Antiosteoporosis Effects, Pharmacokinetics, and Drug Delivery Systems of Icaritin: Advances and Prospects

Icaritin Sensitizes Thrombin- and TxA2-Induced Platelet Activation and Promotes Hemostasis via Enhancing PLCγ2-PKC Signaling Pathways

BACKGROUND

 Vascular injury results in uncontrollable hemorrhage in hemorrhagic diseases and excessive antithrombotic therapy. Safe and efficient hemostatic agents which can be orally administered are urgently needed. Platelets play indispensable roles in hemostasis, but there is no drug exerting hemostatic effects through enhancing platelet function.

METHODS

 The regulatory effects of icaritin, a natural compound isolated from Herba Epimedii, on the dense granule release, thromboxane A2 (TxA2) synthesis, α-granule release, activation of integrin αIIbβ3, and aggregation of platelets induced by multiple agonists were investigated. The effects of icaritin on tail vein bleeding times of warfarin-treated mice were also evaluated. Furthermore, we investigated the underlying mechanisms by which icaritin exerted its pharmacological effects.

RESULTS

 Icaritin alone did not activate platelets, but significantly potentiated the dense granule release, α-granule release, activation of integrin αIIbβ3, and aggregation of platelets induced by thrombin and U46619. Icaritin also shortened tail vein bleeding times of mice treated with warfarin. In addition, phosphorylated proteome analysis, immunoblotting analysis, and pharmacological research revealed that icaritin sensitized the activation of phospholipase Cγ2 (PLCγ2)-protein kinase C (PKC) signaling pathways, which play important roles in platelet activation.

CONCLUSION

 Icaritin can sensitize platelet activation induced by thrombin and TxA2 through enhancing the activation of PLCγ2-PKC signaling pathways and promote hemostasis, and has potential to be developed into a novel orally deliverable therapeutic agent for hemorrhages.

Integrated Janus nanofibers enabled by a co-shell solvent for enhancing icariin delivery efficiency

During the past several decades, nanostructures have played their increasing influences on the developments of novel nano drug delivery systems, among which, double-chamber Janus nanostructure is a popular one. In this study, a new tri-channel spinneret was developed, in which two parallel metal capillaries were nested into another metal capillary in a core-shell manner. A tri-fluid electrospinning was conducted with a solvent mixture as the shell working fluid for ensuring the formation of an integrated Janus nanostructure. The scanning electronic microscopic results demonstrated that the resultant nanofibers had a linear morphology and two distinct compartments within them, as indicated by the image of a cross-section. Fourier Transformation Infra-Red spectra and X-Ray Diffraction patterns verified that the loaded poorly water-soluble drug, i.e. icariin, presented in the Janus medicated nanofibers in an amorphous state, which should be attributed to the favorable secondary interactions between icariin and the two soluble polymeric matrices, i.e. hydroxypropyl methyl cellulose (HPMC) and polyvinylpyrrolidone (PVP). The in vitro dissolution tests revealed that icariin, when encapsulated within the Janus nanofibers, exhibited complete release within a duration of 5 min, which was over 11 times faster compared to the raw drug particles. Furthermore, the ex vivo permeation tests demonstrated that the permeation rate of icariin was 16.2 times higher than that of the drug powders. This improvement was attributed to both the rapid dissolution of the drug and the pre-release of the trans-membrane enhancer sodium lauryl sulfate from the PVP side of the nanofibers. Mechanisms for microformation, drug release, and permeation were proposed. Based on the methodologies outlined in this study, numerous novel Janus nanostructure-based nano drug delivery systems can be developed for poorly water-soluble drugs in the future.

