Development of trisiloxane surfactant vesicles ultrasonic extraction method combined with ultrahigh-performance liquid chromatography tandem mass spectrometry for the rapid differentiation of Bupleuri Radix based on metabolomics

INTRODUCTION

Due to the variety, chemical composition and complex structure, the quality control of Bupleuri Radix (BR) is a challenging task. There are still many trace compounds in BR that are difficult to extract and detect.

OBJECTIVE

To develop an innovative method of trisiloxane surfactant vesicles ultrasonic extraction (TSVUE) combined with ultrahigh-performance liquid chromatography tandem mass spectrometry for the identification from Bupleurum chinense DC. (BC) to Bupleurum scorzonerifolium Willd (BS) based on metabolomics.

METHODS

Based on extraction effect for BR, five different types of surfactants vesicles were prepared and compared. Then, a single-factor test and a response surface methodology study were adopted to obtain the optimal conditions for the surfactant vesicles ultrasonic extraction method. Finally, a non-targeted metabolomics method with information dependent acquisition mode was performed to analyse differential metabolites in BC and BS.

RESULTS

Sugar-based surfactant containing trisiloxane [N-3-propyl-methyltrisiloxane-N-glucoheptonamne (Si(3)N-GHA)] displayed higher extraction efficiency compared to other types of surfactants when it comes to being used in pretreatment methods. And a TSVUE method was established and optimised. In total, 131 constituents were identified in two BR herbs, of which 35 were unreported, and 11 were characterised as chemical markers.

CONCLUSIONS

This method provides promising perspectives for rapidly identifying trace compounds in complex systems of traditional Chinese medicine (TCM), as well as for laying the foundation in the identification of similar herbs from the same species. Meanwhile, these findings serve as a promising application of trisiloxane surfactant vesicles in the extraction field of TCM.

From passive to emerging smart silicones

Amassing remarkable properties, silicones are practically indispensable in our everyday life. In most classic applications, they play a passive role in that they cover, seal, insulate, lubricate, water-proof, weather-proof etc. However, silicone science and engineering are highly innovative, seeking to develop new compounds and materials that meet market demands. Thus, the unusual properties of silicones, coupled with chemical group functionalization, has allowed silicones to gradually evolve from passive materials to active ones, meeting the concept of “smart materials”, which are able to respond to external stimuli. In such cases, the intrinsic properties of polysiloxanes are augmented by various chemical modifications aiming to attach reactive or functional groups, and/or by engineering through proper cross-linking pattern or loading with suitable fillers (ceramic, magnetic, highly dielectric or electrically conductive materials, biologically active, etc.), to add new capabilities and develop high value materials. The literature and own data reflecting the state-of-the art in the field of smart silicones, such as thermoplasticity, self-healing ability, surface activity, electromechanical activity and magnetostriction, thermo-, photo-, and piezoresponsivity are reviewed.

From Amorphous Silicones to Si-Containing Highly Ordered Polymers: Some Romanian Contributions in the Field

Polydimethylsiloxane (PDMS), in spite of its well-defined helical structure, is an amorphous fluid even at extremely high molecular weights. The cause of this behavior is the high flexibility of the siloxane backbone and the lack of intermolecular interactions attributed to the presence of methyl groups. These make PDMS incompatible with almost any organic or inorganic component leading to phase separation in siloxane-siloxane copolymers containing blocks with polar organic groups and in siloxane-organic copolymers, where dimethylsiloxane segments co-exist with organic ones. Self-assembly at the micro- or nanometric scale is common in certain mixed structures, including micelles, vesicles, et cetera, manifesting reversibly in response to an external stimulus. Polymers with a very high degree of ordering in the form of high-quality crystals were obtained when siloxane/silane segments co-exist with coordinated metal blocks in the polymer chain. While in the case of coordination of secondary building units (SBUs) with siloxane ligands 1D chains are formed; when coordination is achieved in the presence of a mixture of ligands, siloxane and organic, 2D structures are formed in most cases. The Romanian research group's results regarding these aspects are reviewed: from the synthesis of classic, amorphous silicone products, to their adaptation for use in emerging fields and to new self-assembled or highly ordered structures with properties that create perspectives for the use of silicones in hitherto unexpected areas.

Microscopic Evidence for the Correlation of Micellar Structures and Counterion Binding Constant for Flexible Nanoparticle Catalyzed Piperidinolysis of PS− in Colloidal System

The interest to determine the ionization degree of counterion initiates the need to study the relationship between counterion binding constant (RX Br) and the growth of self-assembly micellar structure. This paper discussed the microscopic evidence for the correlation of counterion binding constant values and micellar structure of cationic surfactants in the presence of phenolates and 2-ethyl phenolates ions in flexible nanoparticle (FN)-system of ionized phenyl salicylate-catalyzed piperidinolysis. The sizes of micelles were determined by particle size analysis. Transmission electron microscopy (TEM) results showed a spherical micellar structure for phenolates and 2-ethyl phenolates ions at counterion binding constant values 6.3 ± 1.0 and 24.0 ± 1.1 respectively. A study using a semi-emperical kinetic technique in published article proved that the suggested micellar structures at respective counterion binding constant values corresponded with the present microscopic evidence.