Departament of Pharmaceutical Products, Faculty of Pharmacy, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Belo Horizonte, Brazil.
Departament of Pharmacology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Belo Horizonte, Brazil.
J Ethnopharmacol. 2022 Dec 5;299:115692. doi: 10.1016/j.jep.2022.115692. Epub 2022 Sep 6.
Hancornia speciosa Gomes (Apocynaceae) is a tree found in the Brazilian savannah, traditionally used to treat several diseases, including diabetes and hypertension. The anti-hypertensive activity of H. speciosa leaves (HSL) has been demonstrated in different models and is credited to the vasodilator effect and ACE (angiotensin-converting enzyme) inhibition. The hypoglycemic effect of HSL has been also reported.
To establish correlations between the biological activities elicited by H. speciosa extracts and the contents of their major compounds, aiming to define chemical markers related to the potential antihypertensive and antidiabetic effects of the species. Additionally, it aimed to isolate and characterize the chemical structure of a marker related to the α-glucosidase inhibitory effect.
Extracts of a single batch of H. speciosa leaves were prepared by extraction with distinct solvents (ethanol/water in different proportions; methanol/ethyl acetate), employing percolation or static maceration as extraction techniques, at different time intervals. The contents of chlorogenic acid, rutin and FlavHS (a tri-O-glycoside of quercetin) were quantified by a developed and validated HPLC-PDA method. Bornesitol was determined by HPLC-PDA after derivatization with tosyl chloride, whereas total flavonoids were measured spectrophotometrically. Identification of other constituents in the extracts was performed by UPLC-DAD-ESI-MS/MS analysis. The vasorelaxant activity was assayed in rat aortic rings precontracted with phenylephrine, and α-glucosidase inhibition was tested in vitro. Principal component analysis (PCA) was employed to evaluate the contribution of each marker to the biological responses. Isolation of compound 1 was carried out by column chromatography and structure characterization was accomplished by NMR and UPLC-DAD-ESI-MS/MS analyses.
The contents of the chemical markers (mean ± s.d. % w/w) varied significantly among the extracts, including total flavonoids (2.68 ± 0.14 to 5.28 ± 0.29), bornesitol (5.11 ± 0.26 to 7.75 ± 0.78), rutin (1.46 ± 0.06 to 1.97 ± 0.02), FlavHS (0.72 ± 0.05 to 0.94 ± 0.14) and chlorogenic acid (0.67 ± 0.09 to 0.91 ± 0.02). All extracts elicited vasorelaxant effect (pIC between 4.97 ± 0.22 to 6.48 ± 0.10) and α-glucosidase inhibition (pIC between 3.49 ± 0.21 to 4.03 ± 0.10). PCA disclosed positive correlations between the vasorelaxant effect and the contents of chlorogenic acid, rutin, total flavonoids, and FlavHS, whereas a negative correlation was found with bornesitol concentration. No significant correlation between α-glucosidase inhibition and the contents of the above-mentioned compounds was found. On the other hand, PCA carried out with the areas of the ten major peaks from the chromatograms disclosed positive correlations between a peak ascribed to co-eluted triterpenes and α-glucosidase inhibition. A triterpene was isolated and identified as 3-O-β-(3'-R-hydroxy)-hexadecanoil-lupeol.
According to PCA results, the vasorelaxant activity of H. speciosa extracts is related to flavonoids and chlorogenic acid, whereas the α-glucosidase inhibition is associated with lipophilic compounds, including esters of lupeol like 3-O-β-(3'-R-hydroxy)-hexadecanoil-lupeol, described for the first time for the species. These compounds can be selected as chemical markers for the quality control of H. speciosa plant drug and derived extracts.
Hancornia speciosa Gomes（夹竹桃科）是一种生长在巴西热带稀树草原的乔木，传统上用于治疗多种疾病，包括糖尿病和高血压。H. speciosa 叶（HSL）的降压活性已在不同模型中得到证实，这归因于血管扩张作用和 ACE（血管紧张素转换酶）抑制作用。HSL 的降血糖作用也有报道。
建立 H. speciosa 提取物的生物活性与主要化合物含量之间的相关性，旨在确定与该物种潜在的降压和抗糖尿病作用相关的化学标志物。此外，还旨在分离和表征与 α-葡萄糖苷酶抑制作用相关的标志物的化学结构。
采用不同比例的乙醇/水（乙醇/水）和甲醇/乙酸乙酯（甲醇/乙酸乙酯）通过渗滤或静态浸提等不同提取技术从单一批次的 H. speciosa 叶中提取提取物。采用高效液相色谱-光电二极管阵列（HPLC-PDA）法建立并验证了绿原酸、芦丁和 FlavHS（槲皮素的三-O-糖苷）的含量。经对甲苯磺酰氯衍生后，采用 HPLC-PDA 法测定了 bornesitol 的含量，而总黄酮类化合物则采用分光光度法测定。通过超高效液相色谱-二极管阵列-电喷雾质谱/质谱联用（UPLC-DAD-ESI-MS/MS）分析鉴定提取物中的其他成分。用苯肾上腺素预收缩的大鼠主动脉环检测血管舒张活性，体外检测 α-葡萄糖苷酶抑制活性。采用主成分分析（PCA）评估每个标志物对生物反应的贡献。通过柱色谱法分离化合物 1，并通过 NMR 和 UPLC-DAD-ESI-MS/MS 分析完成结构表征。
提取物中的化学标志物含量（平均值±标准差，%w/w）差异显著，包括总黄酮类化合物（2.68±0.14 至 5.28±0.29）、bornesitol（5.11±0.26 至 7.75±0.78）、芦丁（1.46±0.06 至 1.97±0.02）、FlavHS（0.72±0.05 至 0.94±0.14）和绿原酸（0.67±0.09 至 0.91±0.02）。所有提取物均表现出血管舒张作用（pIC 为 4.97±0.22 至 6.48±0.10）和 α-葡萄糖苷酶抑制作用（pIC 为 3.49±0.21 至 4.03±0.10）。PCA 显示血管舒张作用与绿原酸、芦丁、总黄酮类化合物和 FlavHS 的含量呈正相关，而与 bornesitol 浓度呈负相关。未发现 α-葡萄糖苷酶抑制作用与上述化合物含量之间存在显著相关性。另一方面，基于色谱图的十个主要峰的面积进行的 PCA 显示，一个归因于共洗脱三萜的峰与 α-葡萄糖苷酶抑制作用呈正相关。分离并鉴定出一种三萜为 3-O-β-（3'-R-羟基）-十六烷酰基-羽扇醇。
根据 PCA 结果，H. speciosa 提取物的血管舒张活性与类黄酮和绿原酸有关，而 α-葡萄糖苷酶抑制作用与亲脂性化合物有关，包括羽扇醇的酯类，如 3-O-β-（3'-R-羟基）-十六烷酰基-羽扇醇，这是该物种的首次报道。这些化合物可以被选为 H. speciosa 植物药和衍生提取物质量控制的化学标志物。
