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-3β 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.Keywords: Aronia melanocarpa berry, hepatic insulin resistance, PI3K/Akt signaling pathway, type 2 diabetes mellitus 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.
We
investigated the cytoprotective effects of anthocyanins in Aronia melanocarpa against apoptosis induced by Aβ1–42, a key mediator of AD pathophysiology. We measured
intracellular calcium with a colorimetric kit, cellular apoptosis
with DAPI, intracellular ROS with the fluorescent marker 2,3-dimethoxy-1,4-naphthoquinone,
mitochondrial membrane potential with JC-1, and ATP with a colorimetric
kit. Gene transcription and protein expression levels of calmodulin,
cytochrome c, caspase-9, cleaved caspase-3, Bcl-2,
and Bax were analyzed by RT-PCR and Western blotting. The results
showed that pretreatment with anthocyanins significantly inhibited
Aβ1–42-induced apoptosis, decreased intracellular
calcium and ROS, and increased ATP and mitochondrial membrane potential.
RT-PCR and Western blotting revealed that anthocyanins upregulated
the gene transcription and protein expression of calmodulin and Bcl-2
and downregulated those of cytochrome c, caspase-9,
cleaved caspase-3, and Bax. A. melanocarpa anthocyanins
protected SH-SY5Y cells against Aβ1–42-induced
apoptosis by regulating Ca2+ homeostasis and apoptosis-related
genes and inhibiting mitochondrial dysfunction.
BACKGROUND: Free fractions of different blackberry varieties' extracts are high in phenolic compounds with antioxidant activities. However, the phenolic profiles and antioxidant activities against peroxyl radicals of bound fractions of different blackberry varieties' extracts have not been previously reported. In addition, what the key antioxidant phenolic compounds are in free and bound fractions of blackberry extracts remain unknown. This study aimed to investigate the phenolic profiles and antioxidant activities of free and bound fractions of eight blackberry varieties' extracts and reveal the key antioxidant phenolic compounds by boosted regression trees. RESULTS: Fifteen phenolics (three anthocyanins, four flavonols, three phenolic acids, two proanthocyanidins, and three ellagitannins) were identified in blackberry by ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry. Ferulic acid, ellagic acid, procyanidin C1, kaempferol-O-hexoside, ellagitannins hex, and gallic acid were major bound phenolics. Bound fractions of eight blackberry varieties' extracts were high in phenolics and showed great antioxidant activity. Boosted regression trees analysis showed that cyanidin-3-O-glucoside and chlorogenic acid were the most significant compounds, contributing 48.4% and 15.9% respectively to the antioxidant activity of free fraction. Ferulic acid was the most significant antioxidant compound in bound fraction, with a contribution of 61.5%. Principal component analysis showed that Kiowa was the best among the eight varieties due to its phenolic profile and antioxidant activity.CONCLUSION: It was concluded that blackberry varieties contained high amounts of bound phenolics, which confer health benefits through reducing oxidative stress. Ferulic acid was the key compound to explain the antioxidant activities of bound fractions.
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