###### Abstract
In diabetes, oxidative stress leads to the development and progression of micro and macrovascular complications [11]. High free radical production and a disabled antioxidant defence system promote an oxidant/antioxidant imbalance that can  
Figure 1: Beneficial effects of phenolic compounds on managing blood glucose in diabetes. The hypoglycemic effects of phenolic compounds are mainly attributed to reducing intestinal absorption of dietary carbohydrates, modulation of the enzymes involved in glucose metabolism, improvement of \(\beta\)-cell function and insulin action, and stimulation of insulin secretion (Adapted from [11,12]). lead to long-term diabetic complications [13]. The inhibition of intracellular free radical formation provides a therapeutic strategy to prevent oxidative stress, and such pathological conditions [13]. Phenolic compounds inhibit ROS production by inactivating their producing enzymes. Examples are xanthine oxidase, cyclooxygenase, lipoxygenase, microsomal monooxygenase, glutathione-S-transferase, mitochondrial succinoxidase, and NADH oxidase [14]. On the other hand, some phenolic compounds such as green tea catechins decrease lipid peroxidation and increase plasma total antioxidant capacity [15], being their long-term administration advantageous against lipid and glucose metabolism disorders implicated in type II diabetes and minimising the risk of cardiovascular diseases [11; 15]. In addition, studies have shown that phenolic compounds attenuate postprandial blood glucose response, making phenolic compounds promising compounds to tackle type II diabetes [16]. The hypoglycemic effects of phenolic compounds are mainly due to a reduction in the intestinal absorption of dietary carbohydrates, modulating the activity of enzymes involved in the glucose metabolism and improving the \(\alpha\)-cell function and insulin action, stimulating insulin secretion, and the antioxidative and anti-inflammatory properties of these components [11]. Indeed, anthocyanins have been proven to act in carbohydrate metabolism as inhibitors of \(\alpha\)-glucosidase and \(\alpha\)-amylases activity, key enzymes for the digestion of dietary carbohydrates to glucose [17]. They can also inhibit enzymes that reduce blood glucose levels after starch-rich meals, making anthocyanins potential compounds for controlling type II diabetes [17; 18]. Some studies have shown that compounds such as resveratrol can also regulate postprandial glycemia and avoid the development of glucose intolerance by improving the secretion of the glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like polypeptide-1 (GLP-1), potentially used as antidiabetic agents [19]. Moreover, phenolic compounds may also affect peripheral glucose uptake. For example, quercetin, resveratrol, and epigallocatechin gallate (EGCG), one of the most abundant catechins in green tea, have been shown to improve insulin-dependent glucose uptake in muscle cells and adipocytes by translocation of glucose transporter, GLUT4 to the plasma membrane, induced by the AMP-activated protein kinase (AMPK) pathway [20]. Studies support that the disruption of gut microbiota equilibrium (dysbiosis) can be caused by age, diet, lack of exercise, stress, and drug consumption, associated with gastrointestinal and extra-intestinal cardiometabolic diseases, such as obesity and diabetes [21]. Furthermore, there is evidence that phenolic compounds can induce modulation of gene expression and the gut microbiota balance, which might have a protective effect on the gastrointestinal system [22]. More precisely, they can modulate the gut microbiota composition and function, impacting gut metabolism and immunity and fulfilling anti-inflammatory properties [21]. Growing evidence supports the involvement of gut microbiota dysbiosis in obesity and diabetes, and how dietary polyphenols have the ability to modulate the gut microbiota composition and function and interfere with metabolic pathways, bacterial quorum sensing, membrane permeability, and others [21; 23].