Solubilization of saikosaponin a by ginsenoside Ro biosurfactant in aqueous solution: Mesoscopic simulation

Bio-soft matter derived from traditional Chinese medicine: Characterizations of hierarchical structure, assembly mechanism, and beyond

Structural and functional explorations on bio-soft matter such as micelles, vesicles, nanoparticles, aggregates or polymers derived from traditional Chinese medicine (TCM) has emerged as a new topic in the field of TCM. The discovery of such cross-scaled bio-soft matter may provide a unique perspective for unraveling the new effective material basis of TCM as well as developing innovative medicine and biomaterials. Despite the rapid rise of TCM-derived bio-soft matter, their hierarchical structure and assembly mechanism must be unambiguously probed for a further in-depth understanding of their pharmacological activity. In this review, the current emerged TCM-derived bio-soft matter assembled from either small molecules or macromolecules is introduced, and particularly the unambiguous elucidation of their hierarchical structure and assembly mechanism with combined electron microscopic and spectroscopic techniques is depicted. The pros and cons of each technique are also discussed. The future challenges and perspective of TCM-derived bio-soft matter are outlined, particularly the requirement for their precise in situ structural determination is highlighted.

Self-assembled nanodrug delivery systems for anti-cancer drugs from traditional Chinese medicine

Traditional Chinese medicine (TCM) is a combination of raw herbs and herbal extracts with a plethora of documented beneficial bioactivities, which has unique advantages in anti-tumor therapy, and many of its major bioactive molecules have been identified in recent years due to advances in chemical separation and structural analysis. However, the major chemical classes of plant-derived bioactive compounds frequently possess chemical properties, including poor water solubility, stability, and bioavailability, that limit their therapeutic application. Alternatively, natural small molecules (NSMs) containing these components possess modifiable groups, multiple action sites, hydrophobic side chains, and a rigid skeleton with self-assembly properties that can be exploited to construct self-assembled nanoparticles with therapeutic effects superior to their individual constituents. For instance, the construction of a self-assembled nanodrug delivery system can effectively overcome the strong hydrophobicity and poor in vivo stability of NSMs, thereby greatly improving their bioavailability and enhancing their anti-tumor efficacy. This review summarizes the self-assembly methods, mechanisms, and applications of a variety of NSMs, including terpenoids, flavonoids, alkaloids, polyphenols, and saponins, providing a theoretical basis for the subsequent research on NSMs and the development of SANDDS.

Degradation of benzo [a] pyrene in the soil enhanced by soapwort: The role of soapwort and functional microbial community

The limited bioavailability of polycyclic aromatic hydrocarbons (PAHs) in soils poses a challenge for their biodegradation. We hypotheses soapwort (Saponaria officinalis L.) as a factory in-situ providing biosurfactant, which could effectively promote the BaP removal by exogenous or native functional microbes. Rhizo-box and microcosm experiments were conducted to analyze the phyto-microbial remediation mechanism of soapwort, a plant that excretes biosurfactants known as saponins, and combined with two exogenous strains (P. chrysosporium and/or B. subtilis) for benzo[a]pyrene (BaP)-contaminated soils. The results revealed that the natural attenuation treatment (CK) BaP achieved only a 15.90% BaP removal rate after 100 days. In contrast, soapwort (SP), soapwort-bacteria (SPB), soapwort-fungus (SPF), soapwort- bacteria - fungus (SPM) mediated rhizosphere soils treatments yielded removal rates of 40.48%, 42.42%, 52.37%, and 62.57%, respectively. The analysis of the microbial community structure suggested that soapwort stimulated the introduction and native functional microorganisms, such as Rhizobiales, Micrococcales, and Clostridiales, which contributed to BaP removal via metabolic pathways. Furthermore, the efficient BaP removal was attributed to saponins, amino acids, and carbohydrates, which facilitated mobilization, solubilization of BaP, and microbial activity. In conclusion, our study highlights the potential of soapwort and specific microbial strains to effectively remediate PAH-contaminated soils.

