Synthesis and characterization of silibinin/phenanthroline/neocuproine copper(II) complexes for augmenting bone tissue regeneration: an in vitro analysis

Copper-flavonoid family of complexes involved in alkaline phosphatase activation

The flavonoid naringenin and a family of naringenin derivative Cu(II) complexes having phenanthroline-based second ligands were selected to study alkaline phosphatase activation. This enzyme plays a critical role in tissue formation, increasing the inorganic phosphate formation, favoring mineralization, and being essential to producing bone mineralization. The effects of those compounds on the function and structure of the enzyme were evaluated by kinetic measurements, fluorescence, FTIR, and UV-Vis spectroscopies. The results showed that naringenin did not affect alkaline phosphatase activity, having a value of the Michaelis-Menten-constant close to the enzyme (Km = 3.07 × 10-6). The binary complex, Cu(II)-naringenin, and the ternary complex Cu(II)-naringenin-phenanthroline behaved as an enzyme activator in all the concentrations range used in this study. Those complexes increased in c.a. 1.9% the catalytic efficiency concerning enzyme and naringenin. The ternary complex Cu(II)-naringenin-bathophenanthroline, provokes an activator mixed effect, dependent on the substrate concentrations. The different kinetic behavior can be correlated with different conformational changes observed under the interaction with ALP. Fluorescence experiments showed a raising of the binding constant with temperature. FTIR determinations showed that the complex with bathophenanthroline modifies the ALP structure but maintains the helical structure. The other copper complexes provoked a structural unfolding, decreasing the α-helix content. None of them affect the dephosphorylation enzyme ability. Even though the interactions and structural modifications on ALP are different, it is evident that the presence of copper favors enzymatic activity. The observed electrostatic interactions probably benefit the dissociation of the bound phosphate. The results suggest potential biological applications for the studied compounds.

Silybin Showed Higher Cytotoxic, Antiproliferative, and Anti-Inflammatory Activities in the CaCo Cancer Cell Line while Retaining Viability and Proliferation in Normal Intestinal IPEC-1 Cells

The anticancer potential of silymarin is well known, including its anti-inflammatory as well as antiproliferative effect mediated by influencing the cell cycle, suppression of apoptosis, and inhibition of cell-survival kinases. However, less is known about silybin, the main component of the silymarin complex, where studies indicate its dual effect on the proliferation and immune response of various cell types in a dose-dependent manner. Moreover, there is a lack of studies comparing the effect of silybin on the same type of healthy and tumor cells, especially intestinal ones. Therefore, our study aimed to investigate the concentration-dependent effect of silybin on the normal intestinal porcine epithelial cell line-1 (IPEC-1) and the human epithelial colorectal adenocarcinoma cell line (CaCo-2). The metabolic viability, cell cycle, mitochondrial membrane potential, apoptosis, and the relative gene expression for pro- and anti-inflammatory cytokines were monitored in cells treated with silybin. Silybin stimulates metabolic viability as well as proliferation in IPEC-1 cells, protects the mitochondrial membrane, and thus exerts a cytoprotective effect, and has only a minimal effect on the gene expression of pro-inflammatory cytokines but significantly increases the expression of anti-inflammatory TGF-β. In contrast, it inhibits metabolic viability in tumor intestinal CaCo-2 cells, has an antiproliferative effect accompanied by increased apoptosis, and significantly reduces the expression of genes for pro-inflammatory interleukins as well as TGF-β. The antiproliferative and anti-inflammatory effect of silybin on tumor intestinal cells without a negative effect on healthy cells is a prerequisite for its potential use in the adjuvant therapy of colon cancer; however, further studies are necessary.

In vitro and in vivo investigation of chrysin chelated copper complex as biocompatible materials for bone tissue engineering applications

Flavonoid metal complexes have interesting properties and are widely explored for bone regeneration owing to their potent biological activity. In the present study, we investigated the biocompatibility and osteogenic properties of the Copper(II)-chrysin complex (C/Cu). The biocompatibility of C/Cu was assessed in vitro with human osteoblastic cells and in vivo using chick embryo and zebrafish models. The C/Cu complex was found to be cytofriendly with good biocompatibility. The osteogenic property of C/Cu was studied at cellular and molecular levels. C/Cu promoted mineralization in osteoblastic cultures by increasing ALP activity. At the molecular level, C/Cu significantly promoted the mRNA levels of osteoblast differentiation marker genes such as runt-related transcription factor 2 (Runx2), Type 1 collagen and ALP. In addition to this, secretory proteins, osteonectin (ON) and osteocalcin (OC) levels were also stimulated. We have also identified that C/Cu exhibited enhanced osteogenic properties and antibacterial activity compared with Chrysin. Thus, C/Cu can be used as an osteogenic agent in bone tissue engineering.

