Beneficial effects of Aronia melanocarpa berry extract on hepatic insulin resistance in type 2 diabetes mellitus rats.

We aimed to investigate) the effects of Aronia melanocarpa berry extract (AMBE) on hepatic insulin resistance and its mechanism at the molecular level in high-fat diet (HFD)- and streptozotocin (STZ)-induced type 2 diabetes mellitus (T2DM) rats. The rats were supplemented with AMBE at doses of 100 and 400 mg/kg body weight (bw) daily for 8 weeks. AMBE significantly reduced blood glucose and serum insulin levels and the homeostatic model assessment for insulin resistance score; improved glucose tolerance; increased hepatic glycogen content; and regulated glucose metabolism enzyme activity, including glucokinase, pyruvate kinase, phosphoenolpyruvate carboxykinase, and glucose-6-phosphatase in the liver. AMBE also reduced lipid accumulation and oxidative stress along with inflammation in the hepatic tissue of T2DM rats and improved hepatic function. The phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway was activated by AMBE through the elevation of insulin receptor substrate-2, PI3K, Akt, and glycogen synthase kinase-3ß phosphorylation and glucose transporter 2, which might contribute to the promotion of glycogen synthesis and improvement of hepatic insulin resistance. AMBE shows promise as an ingredient of functional foods for alleviating hepatic insulin resistance in T2DM. PRACTICAL APPLICATION: The extract from the berries of Aronia melanocarpa (Michx.) Elliott (AMBE), with its relatively high content of polyphenolic compounds, has been shown to exert hypoglycemic effects in animal models of diabetes. Our findings support the use of A. melanocarpa as a functional food additive for the alleviation of hepatic insulin resistance and the management of glucose homeostasis in T2DM.

Pectin oligosaccharides from hawthorn (Crataegus pinnatifida Bunge. Var. major) inhibit the formation of advanced glycation end products in infant formula milk powder.

Pectin oligosaccharides (POSs) can not only be used as prebiotics to promote the growth of beneficial bacteria in the intestine but also can be used as natural food-borne antiglycation agents to inhibit the formation of advanced glycation end products (AGEs) in vitro, which is related to their structure, including molecular weight and galacturonic acid content. In this study, haw polysaccharides (HPSs) were isolated and purified, and POSs with high antiglycation activity in vitro were prepared. On this basis, the inhibitory effect of POSs on the formation of AGEs in infant formula milk powder was investigated. The results showed that no obvious inhibitory effect of POSs was found on the formation of AGEs in infant formula milk powder under accelerated storage at 25 °C and 45 °C. But, POSs showed a strong inhibitory effect on the formation of furosine, Nε-carboxymethyllysine (CML), Nε-carboxyethyllysine (CEL) and the total AGEs in infant formula milk powder under accelerated storage at 65 °C. In addition, POSs also had a strong inhibitory effect on the formation of lipid oxidation products but did not affect the formation of protein degradation products. Simultaneously, the cytotoxicity experiments using human umbilical vein endothelial cells showed that the infant formula milk powder supplemented with POSs had the lowest cytotoxicity compared to the blank control (BC) and GOS/FOS supplementation milk powder under accelerated storage at 65 °C, which may be related to the inhibitory effect of POSs on the formation of AGEs in infant formula milk powder. Furthermore, the in vitro fermentation experiments showed that the antiglycation process did not affect the prebiotic activity of POSs in infant formula milk powder.

Pectin oligosaccharides from fruit of Actinidia arguta: Structure-activity relationship of prebiotic and antiglycation potentials.

Pectin oligosaccharides (POSs) have prebiotic and antiglycation activities in vitro, but the specific structure-activity relationship is unclear. In this study, POSs were obtained by enzymatic and ultrasound-assisted enzymatic degradation of pectin polysaccharide (PPS), respectively. Based on the chemical characterization, the antiglycation in vitro and prebiotic activities of POSs were compared and the structure-activity relationship was studied. The results showed that the antiglycation activity of POSs in vitro was proportional to the galacturonic acid content and GalA:Rha molar ratios except for the low molecular weight POSs (LM-POSs), and inversely proportional to its branching degree, such as Ara:Rha and Gal:Rha molar ratios. In addition, it was also found that the prebiotic activity of POSs was positively correlated with Ara:Rha and Gal:Rha molar ratios in molecule composition and the neutral sugar content, especially galactose and arabinose. The degree of esterification (DE) was less important for both antiglycation and prebiotic activity of POSs. These results provided an important theoretical basis for POSs application in food.

