A directed co-assembly of herbal small molecules into carrier-free nanodrugs for enhanced synergistic antitumor efficacy

Fabrication of polysaccharide-coated oleanolic acid-curcumin-coassembled nanoparticles (OA/Cur NPs): Enhancement of colloidal stability and water solubility

Natural terpenoid carriers, such as oleanolic acid (OA), can enhance the water solubility and stability of hydrophobic compounds such as curcumin (Cur). However, improving the colloidal stability of nanoparticle emulsions and resolving the redispersion problem of freeze-dried nanoparticle powders remain significant challenges. In this study, we fabricated coassembled oleanolic acid-curcumin nanoparticles (OA/Cur NPs) and applied a polysaccharide surface coating method to improve their colloidal stability and water solubility. The results showed that the optimal ratio of Cur/OA for preparing OA/Cur NPs was 4:10, resulting in a high encapsulation efficiency (EE) of Cur (75.2%). Additionally, TEM, contact angle tests, Turbiscan TOWER optical stability analysis of the polysaccharide-coated OA/Cur NP emulsions and redispersion tests of their lyophilized powders verified the advantages of carboxymethyl chitosan/β-cyclodextrin (CMC/β-CD) coating over other polysaccharides. This study indicated that polysaccharide coating is an effective method for enhancing the colloidal stability, water solubility, and redispersibility of OA/Cur NPs.

Natural Products from Herbal Medicine Self-Assemble into Advanced Bioactive Materials

Novel biomaterials are becoming more crucial in treating human diseases. However, many materials require complex artificial modifications and synthesis, leading to potential difficulties in preparation, side effects, and clinical translation. Recently, significant progress has been achieved in terms of direct self-assembly of natural products from herbal medicine (NPHM), an important source for novel medications, resulting in a wide range of bioactive supramolecular materials including gels, and nanoparticles. The NPHM-based supramolecular bioactive materials are produced from renewable resources, are simple to prepare, and have demonstrated multi-functionality including slow-release, smart-responsive release, and especially possess powerful biological effects to treat various diseases. In this review, NPHM-based supramolecular bioactive materials have been revealed as an emerging, revolutionary, and promising strategy. The development, advantages, and limitations of NPHM, as well as the advantageous position of NPHM-based materials, are first reviewed. Subsequently, a systematic and comprehensive analysis of the self-assembly strategies specific to seven major classes of NPHM is highlighted. Insights into the influence of NPHM structural features on the formation of supramolecular materials are also provided. Finally, the drivers and preparations are summarized, emphasizing the biomedical applications, future scientific challenges, and opportunities, with the hope of igniting inspiration for future research and applications.

Recent Advances of Natural Pentacyclic Triterpenoids as Bioactive Delivery System for Synergetic Biological Applications

Bioactive compounds have drawn much attention according to their various health benefits. However, poor dissolvability, low stability and limited bioavailability largely narrow their applications. Although a variety of nontoxic ingredients have been rapidly developed as vehicles to deliver bioactive compounds in the last few years, most of them are non-bioactive. Pentacyclic triterpenoids, owing to their unique self-assembly and co-assembly behaviors and different physiological functions, can construct bioactive carriers due to their higher biodegradability, biocompatibility and lower toxicity. In this paper, the basic classification, biological activities and physicochemical properties of pentacyclic triterpenoids were summarized. Additionally, applications of self-assembled and co-assembled pentacyclic triterpenoids as bioactive delivery systems to load bioactive components and future research directions were discussed. This study emphasizes the potential of pentacyclic triterpenoids as bioactive delivery systems, offering a new perspective for constructing self- or co-assemblies for further synergetic biological applications.

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.

