Natural antioxidant biomolecules promises future nanomedicine based therapy for cataract

Flavonoids with lipase inhibitory activity from lemon squeezing waste: isolation, multispectroscopic and in silico studies

BACKGROUND

Obesity is recognized as a lifestyle-related disease and the main risk factor for a series of pathological conditions, including cardiovascular diseases, hypertension and type 2 diabetes. Citrus limon is an important medicinal plant, and its fruits are rich in flavonoids investigated for their potential in managing obesity. In the present work, a green extraction applied to lemon squeezing waste (LSW) was optimized to recover pancreatic lipase (PL) inhibitors.

RESULTS

The microwave-assisted procedure yielded an extract with higher lipase inhibitory activity than those obtained by maceration and ultrasound. The main compounds present in the extract were identified by high-performance liquid chromatographic-mass spectrometric analysis, and hesperidin, eriocitrin and 4'-methyllucenin II were isolated. The three compounds were evaluated for in vitro PL inhibitory activity, and 4'-methyllucenin II resulted in the most promising inhibitor (IC50 = 12.1 μmol L-1; Ki = 62.2 μmol L-1). Multispectroscopic approaches suggested the three flavonoids act as competitive inhibitors and the binding studies indicated a greater interaction between PL and 4'-methyllucenin II. Docking analysis indicated the significant interactions of the three flavonoids with the PL catalytic site.

CONCLUSION

The present work highlights flavonoid glycosides as promising PL inhibitors and proposes LSW as a safe ingredient for the preparation of food supplements for managing obesity. © 2024 Society of Chemical Industry.

Natural Product Isolation of the Extract of Cleome rupicola Fruits Exhibiting Antioxidant Activity

Cataracts are the leading cause of blindness worldwide, however, there is currently no drug-based treatment. Plants that exhibit antioxidant properties have shown promising anticataract effects, likely because they supplement the activity of glutathione, the major antioxidant in lens cells. An extract of Cleome rupicola, a desert plant found in the United Arab Emirates, has traditionally been used to treat cataracts. Phytochemical screening of the aqueous extract established the presence of flavonoids, tannins, steroid derivatives, and reducing sugars. Fractioning of extracts from the fruits using high-performance liquid chromatography (HPLC) yielded the isolation of the anthelmintic compound cleomin, and its structure was confirmed using mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy.

Novel Role of Molecular Hydrogen: The End of Ophthalmic Diseases?

Molecular hydrogen (H2) is a colorless, odorless, and tasteless gas which displays non-toxic features at high concentrations. H2 can alleviate oxidative damage, reduce inflammatory reactions and inhibit apoptosis cascades, thereby inducing protective and repairing effects on cells. H2 can be transported into the body in the form of H2 gas, hydrogen-rich water (HRW), hydrogen-rich saline (HRS) or H2 produced by intestinal bacteria. Accumulating evidence suggest that H2 is protective against multiple ophthalmic diseases, including cataracts, dry eye disease, diabetic retinopathy (DR) and other fields. In particular, H2 has been tested in the treatment of dry eye disease and corneal endothelial injury in clinical practice. This medical gas has brought hope to patients suffering from blindness. Although H2 has demonstrated promising therapeutic potentials and broad application prospects, further large-scale studies involving more patients are still needed to determine its optimal application mode and dosage. In this paper, we have reviewed the basic characteristics of H2, and its therapeutic effects in ophthalmic diseases. We also focus on the latest progress in the administration approaches and mechanisms underlying these benefits.