Silibinin-modified Hydroxyapatite coating promotes the osseointegration of titanium rods by activation SIRT1/SOD2 signaling pathway in diabetic rats

The purpose of this study is to investigate the role of Silibinin (SIL)-modified Hydroxyapatite coating on osseointegration in diabetes in vivo and in vitro and explore the mechanism of osteogenic differentiation of MC3T3-E1. RT-qPCR, Immunofluorescence, and Western blot were used to measure the expression level of oxidative Stress Indicators and osteogenic markers proteins. Moreover, CCK-8 assay was conducted to detect cell viability in hyperglycemia. Alizarin red staining and alkaline phosphatase staining were used to examine osteogenic function and calcium deposits. The diabetic rat model receive titanium rod implantation was set up successfully and Von-Gieson staining was used to examine femoral bone tissue around titanium rod. Our results showed that intracellular oxidative stress in hyperglycemia was overexpressed, while FoxO1, SIRT1, GPX1, and SOD2 were downregulated. SIL suppressed oxidative stress to promote osteogenic differentiation. Additionally, it was confirmed that SIL promoted osteogenic differentiation of MC3T3-E1 and obviously restored the osseointegration ability of diabetic rats. Further study indicated that SIL exerted its beneficial function through activation SIRT1/SOD2 signaling pathway to restore osteoblast function, and improved the osseointegration and stability of titanium rods in vivo. Our research suggested that the SIL-modulated oxidative Stress inhibition is responsible for the activation of the process of osteogenic differentiation through activation SIRT1/SOD2 signaling pathway in hyperglycemia, providing a novel insight into improving prosthetic osseointegration in diabetic patients. Hyperglycemia impaired the activity and function of MC3T3-E1 and inhibits bone formation by up-regulating intracellular ROS levels through inhibition of SIRT1/SOD2 signaling pathway. Local administrator SIL can improve the activity and function of osteoblasts and enhance osseointegration by reducing intracellular ROS through activation of SIRT1/SOD2 signaling pathway in DM rat models.

Angiogenic and Osteogenic Effects of Flavonoids in Bone Regeneration

Bone is a highly vascularised tissue that relies on a close spatial and temporal interaction between blood vessels and bone cells. As a result, angiogenesis is critical for bone formation and healing. The vascular system supports bone regeneration by delivering oxygen, nutrients, and growth factors, as well as facilitating efficient cell-cell contact. Most clinical applications of engineered bone grafts are hampered by insufficient vascularization after implantation. Over the last decade, a number of flavonoids have been reported to have osteogenic-angiogenic potential in bone regeneration because of their excellent bioactivity, low cost, availability, and minimal in vivo toxicity. During new bone formation, the osteoinductive nature of certain flavonoids is involved in regulating multiple signaling pathways contributing toward the osteogenic-angiogenic coupling. This review briefly outlines the osteogenic-angiogenic potential of those flavonoids and the mechanisms of their action in promoting bone regeneration. However, further studies are needed to investigate their delivery strategies and establish their clinical efficacy. This article is protected by copyright. All rights reserved.

Silibinin Can Promote Bone Regeneration of Selenium Hydrogel by Reducing the Oxidative Stress Pathway in Ovariectomized Rats

