Preparation and Evaluation of Diosgenin Nanocrystals to Improve Oral Bioavailability

Preparation, stability, and in vitro transport of soybean protein-based diosgenin nanoemulsions

Soybean protein isolate (SPI)-stabilized nanoemulsions (NEs) were formulated to encapsulate diosgenin (DIO) to enhance its water solubility and bioavailability. The influence of DIO concentrations on NEs' properties was investigated, and their environmental stability and cell permeability were also assessed. Results demonstrated that DIO significantly affected all the physicochemical properties of NEs. NEs with 1.0 mg/mL of DIO exhibited smaller droplet size (209 nm), lower polydispersity index (0.17), and higher stability coefficient (95.8 %). Furthermore, DIO-SPI NEs displayed better stability under appropriate pH (<4 or > 5), NaCl concentrations (≤0.3 M), temperatures (≤60 °C), and freeze-thaw cycles (≤2), as well as storage at 4 °C. Moreover, encapsulating DIO in NEs reduced its toxicity towards cells and enhanced its transport efficiency, which reached 3.16 ∼ 4.87 × 10-6. These findings highlight the potential of SPI-based NEs as a promising carrier for the efficient delivery of DIO.

Identification of the Natural Steroid Sapogenin Diosgenin as a Direct Dual-Specific RORα/γ Inverse Agonist

The steroid sapogenin diosgenin is a well-known natural product with a plethora of described pharmacological activities including the amelioration of T helper 17 (Th17)-driven pathologies. However, the exact underlying mode of action of diosgenin leading to a dampened Th17 response is still largely unknown and specific molecular targets have yet to be identified. Here, we show that diosgenin acts as a direct ligand and inverse agonist of the nuclear receptor retinoic acid receptor (RAR)-related orphan receptor (ROR)α and RORγ, which are key transcription factors involved in Th17 cell differentiation and metabolism. IC₅₀ values determined by luciferase reporter gene assays, employing constructs for either RORγ-Gal4 fusion proteins or full length receptors, were in the low micromolar range at around 2 µM. To highlight the functional consequences of this RORα/γ inverse agonism, we determined gene expression levels of important ROR target genes, i.e., IL-17A and glucose-6-phosphatase, in relevant cellular in vitro models of Jurkat T and HepG2 cells, respectively, by RT-qPCR (reverse transcription quantitative PCR). Thereby, it was shown that diosgenin leads to a dose-dependent decrease in target gene expressions consistent with its potent cellular ROR inverse agonistic activity. Additionally, in silico dockings of diosgenin to the ROR ligand-binding domain were performed to determine the underlying binding mode. Taken together, our results establish diosgenin as a novel, direct and dual-selective RORα/γ inverse agonist. This finding establishes a direct molecular target for diosgenin for the first time, which can further explain reported amendments in Th17-driven diseases by this compound.

Diosgenin and Its Analogs: Potential Protective Agents Against Atherosclerosis

Atherosclerosis is a chronic inflammatory disease of the artery wall associated with lipid metabolism imbalance and maladaptive immune response, which mediates most cardiovascular events. First-line drugs such as statins and antiplatelet drug aspirin have shown good effects against atherosclerosis but may lead to certain side effects. Thus, the development of new, safer, and less toxic agents for atherosclerosis is urgently needed. Diosgenin and its analogs have gained importance for their efficacy against life-threatening diseases, including cardiovascular, endocrine, nervous system diseases, and cancer. Diosgenin and its analogs are widely found in the rhizomes of Dioscore, Solanum, and other species and share similar chemical structures and pharmacological effects. Recent data suggested diosgenin plays an anti-atherosclerosis role through its anti-inflammatory, antioxidant, plasma cholesterol-lowering, anti-proliferation, and anti-thrombotic effects. However, a review of the effects of diosgenin and its natural structure analogs on AS is still lacking. This review summarizes the effects of diosgenin and its analogs on vascular endothelial dysfunction, vascular smooth muscle cell (VSMC) proliferation, migration and calcification, lipid metabolism, and inflammation, and provides a new overview of its anti-atherosclerosis mechanism. Besides, the structures, sources, safety, pharmacokinetic characteristics, and biological availability are introduced to reveal the limitations and challenges of current studies, hoping to provide a theoretical basis for the clinical application of diosgenin and its analogs and provide a new idea for developing new agents for atherosclerosis.