Resveratrol-loaded sulfated Hericium erinaceus β-glucan-chitosan nanoparticles: Preparation, characterization and synergistic anti-inflammatory effects

Resveratrol (RES) is a natural polyphenol with excellent biological activity. But the poor stability and bioavailability of RES severely limit its application. Thus, the resveratrol-loaded sulfated Hericium erinaceus β-glucan-chitosan nanoparticles (DS-CS-RES NPs) were prepared using electrostatic self-assembly to solve these problems in this study. The structure of DS-CS-RES NPs was spherical or sub spherical shape with small average particle size (191.07 nm), which was characterized by FT-IR, FS, XRD and TEM. DS-CS-RES NPs exhibited good stability and RES had a sustainable release from the nanoparticles in gastrointestinal digestion. Meanwhile, DS-CS-RES NPs could improve the inflammatory injury of LPS stimulated RAW264.7 macrophages by inhibiting the production of NO, IL-1β, IL-6 and TNF-α. Furthermore, DS-CS-RES NPs had strong anti-inflammatory activity by regulating protein levels of NF-κB p65, STAT1 and TLR4 through NF-κB and JAK-STAT1 signaling pathway in vitro, and sulfated H. erinaceus β-glucan-chitosan nanoparticle (DS-CS NPs) and RES had synergistic anti-inflammatory effect. Overall, DS-CS NPs can serve as a potential green and safe functional carrier for encapsulating resveratrol, which can improve its anti-inflammatory activity. This work may be conducive to the development of functional carrier for encapsulating RES and applications of hydrophobic active molecules in functional foods or medicines.

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.

Carrier-free self-assembled nanomedicine based on celastrol and galactose for targeting therapy of hepatocellular carcinoma via inducing ferroptosis

Triggering ferroptosis is a potential therapeutic pathway and strategy for the prospective treatment of lethal hepatocellular carcinoma (HCC). The asialo-glycoprotein receptor (ASGPR) is an over-expressed receptor on the membranes of hepatocellular carcinoma cells (HCCs) and binds specifically to galactose (Gal) ligand. Celastrol (CE) is a potent anticancer natural product, but its poor water solubility and severe toxicity restrict its clinical application. In this study, a carrier-free self-assembled nanoparticles, CE-Gal-NPs, were designed and prepared by nanoprecipitation method, which could recognize ASGPR receptor by active targeting (Gal ligand) and passive targeting (EPR effect), access to the cell through the clathrin pathway and finally internalize to lysosomes. CE-Gal-NPs triggered reactive oxygen species (ROS)-mediated ferroptosis pathway and exerted anti-HCC effects in vitro and in vivo by down-regulating GPX4 and up-regulating COX-2 expression, depleting glutathione (GSH) levels, and increasing lipid peroxidation levels in cells and tumor tissues. In the H22 xenograft mouse model, the CE-Gal-NPs group exhibited dramatically superior tumor inhibition than the CE group, while Gal conjugating diminished the systemic toxicity of CE. Consequently, this study presented a promising strategy for CE potentiation and toxicity reduction, as well as a potential guideline for the development of clinically targeted therapeutic agents for HCC.

Advance Progress in Assembly Mechanisms of Carrier-Free Nanodrugs for Cancer Treatment

Nanocarriers have been widely studied and applied in the field of cancer treatment. However, conventional nanocarriers still suffer from complicated preparation processes, low drug loading, and potential toxicity of carriers themselves. To tackle the hindrance, carrier-free nanodrugs with biological activity have received increasing attention in cancer therapy. Extensive efforts have been made to exploit new self-assembly methods and mechanisms to expand the scope of carrier-free nanodrugs with enhanced therapeutic performance. In this review, we summarize the advanced progress and applications of carrier-free nanodrugs based on different types of assembly mechanisms and strategies, which involved noncovalent interactions, a combination of covalent bonds and noncovalent interactions, and metal ions-coordinated self-assembly. These carrier-free nanodrugs are introduced in detail according to their assembly and antitumor applications. Finally, the prospects and existing challenges of carrier-free nanodrugs in future development and clinical application are discussed. We hope that this comprehensive review will provide new insights into the rational design of more effective carrier-free nanodrug systems and advancing clinical cancer and other diseases (e.g., bacterial infections) infection treatment.