New Insights into the Phytochemical Profile and Biological Properties of Lycium intricatum Bois. (Solanaceae)

This work aimed to boost the valorisation of Lycium intricatum Boiss. L. as a source of high added value bioproducts. For that purpose, leaves and root ethanol extracts and fractions (chloroform, ethyl acetate, n-butanol, and water) were prepared and evaluated for radical scavenging activity (RSA) on 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals, ferric reducing antioxidant power (FRAP), and metal chelating potential against copper and iron ions. Extracts were also appraised for in vitro inhibition of enzymes implicated on the onset of neurological diseases (acetylcholinesterase: AChE and butyrylcholinesterase: BuChE), type-2 diabetes mellitus (T2DM, α-glucosidase), obesity/acne (lipase), and skin hyperpigmentation/food oxidation (tyrosinase). The total content of phenolics (TPC), flavonoids (TFC), and hydrolysable tannins (THTC) was evaluated by colorimetric methods, while the phenolic profile was determined by high-performance liquid chromatography, coupled to a diode-array ultraviolet detector (HPLC-UV-DAD). Extracts had significant RSA and FRAP, and moderate copper chelation, but no iron chelating capacity. Samples had a higher activity towards α-glucosidase and tyrosinase, especially those from roots, a low capacity to inhibit AChE, and no activity towards BuChE and lipase. The ethyl acetate fraction of roots had the highest TPC and THTC, whereas the ethyl acetate fraction of leaves had the highest flavonoid levels. Gallic, gentisic, ferulic, and trans-cinnamic acids were identified in both organs. The results suggest that L. intricatum is a promising source of bioactive compounds with food, pharmaceutical, and biomedical applications.

New Mesoporous Silica Materials Loaded with Polyphenols: Caffeic Acid, Ferulic Acid and p-Coumaric Acid as Dietary Supplements for Oral Administration

In this study, two types of mesoporous silica with different pore structures and volumes were synthesized by the soft-templating method. The two types of mesoporous silica, type MCM-41 and MCM-48, were loaded with three polyphenols-caffeic acid, p-coumaric acid and trans-ferulic acid-in the same ratio of mesoporous silica:polyphenol (1:0.4 w/w). The materials obtained were characterized from a morphological and structural point of view through different analysis techniques. Through X-ray diffraction (XRD), the crystallization plane and the ordered structure of the mesoporous silica were observed. The difference between the two types of materials containing MCM-41 and MCM-48 was observed through the different morphologies of the silica particles through scanning electron microscopy (SEM) and also through the Brunauer-Emmet-Teller (BET) analysis, that the surface areas and volumes of pores was different between the two types of mesoporous silica, and, after loading with polyphenols, the values were reduced. The characteristic bands of silica and of polyphenols were easily observed by Fourier-transform infrared spectroscopy (FTIR), and, through thermogravimetric analysis (TGA), the residual mass was determined and the estimated amount of polyphenol in the materials and the efficient loading of mesoporous silica with polyphenols could be determined. The in vitro study was performed in two types of simulated biological fluids with different pH-simulated gastric fluid (SGF) and simulated intestinal fluid (SIF). The obtained materials could be used in various biomedical applications as systems with controlled release of natural polyphenols and the most suitable application could be as food supplements especially when a mixture of such materials is used or when the polyphenols are co-loaded within the mesoporous silica.

Feasibility assessment of the Eye Scan Ultrasound System for cataract characterization and optimal phacoemulsification energy estimation: protocol for a pilot, nonblinded and monocentre study

Background

Cataracts are lens opacifications that are responsible for more than half of blindness cases worldwide, and the only treatment is surgical intervention. Phacoemulsification surgery, the most frequently performed cataract surgery in developed countries, has associated risks, some of which are related to excessive phacoemulsification energy levels and times. The protocol proposed in herein will be used to evaluate the feasibility of a new experimental medical device, the Eye Scan Ultrasound System (ESUS), for the automatic classification of cataract type and severity and quantitative estimation of the optimal phacoemulsification energy.

Methods

The pilot study protocol will be used to evaluate the feasibility and safety of the ESUS in clinical practice. The study will be conducted in subjects with age-related cataracts and on healthy subjects as controls. The procedures include data acquisition with the experimental ESUS, classification based on the Lens Opacity Classification System III (LOCS III, comparator) using a slit lamp, contrast sensitivity test, optical coherence tomography, specular microscopy and surgical parameters.