Osteoporosis-related bone defects are a major public health concern. Considering poor effects of a singular pharmacological treatment, many have sought combination therapies, including local treatment combined with systemic intervention. Based on recent evidence that selenium and silibinin increase bone formation and bone mineral density, it is hypothesized that systemic administration with silibinin plus local treatment with selenium may have an additive effect on bone regeneration in an OVX rat model with bone defects. To verify this hypothesis, 3-month-old ovariectomized Sprague- Dawley rats (n = 10/gp) were intraperitoneally with a dose of 50 mg/kg silibinin with selenium hydrogel scaffolds implanted into femoral metaphysis bone defect. Moreover, the MC3T3-E1 cells were co-cultured with selenium and silibinin, and observed any change of cell viability, ROS, and osteogenic activity. Experiment results show that the cell mineralization and osteogenic activity of silibinin plus selenium (SSe) group is enormously higher than the control (Con) group and selenium (Se) group, while ROS appears to be immensely reduced. Osteogenic protein expressions such as SIRT1, SOD2, RUNX-2 and OC of SSe group are significantly higher than Con group and Se group. Micro-CT and Histological analysis evaluation display that group SSe, compared with Con group and Se group, presents the strongest effect on bone regeneration, bone mineralization and higher expression of SIRT1 and SOD2. RT-qPCR analysis indicates that SSe group manifests increased SIRT1, SOD1, SOD2 and CAT than the Con group and Se group (p < 0.05). Our current study demonstrates that systemic administration with SIL plus local treatment with Se is a scheme for rapid repair of femoral condylar defects, and these effects may be achieved via reducing the oxidative stress pathway.

Re-appraising the role of flavonols, flavones and flavonones on osteoblasts and osteoclasts- A review on its molecular mode of action

Bone disorders have become a global concern illustrated with decreased bone mineral density and disruption in microarchitecture of natural bone tissue organization. Natural compounds that promote bone health by augmenting osteoblast functions and suppressing osteoclast functions has gained much attention and offer greater therapeutic value compared to conventional therapies. Amongst several plant-based molecules, flavonoids act as a major combatant in promoting bone health through their multi-faceted biological activities such as antioxidant, anti-inflammatory, and osteogenic properties. They protect bone loss by regulating the signalling cascades involved in osteoblast and osteoclast functions. Flavonoids augment osteoblastogenesis and inhibits osteoclastogenesis through their modulation of various signalling pathways. This review discusses the role of various flavonoids and their molecular mechanisms involved in maintaining bone health by regulating osteoblast and osteoclast functions.

Silybin Alleviates Experimental Autoimmune Encephalomyelitis by Suppressing Dendritic Cell Activation and Th17 Cell Differentiation

Silybin, a peculiar flavonoid compound derived from the fruit and seeds of Silybum marianum, exhibits strong anti-inflammatory activities. In the present study, we found that silybin effectively alleviated experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS), via inhibition of dendritic cell (DC) activation and Th17 cell differentiation. Silybin treatment greatly ameliorated the disease severity and significantly declined inflammation and demyelination of the central nervous system (CNS) of EAE mice. Consistent with the disease development, silybin-treated bone marrow-derived DCs (BM-DCs) exhibited reduced costimulatory molecules (e.g., CD80 and CD86) and MHC II expression. These results demonstrated the distinguished bioactivity of silybin for suppressing DC activation, inhibiting pathogenic Th17 inflammatory cell responses, and, eventually, alleviating EAE severity. Taken together, our results show that silybin has high potential for the development of a novel therapeutic agent for the treatment of autoimmune diseases such as MS.

Assessment of human ovarian follicular fluid derived mesenchymal stem cells in chitosan/PCL/Zn scaffold for bone tissue regeneration

Bone tissue engineering compasses the use of mesenchymal stem cells (MSCs) along with engineered biomaterial construct to augment bone regeneration. Till now, MSCs were isolated from various sources and used in cellular constructs. For the first time, in this study, MSCs were isolated from human Ovarian Follicular Fluid (OFF) and characterized by CD 44⁺ and CD 105⁺ markers via confocal microscopy and flow cytometry. Additionally, MSCs stemness, proliferation and colony-forming unit ability, multi-lineage differentiation potential were also studied. To test its suitability for bone tissue engineering applications, we grew the MSCs with the conditioned medium obtained from biocomposite scaffold by fusing a natural polymer, Chitosan (CS) and a synthetic polymer, Polycaprolactone (PCL) and the scaffold were coated with Zinc divalent ions to impart osteogenic properties. The physico-chemical characterization of scaffold, such as FTIR, XRD, and SEM studies was carried out. The biological characterization showed that the scaffolds were compatible with MSCs and promoted osteoblast differentiation which was confirmed at both cellular and molecular levels. The cellular construct increased calcium deposition, analyzed by alizarin red staining and ALP activity at cellular level. At the molecular level, the osteoblast markers expression such as Runx2 and type 1 collagen mRNAs, and osteonectin (ON) and osteocalcin (OC) secretory proteins were increased in the presence of scaffold. Overall, the current study recommends that MSCs can be easily obtained from human waste OFF, and grown in standard in vitro conditions. Successful growth of such MSCs with CS/PCL/Zn scaffold opens new avenues in utilizing the cell source for bone tissue engineering.