Integrating bioprinting, cell therapies and drug delivery towards in vivo regeneration of cartilage, bone and osteochondral tissue

The biological and biomechanical functions of cartilage, bone and osteochondral tissue are naturally orchestrated by a complex crosstalk between zonally dependent cells and extracellular matrix components. In fact, this crosstalk involves biomechanical signals and the release of biochemical cues that direct cell fate and regulate tissue morphogenesis and remodelling in vivo. Three-dimensional bioprinting introduced a paradigm shift in tissue engineering and regenerative medicine, since it allows to mimic native tissue anisotropy introducing compositional and architectural gradients. Moreover, the growing synergy between bioprinting and drug delivery may enable to replicate cell/extracellular matrix reciprocity and dynamics by the careful control of the spatial and temporal patterning of bioactive cues. Although significant advances have been made in this direction, unmet challenges and open research questions persist. These include, among others, the optimization of scaffold zonality and architectural features; the preservation of the bioactivity of loaded active molecules, as well as their spatio-temporal release; the in vitro scaffold maturation prior to implantation; the pros and cons of each animal model and the graft-defect mismatch; and the in vivo non-invasive monitoring of new tissue formation. This work critically reviews these aspects and reveals the state of the art of using three-dimensional bioprinting, and its synergy with drug delivery technologies, to pattern the distribution of cells and/or active molecules in cartilage, bone and osteochondral engineered tissues. Most notably, this work focuses on approaches, technologies and biomaterials that are currently under in vivo investigations, as these give important insights on scaffold performance at the implantation site and its interaction/integration with surrounding tissues.

Exploring the therapeutic potential of isoorientin in the treatment of osteoporosis: a study using network pharmacology and experimental validation

BACKGROUND

Isoorientin (ISO) is a glycosylated flavonoid with antitumor, anti-inflammatory, and antioxidant properties. However, its effects on bone metabolism remain largely unknown.

METHODS

In this study, we aimed to investigate the effects of ISO on receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast formation in vitro and bone loss in post-ovariectomy (OVX) rats, as well as to elucidate the underlying mechanism. First, network pharmacology analysis indicated that MAPK1 and AKT1 may be potential therapeutic targets of ISO and that ISO has potential regulatory effects on the mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) pathways, as well as oxidative stress. ISO was added to RAW264.7 cells stimulated by RANKL, and its effects on osteoclast differentiation were evaluated using tartrate-resistant acid phosphatase (TRAP) staining, TRAP activity measurement, and F-actin ring analysis. Reactive oxygen species (ROS) production in osteoclasts was detected using a ROS assay kit. The effects of ISO on RANKL-triggered molecular cascade response were further investigated by Western blotting, quantitative real-time polymerase chain reaction, and immunofluorescence staining. In addition, the therapeutic effects of ISO were evaluated in vivo.

RESULTS

ISO inhibited osteoclastogenesis in a time- and concentration-dependent manner. Mechanistically, ISO downregulated the expression of the main transcription factor for osteoclast differentiation by inhibiting MAPK and PI3K/AKT1 signaling pathways. Moreover, ISO exhibited protective effects in OVX-induced bone loss rats. This was consistent with the results derived from network pharmacology.

CONCLUSION

Our findings suggest a potential therapeutic utility of ISO in the management of osteoclast-associated bone diseases, including osteoporosis.

Advancements in the Biotransformation and Biosynthesis of the Primary Active Flavonoids Derived from Epimedium

Epimedium is a classical Chinese herbal medicine, which has been used extensively to treat various diseases, such as sexual dysfunction, osteoporosis, cancer, rheumatoid arthritis, and brain diseases. Flavonoids, such as icariin, baohuoside I, icaritin, and epimedin C, are the main active ingredients with diverse pharmacological activities. Currently, most Epimedium flavonoids are extracted from Epimedium plants, but this method cannot meet the increasing market demand. Biotransformation strategies promised huge potential for increasing the contents of high-value Epimedium flavonoids, which would promote the full use of the Epimedium herb. Complete biosynthesis of major Epimedium flavonoids by microbial cell factories would enable industrial-scale production of Epimedium flavonoids. This review summarizes the structures, pharmacological activities, and biosynthesis pathways in the Epimedium plant, as well as the extraction methods of major Epimedium flavonoids, and advancements in the biotransformation and complete microbial synthesis of Epimedium flavonoids, which would provide valuable insights for future studies on Epimedium herb usage and the production of Epimedium flavonoids.