Challenges in Coopted Hydrophilic and Lipophilic Herbal Bioactives in the Same Nanostructured Carriers for Effective Bioavailability and Anti-Inflammatory Action

There is ongoing research on various herbal bioactives and delivery systems which indicates that both lipid nanocarriers and herbal medicines will be fine tunned and integrated for future bio-medical applications. The current study was undertaken to systematically develop NLC-DSG-yam extract for the improved efficacy of herbal Diosgenin (DSG) in the management of anti-inflammatory disorders. NLCs were characterized regarding the mean size of the particles, morphological characteristics, physical stability in time, thermal behaviour, and entrapment efficiency of the herbal bioactive. Encapsulation efficiency and in vitro antioxidant activity measured the differences between the individual and dual co-loaded-NLC, the co-loaded one assuring a prolonged controlled release of DSG and a more emphasized ability of capturing short-life reactive oxygen species (ROS). NLCs safety properties were monitored following the in vitro MTS ((3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) tetrazolium reduction assay) and RTCA (Real-Time Cell Analysis) assays. Concentrations less than 50 μg/mL showed no cytotoxic effects during in vitro cytotoxicity assays. Besides, the NLC-DSG-yam extract revealed a great anti-inflammatory effect, as the production of pro-inflammatory cytokines (TNF-alpha, IL-6) was significantly inhibited at 50 μg/mL NLC (e.g., 98.2% ± 1.07 inhibition of TNF-α, while for IL-6 the inhibition percentage was of 62% ± 1.07). Concluding, using appropriate lipid nanocarriers, the most desirable properties of herbal bioactives could be improved.

Rod-shaped nintedanib nanocrystals improved oral bioavailability through multiple intestinal absorption pathways

Nintedanib (BIBF) is a biopharmaceutical classification system II (BCS II) drug that has a good therapeutic effect for the treatment of nonsmall cell lung cancer; however, it shows poor oral bioavailability due to low dissolution and intestinal absorption. This study aims to fabricate rod-shaped nanocrystals to enhance oral bioavailability by improving the dissolution and absorption of BIBF in the intestine. By prescription screening, BIBF nanocrystals (BIBF-NCs) with a particle size of 325.30 ± 1.03 nm and zeta potential of 32.70 ± 1.24 mV were fabricated by an antisolvent precipitation-ultrasound approach with a stabilizer of sodium carboxyl methyl cellulose (CMC-Na). BIBF-NCs exhibited a rod-shaped morphology by transmission electron microscopy (TEM). The results of powder X-ray diffraction (PXRD) and differential scanning calorimetry (DSC) showed that the crystal form of BIBF in BIBF-NCs was altered. The BIBF-NCs remarkably improved the saturation solubility and dissolution of BIBF compared with BIBF powder. According to the results of in situ single-pass intestinal perfusion (SPIP), BIBF-NCs showed improved absorption and membrane permeability, with K_a and P_app values in the jejunum of 0.21 ± 0.01 min^-1 and (4.34 ± 0.11) × 10^-4 cm/min, respectively. Further, the K_a and P_app values of BIBF-NCs were all reduced significantly after the addition of inhibitors colchicine, chlorpromazine and indomethacin, which demonstrated that BIBF-NCs could be absorbed by endocytosis mediated by caveolae and clathrin and micropinocytosis in the intestine. The cell evaluation results showed that BIBF-NCs could be taken up by macrophages and transported from Caco-2 monolayers. The in vivo pharmacokinetic results showed that the bioavailability of the BIBF-NCs was 2.51-fold higher than that of the BIBF solution (BIBF-Sol) after oral administration with a longer T_max (4.50 ± 1.00 h vs. 2.60 ± 1.92 h). In summary, rod-shaped BIBF-NCs could significantly improve oral bioavailability through multiple intestinal absorption pathways.

