Tava Aldo, Pecetti Luciano
CRA-FLC Centro di Ricerca per le Produzioni Foraggere e Lattiero Casearie, 26900 Lodi, Italy.
Nat Prod Commun. 2012 Jul;7(7):837-40.
The saponin and sapogenin composition of the aerial growth of 12 annual Medicago species sampled at full senescence were investigated. Saponins were extracted from the plant material and obtained in a highly pure grade by reverse-phase chromatography, with a yield ranging from 0.38 +/- 0.04% to 1.35 +/- 0.08% dry matter, depending on the species. Sapogenins were then obtained after acid hydrolysis of saponins, and evaluated by GC/FID and GC/MS methods. Different compositions of the aglycone moieties were observed in the 12 Medicago species. Medicagenic acid was the dominant aglycone in M. x blancheana, M. doliata, M. littoralis, M. rotata, M. rugosa, M. scutellata, M. tornata and M. truncatula, bayogenin and hederagenin in M. arabica and M. rigidula, echinocystic acid in M. polymorpha, and soyasapogenol B in M. aculeata. The purified saponin mixtures, characterized by different chemical compositions, were then used in a toxicity test using the brine shrimp Artemia salina. The most active compounds were the saponins from M. arabica and M. rigidula with LD50 values of 10.1 and 4.6 microg/mL, respectively. A structure-activity relationship for the tested saponin mixtures was observed.
对12种一年生苜蓿属植物在完全衰老时地上部分的皂苷和皂苷元成分进行了研究。从植物材料中提取皂苷，并通过反相色谱法获得高纯度级别的皂苷，其产量根据物种不同，在干物质的0.38±0.04%至1.35±0.08%之间。皂苷经酸水解后得到皂苷元，并通过气相色谱/氢火焰离子化检测器（GC/FID）和气相色谱/质谱联用（GC/MS）方法进行评估。在12种苜蓿属植物中观察到苷元部分的不同组成。在白三叶草、多荚苜蓿、海滨苜蓿、轮状苜蓿、皱叶苜蓿、盾状苜蓿、撕裂状苜蓿和截形苜蓿中，苜蓿酸是主要的苷元；在阿拉伯苜蓿和硬直苜蓿中，贝萼皂苷元和平卧青藤皂苷元是主要苷元；在多形苜蓿中，刺囊酸是主要苷元；在针刺苜蓿中，大豆皂苷元B是主要苷元。然后，将具有不同化学成分特征的纯化皂苷混合物用于卤虫毒性试验。活性最强的化合物是来自阿拉伯苜蓿和硬直苜蓿的皂苷，其半数致死剂量（LD50）值分别为10.1和4.6微克/毫升。观察到了受试皂苷混合物的构效关系。
