steenis) Extracts on the Levels of Malondialdehyde (MDA) in Cataract Goat Lenses

Cataracts are one of the most causes of blindness in the world. Oxidative stress can form pathological conditions such as cataracts. This oxidative stress ability can be measured by the malondialdehyde (MDA) biomarker. Binahong leaves (Anredera cordifolia (Tenore) Steenis) are native plants from Indonesia that are used to treat various diseases including cataract treatment. Binahong leaf (Anredera cordifolia (Tenore) Steenis) has a high amount of flavonoids and is rich in antioxidants that can be used to treat cataracts. Objective. The purpose of this study was to assess the effect of binahong leaf extract on the levels of MDA in a goat lens with cataract-induced material. Method. As many as possible, 40 goat eye lenses were divided into several groups, namely, group I normal lenses as controls (glucose 5.5 mM), group II lenses were cataract induced with glucose concentration of 55 mM, group III lenses with glucose 55 mM + binahong leaf extract (100 μg/ml), group IV lens with glucose 55 mM + binahong leaf extract (200 μg/ml), and group V lens with glucose 55 mM + quercetin (positive control). Biochemical parameters measured in the lens homogenate are malondialdehyde lens morphology in all groups' observations and comparisons made. Results. The results of the study found that the lens group with the addition of binahong extract showed more results transparency compared to lens groups induced by glucose concentrations of 55 mM). This shows that the diabetic cataract group experienced high oxidative stress due to the accumulation of sorbitol compounds derived from glucose which caused turbidity in the goat eye lens and increased levels of lens MDA. Binahong levels at concentrations of 100 or 200 can inhibit MDA production. Conclusion. Binahong (Anredera cordifolia (Tenore) Steenis) extract has the ability to inhibit the production of MDA levels. In glucose-induced goat lenses, binahong extract and quercetin show antioxidant and anticataract properties.

Protective effects of luteolin on nephrotoxicity induced by long-term hyperglycaemia in rats

Objective

This study aimed to investigate whether luteolin delays the progress of diabetic nephropathy (DN) induced by streptozotocin.

Methods

Fifty-three healthy, 8-week-old, male Sprague–Dawley rats were randomly divided into the control (n = 6), model (n = 23), and experimental groups (n = 24). The rat model of diabetic nephropathy was established by intraperitoneal injection of streptozotocin. Rats in the experimental group were administered luteolin suspension of 80 mg/kg daily for 8 weeks. Blood glucose levels and body weight were recorded until the fourth week. After intragastric administration, blood flow and the protective effect of luteolin on diabetic nephropathy were evaluated.

Results

The degree of renal apoptosis and fibrosis in the experimental group was milder, and glomerular structure was more complete compared with the model group. Nphs2 staining suggested that luteolin delayed apoptosis and deletion and fusion of podocytes under high glucose levels, and protected the filtration function of the basement membrane by upregulating Nphs2 protein expression. Time intensity curve results suggested that luteolin delayed deterioration of renal haemodynamics under hyperglycaemia.

Conclusions

This study shows that luteolin delays progression of diabetic nephropathy. This drug has potential wide applicability in future clinical application.

Mechanism of Salviae Miltiorrhizae Radix et Rhizoma in the Treatment of Knee Osteoarthritis Based on Network Pharmacology

Objective

The molecular mechanism of Salviae Miltiorrhizae Radix et Rhizoma (SMRR) in the treatment of knee osteoarthritis (KOA) was analyzed based on network pharmacology.

Methods

Active components and potential targets of SMRR were obtained from the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform. KOA targets were obtained from the OMIM, DisGeNET, DrugBank, PharmGKB, and GeneCards Databases. The potential targets of SMRR in the treatment of KOA were identified by the Venn diagram. A protein-protein interaction network was generated with the STRING database. Visualization of the interactions in a potential pharmacodynamic component-target network was accomplished with Cytoscape software. The Database for Annotation, Visualization, and Integrated Discovery database and R software were used for Gene Ontology enrichment and Kyoto Encyclopedia of Genes and Genomes pathway annotation analyses of common targets. Molecular docking of the potential leading components, as determined by efficacy with the core target molecules, was performed with Discovery Studio.