Multifaced Role of Dual Herbal Principles Loaded-Lipid Nanocarriers in Providing High Therapeutic Efficacity

Although many phytochemicals have been used in traditional medicine, there is a great need to refresh the health benefits and adjust the shortcomings of herbal medicine. In this research, two herbal principles (Diosgenin and Glycyrrhiza glabra extract) coopted in the Nanostructured Lipid Carriers have been developed for improving the most desirable properties of herbal medicine—antioxidant and anti-inflammatory actions. The contribution of phytochemicals, vegetable oils and of lipid matrices has been highlighted by comparative study of size, stability, entrapment efficiency, morphological characteristics, and thermal behavior. According to the in vitro MTS and RTCA results, the dual herbal-NLCs were no cytotoxic toward endothelial cells at concentrations between 25 and 100 µg/mL. A rapid release of Glycyrrhiza glabra and a motivated delay of Diosgenin was detected by the in vitro release experiments. Dual herbal-NLCs showed an elevated ability to annihilate long-life cationic radicals (ABTS^•+) and short-life oxygenated radicals (an inhibition of 63.4% ABTS^•+, while the ability to capture radical oxygen species reached 96%). The production of pro-inflammatory cytokines was significantly inhibited by the newly herbals-NLC (up to 97.9% inhibition of TNF-α and 62.5% for IL-6). The study may open a new pharmacotherapy horizon; it provides a comprehensive basis for the use of herbal-NLC in the treatment of inflammatory diseases.

Fenugreek steroidal saponins hinder osteoclastogenic bone resorption by targeting CSF-1R which diminishes the RANKL/OPG ratio

Osteoporosis is skeletal fragility caused by the excessive bone resorption due to osteoclastogenesis. But current drugs are less bioavailable and possess higher toxicity. Our study was conducted to identify safe oral bioavailable drugs from Fenugreek steroidal saponins and to delineate underlying mechanism of them to lower the osteoclastogenic bone resorption. We observed higher molecular docked binding affinities in finally selected eight hit compounds within the range of -11.0 to -10.1 kcal/mol which was greater than currently used drugs. Molecular Dynamics simulation with Root Mean Square Deviation (RMSD), Root Mean Square Fluctuation (RMSF), Solvent Accessible Surface Area (SASA) and Gyration trajectory projection reinforced the stability of the protein-ligand complexes. Pharmacokinetics analysis confirmed bioavailability of seven compounds out of eight, and drug likeliness and bioavailability profile evaluation indicated that they all are eligible to be developed as a potent oral inhibitor of CSF-1R. By literature mining knowledge-driven analysis, RNAseq data and Molecular Dynamics Simulation, we proposed that, the hit derivatives block the CSF-1/CSF-1R induced phosphorylation signaling pathway in both osteoclast and osteoblast resulting in hindrance of RANK expression and formation of Reactive oxygen species (ROS) in osteoclast and osteoblast respectively, thus declines the RANKL/OPG ratio, lowering the osteoclast survival, proliferation and differentiation.

