Institute of Agrochemistry and Food Technology (IATA-CSIC), Paterna, Spain.
Department of Chemical Engineering, Universidade de Santiago de Compostela, Santiago de Compostela, Spain.
J Food Sci. 2022 Jun;87(6):2405-2416. doi: 10.1111/1750-3841.16202. Epub 2022 May 19.
Seaweeds are gaining importance due to their antidiabetic characteristics. This study investigated the inhibitory effects of aqueous Ascophyllum nodosum extracts, obtained by ultrasound-assisted extraction with different sonication powers (70-90 W/cm ) and subjected to resin purification, against α-amylase and α-glucosidase enzymes. Different inhibition methodologies were carried out, preincubating the extract either with the enzyme or the substrate. Chemical characterization, in terms of proximate analysis, antioxidant capacity (2,2-diphenyl-1-picryl-hydrazyl-hydrate [DPPH] and FRAP), and polyphenols characteristics (reversed-phase high-performance liquid chromatography [RP-HPLC] and H-NMR) were carried out to explain inhibitory activities of extracts. Sonication power did not influence the proximal composition nor antiradical activity of extracts, but increasing sonication power increased inhibition capacity (>15%) against both starch digestive enzymes. The extract purification largely improved the inhibition efficiency decreasing the IC of α-amylase and α-glucosidase by 3.0 and 6.1 times, respectively. Seaweed extracts showed greater inhibition effect when they were preincubated with the enzyme instead of the substrate. RP-HPLC together with H-NMR spectra allowed relating the presence of uronic acids-polyphenols complexes and quinones in the extracts with the different inhibitory capacities of samples. PRACTICAL APPLICATION: The study confirms that ultrasound-assisted extracts from Ascophyllum nodosum can be used to inhibit digestive enzymes. This opens the alternative to be used in foods for modulating glycemic index.
海藻因其抗糖尿病特性而日益受到重视。本研究考察了不同超声功率（70-90 W/cm ）下超声辅助提取的马尾藻水提取物对α-淀粉酶和α-葡萄糖苷酶的抑制作用。采用不同的抑制方法，分别将提取物预先与酶或底物孵育。通过进行化学特性分析（包括水分、灰分、粗蛋白、粗脂肪和总膳食纤维等的测定）、抗氧化能力（2，2-二苯基-1-苦肼基自由基[DPPH]和铁还原抗氧化能力[FRAP]）和多酚特性（反相高效液相色谱[RP-HPLC]和 H-NMR），解释提取物的抑制活性。超声功率并不影响提取物的组成和抗氧化活性，但随着超声功率的增加，提取物对两种淀粉消化酶的抑制能力均提高了（>15%）。提取物的纯化大大提高了抑制效率，使α-淀粉酶和α-葡萄糖苷酶的 IC 分别降低了 3.0 倍和 6.1 倍。当提取物与酶而非底物预孵育时，其抑制效果更好。RP-HPLC 结合 H-NMR 谱表明，提取物中存在的糖醛酸-多酚复合物和醌类与样品的不同抑制能力有关。实际应用：该研究证实，马尾藻的超声辅助提取物可用于抑制消化酶。这为在食品中调节血糖指数开辟了替代方法。