Screening of superior anti-osteoporotic flavonoids from Epimedii Folium with dual effects of reversing iron overload and promoting osteogenesis

Iron overload is a risk factor for postmenopausal osteoporosis (PMOP) and lowering iron levels to regulate the labile plasma iron is the preferred therapy. Icariin (ICA), baohuoside I (BHS) and icaritin (ICT) are three flavonoids obtained from Epimedii Folium that are efficient in facilitating osteogenesis. In this study, an active flavonoid with dual effects of reversing iron overload and promoting osteogenesis was screened based on pharmacokinetics, iron complexation properties and the potential to downregulate iron overload, reversing PMOP. As a result, the in vivo absorption of three compounds was ICA > ICT > BHS, while the exposure in muscle and bone was BHS > ICT > ICA. In vitro complexation showed that only ICT complexed with Fe (III) at a 1:1 ratio on 3-OH and the ICT-Fe (III) complex (m/z 424.3750) was identified by UPLC-Q-TOF-MS. In vivo dynamic detection also showed that the concentration of ICT-Fe (III) complexes varied with the concentration of ICT in plasma. The behavioral blunting and bone loss in zebrafish induced by Fe (III) were significantly reversed by ICT in a dose-dependent manner. Pharmacokinetic-pharmacodynamic analysis showed that ICT was negatively correlated with serum ferritin and positively correlated with osteogenic markers including alkaline phosphatase, osteocalcin and osteoprotegerin. Bone loss in ovariectomized rats was significantly altered after ICT intervention, with reduced serum ferritin levels and improved osteogenic marker levels. These results demonstrated that ICT had favorable musculoskeletal penetration and iron complexation capability to shrink labile plasma iron, showing superior performance in anti-PMOP through the dual effects of reversing iron overload and promoting osteogenesis.

Effects of genus Epimedium in the treatment of osteoarthritis and relevant signaling pathways

Osteoarthritis (OA) is a common chronic degenerative joint disease in clinical practice with a high prevalence, especially in the elderly. Traditional Chinese Medicine (TCM) believes that OA belongs to the category of "Bi syndrome" and the "bone Bi syndrome". The etiology and pathogenesis lie in the deficiency of the liver and kidney, the deficiency of Qi and blood, and external exposure to wind, cold, and dampness. Epimedium is a yang-reinforcing herb in TCM, which can tonify the liver and kidney, strengthen muscles and bones, dispel wind, cold and dampness, and can treat both the symptoms and the root cause of "bone Bi syndrome". In addition, Epimedium contains a large number of ingredients. Through modern science and technology, more than 270 compounds have been found in Epimedium, among which flavonoids are the main active ingredients. Therefore, our study will review the effects and mechanisms of genus Epimedium in treating OA from two aspects: (1) Introduction of Epimedium and its main active ingredients; (2) Effects of Epimedium and its active ingredients in treating OA and relevant signaling pathways, in order to provide more ideas for OA treatment.

Hypoxia-cleavable and specific targeted nanomedicine delivers epigenetic drugs for enhanced treatment of breast cancer and bone metastasis

Breast cancer bone metastasis has become a common cancer type that still lacks an effective treatment method. Although epigenetic drugs have demonstrated promise in cancer therapy, their nontargeted accumulation and drug resistance remain nonnegligible limiting factors. Herein, we first found that icaritin had a strong synergistic effect with an epigenetic drug (JQ1) in the suppression of breast cancer, which could help to relieve drug resistance to JQ1. To improve tumor-targeted efficacy, we developed a hypoxia-cleavable, RGD peptide-modified poly(D,L-lactide-co-glycolide) (PLGA) nanoparticle (termed ARNP) for the targeted delivery of JQ1 and icaritin. The decoration of long cleavable PEG chains can shield RGD peptides during blood circulation and reduce cellular uptake at nonspecific sites. ARNP actively targets breast cancer cells via an RGD-αvβ3 integrin interaction after PEG chain cleavage by responding to hypoxic tumor microenvironment. In vitro and in vivo assays revealed that ARNP exhibited good biodistribution and effectively suppressed primary tumor and bone metastasis. Meanwhile, ARNP could alleviate bone erosion to a certain extent. Furthermore, ARNP significantly inhibited pulmonary metastasis secondary to bone metastasis. The present study suggests that ARNP has great promise in the treatment of breast cancer and bone metastasis due to its simple and practical potential.

