紫甘薯花青素体外抑制α-糖苷酶活性研究

为了研究紫甘薯花青素体外对α-糖苷酶活性的影响，采用HPLC和LC-MSn对紫A19(ZA1)和京薯(JS6)中花青素的含量和组分进行对比分析。结果表明：两种紫甘薯花青素含量分别为52.44mg/g和39.46mg/g，其组分基本一致，不同的是ZA1另含牵牛花色素类色素，而JS6另含天竺葵色素类色素；这两种紫甘薯花青素对α-糖苷酶活性都有抑制效果，但ZA1的抑制效果最佳，当加入质量浓度为0.1mg/mL 600μL(即抑制剂ZA1占总反应体积的18%)、抑制时间15min、抑制温度40℃时对α-糖苷酶活性抑制率可达50%以上，用Lineweaver-Burk双倒数作图考察其抑制类型，根据曲线可判定为竞争性抑制，抑制常数Ki=5.43×10-2mmol/L，vmax=1.71μmol/(L ·min)。

Inhibitory Effect of Anthocyanins from Purple Sweet Potato on Alpha-Glucosidase Activity

In order to investigate the effect of anthocyanins from purple sweet potato on cultivars ZA1 and JS6 were comparatively analyzed by HPLC and LC-MSn. The results indicated that petunidin was exclusively contained in ZA1 compared to pelargonidin in JS6. Anthocyanins from both purple sweet potato cultivars had inhibitory effect on α-glucosidase activity. Anthocyanins from purple sweet potato cultivar ZA1 showed better anti-α-glucosidase activity with an inhibitory rate of more than 50% obtained after 15 min of reaction at 40 ℃ and 0.1 mg/mL 600 μL concentration (the ratio of anthocyanins weight to total reaction volume was 18%). The Lineweaver-Burk plot showed that anthocyanins from ZA1 inhibited α-glucosidase activity in a competitive pattern with a Ki of 5.43 × 10-2 mmol/L and vmax of 1.71 μmol/(L ·min).