Protective Effect of β-Glucogallin on Damaged Cataract Against Methylglyoxal Induced Oxidative Stress in Cultured Lens Epithelial Cells

Comprehensive Phytochemical Profile of Leaves, Stems and Fruits from Orthopterygium huaucui (A. Gray) Hemsl. and their Antioxidant Activities

Orthopterygium huaucui, commonly known as "Pate", is a medicinal shrub belonging to the Anacardiaceae family used locally to treat burns and stomach pains. Endemic to Peru, chemical studies on O. huaucui are limited. In this study, Ultra-High Performance Liquid Chromatography Quadrupole/Orbitrap Electrospray Ionization Tandem Mass Spectrometry (UHPLC Q/Orbitrap/ESI/MS/MS) was used to identify secondary metabolites in leaves, stems and fruits, and the antioxidant capacities of the different parts were compared. In addition, several compounds such as methyl gallate, gallic acid, kaempferol, quercetin, and quercetin 3-O-β-glucuronide were successfully isolated from the methanolic extract of the leaves of this species for the first time. Untargeted UHPLC Q/Orbitrap/ESI/MS/MS analysis tentatively identified seventy-six compounds in the different parts of the plant, showing that this species as an interesting source of flavonoids, procyanidins and tannins. The phenolic content in leaves and stems was 334.31±4.34 and 295.18±6.38 gallic acid equivalents/100 g dry plant, respectively, while that of fruits was lower (99.92±5.45 mg/100 g). Leaves had twice the flavonoid content than fruits (210.38±3.85 versus 87.42±3.85 quercetin equivalents/100 g). 2,2-Diphenyl-1-picrylhydrazyl (DPPH) results indicated high antioxidant activity in all parts, with stems and leaves showing IC50 of 12.8 μg/mL, and fruits showing less activity (IC50=38.6 μg/mL). The Oxygen Radical Absorbance Capacity (ORAC) test showed higher antioxidant values in the stems (467.82±21.17 μmol Trolox equivalents/100 g). This study provides valuable information on the chemistry of O. huaucui and highlights its antioxidant potential, especially in leaves and stems.

Recent advances in the potential of Phyllanthus emblica L. and its related foods for combating metabolic diseases through methylglyoxal trapping

Methylglyoxal (MG) serves as the primary precursor for the nonenzymatic glycation of proteins and DNA, leading to advanced glycation end products (AGEs). Regular intake of dietary MG is strongly correlated with low-grade inflammation, potentially accelerating the pathogenesis of metabolic diseases, including obesity, diabetes, cancers, liver diseases, Alzheimer's disease, cardiovascular diseases, aging, and bone loss. Although pharmaceutical agents (pimagedine and candesartan) have been developed to inhibit MG formation, they often come with serious side effects (nausea, diarrhea, headache, gastrointestinal disturbance, symptomatic hypotension, abnormal renal and liver function tests, development of antinuclear antibody, pernicious-like anemia, and hyperkalemia), highlighting the need for an efficient and safe approach to scavenging MG. Phyllanthus emblica Linn fruit, a nutritious edible fruit, and medicinal plant contains over 300 bioactive compounds. Among twenty-three herbals, 100 μg/mL of the aqueous extract of Phyllanthus emblica fruit (APF) exhibits the highest potency in trapping MG, achieving an 87.3 % reduction under d-fructose induced BSA-AGEs formation. However, there are few reports detailing APF and its related foods' specific impact on disease prevention through MG trapping. This review summarizes the mechanisms through which MG is linked to the development of metabolic diseases and provides several strategies for reducing MG levels using APF and its bioactive compounds. The potential antiglycation properties of APF may offer new applications in the food industry and pharmacological research.

High sucrose intake exacerbates airway inflammation through pathogenic Th2 and Th17 response in ovalbumin (OVA)-induced acute allergic asthma in C57BL/6 mice

Asthma is an inflammatory disease characterized by chronic inflammation in lung tissues and excessive mucus production. High-fat diets have long been assumed to be a potential risk factor for asthma. However, to date, very few direct evidence indicating the involvement of high sucrose intake (HSI) in asthma progression exists. In this study, we investigate the effect of HSI on ovalbumin (OVA)-sensitized allergic asthma mice. We observed that HSI increased the expression of inflammatory genes (IL-1β, IL-6, TNF-α) in adipose tissues and led to reactive oxygen species generation in the liver and lung. In addition, HSI accelerated the TLR4/NF-κB signaling pathway leading to MMP9 activation, which promotes the chemokines and TGF-β secretion in the lungs of OVA-sensitized allergic asthma mice. More importantly, HSI significantly promoted the pathogenic Th2 and Th17 responses. The increase of IL-17A secretion by HSI increased the expression of chemokines (MCP-1, CXCL1, CXCL5, CXCL8). It resulted in eosinophil and mast cell infiltration in the lung and trachea. We also demonstrated that HSI increased mucus hypersecretion, which was validated by increased main mucin protein (MUC5AC) secreted in the lungs. Our findings suggest that HSI exacerbates the development of Th2/Th17-predominant asthma by upregulating the TLR4-mediated NF-κB pathway, leading to excessive MMP9 production.