Lignin particles as green pore-forming agents for the fabrication of microporous polysulfone membranes

Templating polymeric membranes with micro-nano-scaled solid materials is an effective method to simultaneously improve the water flux and retention ratio. However, the fabrication of a green, recyclable, and size-controlled template material remains a challenge. Here, a new green pore-forming agent, lignin particles (LP), was developed to prepare porous polysulfone (PSF) membranes via the phase inversion technique. A series of LP have uniform sizes from ~200 nm to ~1800 nm. The performances of the templated PSF membranes cast at different sizes and contents of LP were examined for their surface and crosssection morphologies. The LP-templated PSF membranes displayed a remarkable enhancement in flux, porosity, and moisture content. Particularly, the PSF membranes cast with LP from ~200 to 1800 nm broke the traditional trade-off to a certain degree, which possessed stable retentions of bovine serum albumin (> 85 %) and significantly improved water flux (174.275 to 254.775 L m^-2 h^-1). In addition, the LP pore-forming agent is low-cost and environmentally friendly as it was prepared from industrial by-products and can be easily recycled. Overall, this study shows that lignin particles are green pore-forming agents that can be used for the fabrication of porous polymeric membranes with improved performance for water treatment.

Carrier-free nanoplatforms from natural plants for enhanced bioactivity

BACKGROUND

Natural plants as well as traditional Chinese medicine have made outstanding contributions to the health and reproduction of human beings and remain the basis and major resource for drug innovation. Carrier-free nanoplatforms completely self-assembled by pure molecules or therapeutic components have attracted increasing attention due to their advantages of improved pharmacodynamics/pharmacokinetics, reduced toxicity, and high drug loading. In recent years, carrier-free nanoplatforms produced by self-assembly from natural plants have contributed to progress in a variety of therapeutic modalities. Notably, these nanoplatforms based on the interactions of components from different natural plants improve efficiency and depress toxicity.

AIM OF REVIEW

In this review, different types of self-assembled nanoplatforms are first summarized, mainly including nanoassemblies of pure small molecules isolated from different plants, extracellular vesicles separated from fresh plants, charcoal nanocomponents obtained from charred plants, and nanoaggregates from plants formulae decoctions. Key Scientific Concepts of Review: We mainly focus on composition, self-assembly mechanisms, biological activity and modes of action. Finally, a future perspective of existing challenges with respect to the clinical application of plant-based carrier-free nanoplatforms is discussed, which may be instructive to further develop effective carrier-free nanoplatforms from natural plants in the future.

Coptis chinensis polysaccharides dynamically influence the paracellular absorption pathway in the small intestine by modulating the intestinal mucosal immunity microenvironment

BACKGROUND

Traditional Chinese Medicine decoctions (TCMDs) can be used to prepare outstanding pharmaceutical preparations by the patient themselves. Small molecular active ingredients and macromolecular polysaccharides are inevitably co-existed in TCMDs. Different from the pharmacological synergies among small molecules, the macromolecular polysaccharides in TCMDs might contribute to disease treatment in several ways, although it is frequently overlooked.

HYPOTHESIS/PURPOSE

This study proposes that the oral bioavailability of the water-insoluble alkaloids of Coptis chinensis Franch. (Ranunculaceae) (C. chinensis) decoction may be attributed to the co-existing C. chinensis polysaccharides (CCPs) dynamically influencing the small intestine microenvironment and regulating the modulation of the paracellular absorption pathway.

METHODS

First, the effects of CCPs on the oral bioavailability of the main active ingredient of C. chinensis, berberine, were evaluated in vivo. Next, a series of in situ experimental models of intestinal perfusion and models of isolated jejunal mucosa, Caco-2 cell monolayer membranes, and microfold-like cells were established to assess the correlation among CCPs, intestinal mucosal immunity, and paracellular absorption in the small intestine.

RESULTS

It was observed that CCPs could be endocytosed by the microfold cells on the surface of Peyer's patches, allowing CCPs to activate the lymphocytes, modulate the balance of Th1/Th2, control the secretion of immune effectors IFN-γ and IL-4, and finally regulate the tight junctions in the intestinal epithelial cells. This was a dynamic process with the movement of CCPs in the gastrointestinal tract that altered the flora distribution and functioning of the TLR/NF-κB signal pathway in the small intestine.

