A Review on the Molecular Mechanisms of Action of Natural Products in Preventing Bone Diseases

Vitamin D Alleviates Heavy Metal-Induced Cytotoxic Effects on Human Bone Osteoblasts Via the Induction of Bioenergetic Disruption, Oxidative Stress, and Apoptosis

Cadmium (Cd) and lead (Pb) are heavy metals (HMs) that persistently contaminate the ecosystem, and bioaccumulation in bones is a health concern. We used biochemical and molecular assays to assess the cytoprotective effect of vitamin D (VD) on Cd- and Pd-induced chemical toxicity of human bone osteoblasts in vitro. Exposing Cd and Pb to human osteoblast cultures at concentrations of 0.1-1000 µM for 24-72 h significantly reduced osteoblast viability in an exposure time- and concentration-dependent manner. The cytotoxic effect of Cd on osteoblasts was more severe than Pb's, with 72-h exposure estimated half maximal effective concentration (EC50) of 8 and 12 µM, respectively, and VD (1 and 10 nM) alleviated cytotoxicity. Bioenergetics assays of ATP, mitochondrial membrane potential, and mitochondrial complex I and III activity showed that both Cd and Pb (1 and 10 µM) inhibited cellular bioenergetics after 72-h exposure. Cd and Pb increased lipid peroxidation and reactive oxygen species with reduced catalase/superoxide dismutase antioxidant activities and increased activity of caspases -3, -8, and -9. Co-treatment with VD (1 and 10 nM) counteracted bioenergetic disruption, oxidative damage, and apoptosis in a concentration-dependent manner. These findings suggest that VD is effective in managing the toxic effects of environmental pollutants and in treating bone diseases characterized by oxidative stress, apoptosis, and bioenergetic disruption.

Impacts of oxidative stress and anti-oxidants on the development, pathogenesis, and therapy of sickle cell disease: A comprehensive review

Sickle cell disease (SCD) is the most severe monogenic hemoglobinopathy caused by a single genetic mutation that leads to repeated polymerization and depolymerization of hemoglobin resulting in intravascular hemolysis, cell adhesion, vascular occlusion, and ischemia-reperfusion injury. Hemolysis causes oxidative damage indirectly by generating reactive oxygen species through various pathophysiological mechanisms, which include hemoglobin autoxidation, endothelial nitric oxide synthase uncoupling, reduced nitric oxide bioavailability, and elevated levels of asymmetric dimethylarginine. Red blood cells have a built-in anti-oxidant system that includes enzymes like sodium dismutase, catalase, and glutathione peroxidase, along with free radical scavenging molecules, such as vitamin C, vitamin E, and glutathione, which help them to fight oxidative damage. However, these anti-oxidants may not be sufficient to prevent the effects of oxidative stress in SCD patients. Therefore, in line with a recent FDA request that the focus to be placed on the development of innovative therapies for SCD that address the root cause of the disease, there is a need for therapies that target oxidative stress and restore redox balance in SCD patients. This review summarizes the current state of knowledge regarding the role of oxidative stress in SCD and the potential benefits of anti-oxidant therapies. It also discusses the challenges and limitations of these therapies and suggests future directions for research and development.

Exploring the antioxidant potential of endophytic fungi: a review on methods for extraction and quantification of total antioxidant capacity (TAC)

Endophytic fungi have emerged as a significant source of natural products with remarkable bioactivities. Recent research has identified numerous antioxidant molecules among the secondary metabolites of endophytic fungi. These organisms, whether unicellular or micro-multicellular, offer the potential for genetic manipulation to enhance the production of these valuable antioxidant compounds, which hold promise for promoting health, vitality, and various biotechnological applications. In this study, we provide a critical review of methods for extracting, purifying, characterizing, and estimating the total antioxidant capacity (TAC) of endophytic fungi metabolites. While many endophytes produce metabolites similar to those found in plants with established symbiotic associations, we also highlight the existence of novel metabolites with potential scientific interest. Additionally, we discuss how advancements in nanotechnology have opened new avenues for exploring nanoformulations of endophytic metabolites in future studies, offering opportunities for diverse biological and industrial applications.

Improved antioxidant and anti-tubercular potential of liquiritigenin grafted on low molecular weight chitosan from gladius of Sepioteuthis lessoniana

Chitosan (CH) is natural abundant biopolymer present on earth after cellulose. CH can be functionalized by numerous functional groups such as amino and carboxyl groups, potential biologically active compounds. The functionalization of CH with polyphenols had a greater biological than non-grafted CH. In the present study, the polyphenolic compound liquiritigenin (LTG) is chemically functionalized on the low molecular weight chitosan (LMW-CH) (693.09 Da). This was extracted and irradiated with gamma radiation from the gladius of Sepioteuthis lessoniana. The grafted compound was to in vitro anti-oxidant employing physicochemical methods and characterization was made by spectroscopic methods. The degree of deacetylation (DDA) of the LMW-CH was detected in 74 % of the samples, and at higher concentrations (100 g/mL). LMW-CH grafted with LTG had improved water solubility (5 mg/mL), and was thermally stable upto 143.58 °C. Its molecular weight was 855.1 Da. In conclusion the in vitro antioxidant and the anti-tuberculosis (anti-TB) properties of the grafted samples were significantly (P < 0.001) increased compared to the unconjugated LMW-CH and LTG. Overall, functionalization of LTG with LMW-CH improved the anti-tuberculosis activity. Further studies are needed to explore the possibilities of its use in vivo models.