Results

Fifty-seven potential pharmacodynamic components and 58 potential targets of SMRR in the treatment of KOA were found. Bioinformatics analyses showed that the interleukin (IL)-17, hypoxia-inducible factor-1 (HIF-1), and tumor necrosis factor (TNF) signaling pathways, as well as the advanced glycation end product-receptor for advanced glycation end product signaling pathway in cases of diabetic complications, are related to the molecular mechanism of SMRR in the treatment of KOA. Molecular docking results showed that luteolin, tanshinone IIA, cryptotanshinone, and other components of SMRR had a strong affinity for MYC, signal transducer and activator of transcription 3, caspase-3 (CASP3), JUN, cyclin D1, prostaglandin endoperoxide synthase 2 (PTGS2), epidermal growth factor receptor (EGFR), mitogen-activated protein kinase 1 (MAPK1), protein kinase B, vascular endothelial growth factor A, and other targets.

Conclusion

SMRR indirectly regulates IL-17, HIF-1, TNF, and other signal transduction pathways by regulating the expression of proteins, including PTGS2, MAPK1, EGFR, and CASP3, thus playing a role in promoting chondrocyte proliferation, improving microcirculation, eliminating free radicals, and inhibiting inflammatory factors.

WRN inhibits oxidative stress-induced apoptosis of human lensepithelial cells through ATM/p53 signaling pathway and its expression is downregulated by DNA methylation

BACKGROUND

Apoptosis and oxidative stress are the main etiology of age related cataract (ARC). This article aims to investigate the role of WRN in lens epithelial cells (LECs).

METHODS

We estimated the methylation level of WRN in anterior lens capsule tissues of ARC patients. SRA01/04 (LECs) cells were treated with H2O2 or combined with 5-aza-2-deoxycytidine (5-Aza-CdR) or chloroquine. CCK8 and flow cytometry were performed to explore proliferation and apoptosis. The content of ROS was detected by fluorescent probe DCFH-DA. The gene and protein expression was assessed by quantitative real-time PCR or western blot.

RESULTS

WRN was down-regulated and the methylation level of WRN was increased in the anterior lens capsule tissues. WRN overexpression and 5-Aza-CdR enhanced proliferation and repressed apoptosis and oxidative stress of SRA01/04 cells. 5-Aza-CdR enhanced WRN expression. WRN knockdown inhibited proliferation and promoted apoptosis and oxidative stress of SRA01/04 cells, which was rescued by 5-Aza-CdR. WRN overexpression and 5-Aza-CdR repressed ATM/p53 signaling pathway. Furthermore, chloroquine inhibited proliferation and promoted apoptosis and oxidative stress of SRA01/04 cells by activating ATM/p53 signaling pathway. The influence conferred by chloroquine was abolished by WRN overexpression.

CONCLUSION

Our study reveals that DNA methylation mediated WRN inhibits apoptosis and oxidative stress of human LECs through ATM/p53 signaling pathway.

The quest for homeopathic and nonsurgical cataract treatment

PURPOSE OF REVIEW

Age-related cataract occurs when crystallin proteins in the lens partially unfold and subsequently aggregate. Physicians and traditional healers alike have been exploring pharmacologic cataract treatment for hundreds of years. Currently, surgery is the only effective treatment. However, there are an abundance of homeopathic and alternative remedies that have been suggested as treatment for cataract. This article reviews the current understanding of cataract development and discusses several homeopathic remedies purported to treat age-related cataract. Additionally, we will present an overview of evidence regarding the development of pharmacologic cataract reversal therapies.

RECENT FINDINGS

Some homeopathic therapies have been shown to prevent cataract development in experimental models. More studies are required to elucidate the potential medicinal and toxic properties of the various alternative therapies. However, in recent years, scientists have begun to investigate substances that address cataract by reversing lens protein aggregation. One such compound, lanosterol, was reported to reverse cataract opacity in vitro and in animal models. Subsequently, 25-hydroxycholesterol and rosmarinic acid were identified as having similar properties.

SUMMARY

Although challenges and uncertainties remain, further research has the potential to lead to the development of a nonsurgical therapeutic option for age-related cataract.

Effect of Moringa oleifera stem extract on hydrogen peroxide-induced opacity of cultured mouse lens

BACKGROUND

Moringa oleifera, also known as horseradish tree or drumstick tree, has strong antioxidant properties. In the present study, we investigated the potential effect of Moringa oleifera stem extract (MOSE) on cataract formation induced by oxidative stress in cultured mouse lenses.

