Ahmadi Elham, Rezadoost Hassan, Alilou Mostafa, Stuppner Hermann, Moridi Farimani Mahdi
Department of Phytochemistry, Medicinal Plants and Drugs Research Institute, Shahid Beheshti University, Evin, Tehran, Iran.
Institute of Pharmacy/Pharmacognosy, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innrain 80/82, Innsbruck 6020, Austria.
Int J Biol Macromol. 2022 Jan 1;194:1019-1028. doi: 10.1016/j.ijbiomac.2021.11.163. Epub 2021 Nov 27.
Gum ammoniacum is a polymer obtained from Dorema ammoniacum and its medicinal use was already known to the ancient times. In this study, a new D. ammoniacum carbohydrate (DAC-1) with a molecular weight of 27.1 kDa was extracted by hot water and then purified on DEAE-52-cellulose and Sephadex G-100 columns. The structural features of DAC-1 were investigated by partial acid hydrolysis, fourier-transform infrared spectroscopy (FT-IR), methylation, gas chromatography-mass spectrometry (GC-MS), gas chromatography-flame ionization detection (GC-FID), and 1D and 2D nuclear magnetic resonance spectroscopy (1D & 2D NMR). The results indicated that DAC-1 was an arabinogalactan including galactose, arabinose, rhamnose, glucuronic acid and 4-O-methyl-β-d-glucopyranosyl uronic acid (meGlcpA) with a relative percentage of 44.63%, 23.30%, 13.46%. 12.47%, and 6.14%. The structure units of DAC-1 were elucidated as 3,1)-β--Galp-(6 → 1)-β--Galp-(3,6 → containing four branch chains of →1,6)-β--Galp-(3 → 1)-α--Araf-(5 → 1)-β--GlcpA-(4 → 1)-α--Rhap-T (two times), →1,6)-β--Galp-(3→1)-β--Galp-(3 → 1)-β--Galp-(3 → 1)-β--Galp-(3 → 1)-α--Araf-T and →1,6)-β--Galp-(3 → 1)-α--Araf-(5 → 1)-β--meGlcpA-T. X-ray diffraction (XRD) pattern indicated a semi-crystalline structure. Thermal behavior of the polysaccharide was evaluated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) and revealed temperatures higher than 200 °C as dominant region of weight loss. DAC-1 showed acceptable antioxidant activity when analyzed by DPPH, ABTS, FRAP, and OH radical removal methods.
阿魏是一种从阿魏属植物中提取的聚合物，其药用价值在古代就已为人所知。在本研究中，通过热水提取了一种分子量为27.1 kDa的新型阿魏属植物碳水化合物（DAC-1），然后在DEAE-52纤维素柱和Sephadex G-100柱上进行纯化。通过部分酸水解、傅里叶变换红外光谱（FT-IR）、甲基化、气相色谱-质谱联用（GC-MS）、气相色谱-火焰离子化检测（GC-FID）以及一维和二维核磁共振光谱（1D和2D NMR）对DAC-1的结构特征进行了研究。结果表明，DAC-1是一种阿拉伯半乳聚糖，包含半乳糖、阿拉伯糖、鼠李糖、葡萄糖醛酸和4-O-甲基-β-D-吡喃葡萄糖醛酸（meGlcpA），相对含量分别为44.63%、23.30%、13.46%、12.47%和6.14%。DAC-1的结构单元被阐明为3,1)-β-Galp-(6→1)-β-Galp-(3,6→含有四条分支链的→1,6)-β-Galp-(3→1)-α-Araf-(5→1)-β-GlcpA-(4→1)-α-Rhap-T（两次）、→1,6)-β-Galp-(3→1)-β-Galp-(3→1)-β-Galp-(3→1)-β-Galp-(3→1)-α-Araf-T和→1,6)-β-Galp-(3→1)-α-Araf-(5→1)-β-meGlcpA-T。X射线衍射（XRD）图谱表明其具有半结晶结构。通过热重分析（TGA）和差示扫描量热法（DSC）对多糖的热行为进行了评估，结果显示高于200°C是主要的失重区域。通过DPPH、ABTS、FRAP和OH自由基清除方法分析时，DAC-1表现出可接受的抗氧化活性。