Cataractogenesis and molecular pathways, with reactive free oxygen species as a common pathway

Slowing down or stopping the natural process of cataractogenesis is certainly a challenge for those who today propose an option other than surgery. Addressing the same problem in different ways constitutes a new approach to solving what is today the number one cause of reversible blindness worldwide. The technological revolution, as well as the advances in the biological sciences, allows us to conceive mechanisms never thought of before to stop the process that, as a common pathway, constitutes opacification of the crystalline lens. A new dawn for cataracts is coming through molecular, newly-discovered mechanisms. Cataractogenesis and molecular pathways have reactive free oxygen species as a common pathway. Surgical removal is today's gold standard, but perhaps not for much longer.

Astragalin attenuates diabetic cataracts via inhibiting aldose reductase activity in rats

AIM

To investigate the aldose reductase (AR) inhibition capacity of astragalin (AST) against streptozoticin-induced diabetic cataracts (DCs) in rats.

METHODS

Ex vivo investigations were conducted by treating the lens of a goat placed for 72h in artificial aqueous humor (AAH) of pH 7.8 at room temperature with cataract-causing substance (55 mmol/L of galactose) and in vivo studies were performed on rats via induction with streptozotocin. AST was administered at different dose levels and scrutinize for DC activity.

RESULTS

In diabetic rats, AST improved the body weight, blood insulin, and glucose as well as the levels of galactitol in a dose-dependent way, other biochemical parameters i.e. inflammatory mediators and cytokines, and also suppress AR activity. The level of the antioxidant parameters such as superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) activity were also altered on a diabetic lens after the administration of the AST.

CONCLUSION

AST protects against lens opacification to avoid cataracts and polyols formation, indicating that it could be used as a potential therapeutic agent for diabetes.

Alu antisense RNA ameliorates methylglyoxal-induced human lens epithelial cell apoptosis by enhancing antioxidant defense

AIM

To determine whether an antisense RNA corresponding to the human Alu transposable element (Aluas RNA) can protect human lens epithelial cells (HLECs) from methylglyoxal-induced apoptosis.

METHODS

Cell counting kit-8 (CCK-8) and 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays were used to assess HLEC viability. HLEC viability/death was detected using a Calcein-AM/PI double staining kit; the annexin V-FITC method was used to detect HLEC apoptosis. The cytosolic reactive oxygen species (ROS) levels in HLECs were determined using a reactive species assay kit. The levels of malondialdehyde (MDA) and the antioxidant activities of total-superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-Px) were assessed in HLECs using their respective kits. RT-qPCR and Western blotting were used to measure mRNA and protein expression levels of the genes.

RESULTS

Aluas RNA rescued methylglyoxal-induced apoptosis in HLECs and ameliorated both the methylglyoxal-induced decrease in Bcl-2 mRNA and the methylglyoxal-induced increase in Bax mRNA. In addition, Aluas RNA inhibited the methylglyoxal-induced increase in Alu sense RNA expression. Aluas RNA inhibited the production of ROS induced by methylglyoxal, restored T-SOD and GSH-Px activity, and moderated the increase in MDA content after treatment with methylglyoxal. Aluas RNA significantly restored the methylglyoxal-induced down-regulation of Nrf2 gene and antioxidant defense genes, including glutathione peroxidase, heme oxygenase 1, γ-glutamylcysteine synthetase and quinone oxidoreductase 1. Aluas RNA ameliorated methylglyoxal-induced increases of the mRNA and protein expression of Keap1 that is the negative regulator of Nrf2.

CONCLUSION

Aluas RNA reduces apoptosis induced by methylglyoxal by enhancing antioxidant defense.

