Four new oleanene-type triterpenoid saponins together with six known saponins were isolated from the roots of Pulsatilla cernua and their structures were elucidated on the basis of spectroscopic data, including 2D NMR spectra and chemical evidence. Among these one of the aglycones (gypsogenin) is reported for the first time from this genus. Some of these compounds showed significant neuroprotective effects against the cytotoxicity induced by β-amyloid 25-35 (Aβ 25-35 ) on human neuroblastoma SH-SY5Y cells.

Novel 18β-glycyrrhetinic acid derivatives possessing a carbamate moiety and structurally similar ester derivatives were developed and evaluated for their efficacy as antitumor inhibitors. In the cellular assays, most of the N-substituted carbamate derivatives at the C3-position exhibited potent activities. The results of SAR investigation revealed that the introduction of the morpholine group at the C30-COOH led to a significant loss of the inhibitory potency. Among the ester derivatives, the ester group at C3-position also determined a noticeable reduction in the efficacy. Compound 3j exhibited the most prominent antiproliferative activity against six human cancer cells (A549, HT29, HepG2, MCF-7, PC-3, and Karpas299). Furthermore, compound 3j exerted a moderate inhibiting effect on the ALK. The results of molecular docking analyses suggested that it could bind well to the active site of the receptor ALK, which was consistent with the biological data. These results might inspire further structural optimization of 18β-glycyrrhetinic acid aiming at the development of potent antitumor agents. The structures 4d, 4g, 4h, 4j, and 4n were studied by X-ray crystallographic analyses.

Six new triterpene saponins, clematomandshurica saponins F-K (1-6), together with a known compound (7), were isolated from the roots and rhizomes of Clematis mandshurica. Their structures were elucidated on the basis of spectroscopic evidence and hydrolysis. Compounds 5-7 exhibited antiproliferative effects against PC-3 human prostate cancer cells with GI50 values of 1.29, 1.50, and 0.71 µM, respectively.

In the present study, a practical method to prepare piperazinyl amides of 18β-glycyrrhetinic acid was developed. Two main procedures for the construction of important intermediate 8 are discussed. One procedure involves the amidation of 1-Boc-piperazine with 3-acetyl-18β-glycyrrhetinic acid, prepared by the reaction of 18β-glycyrrhetinic acid with acetic anhydride without any solvent at 130 °C. The other procedure to prepare compound 8 involves the amidation of 18β-glycyrrhetinic acid followed by the esterification with acetic anhydride. Finally, compound 8 underwent N-Boc deprotection to prepare product 4. To ascertain the scope of the reaction, another C-3 ester derivative 17 was tested under the optimized reaction conditions. Furthermore, the reasons for the appearance of byproducts were elucidated. Crystallographic data of a selected piperazinyl amide is reported.

To improve the solubility of the fluoroquinolone drug gatifloxacin (GAT), a pharmaceutical salt of GAT with 2,3‐dihydroxybenzoic acid (2,3‐HBA) is designed, synthesized, and characterized. This work is based on previous research into the synthesis of the pharmaceutical salts/cocrystals of fluoroquinolones. A comprehensive assessment of the crystal structure and the molecular electrostatic potential, as well as a Hirshfeld surface analysis, revealed that the H protons of the carboxylic groups in 2,3‐HBA are transferred to the N of the GAT piperazine ring. This results in the ionization of GAT to form charge‐assisted hydrogen bonds (CAHBs) and the construction of a crystal structure. It is precisely the conversion of GAT from a neutral state to an ionic state that results in a significant increase in the solubility of GAT‐2,3‐HBA. Surprisingly, in the process of increasing its solubility, the hygroscopic stability and the antibacterial activities in vitro of GAT‐2,3‐HBA is also superior to GAT. In this study, a pharmaceutical salt of gatifloxacin with targeted structures and desired properties, based on CAHBs is successfully designed and synthesized. These encouraging results suggest that CAHBs play a crucial role in adjusting molecular packing through a co‐crystallization strategy, thus improving the physicochemical properties of fluoroquinolones.