CONCLUSION

The dynamical regulation of CCP on the immune microenvironment of small intestine is responsible for its promotion on the health controlling effects of C. chinensis in traditional dosage forms of decoction.

Supramolecular assemblies based on natural small molecules: Union would be effective

Natural products have been used to prevent and treat human diseases for thousands of years, especially the extensive natural small molecules (NSMs) such as terpenoids, steroids and glycosides. A quantity of studies are confined to concern about their chemical structures and pharmacological activities at the monomolecular level, whereas the spontaneous assemblies of them in liquids yielding supramolecular structures have not been clearly understood deeply. Compared to the macromolecules or synthetic small molecular compounds, NSMs have the inherent advantages of lower toxicity, better biocompatibility, biodegradability and biological activity. Self-assembly of single component and multicomponent co-assembly are unique techniques for designing supramolecular entities. Assemblies are of special significance due to their range of applications in the areas of drug delivery systems, pollutants capture, materials synthesis, etc. The assembled mechanism of supramolecular NSMs which are mainly driven by multiple non-covalent interactions are summarized. Furthermore, a new hypothesis aimed to interpret the integration effects of multi-components of traditional Chinese medicines (TCMs) inspired on the theory of supramolecular assembly is proposed. Generally, this review can enlighten us to achieve the qualitative leap for understanding natural products from monomolecule to supramolecular structures and multi-component interactions, which is valuable for the intensive research and application.

Study on Supramolecules in Traditional Chinese Medicine Decoction

With the application of the concept of supramolecular chemistry to various fields, a large number of supramolecules have been discovered. The chemical components of traditional Chinese medicine have various sources and unique structures. During the high-temperature boiling process, various active components form supramolecules due to complex interactions. The supramolecular structure in a traditional Chinese medicine decoction can not only be used as a drug carrier to promote the absorption and distribution of medicinal components but may also have biological activities superior to those of single active ingredients or their physical mixtures. By summarizing the relevant research results over recent years, this paper introduces the research progress regarding supramolecules in various decoctions, laying a foundation for further research into supramolecules in traditional Chinese medicine decoctions, and provides a new perspective for revealing the compatibility mechanisms of traditional Chinese medicine, guiding clinical medications, and developing new nanometers materials.

Structure and Undulations of Escin Adsorption Layer at Water Surface Studied by Molecular Dynamics

The saponin escin, extracted from horse chestnut seeds, forms adsorption layers with high viscoelasticity and low gas permeability. Upon deformation, escin adsorption layers often feature surface wrinkles with characteristic wavelength. In previous studies, we investigated the origin of this behavior and found that the substantial surface elasticity of escin layers may be related to a specific combination of short-, medium-, and long-range attractive forces, leading to tight molecular packing in the layers. In the current study, we performed atomistic molecular dynamics simulations of 441 escin molecules in a dense adsorption layer with an area per molecule of 0.49 nm2. We found that the surfactant molecules are less submerged in water and adopt a more upright position when compared to the characteristics determined in our previous simulations with much smaller molecular models. The number of neighbouring molecules and their local orientation, however, remain similar in the different-size models. To maintain their preferred mutual orientation, the escin molecules segregate into well-ordered domains and spontaneously form wrinkled layers. The same specific interactions (H-bonds, dipole-dipole attraction, and intermediate strong attraction) define the complex internal structure and the undulations of the layers. The analysis of the layer properties reveals a characteristic wrinkle wavelength related to the surface lateral dimensions, in qualitative agreement with the phenomenological description of thin elastic sheets.

Lipid Membranes as Key Targets for the Pharmacological Actions of Ginsenosides

In this review, we will focus on the activity of ginsenosides on membranes and their related effects, from physicochemical, biophysical, and pharmacological viewpoints. Ginsenosides are a class of saponins with a large structural diversity and a wide range of pharmacological effects. These effects can at least partly be related to their activity on membranes which results from their amphiphilic character. Some ginsenosides are able to interact with membrane lipids and associate into nanostructures, making them possible adjuvants for vaccines. They are able to modulate membrane biophysical properties such as membrane fluidity, permeability or the formation of lateral domains with some degree of specificity towards certain cell types such as bacteria, fungi, or cancer cells. In addition, they have shown antioxidant properties which protect membranes from lipid oxidation. They further displayed some activity on membrane proteins either through direct or indirect interaction. We investigate the structure activity relationship of ginsenosides on membranes and discuss the implications and potential use as anticancer, antibacterial, and antifungal agents.