Self-Assembled nanoparticles of natural bioactive molecules enhance the delivery and efficacy of paclitaxel in glioblastoma

BACKGROUND

Glioblastoma (GBM) is the most common primary malignant tumor in the central nervous system. Paclitaxel (PTX) is a well-established and highly effective anti-cancer drug for peripheral solid tumors. However, the application of PTX in GBM is hindered by several limitations, including poor water solubility, restricted entry across the blood-brain barrier (BBB), and enhanced excretion by efflux transporters. P-glycoprotein (P-gp) is a crucial efflux transporter that is abundantly present in cerebral vascular endothelial cells and GBM cells. It plays a significant role in the exocytosis of PTX within tumor tissues.

METHODS

Recently, we have developed a novel technique for creating self-assembled nanoparticles utilizing a range of natural bioactive molecules. These nanoparticles can encapsulate insoluble drugs and effectively cross the BBB. In additional, we revealed that certain nanoparticles have the potential to act as P-gp inhibitors, thereby reducing the excretion of PTX. In this study, we conducted a screening of bioactive molecular nanoparticles to identify those that effectively inhibit the function of P-gp transporters.

RESULTS

Among the candidates, we identified ursolic acid nanoparticles (UA NPs) as the P-gp inhibitors. Furthermore, we prepared co-assembled UA NPs embedded with paclitaxel, referred to as UA-PTX NPs. Our results demonstrate that UA-PTX NPs can enhance the blood concentration of PTX, facilitate its entry into the BBB, and inhibit the function of P-gp, resulting in a decrease in the excretion of PTX. This discovery effectively addressed the above three issues associated with the use of PTX in glioma treatment.

CONCLUSIONS

UA-PTX NPs demonstrate strong anti-tumor effects and show great potential for treating GBM.

Effects of Tenofovir Disoproxil Fumarate on Bone Quality beyond Bone Density-A Scoping Review of the Literature

Tenofovir disoproxil fumarate (TDF) is a widely used pharmacological agent for the treatment of human immunodeficiency virus infection. While prolonged exposure to TDF has been associated with a decrease in bone mineral density (BMD) and increased fracture risk, limited discussion exists on its effects on various aspects of bone quality. This scoping review aims to provide a comprehensive overview of the impact of TDF on bone quality beyond BMD. A literature search was conducted using the PubMed and Scopus databases to identify studies investigating the effects of TDF on bone quality. Original research articles written in English, irrespective of study type or publication year, were included in the review. Seven articles met the inclusion criteria. Findings indicate that prolonged exposure to TDF adversely affects bone microarchitecture and strength, impeding fracture healing and skeletal microdamage repair. The observed effects suggest a complex interplay involving bone cell signalling, cytokines and bone remodelling processes as potential mechanisms underlying TDF's impact on bone quality. As a conclusion, TDF impairs bone remodelling and microarchitecture by influencing dynamic bone cell behaviour and signalling pathways. Future studies should delve deeper into understanding the intricate negative effects of TDF on bone and explore strategies for reversing these effects.

Evaluation of the antibacterial effect of Epigallocatechin gallate on the major pathogens of canine periodontal disease and therapeutic effects on periodontal disease mice

Background

Periodontal disease (PD) is a prevalent oral affliction in canines, with limited therapeutic options available. The potential transmission of oral bacteria from canines to humans through inter-species contact poses a risk of zoonotic infection. Epigallocatechin gallate (EGCG), the principal catechin in green tea polyphenols, exhibits antibacterial properties effective against human PD. Given the clinical parallels between canine and human PD, this study explores the feasibility of employing EGCG as a therapeutic agent for canine PD.

Methods and results

Initially, a survey and statistical analysis of bacterial infection data related to canine PD in China were conducted. Subsequently, the primary pathogenic bacteria of canine PD were isolated and cultivated, and the in vitro antibacterial efficacy of EGCG was assessed. Furthermore, verify the therapeutic effect of EGCG on a mouse PD model in vivo. The high-throughput 16S rRNA gene sequencing identified Porphyromonas, Fusobacterium, Treponema, Moraxella, and Capnocytophaga as the genera that distinguishing PD from healthy canines' gingival crevicular fluid (GCF) samples in China. The anaerobic culture and drug susceptibility testing isolated a total of 92 clinical strains, representing 22 species, from 72 canine GCF samples, including Porphyromonas gulae, Prevotella intermedia, Porphyromonas macacae, etc. The minimum inhibitory concentration (MIC) ranging of EGCG was from 0.019 to 1.25 mg/mL. Following a 7 days oral mucosal administration of medium-dose EGCG (0.625 mg/mL), the abundance of periodontal microorganisms in PD mice significantly decreased. This intervention ameliorated alveolar bone loss, reducing the average cementoenamel junction to the alveolar bone crest (CEJ-ABC) distance from 0.306 mm ± 0.050 mm to 0.161 mm ± 0.026 mm. Additionally, EGCG (0.3125 mg/mL) markedly down-regulated the expression of inflammatory factor IL-6 in the serum of PD mice.