Nanoparticles prepared by polysaccharides extracted from Biyang floral mushroom loaded with resveratrol: Characterization, bioactivity and release behavior under in vitro digestion

Resveratrol (RES) is a common active factor in the functional food field, but poor water solubility and low bioavailability have limited its application. In the present study, the novel nanoparticles (RES-CBFMP NPs) using floral mushroom polysaccharide as the wall material have been developed for delivering RES, aiming to overcome its application shortcomings. After ratio optimization, RES-CBFMP NPs (RES-CBFMP,1:8 w/w), which combined through the hydrogen bonds between RES and CBFMP, showed the best overall performance, with the encapsulation efficiency (EE) of 49.74 ± 0.16%, loading efficiency (LE) of 5.53 ± 0.02%, particle size of 158.56 ± 1.97 nm and zeta-potential of -17.56 ± 0.24 mV. In addition, RES-CBFMP NPs exhibited good physicochemical stabilities, sustained gastrointestinal digestive release property, as well as improved in vitro antioxidant and anticancer activities. This study may contribute to the development of RES oral delivery systems and the application of hydrophobic active molecules in the functional food field.

A novel nonreversible heat-induced low-molecular-weight gel based on naturally-occurring self-assembled fupenzic acid for tumor therapy

Herein, a nonreversible heat-induced supramolecular gel based on natural products was reported for the first time. This natural triterpenoid, fupenzic acid (FA), isolated from the roots of Rosa laevigata, was discovered to be capable of forming supramolecular gel spontaneously in 50 % ethanol-water solution induced by heating. Distinguished from the common thermosensitive gels, the FA-gel showed a distinctive nonreversible phase transition from the liquid to gel state upon heating. In this work, the entire gelation process of FA-gel induced by heating was recorded digitally by microrheology monitor. And a unique heat-induced gelation mechanism based on self-assembled FA has been proposed by using various experimental methods and molecular dynamics (MD) simulation. Its excellent injectability and stability were also demonstrated. Furthermore, the FA-gel had been evaluated to exhibit better anti-tumor activity and higher biosafety comparing with its equivalent free-drug, which opened up a new possibility to reinforce antitumor efficacy by using natural product gelator originated from traditional Chinese medicine (TCM) without any complicated chemical modifications.

Recent advances in natural small molecules as drug delivery systems

Drug delivery systems (DDSs) are a multidisciplinary approach toward the effective delivery of drugs to their target sites. Natural small molecule (NSM) compounds with anticancer activity, self-assembly and co-assembly functions show great potential for application as novel DDSs in the biomedical field. NSMs are widely sourced, have many modification sites, and readily form hydrogen bonds, π-π interactions, van der Waals interactions, and other non-covalent bonds in solvents, resulting in ordered structures. Moreover, their good biocompatibility and bioactivity allow compositions based on these compounds to be used in life science applications such as tissue engineering, drug delivery and cell imaging, showing the potential medical value of NSMs as DDSs. In this review, we summarise the role, assembly principles and applications of natural products such as triterpenoids, diterpenoids, sterols, alkaloids and polysaccharides in the construction of small molecule systems, which are expected to provide an important reference for the development of more active natural nanomaterials and the study of single or multi-component interactions.

Self-assembly and self-delivery of the pure nanodrug dihydroartemisinin for tumor therapy and mechanism analysis