Solubilization of phloretin via steviol glycoside-based solid dispersion and micelles

In this study, the solubility of phloretin (PT) was enhanced via steviol glycoside (STE)-based micelle (MC) and solid dispersion (SD). Computer simulation, characterization, interaction with serum albumin (SA) and in vitro release were carried out to investigate the solubilization mechanisms and the difference in their solubilization capacities. For PT-loaded MC (STE-PT MC), PT was encapsulated into the hydrophobic core of a spherical micelle with a droplet diameter of 5 nm. For PT-loaded SD (STE-PT SD), PT was completely dispersed with the amorphous state in STE. Most of those PTs were directly dissolved in water, and few were encapsulated by STE micelles. The amorphous state combined with relatively large micelles contributed to the high solubilization capacity of STE-PT SD. In addition, PT of STE-PT SD exhibited a higher dissolution rate and more effective interaction with SA than that of STE-PT MC. No undesirable chemical interaction between PT and STE occurred.

Structure of Dense Adsorption Layers of Escin at the Air-Water Interface Studied by Molecular Dynamics Simulations

Saponins are natural surfactants with high surface activity and unique surface properties. Escin is a triterpenoid saponin which has unusually high surface viscoelasticity [Golemanov et al. Soft Matter 2013, 9, 5738] and low permittivity to molecular gas diffusion of its adsorption layers. In our previous study [Tsibranska et al. Langmuir 2017, 33, 8330], we investigated the molecular origin of this unconventional behavior and found that escin molecules rapidly assemble in a compact and stable surface cluster. This behavior was explained with long-range attraction between the hydrophobic aglycones combined with intermediate dipole-dipole attraction and strong short-range hydrogen bonds between the sugar residues in the adsorbed escin molecules. In this study, we performed atomistic molecular simulations of escin molecules in dense adsorption layers with two different areas per molecule. The results show that the surfactant molecules in these systems are much less submerged in water and adopt a more upright position compared to the dilute layers studied previously. A significant number of trapped water molecules are located around the hydrophilic groups placed above the water equimolecular surface to solvate them in the dense layer. To maintain the preferred orientation of the escin molecules with respect to the interface, the most compact adsorption layer acquires a significant spontaneous curvature. The substantial elasticity of the neutral escin layers, as in our previous study, is explained with the presence of a specific interaction, which is intermediate between hydrogen bonding and dipole-dipole attraction (populated lengths in the range 0.16 to >0.35 nm), supplemented by substantial flexibility of the surfactant heads, optimal curvature of the interface, and significant normal displacement of the molecules to allow their tight surface packing. The simulations reveal long-range order within the layers, which signifies the role of the collective behavior of the saponin molecules in such dense adsorption layers.

Dissipative Particle Dynamics Investigation of the Transport of Salicylic Acid through a Simulated In Vitro Skin Permeation Model

Permeation models are often used to determine diffusion properties of a drug through a membrane as it is released from a delivery system. In order to circumvent problematic in vivo studies, diffusion studies can be performed in vitro, using (semi-)synthetic membranes. In this study salicylic acid permeation was studied, employing a nitrocellulose membrane. Both saturated and unsaturated salicylic acid solutions were studied. Additionally, the transport of salicylic acid through the nitrocellulose membrane was simulated by computational modelling. Experimental observations could be explained by the transport mechanism that was revealed by dissipative particle dynamics (DPD) simulations. The DPD model was developed with the aid of atomistic scale molecular dynamics (AA-MD). The choice of a suitable model membrane can therefore, be predicted by AA-MD and DPD simulations. Additionally, the difference in the magnitude of release from saturated and unsaturated salicylic acid and solutions could also be observed with DPD. Moreover, computational studies can reveal hidden variables such as membrane-permeant interaction that cannot be measured experimentally. A recommendation is made for the development of future model permeation membranes is to incorporate computational modelling to aid the choice of model.