METHODS

Mouse lenses cultured in vitro were pretreated with MOSE (0.5 and 1 mg/mL) for 24 h. Then, 1 mM hydrogen peroxide was added, and mouse lenses were cultured for a further 24 h. The medium was then changed to normal culture medium. After 48 h, lens opacification, reactive oxygen species (ROS) generation, reduced glutathione (GSH) content, and activities of superoxide dismutase (SOD) and catalase (CAT) were measured in lens tissues. In addition, the protein expression of peroxisome proliferator-activated receptor alpha (PPARα), a nuclear receptor with potential benefits to improve vision-threatening eye diseases, was assayed.

RESULTS

MOSE (1 mg/mL) alleviated lens opacification, reduced ROS generation, increased GSH content, and elevated SOD and CAT activities in cultured lenses. Moreover, MOSE upregulated the expressions of SOD, CAT, and PPARα.

CONCLUSIONS

This study showed that MOSE alleviates oxidative stress-induced cataract formation, and the mechanism of the effect is mainly related to its improvement of the endogenous antioxidant system in the lens.

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.

Luteolin improves myocardial cell glucolipid metabolism by inhibiting hypoxia inducible factor-1α expression in angiotensin II/hypoxia-induced hypertrophic H9c2 cells

Luteolin, a natural flavonoid, can attenuate hepatic lipid accumulation and insulin resistance in obese mice. Therefore, we hypothesized that luteolin may also improve the abnormal glucolipid metabolism of hypertrophic myocardial cells. This study aimed to investigate the effect and possible molecular mechanisms of luteolin. Hypertrophic H9c2 cells were induced by angiotensin II/hypoxia and simultaneously treated with 2 to 8 μg/mL luteolin for 24 h. Luteolin might dose-dependently decrease intracellular total protein, atrial natriuretic peptide, and free fatty acid levels, and increase supernatant glucose levels. Western blot assay showed that luteolin could inhibit the expressions of intracellular hypoxia inducible factor-1α (HIF-1α) and glucose transporter-4 (GLUT-4) proteins, and increase the expressions of intracellular peroxisome proliferator-activated receptor α (PPARα), carnitine palmitoyltransferase-1A (CPT-1A), and pyruvate dehydrogenase kinase-4 (PDK-4) proteins. These findings demonstrate that luteolin can improve abnormal glucolipid metabolism in angiotensin II/hypoxia-induced hypertrophic H9c2 cells, and its mechanisms are related to the inhibition of HIF-1α expression and subsequent modulation of PPARα-mediated target genes, including CPT-1A, PDK-4, and GLUT-4.

Plant-derived medicines for treatment of endometriosis: A comprehensive review of molecular mechanisms

Endometriosis is an estrogen-dependent disease with inflammatory lesions at extra-uterine sites, causing pelvic pain and fertility reduction. Conventional therapies primarily focus on reducing systemic levels of estrogens; however, they do not have desirable effectiveness and possess considerable side effects. Therefore, there is a growing interest in the use of herbal medicine for the treatment of endometriosis. In this paper, electronic databases including PubMed, Scopus, Cochrane library and Google Scholar were searched to obtain any studies evaluating any herbal products in the management of endometriosis. Data were collected from 1980 to 2018. Most of studies investigating the effect of herbal medicines in endometriosis were in vitro and animal and only three clinical trials were found; one on Pinus pinaster bark extract (Pycnogenol) and two on Chinese herbal formulas. The studies on phytochemicals had mostly focused on polyphenolic compounds (epigallocatechin-3-gallate, genistein) and sesquiterpenes (β-caryophyllene, parthenolide). Various molecular mechanisms of action have been involved in beneficial effects of herbal medicines and phytochemicals including anti-inflammatory (via reduction of proinflammatory cytokines such as interleukin -1, interleukin -6, interleukin -8, transforming growth factor-beta, tumor necrosis factor-α, nuclear factor-kappa B, growth factors, monocyte chemoattractant protein-1), antioxidant (through downregulation of hydrogen peroxide, malondialdehyde, reactive oxygen species and upregulation of superoxide dismutase), anti-proliferative and apoptotic (via enhancing Bcl-2-associated X protein/ B-cell lymphoma-2 and caspase3, 8 and 9 activity), anti-angiogenic (by downregulation of vascular endothelial growth factor receptors/ vascular endothelial growth factor), anti-invasive (via decreasing expression of intercellular adhesion molecule-1, vascular cell adhesion molecule-1 and matrix metalloproteinases), immunomodulatory, and estrogen modulating activities. So, medicinal plants seem to be a valuable source for identifying new drugs for treatment of endometriosis; however, since most of studies are preclinical, further clinical trials are required to achieve more conclusive results.