Pectin oligosaccharides from hawthorn (Crataegus pinnatifida Bunge. Var. major): Molecular characterization and potential antiglycation activities.

The crude polysaccharide was extracted from hawthorn (Crataegus pinnatifida Bunge. Var. major) and a salt-eluted polysaccharide (SPS-2) was fractionated by DEAE cellulose-52 chromatography. Monosaccharide composition and Fourier-transform infrared (FT-IR) analysis indicated that the SPS-2 contained 72.3% galacturonic acid and may be pectin. The results of antiglycation activity in vitro showed that the medium molecular weight pectin oligosaccharide (MM-POS) had the highest antiglycation activity among SPS-2 degradation products. Moreover, the MM-POS obtained by enzymatic degradation had stronger antiglycation activity than that by ultrasonic assisted enzymatic degradation. Composition analysis of MM-POS obtained from ultrasound-assisted enzymatic degradation showed that polygalacturonans content decreased from 85.1% to 61.9% but the arabinan and rhamnogalacturonans increased from 10.6% to 22.7% and from 3.5% to 13.2%, respectively, compared to the MM-POS obtained from enzymatic degradation. This study will provide a theoretical basis for the application of POSs in the food field, especially the exploitation of antiglycation agents.

Chicory inulin ameliorates type 2 diabetes mellitus and suppresses JNK and MAPK pathways in vivo and in vitro.

SCOPE: Chicory inulin is a naturally occurring fructan that is conducive to glucose and lipid metabolism in patients with diabetes mellitus. This study aims to investigate the mechanism by which chicory inulin improves glucolipid metabolism in diabetic conditions. METHODS AND RESULTS: Rats were injected with streptozotocin and fed with high fat diet to induce diabetes, and then administrated with different doses of chicory inulin for 8 weeks. The glycometabolism and lipid metabolism parameters were determined, the activity of insulin receptor substrate (IRS) and mitogen-activated protein kinase (MAPK) pathways were examined by western blot. The effect of chicory inulin on glucose uptake of myoblast and hepatocyte were also measured in vitro. Data were analyzed by student's t-test or one-way analysis of variance followed by the Bonferroni post-hoc testing. The results showed that chicory inulin improved glucolipid metabolism, and it activated IRS but suppressed the MAPK pathways in vivo and in vitro. CONCLUSION: Our study demonstrates that chicory inulin, as a nutritional supplement, may be beneficial for the patients with type 2 diabetes mellitus, and the metabolism-modulatory effect seems to be related with the inhibition of JNK and P38 MAPK pathways.

Comparison of polyphenol, anthocyanin and antioxidant capacity in four varieties of Lonicera caerulea berry extracts.

Four varieties of Lonicera caerulea berries--'Wild', 'Beilei', 'No. 1', and 'No. 2'--were compared with respect to extraction yield, fruit weight, total soluble solids, polyphenol and anthocyanin contents, oxygen radical absorbance capacity (ORAC), and anthocyanin composition. Sixteen individual anthocyanins were identified in the selected varieties. Acylated anthocyanins, cyanidin 3-acetylhexoside and peonidin 3-acetylhexoside, were identified in L. caerulea berries for the first time. Cyanidin-3-glucoside was the most prominent anthocyanin in all four tested varieties. Wild type of L. caerulea fruit ('Wild'), with the highest polyphenol content, contained 14 anthocyanins and the highest ORAC value. Eleven anthocyanins were found in 'Beilei' berries, which had a higher ORAC value than 'No. 1' and 'No. 2'. The highest total soluble solid content and extraction yield were found in 'No. 2' and 'Wild' berries, respectively.