ESUS works in A-scan pulse-echo mode, with a central frequency of 20 MHz. From the collected signals, acoustic parameters will be extracted and used for automatic cataract characterization and optimal phacoemulsification energy estimation.

The study includes two phases. The data collected in the first phase (40 patients, 2 eyes per patient) will be used to train the ESUS algorithms, while the data collected in the second phase (10 patients, 2 eyes per patient) will be used to assess the classification performance. System safety will be monitored during the study.

Discussion

The present pilot study protocol will evaluate the feasibility and safety of the ESUS for use in clinical practice, and the results will support a larger clinical study for the efficacy assessment of the ESUS as a diagnostic tool. Ultimately, the ESUS is expected to represent a valuable tool for surgical planning by reducing complications associated with excessive levels of phacoemulsification energy and surgical times, which will have a positive impact on healthcare systems and society. The study is not yet recruiting.

Trial registration

ClinicalTrials.gov identifier NCT04461912, registered on July 8, 2020.

Glycation-induced age-related illnesses, antiglycation and drug delivery strategies

OBJECTIVES

Ageing is a major cause of multiple age-related diseases. Several mechanisms have been reported to contribute to these abnormalities including glycation, oxidative stress, the polyol pathway and osmotic stress. Glycation, unlike glycosylation, is an irregular biochemical reaction to the formation of active advanced glycation end-products (AGEs), which are considered to be one of the causes of these chronic diseases. This study provides a recent and comprehensive review on the possible causes, mechanisms, types, analytical techniques, diseases and treatments of the toxic glycation end products.

KEY FINDINGS

Several mechanisms have been found to play a role in generating hyperglycaemia-induced oxidative stress including an increase in the levels of reactive oxygen species (ROS), increase in the levels of AGEs, binding of AGEs and their receptors (RAGE) and the polyol pathway and thus have been investigated as promising novel targets.

SUMMARY

This review focuses on the key mechanisms attributed to cumulative increases of glycation and pathological RAGE expression as a significant cause of multiple age-related diseases, and reporting on different aspects of antiglycation therapy as a novel approach to managing/treating age-related diseases. Additionally, historical, current and possible future antiglycation approaches will be presented focussing on novel drug delivery methods.

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.

The Pathomechanism, Antioxidant Biomarkers, and Treatment of Oxidative Stress-Related Eye Diseases

Oxidative stress is an important pathomechanism found in numerous ocular degenerative diseases. To provide a better understanding of the mechanism and treatment of oxidant/antioxidant imbalance-induced ocular diseases, this article summarizes and provides updates on the relevant research. We review the oxidative damage (e.g., lipid peroxidation, DNA lesions, autophagy, and apoptosis) that occurs in different areas of the eye (e.g., cornea, anterior chamber, lens, retina, and optic nerve). We then introduce the antioxidant mechanisms present in the eye, as well as the ocular diseases that occur as a result of antioxidant imbalances (e.g., keratoconus, cataracts, age-related macular degeneration, and glaucoma), the relevant antioxidant biomarkers, and the potential of predictive diagnostics. Finally, we discuss natural antioxidant therapies for oxidative stress-related ocular diseases.

Protective Effects of Nicotinamide Riboside on H2O2-induced Oxidative Damage in Lens Epithelial Cells

