Oral Administration of Apple Procyanidins Ameliorates Insulin Resistance via Suppression of Pro-Inflammatory Cytokine Expression in Liver of Diabetic ob/ob Mice

Abstract

Procyanidins, the main ingredient of apple polyphenols, are known to possess antioxidative and anti-inflammatory effects associated closely with the pathophysiology of insulin resistance and type 2 diabetes. We investigated the effects of orally administered apple procyanidins (APCs) on glucose metabolism using diabetic ob/ob mice. We found no difference in body weight or body composition between mice treated with APCs and untreated mice. A 4 week oral administration of APCs containing water [0.5% (w/v)] ameliorated glucose tolerance, insulin resistance, and hepatic gluconeogenesis in ob/ob mice. APCs also suppressed the increase in the level of the pancreatic β-cell. Insulin-stimulated Akt phosphorylation was significantly enhanced; pro-inflammatory cytokine expression levels were significantly decreased, and c-Jun N-terminal kinase phosphorylation was downregulated in the liver of those mice treated with APCs. In conclusion, APCs ameliorate insulin resistance by improving hepatic insulin signaling through suppression of hepatic inflammation in ob/ob mice, which may be a mechanism with possible beneficial health effects of APCs in disturbed glucose metabolism.

Vanillin Alleviates High Fat Diet-Induced Obesity and Improves the Gut Microbiota Composition

“…However, weight loss can restore the unbalanced GM ( Liu et al, 2017 ). Numerous animal studies demonstrate that PPs can treat obesity and improve the resultant metabolic syndromes in HFD-induced and (ob/ob) obese mice, including hyperglycemia, insulin resistance (IR), and inflammation, as well as restore the GM balance ( Axling et al, 2012 ; Roopchand et al, 2015 ; Ogura et al, 2016 ). However, crowd tests showed inconsistent results: many studies employing fruit juices/extracts (which contain abundant PPs) found that they can alleviate hyperglycemia and IR in people suffering from T2DM, ( Chiva-Blanch et al, 2012 ; Saez-Lopez et al, 2017 ) while other studies found no significant effect ( Botden et al, 2012 ; Woerdeman et al, 2018 ).…”

Wild blueberry proanthocyanidins shape distinct gut microbiota profile and influence glucose homeostasis and intestinal phenotypes in high-fat high-sucrose fed mice

“…which PACs regulate metabolic health, ranging from immunomodulatory signaling, stimulation of glucose and lipid metabolism, dampening of metabolic endotoxemia, as well as through inhibition of digestives enzymes [7][8][9] . However, since high molecular weight PACs are poorly absorbed in the small intestine 10 , they reach the large intestine where they interact with the gut microbiota and exert prebiotic-like effects 11 .…”

A Review of the Science of Colorful, Plant-Based Food and Practical Strategies for “Eating the Rainbow”

“…Vitamin C (ascorbic acid) is well known for its effects on the immune system, and in states of increased inflammation, vitamin C levels tend to decrease in the body [52]. Several studies in cell, animals, and humans have suggested that red-colored foods and/or their isolated constituents [53] may assist with reducing systemic inflammation and bolstering immune status by reducing infections, including watermelon [54], apples [55][56][57][58][59][60][61], cherries [61][62][63], cranberries [57,64,65] pomegranate [66][67][68][69][70], and raspberries [71][72][73].…”