Antioxidant Activity and In Vitro Antiglycation of the Fruit of Spondias purpurea

Spondias purpurea L. Bark Extract Protects against Oxidative Stress and Reduces Hypercholesterolemia in Mice Fed High-Fat Diet

Oxidative stress plays a key role in the initiation and progression of metabolic diseases, including obesity. Preventing the accumulation of reactive oxygen species and oxidative damage to macromolecules is a beneficial strategy for reducing comorbidities associated with obesity. Fruits from the Spondias genus are known for their antioxidant activity, but they are not available year-round due to their seasonality. In this context, we investigated the antioxidant activity and identified the chemical constituents of the aqueous extract of the stem bark of Spondias purpurea L. (EBSp). Additionally, we evaluated the effect of EBSp consumption on metabolic parameters in mice with obesity induced by a high-fat diet. Chemical analyses revealed 19 annotated compounds from EBSp, including flavan-3-ols, proanthocyanidins, methoxylated coumarin, and gallic and ellagic acids, besides other phenolic compounds. In vitro, EBSp showed antioxidant activity through the scavenging of the free radicals and the protection of macromolecules against oxidative damage. Cellular assays revealed that EBSp reduced the levels of malondialdehyde produced by erythrocytes exposed to the oxidizing agent AAPH. Flow cytometry studies showed that EBSp reduced reactive oxygen species levels in human peripheral blood mononuclear cells treated with hydrogen peroxide. Obese mice treated with EBSp (400 mg.kg-1) for 60 days showed reduced levels of malondialdehyde in the heart, liver, kidneys, and nervous system. The total cholesterol levels in mice treated with EBSp reached levels similar to those after treatment with the drug simvastatin. Together, the results show that the combination of the different phenolic compounds in S. purpurea L. bark promotes antioxidant effects in vitro and in vivo, resulting in cytoprotection in the context of oxidative stress associated with obesity and a reduction in hypercholesterolemia. From a clinical perspective, the reduction in oxidative stress in obese individuals contributes to the reduction in the emergence of comorbidities associated with this metabolic syndrome.

Indole-linked 1,2,3-triazole derivatives efficiently modulate COX-2 protein and PGE2 levels in human THP-1 monocytes by suppressing AGE-ROS-NF-kβ nexus

AIMS

AGEs augment inflammatory responses by activating inflammatory cascade in monocytes, and hence lead to vascular dysfunction. The current study aims to study a plausible role and mechanism of a new library of indole-tethered 1,2,3-triazoles 2-13 in AGEs-induced inflammation.

MATERIAL AND METHODS

Initially, the analogs 2-13 were synthesized by cycloaddition reaction between prop-2-yn-1-yl-2-(1H-indol-3-yl) acetate (1) and azidoacetophenone (1a). In vitro glycation, and metabolic assays were employed to investigate antiglycation and cytotoxicity activities of new indole-triazoles. DCFH-DA, immunostaining, Western blotting, and ELISA techniques were used to study the reactive oxygen species (ROS), and pro-inflammatory mediators levels.

KEY FINDINGS

Among all the synthesized indole-triazoles, compounds 1-3, and 9-13, and their precursor molecule 1 were found to be active against AGEs production in in vitro glucose- and methylglyoxal (MGO)-BSA models. Compounds 1-2, and 11-13 were also found to be nontoxic against HEPG2, and THP-1 cells. Our results show that pretreatment of THP-1 monocytes with selected lead compounds 1-2, and 11-13, particularly compounds 12, and 13, reduced glucose- and MGO-derived AGEs-mediated ROS production (P < 0.001), as compared to standards, PDTC, rutin, and quercetin. They also significantly (P < 0.001) suppressed NF-ĸB translocation in THP-1 monocytes. Moreover, compounds 12, and 13 attenuated the AGEs-induced COX-2 protein levels (P < 0.001), and PGE₂ production (P < 0.001) in THP-1 monocytes.

SIGNIFICANCE

Our data revealed that the indole-triazoles 12, and 13 can significantly attenuate the AGEs-induced proinflammatory COX-2 levels, and associated PGE₂ production by suppressing AGE-ROS-NF-Kβ nexus in THP-1 monocytes. These compounds can thus serve as leads for further evaluation as treatment to delay early onset of diabetic complications.

Anti-glycation activities of methyl gallate in vitro and in human explants

BACKGROUND

The build-up of advanced glycation end products (AGEs) is one of important factor of skin aging. Natural compounds with anti-glycation activities might have great anti-aging potential.

AIMS

The objective of this study was to evaluate an anti-glycation effects of methyl gallate as a potent ingredient for anti-aging.

METHODS

We first evaluated the AGEs inhibitory ability of methyl gallate in BSA/glucose system. Levels of Nε-CML and carbonyl contents were also measured in BSA/glucose system. To further investigate if methyl gallate could prevent glycation in full-thickness human skin explants. Glycation action was determined by the observation of the general morphology of dermis and epidermis structures and FBN-1 and of CML immunostaining. In an in-vivo study, primary irritation test was also performed to ensure the safety of methyl gallate for human skin.