Purpose: To investigate the protective effects of nicotinamide riboside (NR) on oxidative damage in hydrogen peroxide (H₂O₂)-exposed human lens epithelial cell lines (SRA01/04) and the possible mechanisms underlying its protective effects.Materials and methods: SRA01/04 cells were divided into three groups: the control (CON) group, model (H₂O₂) group and treatment (NR+H₂O₂) group. Superoxide dismutase (SOD), catalase (CAT) and total glutathione (GSH) levels were detected to evaluate oxidative damage induced by different concentrations of H₂O₂ in SRA01/04 cells. After SRA01/04 cells were treated with NR and/or H₂O₂, cell viability was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and Hoechst staining, cell apoptosis was analysed using flow cytometry, reactive oxygen species (ROS) were measured with the DCFH-DA probe, and mitochondria were stained with MitoTracker to measure the mitochondrial membrane potential (MMP). In addition, western blotting was performed to detect the levels of proteins associated with apoptosis and related signalling pathways.Results: H₂O₂ induced oxidative damage in SRA01/04 cells by inhibiting the activity of SOD and CAT and reducing total GSH levels. Treatment of SRA01/04 cells with NR significantly increased cell viability and reduced cell apoptosis and ROS generation, whereas SOD and CAT activities and total GSH and MMP levels were improved by the NR treatment in an H₂O₂-exposed cell model. Furthermore, NR significantly inhibited the activation of the MAPK pathway but promoted activation of the JAK2/Stat3 pathway compared with the model group.Conclusions: NR may alleviate oxidative damage by targeting the MAPK and JAK2/Stat3 pathways in H₂O₂-treated SRA01/04 cells. NR may represent anovel drug for preventing or treating cataracts.

Ginsenosides induce extensive changes in gene expression and inhibit oxidative stress-induced apoptosis in human lens epithelial cells

Background

The effect of ginsenosides on the growth and apoptosis of human lens epithelial (HLE) B3 cells exposed to H₂O₂ was investigated. In addition, the effect of ginsenosides on gene expression in HLE-B3 cells was analyzed using microarray assays to determine its molecular mechanism.

Methods

HLE-B3 cells were treated with 1.75 M H₂O₂ in the presence or absence of 5, 10 or 20 μM ginsenosides. Cell viability and apoptosis were examined by MTT assays and flow cytometry, respectively, at 24 to 120 h after the treatment. Furthermore, HLE-B3 cells were treated with 20 μM ginsenosides for 8 days and total RNA was isolated and analyzed using the Affymetrix GeneChip Array. Principal component analysis was performed to visualize the microarray data.

Results

Addition of ginsenosides significantly alleviated the growth inhibitory effect of H₂O₂ on HLE-B3 cells and the percentage of viable cells was increased by more than 3 folds. Flow cytometric analysis showed that 6.16 ± 0.29% of H₂O₂-treated HLE-B3 cells were early apoptotic cells, and the percentage was reduced to 4.78 ± 0.16% (P < 0.05) in the presence of 20 μM ginsenosides. Principal component analysis revealed that ginsenoside caused extensive changes in gene expression in HLE-B3 cells. A total of 6219 genes showed significant differential expression in HLE-B3 cells treated with ginsenoside; among them, 2552 (41.0%) genes were significantly upregulated, whereas 3667 (59.0%) genes were significantly downregulated. FOXN2, APP and RAD23B were the top three upregulated genes while WSB1, PSME4 and DCAF7 were the top three downregulated genes in HLE-B3 cells treated with ginsenosides.

Conclusion

Ginsenosides induce extensive changes in the expression of genes involved in multiple signaling pathways, including apoptotic signaling pathway and DNA damage response signaling pathway. Ginsenosides alleviate H₂O₂-induced suppression of the growth of HLB cells and inhibit H₂O₂-induced apoptosis of HLB cells.

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.

Rosmarinic and Sinapic Acids May Increase the Content of Reduced Glutathione in the Lenses of Estrogen-Deficient Rats