Cataract Preventive Role of Isolated Phytoconstituents: Findings from a Decade of Research

Cataract is an eye disease with clouding of the eye lens leading to disrupted vision, which often develops slowly and causes blurriness of the eyesight. Although the restoration of the vision in people with cataract is conducted through surgery, the costs and risks remain an issue. Botanical drugs have been evaluated for their potential efficacies in reducing cataract formation decades ago and major active phytoconstituents were isolated from the plant extracts. The aim of this review is to find effective phytoconstituents in cataract treatments in vitro, ex vivo, and in vivo. A literature search was synthesized from the databases of Pubmed, Science Direct, Google Scholar, Web of Science, and Scopus using different combinations of keywords. Selection of all manuscripts were based on inclusion and exclusion criteria together with analysis of publication year, plant species, isolated phytoconstituents, and evaluated cataract activities. Scientists have focused their attention not only for anti-cataract activity in vitro, but also in ex vivo and in vivo from the review of active phytoconstituents in medicinal plants. In our present review, we identified 58 active phytoconstituents with strong anti-cataract effects at in vitro and ex vivo with lack of in vivo studies. Considering the benefits of anti-cataract activities require critical evaluation, more in vivo and clinical trials need to be conducted to increase our understanding on the possible mechanisms of action and the therapeutic effects.

One Ion to Rule Them All: Combined Antibacterial, Osteoinductive and Anticancer Properties of Selenite-Incorporated Hydroxyapatite

Although hydroxyapatite (HAp) has been doped with dozens of different ions, the quest for an ion imparting a combination of properties conducive to bone healing is still ongoing. Because of its protean potency and the similarity in size and shape to the phosphate tetrahedron, selenite ion presents a natural ionic substitute in HAp. The incorporation of selenite into synthetic HAp using two different methods - co-precipitation and ion-exchange sorption - was studied for its effect on crystal properties and on a triad of biological responses: antibacterial, anticancer and osteoinductive. Co-precipitation yielded HAp with higher selenite contents than sorption and the stoichiometry of HAp richest in selenite was represented as Ca_9.75(PO₄)_5.75(SeO₃)_0.25(OH)_1.75. Crystallinity of HAp decreased in direct proportion with the amount of selenite incorporated. Because of their lower selenite content, HAp powders prepared by ion-exchange exhibited a consistently higher crystallinity compared to the co-precipitated ones. Annealing partially recovered the crystallinity, yet the difference in crystallinity between powders prepared by co-precipitation and by ion-exchange remained, suggesting that the amorphization is mainly due to structural incorporation of selenite, not its effect on the crystal growth kinetics. The addition of selenite changed the morphology of HAp nanoparticles from acicular to rounded and affected the crystal lattice parameters in different ways depending on whether the powders were annealed or not. As for the annealed powders, the incorporation of selenite contracted the lattice in both a and c crystallographic directions. In the agar diffusion assay, the effectiveness of HAp was more dependent on the presence or absence of selenite in it than on its concentration and was highest against E. coli and S. aureus, moderately high against S. enteritidis and ineffective against P. aeruginosa. In liquid inoculation tests, on the other hand, the antibacterial activity of HAp was directly proportional to the amount of selenite contained in it. The viability of K7M2 osteosarcoma cells decreased in direct proportion with the amount of selenite in HAp and was significantly different from the untreated control and from pure HAp at contents equal to or higher than 1.9 wt.%. In contrast, no reduction was observed in the viability of primary fibroblasts treated with HAp incorporating different amounts of selenite ions, suggesting their potentially selective anticancer activity: lethal for the cancer cells and harmless for the healthy cells. Finally, mRNA expression of bone gamma-carboxyglutamate protein (BGLAP3) was higher in differentiated MC3T3-E1 osteoblastic cells treated with selenite-incorporated HAp particles than in cells treated with pure HAp. The osteoinductive effect was due to an overall higher metabolic activity of cells treated with the particles and not due to increased proliferation. In such a way, a triad of antibacterial, osteoinductive and anticancer activities was attributed to selenite-incorporated HAp.

Luteolin ameliorates dextran sulfate sodium-induced colitis in mice possibly through activation of the Nrf2 signaling pathway

BACKGROUND

Luteolin has a reputation for being a safe and effective natural antioxidant that has strong radical scavenging and cell protective properties. The role of oxidative stress in inflammatory bowel disease (IBD) has been well established and is increasingly highlighted. Thus, we studied the protective effect of luteolin administration in a mouse model of experimental colitis.