Dihydroartemisinin (DHA), a plant-derived natural product, has recently been proven to be an effective therapeutic agent for cancer treatment. Nevertheless, the poor water solubility and low bioavailability of DHA seriously impede its clinical applications. Herein, a simple and green strategy based on the self-assembly of DHA was developed to synthesize carrier-free nanoparticles (NPs). The resulting nanodrug (DHA NPs) was formed by the self-assembly of DHA molecules via hydrogen bonding and hydrophobic interactions. The DHA NPs exhibited a near-spherical morphology with narrow size distribution, favorable drug encapsulation efficiency (>92%), excellent stability, and on-demand drug release behavior. Furthermore, the in vitro and in vivo experiments revealed that the DHA NPs exhibited significantly higher therapeutic efficacy than the DHA equivalent. In addition, we further explored the potential molecular mechanism of the DHA NPs by utilizing RNA-seq technology and western blotting analysis, which demonstrated that the p53 signaling pathway plays a crucial part in the process of inhibiting tumor cell growth and inducing apoptosis. This work not only reveals the rationale for developing pure nanodrugs via the self-assembly of natural small molecules for oncotherapy but also the investigation of the antitumor mechanism and provides novel theoretical support for the clinical usage of DHA.

Edible pentacyclic triterpenes: A review of their sources, bioactivities, bioavailability, self-assembly behavior, and emerging applications as functional delivery vehicles

Edible pentacyclic triterpenes (PTs) are a group of nutraceutical ingredients commonly distributed in human diets. Existing evidence has proven that they have various biological functions, including anticancer, antioxidant, anti-inflammatory and hypoglycemic activities, making them as "functional factor" for a long time. However, their properties of strong hydrophobicity, poor permeability, poor absorption, and rapid metabolism result in low oral bioavailability, which dramatically hinders their efficacy for use. Recently, free PTs have successively been found to self-assemble or co-assemble into self-contained nanostructures with enhanced water dispersibility and oral bioavailability, which seems to be an efficient processing method for increased oral efficacy. Of particular interest, formulating them into nanostructures can also be introduced as functional delivery carriers for bioactive compounds or drugs with various advantages, such as improved stability, controlled release, enhanced oral bioavailability, synergistic bioactivity, and targeted delivery. This review systematically summarized the chemical structures, plant sources, bioactivities, absorption, metabolism, and oral bioavailability of PTs. Notably, we emphasized their self-assembly properties and emerging role as functional delivery carriers for nutrients, suggesting that PT nanostructures are not only efficient oral forms when introduced into foods but also functional delivery materials for nutrients to expand their commercial food applications.

When Natural Compounds Meet Nanotechnology: Nature-Inspired Nanomedicines for Cancer Immunotherapy

Recent significant strides of natural compounds in immunomodulation have highlighted their great potential against cancer. Despite many attempts being made for cancer immunotherapy, the biomedical application of natural compounds encounters a bottleneck because of their unclear mechanisms, low solubility and bioavailability, and limited efficacy. Herein, we summarize the immune regulatory mechanisms of different natural compounds at each step of the cancer-immunity cycle and highlight their anti-tumor potential and current limitations. We then propose and present various drug delivery strategies based on nanotechnology, including traditional nanoparticles (NPs)-based delivery strategies (lipid-based NPs, micelles, and polysaccharide/peptide/protein-based NPs) and novel delivery strategies (cell-derived NPs and carrier-free NPs), thus providing solutions to break through existing bottlenecks. Furthermore, representative applications of nature-inspired nanomedicines are also emphasized in detail with the advantages and disadvantages discussed. Finally, the challenges and prospects of natural compounds for cancer immunotherapy are provided, hopefully, to facilitate their far-reaching development toward clinical translation.

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.

Phytonanomaterials as therapeutic agents and drug delivery carriers

Medicinal plants have been a major resource for drug discovery. Emerging evidence shows that in addition to pharmacologically active components, medicinal plants also contain phytochemical nanomaterials, or phytonanomaterials, which form nanoparticles for drug delivery. In this review, we examine the evidence supporting the existence of phytonanomaterials. Next, we review identification, isolation, and classification of phytonanomaterials, characteristics of phytonanomaterial-derived nanoparticles, and molecular mechanisms of phytonanomaterial assembly. We will then summarize the current progress in exploring phytonanomaterial-derived NPs as therapeutic agents and drug delivery carriers for disease treatment. Last, we will provide perspectives on future discovery and applications of phytonanomaterials.