Effect of the main constituents of Pistacia lentiscus leaves against the DPPH radical and xanthine oxidase: experimental and theoretical study

The aim of this work is to study the content of phenolic compounds in P lentiscus leaves and their antioxidant effect. After extracting the phenolic compounds, fractionation by liquid/liquid partition with increasing polarity gives five extracts. Three of them (ButF, AqF and ButA) were found to have good antioxidant activity. Their IC_50s for the inhibition of the free radical formation of DPPH are 1.76 µg/mL, 1.307 µg/ml, and 1.77 µg/mL, respectively. These values are very interesting, considering the effect of the powerful flavonoid quercetin, whose IC₅₀ against DPPH is 1.53 µg/mL. These extracts are also active against xanthine oxidase (XO). The IC_50s measured are 0.14 mg/mL, 0.186 mg/mL and 0.33 mg/mL for ButF, Aq F and ButAq F extract respectively, in comparison with allopurinol (0.44 mg/mL). A phytochemical analysis by LC/ESI-MS-MS was performed to explain the observed activities. The results show 22 peaks representing: flavanols, namely catechin, d-Gallocatechin, and gallocatechin gallate. The only flavone detected in the studied extracts was luteolin glucuronide and was found to be in higher amounts in butanolic extract (2,71mg/mL). The phenolic acids and derivatives were also identified in the extracts. A theoretical study was performed to deduce the specificity of the binding between the major compounds identified in the P. lentiscus extract and the xanthine oxidase enzyme using Schrödinger software. The docking procedure was validated using the extraction of ligands from the binding site. Their re-anchoring to the xanthine oxidase structure using quercetin and allopurinol was considered reference molecules. After docking, post-docking minimization was performed to achieve the best scoring poses with the MM-GBSA approach. The dGBind energy of MM-GBSA representing the binding energy of the receptor and the ligand was calculated based on molecular mechanics. Results reveal that β-Glucogallin compounds such as Digalloylquinic acid, Gallocatechin, and Myricetin-3-O rhamnoside are more active than allopurinol, with stronger Docking score (Gscore) and MM-GBSA dGBind.Communicated by Ramaswamy H. Sarma.

Novel Emblica officinalis extract containing β-glucogallin vs. metformin: a randomized, open-label, comparative efficacy study in newly diagnosed type 2 diabetes mellitus patients with dyslipidemia

The efficacy of Emblica officinalis extract (EOE) containing 10% β-glucogallin was compared against metformin in newly diagnosed subjects with diabetic dyslipidemia which is a significant factor in cardiovascular disease. Daily administration with EOE-1 g, EOE-2 g, or metformin 500 mg for 90 days significantly decreased fasting blood sugar and postprandial blood sugar (FBS and PPBS), hemoglobin A1c (HbA1c) and lipid levels in all three treatment groups. The FBS, PPBS and HbA1c were significantly lower in the EOE-2 g group compared with metformin and EOE-1 g groups. The reductions in LDL and TC in the EOE-2 g group were also significantly higher than in the EOE-1 g group and were comparable to the metformin group. No serious adverse effects were observed in any study participants. EOE-1 g and 2 g day^-1 are safe and potent antidiabetic agents, with comparable efficacy to the pharmaceutical drug, metformin. Supplementation with EOE-2 g day^-1 showed greater efficacy than metformin in reducing circulating glucose levels.

Antiglaucoma Potential of β-Glucogallin Is Mediated by Modulating Mitochondrial Responses in Experimentally Induced Glaucoma

BACKGROUND

The use of phytochemicals for the treatment of various bodily ailments has been in practice since ancient days. Even though in practice, scientific studies on the protective effect of β-glucogallin (BG) against glaucoma is limited.

OBJECTIVES

In the present study, the in vitro glaucoma model (hydrostatic pressure) using PC12 neuronal cells exposed to BG were used to elucidate its protective effects.

METHOD

The cultured cells were analyzed for the mitochondrial responses, oxidant-antioxidant status, and expression of caveolin-1, ANGPTL7, the glaucoma markers, and cytokines.

RESULTS

We demonstrated a significant increase in the expression of glial fibrillary acidic protein, ANGPTL7, with altered mitochondrial enzymes in glaucoma cells compared to the control. Moreover, cells predisposed to hydrostatic pressure demonstrated an increase in oxidative stress with augmented (p < 0.01) inflammatory cytokines such as IL-2, CXCR4, IL-6, IL-8, MCP-1, and TNF-α. On the other hand, cells pretreated with BG attenuated the reactive oxygen species levels with improved antioxidant enzymes. Simultaneously, the levels of inflammatory cytokines and ANGPTL7 proteins were found attenuated with restored mitochondrial responses in BG pretreated cells.

CONCLUSION

Thus, the results of the present study demonstrate that the use of BG on retinal cells against relieving the intraocular pressure may be a promising therapeutic for controlling the disease progression.