METHODS

Experimental acute colitis was induced by administering 3% dextran sulfate sodium (DSS) in the drinking water of mice for 7days. The disease activity index (DAI); colon length; histological assessment; mRNA levels of nuclear factor-erythroid 2-related factor 2 (Nrf2), tumor necrosis factor (TNF-α), interleukin-6 (IL-6), heme oxygenase-1 (HO-1), and NADP(H): quinone oxidoreductase 1 (NQO-1); protein expression of Nrf2 and inducible nitric oxide synthase (iNOS); colon malondialdehyde (MDA) levels; and the activity levels of colonic superoxide dismutase (SOD) and catalase (CAT) were examined.

RESULTS

Luteolin (20 and 50mg/kg) significantly attenuated the DAI, colon shortening and histological damage. In addition, luteolin administration effectively decreased the expression of inflammatory mediators, such as iNOS, TNF-α and IL-6. Luteolin also decreased the colonic content of MDA. The activities of colonic SOD and CAT and the levels of Nrf2 and its downstream targets, HO-1 and NQO1, were elevated by luteolin treatment.

CONCLUSION

These observations indicate that luteolin may suppress experimental colitis through the Nrf2 signaling pathway.

Flavonoid intake and the risk of age-related cataract in China's Heilongjiang Province

Background/objectives

Epidemiological evidence suggests that diets rich in flavonoids may reduce the risk of developing age-related cataract (ARC). Flavonoids are widely distributed in foods of plant origin, and the objective of this study was to evaluate retrospectively the association between the intakes of the five flavonoid subclasses and the risk of ARC.

Subjects/methods

A population-based case-control study (249 cases and 66 controls) was carried out in Heilongjiang province, which is located in the northeast of China, and where intakes and availability of fresh vegetables and fruits can be limited. Dietary data gathered by food-frequency questionnaire (FFQ) were used to calculate flavonoid intake. Adjusted odds ratio (OR) and 95% confidence interval (CI) were estimated by logistic regression.

Results

No linear associations between risk of developing ARC and intakes of total dietary flavonoids, anthocyanidins, flavon-3-ol, flavanone, total flavones or total flavonols were found, but quercetin and isorhamnetin intake was inversely associated with ARC risk (OR 11.78, 95% CI: 1.62–85.84, p<0.05, and OR 6.99, 95% CI: 1.12–43.44, p<0.05, quartile 4 vs. quartile 1, respectively).

Conclusion

As quercetin is contained in many plant foods and isorhamnetin in very few foods, we concluded that higher quercetin intake may be an important dietary factor in the reduction of the risk of ARC.

Ocular delivery of cyanidin-3-glycoside in liposomes and its prevention of selenite-induced oxidative stress

CONTEXT

Cataracts have become the leading cause of blindness around the world, which is mainly mediated by oxidative stress.

OBJECTIVE

N-trimethyl chitosan (TMC)-coated liposomes of cyanidin-3-glycoside (C3G) (C3G-TCL) were prepared to attenuate oxidative stress induced by selenite sodium in rats.

MATERIALS AND METHODS

C3G-TCL were prepared by reverse-phase evaporation method and then coated with self-synthesized TMC. The physicochemical properties were determined. A gamma-scintigraphy study was employed to evaluate the precorneal elimination of the radioactive preparations. The transcorneal visualization for fluorescence-labeled samples was determined by confocal laser scanning microscopy (CLSM). The in vivo anti-oxidative study using C3G-TCL was carried out in rats with selenite-induced cataracts by topical administration.

RESULTS

The sphere-like morphological characterization of the vesicles was confirmed by TEM, with a size of 158.3 ± 2.8 nm and a zeta potential of 31.7 mV. The encapsulation efficiency was (53.7 ± 0.2) % as measured by ultrafiltration. C3G-TCL showed a 3.3-fold increment in precorneal residence time when compared with that of the (99m)Tc-solution. A TMC coating enhanced the transepithelial transport of liposomes to a depth of 40-μm in the cornea. Moreover, C3G-TCL could significantly elevate the activity of superoxide dismutase and catalase in lens and also show a considerable reversal of reduced glutathione activity. The lipid peroxidation in lens was strongly prevented when compared with that of groups treated with uncoated C3G-loaded liposomes.

DISCUSSION AND CONCLUSION

The coating material TMC for liposomes helps improve the anti-oxidative effect of C3G in vivo through prolonged residence time on the cornea and improved permeability in the corneal epithelium.