Preparation and antitumor evaluation of quercetin nanosuspensions with synergistic efficacy and regulating immunity

To study the effect of quercetin (QUR) on modulating immune effects, enhancing anti-tumor activity, and reducing drug related side effects, three QUR nanosuspensions (QUR-NPs) with different particle sizes were prepared by a microprecipitation-high pressure homogenization method using mPEG-DCA as a stabilizer. Dynamic light scattering was used to analyze the particle sizes of the three QUR-NPs. The results of stability tests showed that the three QUR-NPs had good storage and plasma stability. It was confirmed that plasma protein adsorption occurred for all three QUR-NPs. The results of DSC, DTG, XRPD, and Raman spectroscopy showed that there was no significant change in the crystal form of QUR for any of the three QUR-NPs compared with the commercial QUR. The in vitro dissolution rate of the three QUR-NPs was significantly faster than that of the micronized QUR, with the dissolution rate increasing as particle size decreased. All three QUR-NPs showed stronger in vitro inhibitory activity on MCF-7 cells than the pure QUR solution, with the largest NPs having the strongest inhibitory effect. The pharmacokinetic parameters in rats showed that the MRT and t_1/2 of the QUR-NPs increased as particle size increased. QUR-NPs and the pure QUR solution showed obvious anti-tumor effects against murine hepatic carcinoma H22 model in vivo, although they were not as effective as cyclophosphamide (CTX). However, the anti-tumor effect of the large QUR-NPs combined with CTX was the strongest among all the tested groups. From the results of the thymus and spleen index, it was found that the QUR-NPs could not only regulate the immunity of tumor-bearing mice, but also alleviate the immunosuppression caused by CTX and protect normal tissues, all while enhancing the anti-tumor effect. The immunomodulatory effect of the QUR-NPs on tumor-bearing mice was significantly better than that of the pure QUR solution. Therefore, nanosuspensions can be used as a new drug delivery system for QUR to assist tumor therapy and regulate immunity.

Diosgenin, a steroidal saponin, and its analogs: Effective therapies against different chronic diseases

BACKGROUND

Chronic diseases are a major cause of mortality worldwide, and despite the recent development in treatment modalities, synthetic drugs have continued to show toxic side effects and development of chemoresistance, thereby limiting their application. The use of phytochemicals has gained attention as they show minimal side effects. Diosgenin is one such phytochemical which has gained importance for its efficacy against the life-threatening diseases, such as cardiovascular diseases, cancer, nervous system disorders, asthma, arthritis, diabetes, and many more.

AIM

To evaluate the literature available on the potential of diosgenin and its analogs in modulating different molecular targets leading to the prevention and treatment of chronic diseases.

METHOD

A detailed literature search has been carried out on PubMed for gathering information related to the sources, biosynthesis, physicochemical properties, biological activities, pharmacokinetics, bioavailability and toxicity of diosgenin and its analogs.

KEY FINDINGS

The literature search resulted in many in vitro, in vivo and clinical trials that reported the efficacy of diosgenin and its analogs in modulating important molecular targets and signaling pathways such as PI3K/AKT/mTOR, JAK/STAT, NF-κB, MAPK, etc., which play a crucial role in the development of most of the diseases. Reports have also revealed the safety of the compound and the adaptation of nanotechnological approaches for enhancing its bioavailability and pharmacokinetic properties.

SIGNIFICANCE

Thus, the review summarizes the efficacy of diosgenin and its analogs for developing as a potent drug against several chronic diseases.

Soluplus-Mediated Diosgenin Amorphous Solid Dispersion with High Solubility and High Stability: Development, Characterization and Oral Bioavailability

Background and Purpose

The traditional Chinese medicine, diosgenin (Dio), has attracted increasing attention because it possesses various therapeutic effects, including anti-tumor, anti-infective and anti-allergic properties. However, the commercial application of Dio is limited by its extremely low aqueous solubility and inferior bioavailability in vivo. Soluplus, a novel excipient, has great solubilization and capacity of crystallization inhibition. The purpose of this study was to prepare Soluplus-mediated Dio amorphous solid dispersions (ASDs) to improve its solubility, bioavailability and stability.

Methods

The crystallization inhibition studies were firstly carried out to select excipients using a solvent shift method. According to solubility and dissolution results, the preparation methods and the ratios of drug to excipient were further optimized. The interaction between Dio and Soluplus was characterized by differential scanning calorimetry (DSC), fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), powder X-ray diffraction (PXRD) and molecular docking. The pharmacokinetic study was conducted to explore the potential of Dio ASDs for oral administration. Furthermore, the long-term stability of Dio ASDs was also investigated.