Strophiofimbrins A and B: Two Rearranged Norditerpenoids with Novel Tricyclic Carbon Skeletons from Strophioblachia fimbricalyx

Two rearranged norditerpenoids with novel tricyclic carbon skeletons, strophiofimbrin A (1) and strophiofimbrin B (2), were isolated from Strophioblachia fimbricalyx. Their structures were established by 1D/2D NMR spectroscopy, HRESIMS, quantum chemistry calculations, and X-ray diffraction analyses. 1 and 2 represented the first examples of diterpenoids with unprecedented 5/6/7-fused ring systems. In the proposed biosynthetic pathway, they were suspected to derive from cleistanthane norditerpenoids via ring opening, expansion, cyclization, and rearrangement based on the existence of phenanthrenone and cleistanthane diterpenoids from Strophioblachia and Trigonostemon, two closely related genera of the Euphorbiaceae family. Furthermore, compounds 1 and 2 exhibited significant proliferation inhibition and obvious neuroprotective effects.

Polymeric Systems for the Controlled Release of Flavonoids

Flavonoids are natural compounds that are attracting great interest in the biomedical field thanks to the wide spectrum of their biological properties. Their employment as anticancer, anti-inflammatory, and antidiabetic drugs, as well as for many other pharmacological applications, is extensively investigated. One of the most successful ways to increase their therapeutic efficacy is to encapsulate them into a polymeric matrix in order to control their concentration in the physiological fluids for a prolonged time. The aim of this article is to provide an updated overview of scientific literature on the polymeric systems developed so far for the controlled release of flavonoids. The different classes of flavonoids are described together with the polymers most commonly employed for drug delivery applications. Representative drug delivery systems are discussed, highlighting the most common techniques for their preparation. The flavonoids investigated for polymer system encapsulation are then presented with their main source of extraction and biological properties. Relevant literature on their employment in this context is reviewed in relationship to the targeted pharmacological and biomedical applications.

Icaritin Derivative IC2 Induces Cytoprotective Autophagy of Breast Cancer Cells via SCD1 Inhibition

Breast cancer is one of the most prevalent malignancies and the leading cause of cancer-associated mortality in China. Icaritin (ICT), a prenyl flavonoid derived from the Epimedium Genus, has been proven to inhibit the proliferation and stemness of breast cancer cells. Our previous study demonstrated that IC2, a derivative of ICT, could induce breast cancer cell apoptosis by Stearoyl-CoA desaturase 1 (SCD1) inhibition. The present study further investigated the mechanism of the inhibitory effects of IC2 on breast cancer cells in vitro and in vivo. Our results proved that IC2 could stimulate autophagy in breast cancer cells with the activation of adenosine monophosphate (AMP)-activated protein kinase (AMPK) signaling and mitogen-activated protein kinase (MAPK) signaling. Combination treatment of the AMPK inhibitor decreased IC2-induced autophagy while it markedly enhanced IC2-induced apoptosis. In common with IC2-induced apoptosis, SCD1 overexpression or the addition of exogenous oleic acid (OA) could also alleviate IC2-induced autophagy. In vivo assays additionally demonstrated that IC2 treatment markedly inhibited tumor growth in a mouse breast cancer xenograft model. Overall, our study was the first to demonstrate that IC2 induced cytoprotective autophagy by SCD1 inhibition in breast cancer cells and that the autophagy inhibitor markedly enhanced the anticancer activity of IC2. Therefore, IC2 was a potential candidate compound in combination therapy for breast cancer.