Self-Assembly of Escin Molecules at the Air-Water Interface as Studied by Molecular Dynamics

Escin belongs to a large class of natural biosurfactants, called saponins, that are present in more than 500 plant species. Saponins are applied in the pharmaceutical, cosmetics, and food and beverage industries due to their variously expressed bioactivity and surface activity. In particular, escin adsorption layers at the air-water interface exhibit an unusually high surface elastic modulus (>1100 mN/m) and a high surface viscosity (ca. 130 N·s/m). The molecular origin of these unusual surface rheological properties is still unclear. We performed classical atomistic dynamics simulations of adsorbed neutral and ionized escin molecules to clarify their orientation and interactions on the water surface. The orientation and position of the escin molecules with respect to the interface, the intermolecular interactions, and the kinetics of molecular aggregation into surface clusters are characterized in detail. Significant differences in the behavior of the neutral and the charged escin molecules are observed. The neutral escin rapidly assembles in a compact and stable surface cluster. This process is explained by the action of long-range attraction between the hydrophobic aglycones, combined with intermediate dipole-dipole attraction and short-range hydrogen bonds between the sugar residues in escin molecules. The same interactions are expected to control the viscoelastic properties of escin adsorption layers.

Nanosystem trends in drug delivery using quality-by-design concept

Quality by design (QbD) has become an inevitable trend because of its benefits for product quality and process understanding. Trials have been conducted using QbD in nanosystems' optimization. This paper reviews the application of QbD for processing nanosystems and summarizes the application procedure. It provides prospective guidelines for future investigations that apply QbD to nanosystem manufacturing processes. Employing the QbD concept in this way is a novel area in nanosystem quality.

Dissipative particle dynamics study on self-assembled platycodin structures: the potential biocarriers for drug delivery

Platycodin, as a kind of plant based biosurfactants, are saponins which derived from the root of Platycodon grandiflorum A. DC. It has been confirmed that platycodin have the potential to enhance the solubility of hydrophobic drugs and function as the drug carrier, which depends on their micellization over critical micelle concentration (CMC) in aqueous solutions. With the purpose of investigating the effects of influencing factors on the micellization behavior of platycodin and obtaining the phase behavior details at a mesoscopic level, dissipative particle dynamics (DPD) simulations method has been adopted in this study. The simulations reveal that a rich variety of aggregates morphologies will appear with changes of structure or the concentration of saponins, including spherical, ellipse and oblate micelles and vesicles, multilamellar vesicles (MLVs), multicompartment vesicles (MCMs), tubular and necklace-like micelle. They can be formed spontaneously from a randomly generated initial state and the result has been represented in the phase diagrams. Furthermore, deeper explorations have been done on the concentration-dependent structure variation of spherical vesicles as well as the formation mechanism of MLVs. This work provides insight into the solubilization system formed by platycodin, and may serve as guidance for further development and application in pharmaceutical field of platycodin and other saponins.

Differences in physicochemical properties to consider in the design, evaluation and choice between microparticles and nanoparticles for drug delivery

INTRODUCTION

The increase in the development of novel nanoparticle drug delivery systems makes the choice between micro- and nanoscale drug delivery systems ubiquitous. Changes in physical and chemical properties between micro- to nanosized particles give them different properties that influence their physiological, anatomical and clinical behavior and therefore potential application.

AREAS COVERED

This review focuses on the effect changes in the surface-to-volume ratio have on the thermal properties, solubility, dissolution and crystallization of micro- versus nanosized drug delivery systems. With these changes in the physicochemical properties in mind, the review covers computational and biophysical approaches to the design and evaluation of micro- and nanodelivery systems. The emphasis of the review is on the effect these properties have on clinical performance in terms of drug release, tissue retention, biodistribution, efficacy, toxicity and therefore choice of delivery system.

EXPERT OPINION

Ultimately, the choice between micro- and nanometer-sized delivery systems is not straightforward. However, if the fundamental differences in physical and chemical properties are considered, it can be much easier to make a rational choice of the appropriate drug delivery system size.