Self-assembly in saponin mixtures: Escin/tea, tea/glycyrrhizic acid, and escin/glycyrrhizic acid mixtures

Self-assembled antioxidant enzyme-mimicking hydrogel: Targeting oxidative stress and macrophage organization for improving degenerated intervertebral discs

Intervertebral disc degeneration (IVDD) is a major contributor to lower back pain. At present, antioxidant therapy is regarded as one of the most promising strategies for treating IVDD, due to the critical role of reactive oxygen species (ROS) in its pathogenesis. Herein, we presented a self-assembled hydrogel, termed MnGAHs, formed through the crossing of manganese ions (Mn2+) and glycyrrheic acid (GA), which possessed the activities of antioxidant enzymes, including catalase (CAT) and superoxide dismutase (SOD). The obtained MnGAHs effectively scavenge ROS, reducing oxidative stress levels and alleviating the senescence of nucleus pulposus-derived mesenchymal stem cells (NPMSC), thereby mitigating IVDD. Furthermore, MnGAHs also promoted macrophage polarization towards M2 phenotype, reducing the inflammatory response and thereby inhibiting the progression of IVDD. By combining theoretical calculations with analyses of public databases, we revealed that the ROS-p53-p21 axis played a crucial role in the function of MnGAHs to reverse IVDD, a finding further confirmed by Western blot analysis. As a result, the injection of MnGAHs into the intervertebral disc (IVD) significantly alleviated the degeneration process in a rat model of puncture-induced IVDD. Therefore, the as-prepared antioxidant enzyme-mimicking hydrogels provide a promising and effective approach for treating IVDD.

Ultrasonic-assisted membrane processes for the systematic purification of glycyrrhiza wastewater

A significant amount of glycyrrhiza wastewater is generated in the cleaning process of glycyrrhiza. The wastewater contains polysaccharide, glycyrrhizic acid, liquiritin, and other polyphenols, which is expensive for cleanup and wastes medical resources. To reduce environmental pollution from glycyrrhiza wastewater and increase the resource usage efficiency of glycyrrhiza components. According to the physicochemical properties of the component in glycyrrhiza wastewater, the ultrasonic assisted membrane separation mode was adopted to regulate the micellar state of glycyrrhizic acid and enhance the differences in membrane separation of polysaccharides, saponins, and flavones, in order to achieve the classification and separation of polysaccharides, saponins, and flavones while removing organic matter in glycyrrhiza wastewater. However, the efficiency, application, and mechanism of ultrasonic-assisted membrane technology for the separation of polysaccharides, saponins, and flavonoids from glycyrrhiza wastewater remain unclear. This study presents a green and feasible technical strategy for glycyrrhiza wastewater treatment that was developed by adjusting the parameters of ultrasonic assisted membrane separation. In this study, the systematic separation mode of ultrasonic enhanced ultrafiltration combined with nanofiltration is provided. The SCQ-9200E ultrasonic system was provided for the study with adjustable ultrasonic power, and the ultrasonic frequency was 40 kHz. The glycyrrhizic acid micelle was changed using ultrasonic power, pH, and molecular weight cut off (MWCO), and the separation differences among polysaccharide, glycyrrhizic acid, and liquiritin were enhanced. The optimal polysaccharide separation parameters used in the first step: MWCO 30 kDa, ultrasonic power 500 W and pH 5.00, and the rejections of polysaccharide, glycyrrhizic acid, and liquiritin were 87.72 %, 8.01 %, and 6.57 %, respectively. The second step included the following parameters for the separation of liquiritin and glycyrrhizic acid: MWCO 10 kDa, ultrasonic power 100 W and pH 8.00, the rejections of liquiritin and glycyrrhizic acid were 9.22 % and 40.65 %, respectively. The third step is to remove the low molecular sugar in liquiritin by nanofiltration: MWCO 800 Da, pH 8.00, retention solution diluted and separated twice, the rejection of liquiritin and total sugar were 95.72 % and 3.70 %, respectively. Ultrasonic may regulate the microtopography of glycyrrhiza wastewater with the power intensity of 50 W/L, improving the mass transfer efficiency of glycyrrhizic acid and liquiritin in the ultrafiltration separation process. As the separation volume of wastewater increased from 2.00 L to 20.00 L, the concentrations of polysaccharide, glycyrrhizic acid, and liquiritin increased by 2.5-35.4 times, 0.6-15.2 times, and 2.4-32.8 times, respectively, significantly increasing the content of index components in wastewater and solving the problem of recycling and resource utilization in glycyrrhiza wastewater.