Nanomedicine-boosting icaritin-based immunotherapy of advanced hepatocellular carcinoma

Traditional treatments for advanced hepatocellular carcinoma (HCC), such as surgical resection, transplantation, radiofrequency ablation, and chemotherapy are unsatisfactory, and therefore the exploration of powerful therapeutic strategies is urgently needed. Immunotherapy has emerged as a promising strategy for advanced HCC treatment due to its minimal side effects and long-lasting therapeutic memory effects. Recent studies have demonstrated that icaritin could serve as an immunomodulator for effective immunotherapy of advanced HCC. Encouragingly, in 2022, icaritin soft capsules were approved by the National Medical Products Administration (NMPA) of China for the immunotherapy of advanced HCC. However, the therapeutic efficacy of icaritin in clinical practice is impaired by its poor bioavailability and unfavorable in vivo delivery efficiency. Recently, functionalized drug delivery systems including stimuli-responsive nanocarriers, cell membrane-coated nanocarriers, and living cell-nanocarrier systems have been designed to overcome the shortcomings of drugs, including the low bioavailability and limited delivery efficiency as well as side effects. Taken together, the development of icaritin-based nanomedicines is expected to further improve the immunotherapy of advanced HCC. Herein, we compared the different preparation methods for icaritin, interpreted the HCC immune microenvironment and the mechanisms underlying icaritin for treatment of advanced HCC, and discussed both the design of icaritin-based nanomedicines with high icaritin loading and the latest progress in icaritin-based nanomedicines for advanced HCC immunotherapy. Finally, the prospects to promote further clinical translation of icaritin-based nanomedicines for the immunotherapy of advanced HCC were proposed.

Bioactive Scaffold Fabricated by 3D Printing for Enhancing Osteoporotic Bone Regeneration

We develop a poly (lactic-co-glycolic acid)/β-calcium phosphate (PLGA/TCP)-based scaffold through a three-dimensional (3D) printing technique incorporating icaritin (ICT), a unique phytomolecule, and secretome derived from human fetal mesenchymal stem cells (HFS), to provide mechanical support and biological cues for stimulating bone defect healing. With the sustained release of ICT and HFS from the composite scaffold, the cell-free scaffold efficiently facilitates the migration of MSCs and promotes bone regeneration at the femoral defect site in the ovariectomy (OVX)-induced osteoporotic rat model. Furthermore, mechanism study results indicate that the combination of ICT and HFS additively activates the Integrin-FAK (focal adhesion kinase)-ERK1/2 (extracellular signal-regulated kinase 1/2)-Runx2 (Runt-related transcription factor 2) axis, which could be linked to the beneficial recruitment of MSCs to the implant and subsequent osteogenesis enhancement. Collectively, the PLGA/TCP/ICT/HFS (P/T/I/S) bioactive scaffold is a promising biomaterial for repairing osteoporotic bone defects, which may have immense implications for their translation to clinical practice.

Traditional Chinese medicine promotes bone regeneration in bone tissue engineering

Bone tissue engineering (BTE) is a promising method for the repair of difficult-to-heal bone tissue damage by providing three-dimensional structures for cell attachment, proliferation, and differentiation. Traditional Chinese medicine (TCM) has been introduced as an effective global medical program by the World Health Organization, comprising intricate components, and promoting bone regeneration by regulating multiple mechanisms and targets. This study outlines the potential therapeutic capabilities of TCM combined with BTE in bone regeneration. The effective active components promoting bone regeneration can be generally divided into flavonoids, alkaloids, glycosides, terpenoids, and polyphenols, among others. The chemical structures of the monomers, their sources, efficacy, and mechanisms are described. We summarize the use of compounds and medicinal parts of TCM to stimulate bone regeneration. Finally, the limitations and prospects of applying TCM in BTE are introduced, providing a direction for further development of novel and potential TCM.