The hypoglycaemic effects of two Ribes sp. i.e., anthocyanin-rich black currants (BC) were compared to green currants (GC), which are low in anthocyanins to establish which compounds are involved in the regulation of postprandial glycaemia. We determined the effect of the currants on inhibiting carbohydrate digestive enzymes (α-amylase, α-glucosidase), intestinal sugar absorption and transport across CaCo-2 cells. The digestion of these currants was modelled using in vitro gastrointestinal digestion (IVGD) to identify the metabolites present in the digested extracts by LC–MS/MS. Freeze-dried BC and IVDG extracts inhibited yeast α-glucosidase activity (P<.0001) at lower concentrations than acarbose, whereas GC and IVDG GC at the same concentrations showed no inhibition. BC and GC both showed significant inhibitory effects on salivary α-amylase (P<.0001), glucose uptake (P<.0001) and the mRNA expression of sugar transporters (P<.0001). Taken together this suggests that the anthocyanins which are high in BC have their greatest effect on postprandial hyperglycaemia by inhibiting α-glucosidase activity. Phytochemical analysis identified the phenolics in the currants and confirmed that freeze-dried BC contained higher concentrations of anthocyanins compared to GC (39.80 vs. 9.85 g/kg dry weight). Specific phenolics were also shown to inhibit salivary α-amylase, α-glucosidase, and glucose uptake. However, specific anthocyanins identified in BC which were low in GC were shown to inhibit α-glucosidase. In conclusion the anthocyanins in BC appear to regulate postprandial hyperglycaemia primarily but not solely by inhibiting α-glucosidase while other phenolics modulate salivary α-amylase, glucose uptake and sugar transporters which together could lower the associated risk of developing type-2 diabetes.

两个Ribes sp的降血糖作用。即，将花青素含量高的黑加仑子（BC）与花青素含量低的绿加仑（GC）进行比较，以确定哪些化合物参与了餐后血糖的调节。我们确定了葡萄干对抑制碳水化合物消化酶（α-淀粉酶，α-葡萄糖苷酶），肠糖吸收和跨CaCo-2细胞转运的作用。使用体外胃肠道消化（IVGD）对这些黑醋栗的消化进行建模，以通过LC-MS / MS鉴定消化提取物中存在的代谢产物。冷冻干燥的BC和IVDG提取物抑制酵母α-葡萄糖苷酶活性（P浓度小于阿卡波糖的浓度（<.0001），而相同浓度的GC和IVDG GC则无抑制作用。BC和GC均对唾液α-淀粉酶（P <.0001），葡萄糖摄取（P <.0001）和糖转运蛋白的mRNA表达（P<.0001）。综上所述，这表明BC含量高的花色苷通过抑制α-葡糖苷酶活性而对餐后高血糖症具有最大的作用。植物化学分析确定了黑醋栗中的酚类成分，并证实与GC相比，冻干的BC包含更高浓度的花色素苷（39.80对9.85 g / kg干重）。还显示出特定的酚类物质可抑制唾液α-淀粉酶，α-葡萄糖苷酶和葡萄糖摄取。但是，在BC中鉴定出的GC中含量较低的特定花色苷可以抑制α-葡萄糖苷酶。总之，不列颠哥伦比亚省的花色苷似乎主要是通过调节α-葡萄糖苷酶来调节餐后高血糖，而其他酚类药物则可以调节唾液中的α-淀粉酶，