Triterpene-Based Prodrug for Self-Boosted Drug Release and Targeted Oral Squamous Cell Carcinoma Chemotherapy

Chemotherapy is one of the main treatments for oral squamous cell carcinoma (OSCC), especially as a combined modality approach with and after surgery or radiotherapy. Limited therapeutic efficiency and serious side effects greatly restrict the clinical performance of chemotherapeutic drugs. The development of smart nanomedicines has provided new research directions, to some extent. However, the involvement of complex carrier compositions inevitably brings biosafety concerns and greatly limits the "bench-to-bed" translation of most nanomedicines reported. In this study, a carrier-free self-assembled prodrug was fabricated by two triterpenes (glycyrrhetinic acid, GA and ginsenoside Rh2, Rh2) isolated from medicinal plants, licorice, and ginseng, for the targeted and highly effective treatment of OSCC. Reactive oxygen species (ROS) self-supplied molecule TK-GA2 was synthesized with ROS-responsive thioketal linker and prodrug was prepared by a rapid-solvent-exchange method with TK-GA2 and Rh2. After administration, oral tumor cells transported large amounts of prodrugs with glucose ligands competitively. Endogenous ROS in oral tumor cells then promoted the release of GA and Rh2. GA further evoked the generation of a large number of ROS to help self-boosted drug release and increase oxidative stress, synergistically causing tumor cell apoptosis with Rh2. Overall, this carrier-free triterpene-based prodrug might provide a preeminent opinion on the design of effective chemotherapeutics with low systemic toxicity against OSCC.

Glycyrrhizic acid aggregates seen from a synthetic surfactant perspective

Bio- or plant-based surfactants are a sustainable and renewable alternative to replace synthetic chemicals for environmental, drugs and food applications. However, these "green" surfactants have unique molecular structures, and their self-assembly in water might lead to complex morphologies and unexpected properties. The micellization of saponin molecules, such as glycyrrhizic acid (GA), differs significantly from those of conventional synthetic surfactants, yet these differences are often overlooked. Saponins self-assemble in complex hierarchical helical morphologies similar to bile salts, rather than the expected globular, ellipsoidal and wormlike micelles. Here, we review two potential routes for molecular self-assembly of GA, namely kinetics of crystallization and thermodynamic equilibrium, focusing on their structure as a function of concentration. Some uncertainty remains to define which route is followed by GA self-assembly, as well as the first type of aggregate formed at low concentrations, thus we review the state-of-the-art information about GA assembly. We compare the self-assembly of GA with conventional linear surfactants, and identify their key similarities and differences, from molecular and chemical perspectives, based on the critical packing parameter (CPP) theory. We expect that this work will provide perspectives for the unclear process of GA assembly, and highlight its differences from conventional micellization.

Self-assembled glycyrrhetinic acid derivatives for functional applications: a review

Glycyrrhetinic acid (GA), a famous natural product, has been attracting more attention recently because of its remarkable biological activity, natural sweetness, and good biocompatibility. In the past few years, a considerable amount of literature has grown up around the theme of GA-based chemical modification to broaden its functional applications. Promising structures including gels, micelles, nanoparticles, liposomes, and so forth have been constantly reported. On the one hand, the assembly mechanisms of various materials based on GA derivatives have been elucidated via modern analytical techniques. On the other hand, their potential application prospects in edible additives, intelligent drug delivery, and other fields have been investigated fully due to availability, biocompatibility, and controllable degradability. Inspired by these findings, a systematic summary and classification of the materials formed by GA derivatives seems necessary and meaningful. This review sums up the new functional applications of GA derivatives for the first time and provides better prospects for their application and development.