ABSTRACT Twenty compounds comprising four pregnane steroids ( 2 – 4 & 20 ) and 16 pregnane glycosides ( 1 & 5 – 19 ) have been obtained from the ethanol extract of the roots of a Dai ethnological herb, Marsdenia tenacissima . Their structures were characterized on the basis of comprehensive spectroscopic analyses with 17 ones ( 1 – 17 ) being reported for the first time, including the rare cases ( 2 & 3 ) of free C 21 steroids with 17α-acetyl substitution, compounds 4 – 7 bearing an unusual 14α-OH, and the first examples with simultaneous 14α-OH/17α-acetyl substitution ( 7 ) and glycosylation at C-12 position ( 10 & 11 ). An empirical rule for the identification of C-17 configuration, in C 21 steroids incorporating the marsdenin constitution structure, was also proposed. All the isolates, along with an array of previously reported analogues in our compound library, were screened for their chemo-reversal ability against P-glycoprotein (P-gp)-mediated multidrug resistance (MDR) in MCF-7/ADR cell line, and six compounds exhibited moderate MDR reversal activity with reversal folds ranging from 1.92 to 4.44.
Shaojie Zhang,Renjie Gao,Baocong Ding,Junhao Li,Tanggan Wang,Jiaheng Chen,Chong Li,Yukun Jiao,Lijun Song
Combining selenium nanoparticles (SeNPs) with bioactive polysaccharides is one of the effective ways to overcome the shortcomings of SeNPs and polysaccharide and obtain novel antitumor drug candidates. In this study, a heteropolysaccharide (MTP70) with moderate antihepatoma activity was isolated from the stems of Marsdenia tenacissima (Roxb.) Wight et Arn. To further improve the antihepatoma activity of MTP70 and the application of SeNPs, a novel stable nanoparticle (MTP-SeNP) was designed and fabricated. MTP-SeNPs (Se content of 8.25 %) were characterized as monodisperse spherical nanoparticles (50 nm) with MTP70 wrapped on the surface of the SeNPs by the formation of C O⋯Se bonds and possessed high stability and good dispersion in water for almost a month. In addition, MTP-SeNPs showed higher inhibitory effect compared with MTP70. MTP-SeNPs could effectively inhibit the proliferation, invasion, and metastasis of HePG2 cells by inducing apoptosis and arresting the cell cycle at the S phase, which were closely related to the activation of the Bax/Bcl-2/Caspases and p-21/Akt/Cyclin A2 signaling pathways. Our results provide a theoretical basis for further development and application of M. tenacissima polysaccharide, and show that MTP-SeNPs could be explored as a promising anti-hepatoma agent in the pharmaceutical and biomedical industries.
危险品化学品经营许可证（带存储）