A High-Fructose Diet Formulated with Thermally Oxidized Monounsaturated Fat Aggravates Metabolic Dysregulation in Colon Epithelial Tissues of Rats

Effect of Natural Antioxidants from Marigolds (Tagetes erecta L.) on the Oxidative Stability of Soybean Oil

In recent years, synthetic antioxidants that are widely used in foods have been shown to cause detrimental health effects, and there has been growing interest in antioxidants realised from natural plant extracts. In this study, we investigate the potential effects of natural antioxidant components extracted from the forage plant marigold on the oxidative stability of soybean oil. First, HPLC-Q-TOF-MS/MS was used with 1,1-diphenyl-2-picrylhydrazyl (DPPH) to screen and identify potential antioxidant components in marigold. Four main antioxidant components were identified, including quercetagetin-7-O-glucoside (1), quercetagetin (2), quercetin (3) and patuletin (4). Among them, quercetagetin (QG) exhibited the highest content and the strongest DPPH radical scavenging activity and effectively inhibited the production of oxidation products in soybean oil during accelerated oxidation, as indicated by reductions in the peroxide value (PV) and acid value (AV). Then, the fatty acids and volatile compounds of soybean oil were determined with gas chromatography–mass spectrometry (GC-MS) and headspace solid-phase microextraction–gas chromatography–mass spectrometry (HS-SPME-GC-MS). A total of 108 volatile components, including 16 alcohols, 23 aldehydes, 25 ketones, 4 acids, 15 esters, 18 hydrocarbons, and 7 other compounds, were identified. QG significantly reduced the content and number of aldehydes and ketones, whereas the formation of acids and hydrocarbons was completely prevented. In addition, the fatty acid analysis demonstrated that QG significantly inhibited oxidation of unsaturated fatty acids. Consequently, QG was identified as a potential, new natural antioxidant that is believed to be safe, effective and economical, and it may have potential for use in plant extracts feed additives.

Protective Effect of Borassus flabellifer Haustorium Extract against Alkoxyl Radical-Induced Cytotoxicity by Improving Glutathione Metabolism by Modulating Nrf2/Haeme Oxygenase-1 Expression

AIM

The study was aimed to assess the ability of Borassus flabellifer haustorium methanolic extract (BHE) on de novo glutathione biosynthesis in normal and pro-oxidant exposed cells via Nuclear factor erythroid 2-related factor 2 (Nrf2) and haeme oxygenase-1 (HO1) signaling in 2,2'-Azobis(2-methylpropionamidine) di-hydrochloride (AAPH) induced cytotoxicity in normal intestinal epithelial cells (IEC-6 cells).

METHODS

The in vitro antioxidant activity was determined in terms of radical scavenging and ex vivo hemolysis. The cytoprotective effect was studied using AAP H as the alkoxyl radical inducer in IEC-6 cell model. The mechanistic basis of protection is determined by Nrf2/HO1 expression using qPCR.

RESULTS

In vitro screening observed DPPH, hydrogen peroxide and ABTS radical scavenging activity for the BHE; further, BHE also protected the oxidative hemolysis in the erythrocytes induced by AAPH. In IEC-6 cells, AAPH treatment significantly reduced the cell viability (p < 0.001) by inducing lipid peroxidation. Further, there observed a significant reduction in the activities of enzymes involved in the de novo glutathione biosynthesis (p < 0.01) and glutathione reductase in these cells. However, pretreatment with BHE (10, 25 and 50 µg/mL) dose-dependently protected from the cytotoxicity of AAPH-derived alkoxyl radicals (p < 0.05); besides, the de novo glutathione biosynthesis and regeneration of GSH from oxidized form was also increased in these cells. In corroboration with the biochemical parameters, the Nrf2/HO1 expression was upregulated by the BHE pretreatment concomitantly reducing the cellular lipid peroxidation products. The improvement glutathione biosynthesis was also observed in BHE alone treated cells.

CONCLUSION

The study indicated the potential of methanolic extract of Borassus flabellifer haustorium in enhancing the de novo glutathione biosynthesis in normal and pro-oxidant exposed cells by Nrf2/HO1 dependent manner, concomitantly mitigating the toxicity of AAPH-derived alkoxyl radicals in intestinal epithelial cells.

The Glucose-Lowering Effects of Coconut Oil: A Case Report and Review of the Literature

Background

Coconut oil, a saturated fat comprised mostly of the medium-chain fatty acid, lauric acid, has become increasingly popular over the past few decades due to its touted anti-inflammatory, metabolic, and lipid-lowering properties. There have been many studies with mixed results evaluating the effects of coconut oil consumption on lipid metabolism and cardiometabolic risk. However, the effects on glucose metabolism are less clear. There are few trials on the effects of coconut oil on glucose homeostasis but no case reports prior to the current one.

Case

We present a case of a 66-year-old man with a history of type 2 diabetes managed with insulin who developed recurrent hypoglycemia and required reduction in insulin therapy quickly after consuming coconut oil supplementation.

Conclusion

This is the first known case report of coconut oil supplementation in a diabetic patient on insulin resulting in hypoglycemia. Review of the literature shows that coconut oil supplementation can have a favorable effect on glycemic control, possibly through phenolic compounds mediating anti-inflammatory effects. This effect is inconsistent throughout the studies reviewed, likely due to variations in types of coconut oil supplementation and scarcity of trials. Further research is required both in animal models and in humans before coconut oil intake is widely advised and popularized. This is especially true in patients with diabetes, who are at increased risk of cardiovascular disease, and in whom reduction in saturated fat intake is advised.