Oxidative stress is believed to be associated with both postmenopausal disorders and cataract development. Previously, we have demonstrated that rosmarinic and sinapic acids, which are diet-derived antioxidative phenolic acids, counteracted some disorders induced by estrogen deficiency. Other studies have shown that some phenolic acids may reduce cataract development in various animal models. However, there is no data on the effect of phenolic acids on oxidative stress markers in the lenses of estrogen-deficient rats. The study aimed to investigate whether administration of rosmarinic acid and sinapic acid affects the antioxidative abilities and oxidative damage parameters in the lenses of estrogen-deficient rats. The study was conducted on three-month-old female Wistar rats. The ovariectomized rats were orally treated with rosmarinic acid at doses of 10 and 50 mg/kg or sinapic acid at doses of 5 and 25 mg/kg, for 4 weeks. The content of reduced glutathione (GSH), oxidized glutathione and amyloid β1-42, as well as products of protein and lipid oxidation, were assessed. Moreover, the activities of superoxide dismutase, catalase, and some glutathione-related enzymes in the lenses were determined. Rosmarinic and sinapic acids in both doses resulted in an increase in the GSH content and glutathione reductase activity. They also improved parameters connected with protein oxidation. Since GSH plays an important role in maintaining the lens transparency, the increase in GSH content in lenses after the use of rosmarinic and sinapic acids seems to be beneficial. Therefore, both the investigated dietary compounds may be helpful in preventing cataract.

Therapeutic Properties of Stingless Bee Honey in Comparison with European Bee Honey

Both honeybees (Apis spp.) and stingless bees (Trigona spp.) produce honeys with high nutritional and therapeutics value. Until recently, the information regarding potential health benefits of stingless bee honey (SBH) in medical databases is still scarce as compared to the common European bee honey (EBH) which is well known for their properties as therapeutic agents. Although there have been very few reports on SBH, empirically these products would have similar therapeutic quality as the EBH. In addition, due to the structure of the nest, few studies reported that the antimicrobial activity of SBH is a little bit stronger than EBH. Therefore, the composition of both the types of honey as well as the traditional uses and clinical applications were compared. The results of various studies on EBH and SBH from tissue culture research to randomised control clinical trials were collated in this review. Interestingly, there are many therapeutic properties that are unique to SBH. Therefore, SBH has a great potential to be developed for modern medicinal uses.

An approach to revolutionize cataract treatment by enhancing drug probing through intraocular cell line

The purpose of this study is to prepare and characterize solid lipid nanoparticles (SLN) of N-Acetyl Carnosine (NAC) to treat cataract since surgery necessitates equipments and professional help. Cataract is believed to be formed by the biochemical approach where the crystalline eye proteins lose solubility and forms high molecular weight masses. Added advantages of SLN of NAC (henceforth referred as SLN-NAC) in the study are reduced size, sustained release and better corneal penetration of drug. The method of preparation of SLN-NAC by Mill’s method is unique in itself.

The size of the SLN-NAC was 75 ± 10 nm in the range of ideal for penetration. The in-vitro release study and the SLN-NAC formulations prepared with Mill’s method demonstrated sustained release up to 24 h following an initial burst after 1 h. The zeta potential of the prepared formulation was −22.1 ± 1 mV. Corneal permeation studies using goat corneas indicate that SLN-NAC penetration rate was higher than those from NAC eye drops. Corneal hydration studies indicated that the formulation caused no harm to the corneal cells.

Therefore it may be concluded that SLN-NAC may revolutionize cataract treatment and reversal by improving drug permeation, reducing toxicity and no damage to corneal tissue.

Drug delivery to the lens for the management of cataracts

Cataracts are one of the most prevalent diseases of the lens, affecting its transparency and are the leading cause of reversible blindness in the world. The clarity of the lens is essential for its normal physiological function of refracting light onto the retina. Currently there is no pharmaceutical treatment for prevention or cure of cataracts and surgery to replace the affected lens remains the gold standard in the management of cataracts. Pharmacological treatment for prevention of cataracts is hindered by many physiological barriers that must be overcome by a therapeutic agent to reach the avascular lens. Various therapeutic agents and formulation strategies are currently being investigated to prevent cataract formation as access to surgery is limited. This review provides a summary of recent research in the field of drug delivery to the lens for the management of cataracts including models used to study cataract treatments and discusses the future perspectives in the field.

