Synthesis, cytotoxicity, and hemolytic activity of 6'-O-substituted dioscin derivatives

Dioscin derivatives (1-12) with a variety of substitutions at the 6'-OH of the chacotriosyl residue and the 3',6'-anhydrosaponin derivatives (26, 30, and 32) were synthesized. All these derivatives showed much lower cytotoxicity than that of the parent dioscin, while their hemolytic activities were partially retained depending on the various 6'-O-substitutions.     

盾叶薯蓣根状茎的发育解剖学和组织化学研究

盾叶薯蓣根状茎顶端的生长点由鳞片包被,其衍生细胞分化为原表皮、基本分生组织和散生的原形成层束,以后分化为表皮、基本组织和散生的维管束构成的初生结构。根状茎顶端下方的原表皮内存在初生增厚分生组织,其细胞不断向内分裂和其衍生细胞的体积增大使根状茎能够迅速增粗。分化完成的根状茎主要由周皮、基本组织和散生的维管束构成。周皮由木栓层、木栓形成层和栓内层组成;基本组织由薄壁细胞组成;维管束属于有限维管束。薯蓣皂甙主要存在于基本组织薄壁细胞中。原分生组织和原形成层不含薯蓣皂甙,维管束的木质部和韧皮部中的韧皮纤维也无薯蓣皂甙的分布,韧皮部的生活细胞和维管束鞘细胞有薯蓣皂甙的积累。近顶端的基本分生组织细胞内薯蓣皂甙不形成液滴,随着细胞分裂逐渐停止,细胞内开始形成含薯蓣皂甙的液滴,反映皂甙是在成熟细胞内积累。其中,有小型维管束分布的基本组织中薯蓣皂甙的积累与分布最丰富,两年生根状茎中薯蓣皂甙的含量比一年生的高。     

Syntheses of chlorogenin 6alpha-O-acyl-3-O-beta-chacotriosides and their antitumor activities

Chlorogenin 3-O-beta-chacotrioside (1) and its 6alpha-O-acyl derivatives (2-6) were concisely synthesized. Introduction of a hydroxyl or acyloxy group onto the C-6 of the steroidal aglycone of dioscin decreased significantly the cytotoxicity of the parent saponin (dioscin).     

The Identification and Isolation of Steroidal Saponin from Dioscorea gracillima Miq.

Two trisaecharides of diosgenin (A, B) had been isolated from the rhizome of Dioseorea gracillima Maq. (collected from Jiangsi, Lu Shan). By means of acetylafion, acid hydrolysis, IR, MS and 13C-NMR etc. saponin A and saponin B were identifieated as dioscin and gracillin, respectively. Its yieldingratio is 3:1 (A:B).     

Dioscin suppresses TGF-β1-induced epithelial-mesenchymal transition and suppresses A549 lung cancer migration and invasion

Epithelial-to-mesenchymal transition (EMT), an important cellular process, occurs during cancer development and progression, has a crucial role in metastasis by enhancing the motility of tumor cells. Dioscin is a polyphenolic component isolated from Phyllanthus amarus, which exhibits a wide range of pharmacological and physiological activities, such as anti-tumor, anti-inflammatory, anti-obesity, anti-fungal, and anti-viral activities. However, the possible role of dioscin in the EMT is unclear. We investigated the suppressive effect of dioscin on the EMT. Transforming growth factor-beta 1 (TGF-β1) is known to induce EMT in a number of cancer cell types and promote lung adenocarcinoma migration and invasion. To verify the inhibitory role of dioscin in lung cancer migration and invasion, we investigated the use of dioscin as inhibitors of TGF-β1-induced EMT in A549 lung cancer cells in vitro. Here, we found that dioscin prominently increased expression of the epithelial marker E-cadherin and expression of the mesenchymal marker N-cadherin and Snail during the TGF-β1-induced EMT. In addition, dioscin inhibited the TGF-β1-induced increase in cell migration and invasion of A549 lung cancer cells. Also, dioscin remarkably inhibited TGF-β1-regulated activation of MMP-2/9, Smad2, and p38. Taken together, our findings provide new evidence that dioscin suppresses lung cancer migration, and invasion in vitro by inhibiting the TGF-β1-induced EMT.     

Isolation and Identification of Steroidal Saponins from Dioscorea panthaica Prain et Burkill

Two steroidal saponins have been isolated from the rhizomes of Dioscorea panthaica Prain et Burkill. collected from Sichuan province. They were identified as 3-0-{α-L- rhamnopyranosyl (1→4)- [α-L-rhamnopyranosyl (1→2) ]-β-D-glucopyranosyl } -diosgenin (dioscin) and 3-O-{β-D-glucopyranosyl (1→3)-[α-L-rhamnopyranosyl (1→2)]-β-D-glucopyranosyl}-diosgenin (gracillin) on the basis of mp., m. mp., TLC. acetylation, acid hydrolysis, IR, MS, and 13C NMR.     

Direct Biotransformation of Dioscin into Diosgenin in Rhizome of Dioscorea zingiberensis by Penicillium dioscin

Diosgenin is an important precursor for synthesis of more than 200 steroidal hormone medicines. Rhizome of Dioscorea zingiberensis C. H. Wright (RDZ) contained the highest content of diosgenin in Dioscorea plant species. Diosgenin is traditionally extracted by acid hydrolysis from RDZ. However, the acid hydrolysis process produces massive wastewater which caused serious environment pollution. In this study, diosgenin extraction by direct biotransformation with Penicillium dioscin was investigated. The spawn cultivation conditions were optimized as: Czapeks liquid culture medium without sugar and agar (1,000 ml) + 6.0 g dioscin/6.0 g DL, 30 °C, 36 h; solid fermentation of RDZ: mycelia/RDZ of 0.05 g/kg, 30 °C, 50 h; the yield of diosgenin was over 90 %. Spawn cultivation was crucial for the direct biotransformation. In the spawn cultivation, amount and ratio of dioscin/DL were the key factors to promote biotransformation activity of P. dioscin. This biotransformation method was environment-friendly, simple and energy saving, and might be a potential substitute for acid hydrolysis in diosgenin extraction industry.     

微生物薯蓣皂苷糖苷酶的分离纯化的研究

产薯蓣皂苷酶的sp.s00c菌发酵液,通过分级沉淀的分离方法,经离子交换柱提纯分离,得到聚丙烯酰胺凝胶电泳单点的酶,其酶蛋白分子量为59 ku,提纯酶最适酶反应温度为40℃,最适pH值为5.0。提纯酶不仅能水解薯蓣皂苷的鼠李糖基,也能水解薯蓣皂苷的葡萄糖基。