Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Ceará. Fortaleza, Ceará, Brazil.
Embrapa Agroindústria Tropical, Fortaleza, Ceará, Brazil.
J Ethnopharmacol. 2020 May 10;253:112644. doi: 10.1016/j.jep.2020.112644. Epub 2020 Feb 11.
Himatanthus drasticus is an important medicinal plant whose latex is traditionally used in Northeast Brazil to treat various diseases, including diabetes. The use of α-amylase and α-glucosidase inhibitors can be an effective strategy to modulate levels of postprandial hyperglycemia via control of starch metabolism.
This study aimed to verify if H. drasticus latex has inhibitory activity against enzymes linked to type 2 diabetes, besides chemically characterizing the metabolites responsible for such activities. In addition, in silico analysis was performed to support the traditional claim of possible antidiabetic activity of this latex.
Latex from H. drasticus stems was sequentially partitioned with n-hexane (FHDH), CHCl (FHDC) and EtOH (FHDHA). Wash extraction of the FHDHA fraction was performed to obtain the other extract fractions. The FHDHA was submitted to chromatography in a SPE C cartridge using gradient elution with MeOH/HO to produce five fractions: FHDHA1, FHDHA2, FHDHA3, FHDHA4 and FHDHA5. The FHDHA1 was subjected to semi-preparative reverse phase HPLC. Lineweaver-Burk plots were used to investigate the kinetic parameters of α-amylase and α-glucosidase inhibitory activity. The interactions between plumieride and porcine pancreatic α-amylase and α-glucosidase were analyzed through an in silico molecular docking study.
Phytochemical identification of compounds present in the FHDHA fraction of H. drasticus latex was possible by 1H, 13C NMR analysis and mass spectrometry, and the results were compared with the literature. The identified compounds were α-ethyl glucoside, protocatechuic acid, 3-O-caffeoylquinic acid, 15-demethylplumieride acid, 5-O-caffeoylquinic acid, caffeic acid, vanillic acid, plumieride, and catechin. The inhibition results of the fractions tested against α-amylase and α-glucosidase showed inhibitory activities dependent on the increase of fractions and compound concentrations. The IC results obtained from FHDHA, FHDHA1 and plumieride fractions against α-amylase were 36.46, 72.61, 33.87 μg/mL respectively. The IC of plumieride was the closest to that of acarbose (22.52 μg/mL), a result similar to that obtained for α-glucosidase. The type of inhibition was competitive for both enzymes.
There was strong inhibition of α-amylase and α-glucosidase by FHDHA, FHDHA1 and plumieride, suggesting that these enzymes slow glucose absorption.
希曼托斯·德拉斯特库斯是一种重要的药用植物，其乳汁在巴西东北部传统上被用于治疗各种疾病，包括糖尿病。使用α-淀粉酶和α-葡萄糖苷酶抑制剂可以通过控制淀粉代谢来有效调节餐后高血糖水平。
本研究旨在验证希曼托斯·德拉斯特库斯乳胶是否对与 2 型糖尿病相关的酶具有抑制活性，并对产生这种活性的代谢物进行化学表征。此外，还进行了计算机模拟分析，以支持这种乳胶可能具有抗糖尿病活性的传统说法。
希曼托斯·德拉斯特库斯茎的乳胶依次用正己烷（FHDH）、CHCl（FHDC）和 EtOH（FHDHA）进行萃取。对 FHDHA 部分进行洗涤萃取，以获得其他萃取部分。FHDHA 经 SPE C 柱色谱用 MeOH/HO 梯度洗脱，得到 5 个馏分：FHDHA1、FHDHA2、FHDHA3、FHDHA4 和 FHDHA5。FHDHA1 经半制备反相 HPLC 分离。通过 Lineweaver-Burk 作图研究了α-淀粉酶和α-葡萄糖苷酶抑制活性的动力学参数。通过计算机分子对接研究分析了 plumieride 与猪胰腺α-淀粉酶和α-葡萄糖苷酶之间的相互作用。
通过 1H、13C NMR 分析和质谱对希曼托斯·德拉斯特库斯乳胶 FHDHA 部分中存在的化合物进行了化学鉴定，并与文献进行了比较。鉴定出的化合物为α-乙基葡萄糖苷、原儿茶酸、3-O-咖啡酰奎宁酸、15-去甲基 plumieride 酸、5-O-咖啡酰奎宁酸、咖啡酸、香草酸、plumieride 和儿茶素。测试的各个部分对α-淀粉酶和α-葡萄糖苷酶的抑制结果表明，抑制活性取决于各部分和化合物浓度的增加。从 FHDHA、FHDHA1 和 plumieride 部分获得的对α-淀粉酶的 IC50 值分别为 36.46、72.61 和 33.87μg/mL。plumieride 的 IC 与阿卡波糖（22.52μg/mL）最接近，这与对α-葡萄糖苷酶的结果相似。两种酶的抑制类型均为竞争性。
FHDHA、FHDHA1 和 plumieride 对α-淀粉酶和α-葡萄糖苷酶有很强的抑制作用，提示这些酶能减缓葡萄糖的吸收。