Switching to instant black coffee modulates sodium selenite-induced cataract in rats

The influence of daily consumption of some common beverages on the development of cataract in rats was investigated. Total phenol content was determined in the beverages and an oral standardized dose of total phenols from each beverage was given to the treated rats. Weaned male albino rats were used and divided into five groups (n=7). Rats were fed Ain 93G and administered the standardized dose of instant coffee, black tea and hibiscus beverages for 30 days. On day 14 all rats were injected with a single dose of sodium selenite (Na₂SeO₃) 15 µmol/kg bodyweight, except the control groups NC (negative control, did not receive Na₂SeO₃) and PC (positive control, was already injected on day 1 of the study). The rats were continued on Ain 93G and the standardized dose for another 16 days. Positive control rats were used. Total phenols were 210, 40, and 44 mg/g dry weight gallic acid equivalent in black coffee, black tea, and hibiscus, respectively. Decreased levels (statistically significant P<0.05) of malondialdehyde, total nitric oxide, Ca-ATPase, tumor necrosis factor-α, interleukin-1β, superoxide dismutase, and conversely, increased levels (statistically significant P<0.05) of total protein, reduced glutathione, catalase were found in the lenses of the coffee group compared to PC. There are co-phenol substances in the instant black coffee that promoted coffee to be the most effective beverage.

Featured Article: Inhibition of diabetic cataract by glucose tolerance factor extracted from yeast

Diabetes leads to many complications; among them is the development of cataract. Hyperglycemia brings to increased polyol concentration in the lens, to glycation of lens proteins, and to elevated level of ROS (Reactive Oxygen Species) causing oxidative stress. The glucose tolerance factor (GTF) was found by several groups to decrease hyperglycemia and oxidative stress both in diabetic animals and humans. The aim of our study was to explore the damages induced by high glucose to the eye lens and to assess the protective effects of GTF both in vivo and in vitro The in vivo study included control healthy rats, streptozotocin (STZ) diabetic untreated rats, and STZ diabetic rats orally treated with 15 doses of GTF. The diabetic untreated rats developed cataracts, whereas the development of cataract was totally or partially prevented in GTF treated animals. In vitro studies were done on bovine lenses incubated for 14 days. Half of the lenses were incubated in normal glucose conditions, and half in high glucose conditions (450 mg%). To one group of the normal or high glucose condition GTF was added. The optical quality of all the lenses was measured daily by an automated scanning laser system. The control lenses, whether with or without GTF addition, did not show any reduction in their quality. High glucose conditions induced optical damage to the lenses. Addition of GTF to high glucose conditions prevented this damage. High glucose conditions affected the activity of aldose reductase and sodium potassium ATPase in lens epithelial cell. Addition of GTF decreased the destructive changes induced by high glucose conditions. The amount of soluble cortical lens proteins was decreased and structural changes were detected in lenses incubated in high glucose medium. These changes could be prevented when GTF was added to high glucose medium. Our findings demonstrate the anticataractogenic potential of GTF.

Anthraquinones and flavonoids of Cassia tora leaves ameliorate sodium selenite induced cataractogenesis in neonatal rats

The present study was undertaken to evaluate the efficacy ofCassia toraleaves, an edible plant traditionally used for eye ailments, in preventing experimental cataractogenesis.

Nanotechnology for the Prevention and Treatment of Cataract

PURPOSE

The purpose of this article was to review recent advances in the applications of nanotechnology in cataract treatment and prevention strategies.

DESIGN

A literature review on the use of nanotechnology for the prevention and treatment of cataract was done.

METHODS

Research articles about nanotechnology-based treatments and prevention technologies for cataract were searched on Web of Science, and the most recent advances were reported.

RESULTS

Nonsteroid anti-inflammatory drugs, natural antioxidants, biologic and chemical chaperones, and chaperones such as molecules have found great application in preventing and treating cataracts. Current scientific research on new treatment strategies, which focuses on the biochemical basis of the disease, will likely result in new anticataract agents. However, none of the drug formulations will be approved for use unless efficient delivery is promised. Nanoparticle engineering together with biomimetic strategies enable the development of next-generation, more efficient, less complex, and personalized treatments.