RESULTS

It is known that methyl gallate can suppress glycation reaction between BSA and glucose. Methyl gallate also has a remarkable potential to reduce the oxidation of proteins. Furthermore, the anti-glycation activity of methyl gallate has been confirmed in a human skin ex-vivo model. Methyl gallate decreased the expression of CML but stimulated the expression of FBN-1 compared with MGO treatment. In an in-vivo study, methyl gallate (0.1%) did not cause any skin irritation, suggesting that methyl gallate could be used as an active ingredient in cosmetics.

CONCLUSION

Our results showed that methyl gallate could protect against glucose-mediated glycation in vitro. Furthermore, methyl gallate significantly prevented glycation in living human skin explants. Due to these beneficial effects, methyl gallate can be used to prevent or manage AGE-mediated skin aging.

Evaluation of the Antidiabetic and Antihyperlipidemic Activity of Spondias purpurea Seeds in a Diabetic Zebrafish Model

Diabetes mellitus (DM) is a serious chronic degenerative disease characterized by high levels of glucose in the blood. It is associated with an absolute or relative deficiency in the production and/or action of insulin. Some of the complications associated with DM are heart disease, retinopathy, kidney disease, and neuropathy; therefore, new natural alternatives are being sought to control the disease. In this work, we evaluate the antidiabetic effect of Spondias purpurea seed methanol extract (CSM) in vitro and in a glucose-induced diabetic zebrafish model. CSM is capable of lowering blood glucose and cholesterol levels, as well as forming advanced glycation end-products, while not presenting toxic effects at the concentrations evaluated. These data show that CSM has a promising antidiabetic effect and may be useful in reducing some of the pathologies associated with diabetes mellitus.

Glycation and Antioxidants: Hand in the Glove of Antiglycation and Natural Antioxidants

The non-enzymatic interaction of sugar and protein resulting in the formation of advanced glycation end products responsible for cell signaling alterations ultimately leads to the human chronic disorders such as diabetes mellitus, cardiovascular diseases, cancer, etc. Studies suggest that AGEs upon interaction with receptors for advanced glycation end products (RAGE) result in the production of pro-inflammatory molecules and free radicals that exert altered gene expression effect. To date, many studies unveiled the potent role of synthetic and natural agents in inhibiting the glycation reaction at a lesser or greater extent. This review focuses on the hazards of glycation reaction and its inhibition by natural antioxidants, including polyphenols.

Antidiabetic Activity of Aloe vera Leaves

This research evaluated the potential of using the methanol extract of Aloe vera (L.) Burm.f (AVM) to prevent the formation of AGEs by means of the BSA/glucose assay, BSA-methylglyoxal assay, arginine-methylglyoxal assay, fructosamine, Nɛ-(carboxymethyl) lysine (CML), thiol groups, and carbonyl protein in vitro. The effect of AVM was also evaluated with regard to inhibiting the enzymes α-amylase, α-glucosidase, and pancreatic lipase. For this, the plant was dried, ground, and subsequently macerated with methanol. Aloe vera methanol extract (AVM) significantly decreased the formation of AGEs, as well as the formation of fructosamine, CML, and carbonyl protein. The concentration of 5 mg/ml of AVM presented the best results. AVM significantly inhibited the α-amylase and α-glucosidase enzymes. As regards the content of thiol groups, a significant increase was observed during the four weeks of the experiment. So, we can conclude that Aloe vera methanol extract decreases the formation of AGEs and may inhibit the increase in postprandial glucose, suggesting that AVM can prevent diabetes complications associated with AGE.

Heuchera Creme Brulee and Mahogany Medicinal Value under Water Stress and Oligosaccharide (COS) Treatment

Food borne pathogens cause serious human illnesses and diseases and their control using natural bioactive compounds becomes essential for the progress of agricultural and food industries. Developing novel tools to enhance the medicinal values of traditional horticultural medicinal crops is one of the promising methods for achieving food borne pathogens control. In this study, oligosaccharide water solutions were applied to Heuchera Creme Brulee and Mahogany subjected to a normal irrigation interval (2 days) or to prolonged irrigation intervals (6 days) for 6 weeks. Plant morphological, physiological, and metabolic markers associated with the bioactivity of leaf extracts against selected microbes. Oligosaccharide-treated plants showed significant increases in all morphological parameters during normal and prolonged irrigation intervals as compared to those of the controls. Morphological improvement associated with a significant increase in chlorophyll, carbohydrates, proline, K, Ca, phenols, and free and total ascorbate and antioxidants. Superoxide dismutase, catalase, and ascorbate peroxidase activities were higher, while H₂O₂ accumulated to a lower extent in oligosaccharide-treated plants. These morphological and metabolic changes associated with increased antibacterial and antifungal activities of leaf extracts and their activities were comparable to antibiotics and antifungal agents (minimum inhibitory concentrations values were 0.5 -0.20 mg⁻¹mL for bacteria and 0.08 -0.20 mg⁻¹mL for fungi in Mahogany). The application of oligosaccharide and/or water stress might be of great value for producing natural bioactive compounds for food borne pathogens control.