Silymarin effect on experimental bone defect repair in rat following implantation of the electrospun PLA/carbon nanotubes scaffold associated with Wharton's jelly mesenchymal stem cells

In this study, the ability of silymarin to heal rat calvarial bone critical defects with mesenchymal stem cells isolated from human Wharton's jelly (HWJMSC) cultured on the electrospun scaffold of poly (lactic acid)/carbon nanotube (PLA/CNT) has been examined. In this study, 20 adult male Wistar rats were divided into four groups of five each. Under general anesthesia, 8 mm defects were created in the calvarial bone of the rats. Then, study groups were defined as no treatment group, the scaffold alone, the scaffold and HWJMSCs, and the scaffold/cells plus oral silymarin, respectively. The histomorphometric study was performed using H&E staining and Goldner's Masson trichrome as specific staining. The results of this study showed that the electrospun PLA/CNT scaffold is a biocompatible scaffold and HWJMSCs can considerably attach and proliferate on this scaffold, and the scaffold itself is also a suitable option for improving the bone repair process. The results of the histomorphometric analysis also showed a significantly higher amount of recently formed bone in the silymarin group plus scaffold/cells compared to the scaffold and cell group alone (p < .05). Utilizing silymarin plus HWJMSCs cultured on PLA/CNT scaffold can be used as a suitable method for the process of osteogenesis and bone repair.

The effects of morin on bone regeneration to accelerate healing in bone defects in mice

Restoring bone defects are the major challenge facing clinical trial therapy, particularly skull related problems. Morin, a naturally occurring compound, has pro-osteogenesis. This research focuses on assessing the role of morin for its pro-osteogenesis activities. We utilized in vivo and in vitro models to investigate the molecular-level mechanisms of morin's osteoblastic biological activity. The effectiveness of morin on pro-osteogenesis (100 mg/kg/day) was assessed by monitoring modifications in the bone histomorphometry score, the development of immature osteoblasts from mesenchymal stems cells and improvements in the expression of pro-osteogenic cytokines in skull defected (SD) mice. Quantitative-PCR, Western blot analysis, and immunofluorescence were studied to investigate the signaling pathways. Morin has a substantial in vivo pro-osteogenesis effect which can facilitate the development of osteoblasts, the production of osteoblast related marker genes, and in vitro protein markers for osteoblasts. From a molecular biology standpoint, morin contributes to the development of osteoblasts and stimulation of the Wnt pathway with the activation and translocation of β-catenin nuclei. Our findings from the study revealed that morin may be a beneficial substitute for helping regenerate bone defects.

Biogenic gold nanoparticles synthesis mediated by Mangifera indica seed aqueous extracts exhibits antibacterial, anticancer and anti-angiogenic properties

During the last few decades, gold nanoparticles (AuNP's) have gained considerable attention in nanomedicine and expanded its application in clinical diagnosis and as therapeutics. Employing plant extract for synthesising gold nanoparticles proves to be an eco-friendly technology for large scale production. It is highly economical and suitable for biological applications by negating the use of chemicals involved in conventional route. In this study, AuNP's was prepared by a simple one step method of employing aqueous Mangifera indica seed extract as a reducing agent. Scanning electron microscopy and transmission electron microscopy revealed spherical shaped nanoparticles and dynamic light scattering analysis indicated the AuNP's to be approximately 46.8 nm in size. AuNP's efficiently inhibited the growth of E. coli and S. aureus by its inherent ability to generate reactive oxygen species (ROS) and exhibited detrimental effects towards the tested bacterial species. Biocompatibility assessment indicated the non-toxic nature of AuNP's towards mesenchymal stem cells at 25 μg/ml and interestingly, suppressed the growth of human gastric cancer cells under in vitro culture conditions. AuNP's significantly exhibited anti-angiogenic property in chick chorioallantoic membrane model (CAM) by downregulating Ang-1/Tie2 pathway. Overall, the synthesized AuNP's exhibited antibacterial and anti-angiogenic properties with high biocompatibility thereby supporting its candidature for various biomedical applications. It can be employed in suppressing tumor growth, combat inflammatory diseases that necessitate the involvement of angiogenesis suppression, and antibacterial activity is suitable for its clinical translation to negate surgery associated infections.