Results

Soluplus was preliminarily selected from various excipients because of its potential to improve solubility and stability. The optimized ASDs significantly improved the aqueous solubility of Dio due to its amorphization and the molecular interactions between Dio and Soluplus, as evidenced by dissolution test in vitro, DSC, FT-IR spectroscopy, SEM, PXRD and molecular docking technique. Furthermore, pharmacokinetic studies in rats revealed that the bioavailability of Dio from ASDs was improved about 5 times. In addition, Dio ASDs were stable when stored at 40°C and 75% humidity for 6 months.

Conclusion

These results indicated that Dio ASDs, with its high solubility, high bioavailability and high stability, would open a promising way in pharmaceutical applications.

Effects of diosgenin on the skeletal system in rats with experimental type 1 diabetes

There is a great interest in substances of plant origin, which may exert health-promoting activities in diabetes and its complications. Previous studies suggested that diosgenin may favorably affect both glucose metabolism and osteoporosis. The aim of the study was to investigate the effects of diosgenin on the skeletal disorders induced by experimental type 1 diabetes (T1D) in rats. The experiments were performed on 3-month-old female rats, divided into three groups: I - healthy control rats, II - streptozotocin-induced diabetic control rats, III - diabetic rats receiving diosgenin. T1D was induced by a single streptozotocin injection (60 mg/kg i.p.). Diosgenin administration (50 mg/kg/day p.o.) started two weeks later and lasted four weeks. Serum bone turnover markers and other biochemical parameters, bone mass and mineralization, mechanical properties and histomorphometric parameters were examined. Diabetes induced profound metabolic disturbances and disorders of cancellous bone microarchitecture and strength. Diosgenin did not favorably affect the serum bone turnover markers and other biochemical parameters, bone mass, mineralization and mechanical properties in the diabetic rats. However, it counteracted the effect of diabetes on the growth plate and cancellous bone microarchitecture in the distal femur, indicating some limited beneficial influence on the skeleton.

The role of diosgenin in diabetes and diabetic complications

Diabetes mellitus is a chronic and common metabolic disease that seriously endangers human health. Hyperglycemia and long-term metabolic disorders in diabetes will cause damage to the whole body tissues and organs, resulting in serious complications. Nowadays, drugs for treating diabetes on the market has strong side effects, new treatments thus are urgently needed. Natural therapy of natural ingredients is a promising avenue, this is because natural ingredients are safer and they also show strong activity in the treatment of diabetes. Diosgenin is such a very biologically active natural steroidal sapogenin. The research of diosgenin in the treatment of diabetes and its complications has been widely reported. This article reviews the effects of diosgenin through multiple targets and multiple pathways in diabetes and its complications which including diabetic nephropathy, diabetic liver disease, diabetic neuropathy, diabetic vascular disease, diabetic cardiomyopathy, diabetic reproductive dysfunction, and diabetic eye disease.

Therapeutic Potential of Diosgenin and Its Major Derivatives against Neurological Diseases: Recent Advances