CONCLUSIONS

The only currently available treatment for cataracts, surgical replacement of the opacified lens, is not an easily accessible option in developing countries. New treatment strategies based on topical drugs would enable treatment to reach massive populations facing the threat of blindness and more effectively deal with the postsurgical complications. Nanotechnology plays a key role in improving drug delivery systems with enhanced controlled release, targeted delivery, and bioavailability to overcome diffusion limitations in the eye.

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.

Age-related cataract and drug therapy: opportunities and challenges for topical antioxidant delivery to the lens

Objectives

The search for anticataract drugs has been continuing for decades; some treatments no longer exist but antioxidants are still of much interest.

Key findings

The primary function of the human lens, along with the cornea, is to refract light so that it is correctly focused onto the retina for optimum image quality. With age, the human lens undergoes morphological, biochemical and physical changes leading to opacification. Age-related or senile cataract is one of the main causes of visual impairment in the elderly; given the lack of access to surgical treatment in many parts of the world, cataract remains a major cause of sight loss. Surgical treatment is the only means of treating cataract; this approach, however, has limitations and complications.

Summary

This review discusses the anatomy and physiology of the lens and the changes that are understood to occur with ageing and cataract formation to identify potential areas for effective therapeutic intervention. Experimental techniques and agents used to induce cataract in animal models, the advantages and disadvantages of potential pharmacological treatments specific barriers to delivery of exogenous antioxidants to the lens and the prospects for future research are discussed.

Parmotrema tinctorum exhibits antioxidant, antiglycation and inhibitory activities against aldose reductase and carbohydrate digestive enzymes: an in vitro study

This study evaluated the inhibitory potential of ethyl acetate extract of Parmotrema tinctorum (PTEE), an edible lichen, against aldose reductase (AR) and carbohydrate digestive enzymes such as α-glucosidase and α-amylase. It was also screened for antioxidant activities by using DPPH, ABTS, superoxide and hydroxyl radical-scavenging assays. PTEE exhibited α-glucosidase, α-amylase and AR inhibition along with significant antiglycation potential with an estimated IC50 value of 58.45 ± 1.24, 587.74 ± 3.27, 139.28 ± 2.6 and 285.78 ± 1.287 μg/mL, respectively. Antioxidant activity of PTEE against DPPH (IC50 396.83 ± 2.98 μg/mL), ABTS (151.34 ± 1.79 μg/mL), superoxide (30.29 ± 1.17 μg/mL) and hydroxyl (35.42 ± 1.22 μg/mL) radicals suggests the antioxidant potential of P. tinctorum. Significant antioxidant activity and inhibitory potential against carbohydrate digestive enzymes and AR suggest that P. tinctorum can be developed as functional food/nutraceuticals for diabetes after detailed study.

Membrane composition and dynamics: a target of bioactive virgin olive oil constituents

The endogenous synthesis of lipids, which requires suitable dietary raw materials, is critical for the formation of membrane bilayers. In eukaryotic cells, phospholipids are the predominant membrane lipids and consist of hydrophobic acyl chains attached to a hydrophilic head group. The relative balance between saturated, monounsaturated, and polyunsaturated acyl chains is required for the organization and normal function of membranes. Virgin olive oil is the richest natural dietary source of the monounsaturated lipid oleic acid and is one of the key components of the healthy Mediterranean diet. Virgin olive oil also contains a unique constellation of many other lipophilic and amphipathic constituents whose health benefits are still being discovered. The focus of this review is the latest evidence regarding the impact of oleic acid and the minor constituents of virgin olive oil on the arrangement and behavior of lipid bilayers. We highlight the relevance of these interactions to the potential use of virgin olive oil in preserving the functional properties of membranes to maintain health and in modulating membrane functions that can be altered in several pathologies. This article is part of a Special Issue entitled: Membrane Structure and Function: Relevance in the Cell's Physiology, Pathology and Therapy.