Conclusion

Our research demonstrates the significant antibacterial effects of EGCG against the prevalent bacterium P. gulae in canine PD. Moreover, EGCG exhibits anti-inflammatory properties and proves effective in addressing bone loss in a PD mouse model. These findings collectively suggest the therapeutic potential of EGCG in the treatment of canine PD. The outcomes of this study contribute valuable data, laying the foundation for further exploration and screening of alternative antibiotic drugs to advance the management of canine PD.

Overhauling the ecotoxicological impact of synthetic pesticides using plants' natural products: a focus on Zanthoxylum metabolites

The reduction in agricultural production due to the negative impact of insects and weeds, as well as the health and economic burden associated with vector-borne diseases, has promoted the wide use of chemicals that control these "enemies." However, the use of these synthetic chemicals has been recognized to elicit negative impacts on the environment as well as the health and wellbeing of man. In this study, we presented an overview of recent updates on the environmental and health impacts of synthetic pesticides against agro-pest and disease vectors while exhaustive reviewing the potentials of natural plant products from Zanthoxylum species (Rutaceae) as sustainable alternatives. This study is expected to spur further research on exploiting these plants and their chemicals as safe and effective pesticide entities to minimize the impact of their chemical and synthetic counterparts on health and the environment.

Differential Expression of Non-Coding RNAs in Stem Cell Development and Therapeutics of Bone Disorders

Stem cells' self-renewal and multi-lineage differentiation are regulated by a complex network consisting of signaling factors, chromatin regulators, transcription factors, and non-coding RNAs (ncRNAs). Diverse role of ncRNAs in stem cell development and maintenance of bone homeostasis have been discovered recently. The ncRNAs, such as long non-coding RNAs, micro RNAs, circular RNAs, small interfering RNA, Piwi-interacting RNAs, etc., are not translated into proteins but act as essential epigenetic regulators in stem cells' self-renewal and differentiation. Different signaling pathways are monitored efficiently by the differential expression of ncRNAs, which function as regulatory elements in determining the fate of stem cells. In addition, several species of ncRNAs could serve as potential molecular biomarkers in early diagnosis of bone diseases, including osteoporosis, osteoarthritis, and bone cancers, ultimately leading to the development of new therapeutic strategies. This review aims to explore the specific roles of ncRNAs and their effective molecular mechanisms in the growth and development of stem cells, and in the regulation of osteoblast and osteoclast activities. Furthermore, we focus on and explore the association of altered ncRNA expression with stem cells and bone turnover.

Could eggshell membrane be an adjuvant for recombinant Hepatitis B vaccine?: A preliminary investigation

Background

Despite the invasiveness of the Hepatitis B infection, its vaccines are only formulated with FDA-approved alum-based adjuvants, which poorly elicit a lasting immune response, hence the need for a more effective adjuvant system. This study evaluated the immunogenicity and toxicity of eggshell membranes (ESM) when administered as an adjuvant for the recombinant HBV vaccine (rHBsAg) in albino mice. Differential white blood cell analysis, as well as the titer measurement of Immunoglobulin G, subclass G1 and G2a on indirect ELISA, was performed to measure the immune-modulatory potentials of ESM. Moreover, analysis of the liver marker enzyme (AST and ALT) and body/liver weights was performed to ascertain the toxicity level of ESM. Finally, Immuno-informatic analysis was used to investigate the immune-modulatory potential of individual member proteins of ESM.

Results

Our results showed a significant improvement in the experimental group's lymphocyte count after boost-dose administration compared to the controls, whereas there was no significant change in the granulocyte population. Furthermore, the formulations (ESM-rHBsAg) significantly improved IgG and IgG1 titers after each successive immunization. Body/liver weight and liver function showed ESM non-toxic to mice. The immunoinformatic analysis discovered ovalbumin, lysozyme-C, and UFM-1 as the member proteins of ESM with immune-modulatory activities of activating antigen-presenting cells (APC).

Conclusion

This study has provided a clue into the potential valorization of eggshell membranes and their peptides as an adjuvant for vaccines such as HBV. We recommend more in-depth molecular analysis to support our findings as well as foster real-life application.

Supplementary Information

The online version contains supplementary material available at 10.1186/s43094-023-00481-5.