Diosgenin (DG), a well-known steroidal sapogenin, is present abundantly in medicinal herbs such as Dioscorea rhizome, Dioscorea villosa, Trigonella foenum-graecum, Smilax China, and Rhizoma polgonati. DG is utilized as a major starting material for the production of steroidal drugs in the pharmaceutical industry. Due to its wide range of pharmacological activities and medicinal properties, it has been used in the treatment of cancers, hyperlipidemia, inflammation, and infections. Numerous studies have reported that DG is useful in the prevention and treatment of neurological diseases. Its therapeutic mechanisms are based on the mediation of different signaling pathways, and targeting these pathways might lead to the development of effective therapeutic agents for neurological diseases. The present review mainly summarizes recent progress using DG and its derivatives as therapeutic agents for multiple neurological disorders along with their various mechanisms in the central nervous system. In particular, those related to therapeutic efficacy for Parkinson's disease, Alzheimer's disease, brain injury, neuroinflammation, and ischemia are discussed. This review article also critically evaluates existing limitations associated with the solubility and bioavailability of DG and discusses imperatives for translational clinical research. It briefly recapitulates recent advances in structural modification and novel formulations to increase the therapeutic efficacy and brain levels of DG. In the present review, databases of PubMed, Web of Science, and Scopus were used for studies of DG and its derivatives in the treatment of central nervous system diseases published in English until December 10, 2019. Three independent researchers examined articles for eligibility. A total of 150 articles were screened from the above scientific literature databases. Finally, a total of 46 articles were extracted and included in this review. Keywords related to glioma, ischemia, memory, aging, cognitive impairment, Alzheimer, Parkinson, and neurodegenerative disorders were searched in the databases based on DG and its derivatives.

Effects of diosgenin and its derivatives on atherosclerosis

The effects of diosgenin are discussed with respect to endothelial dysfunction, lipid profile, macrophage foam cell formation, VSMC viability, thrombosis and inflammation during the formation of atherosclerosis.

Spice-Derived Bioactive Ingredients: Potential Agents or Food Adjuvant in the Management of Diabetes Mellitus

Spices possess tremendous therapeutic potential including hypoglycemic action, attributed to their bioactive ingredients. However, there is no study that critically reviewed the hypoglycemic potency, safety and the bioavailability of the spice-derived bioactive ingredients (SDBI). Therefore, the aim of the study was to comprehensively review all published studies regarding the hypoglycemic action of SDBI with the purpose to assess whether the ingredients are potential hypoglycemic agents or adjuvant. Factors considered were concentration/dosages used, the extent of blood glucose reduction, the IC50 values, and the safety concern of the SDBI. From the results, cinnamaldehyde, curcumin, diosgenin, thymoquinone (TQ), and trigonelline were showed the most promising effects and hold future potential as hypoglycemic agents. Conclusively, future studies should focus on improving the tissue and cellular bioavailability of the promising SDBI to achieve greater potency. Additionally, clinical trials and toxicity studies are with these SDBI are warranted.

Transmembrane Pathways and Mechanisms of Rod-like Paclitaxel Nanocrystals through MDCK Polarized Monolayer

Drug nanocrystals (NCs) appear to be favorable to improving oral bioavailability of poorly water-soluble drugs as evidenced by the great success they have had in the market. However, the pathway and mechanism of drug NCs through epithelial membrane are still unclear. In an attempt to clarify their transport features, paclitaxel nanocrystals (PTX-NCs), and paclitaxel hybrid NCs with lipophilic carbocyanine dyes, were prepared and characterized as the models. The endocytosis, intracellular trafficking, paracellular transport, and transcytosis of PTX-NCs were carefully investigated with Förster resonance energy transfer (FRET) analysis, as well as a colocalization assay, flow cytometry, gene silencing, Western-blot, transepithelial electrical resistance (TEER) study and other approaches on MDCK cells. It was found that rod-like PTX-NCs could transport through the monolayer intact, and the process of endocytosis proved to be time and energy dependent. Endoplasmic reticulum (ER) and Golgi complexes were colocalized with PTX-NCs in cells, so the ER-Golgi complexes/Golgi complexes-basolateral membrane pathway may be involved in the intracellular trafficking and transcytosis of PTX-NCs. It was demonstrated here that cav-1, dynamin, and actin filament modulated the endocytosis process, and Cdc 42 regulated the transcytosis process. In addition, no paracellular transport of PTX-NCs was observed. These findings demonstrated that the rod-like nanocrystals not only enhanced the transcytosis of PTX compared with microparticles of raw drug materials but also changed the pathways of drug delivery. This study certainly provides insight for the oral absorption mechanism of nanocrystals of poorly soluble drugs.