Silymarin loaded liposomes for hepatic targeting: in vitro evaluation and HepG2 drug uptake

Formulation of Silymarin-β Cyclodextrin-TPGS Inclusion Complex: Physicochemical Characterization, Molecular Docking, and Cell Viability Assessment against Breast Cancer Cell Lines

Silymarin (SIL) is a poorly water-soluble flavonoid reported for different pharmacological properties. Its therapeutic applications are limited due to poor water solubility. In this study, the solubility of silymarin has been enhanced by preparing freeze-dried binary and ternary complexes using beta cyclodextrin (βCD) and d-α-tocopherol polyethylene glycol 1000 succinate (TPGS). The stoichiometry of the drug and the carrier was selected from the phase solubility study. The dissolution study was performed to assess the effect of complexation on the release pattern of SIL. The formation of inclusion complexes was confirmed by different physicochemical studies. Finally, a cell viability assay (MCF 7; breast cancer cell line) was performed to compare the activity with free SIL. The phase solubilization results revealed the formation of a stable complex (binary) with a stability constant and complexation efficiency (CE) value of 288 mol L-1 and 0.045%. The ternary sample depicted a significantly enhanced stability constant and CE value (890 mol L-1 and 0.14%). The release study results showed a marked increase in the release pattern after addition of βCD (alone) in the binary mixture (49.4 ± 3.1%) as well as inclusion complex (66.2 ± 3.2%) compared to free SIL (32.7 ± 1.85%). Furthermore, with the addition of TPGS in SIL-βCD (ternary), the SIL release was found to be significantly enhanced from the SIL ternary mixture (79.2 ± 2.13%) in 120 min. However, fast SIL release was achieved with 99.2 ± 1.7% in 45 min for the SIL ternary complex. IR and NMR spectral analysis results revealed the formation of a stable complex with no drug-polymer interaction. The formation of complexes was also confirmed by the molecular docking study (docking scores of 4.1 and -6.4 kcal/mol). The in vitro cell viability result showed a concentration-dependent activity. The IC50 value of the SIL ternary complex was found to be significantly lower than that of free SIL. The findings of the study concluded that the prepared SIL inclusion complex can be used as an alternative oral delivery system to enhance solubility, dissolution, and biological activity against the tested cancer cell line.

Silymarin-Loaded Tin(IV) Nanoparticles Exhibit Enhanced Bioavailability and Antiproliferative Effects on Colorectal Cancer Cells

Silymarin (SM) exhibits potential therapeutic effects due to having antioxidant activity. However, the low solubility and bioavailability of SM restrict its biological performance. To overcome this limitation, this study aimed to develop a nanoformulation composed of SM and dimethyltindichloride and investigate the effect of SM-loaded Sn nanoparticles on cancer cell growth and survival. An SM-Sn complex was synthesized and then characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR), EDS-MAP, dynamic light scattering (DLS), and ζ-potential analysis. After that, the SW480 colorectal cancer cell line was treated with different concentrations of SM and the SM-Sn complex. Cell viability was examined through the 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, analyzing apoptosis, and live-dead assay. The lipid peroxidation rate was assessed through the measurement of thiobarbituric acid (TBA). Intracellular reactive oxygen species (ROS) level and cell population in the cell cycle were measured using a flow cytometry instrument. To evaluate the colonization ability of SW480 cells, a colony formation assay was performed. Gene expression analysis was also conducted using a real-time polymerase chain reaction (PCR) technique. The findings of this study revealed the effectiveness of the SM-Sn complex in decreasing SW480 cell viability by inducing cell death-associated mechanisms. We found that the SM-Sn complex increases intracellular ROS level and malondialdehyde (MDA) content. It was also revealed that the SM-Sn complex induces cell cycle arrest and the expression of apoptotic genes. In addition, the SM-Sn complex could effectively hinder SW480 cells from constituting colonies. We conclude that the use of tin(IV) as a scaffold for enhanced delivery of SM could be considered an efficient option for inhibiting cancer cell proliferation and survival.

Lipid-Based Delivery Systems for Flavonoids and Flavonolignans: Liposomes, Nanoemulsions, and Solid Lipid Nanoparticles

Herbal chemicals with a long history in medicine have attracted a lot of attention. Flavonolignans and flavonoids are considered as two classes of the above-mentioned compounds with different functional groups which exhibit several therapeutic capabilities such as antimicrobial, anti-inflammatory, antioxidant, antidiabetic, and anticancer activities. Based on the studies, high hydrophobic properties of the aforementioned compounds limit their bioavailability inside the human body and restrict their wide application. Nanoscale formulations such as solid lipid nanoparticles, liposomes, and other types of lipid-based delivery systems have been introduced to overcome the above-mentioned challenges. This approach allows the aforementioned hydrophobic therapeutic compounds to be encapsulated between hydrophobic structures, resulting in improving their bioavailability. The above-mentioned enhanced delivery system improves delivery to the targeted sites and reduces the daily required dosage. Lowering the required daily dose improves the performance of the drug by diminishing its side effects on non-targeted tissues. The present study aims to highlight the recent improvements in implementing lipid-based nanocarriers to deliver flavonolignans and flavonoids.

Conventional and PEGylated Liposomes as Vehicles of Copaifera sabulicola

Traditional medicine uses resin oils extracted from plants of the genus Copaifera for several purposes. Resin oils are being studied to understand and profile their pharmacological properties. The aim of this work was to prepare and to characterize conventional and pegylated liposomes incorporating resin oils or the hexanic extract obtained from Copaifera sabulicola (copaiba) leaves. The cytotoxic effect of these products was also investigated. Conventional and stealth liposomes with copaiba extract showed similar average diameters (around 126 nm), encapsulation efficiencies greater than 75% and were stable for 90 days. A cytotoxicity test was performed on murine glioma cells and the developed liposomes presented antiproliferative action against these cancer cells at the average concentration of 30 μg/mL. Phytochemicals encapsulated in PEGylated liposomes induced greater reduction in the viability of tumor cells. In addition, bioassay-s measured the cytotoxicity of copaiba resin oil (Copaifera sabulicola) in liposomes (conventional and PEGylated), which was also checked against pheochromocytoma PC12 cells. Its safety was verified in normal rat astrocytes. The results indicate that liposomes encapsulating copaiba oil showed cytotoxic activity against the studied tumor strains in a dose-dependent fashion, demonstrating their potential applications as a chemotherapeutic bioactive formulation.

Ethnopharmacological impact of Melaleuca rugulosa (Link) Craven leaves extract on liver inflammation

ETHNOPHARMACOLOGICAL RELEVANCE

Melaleuca species have been used by many ethnic communities for the management and treatment of several ailments as hemorrhoids, cough, skin infections, rheumatism, sore throat, pain, inflammation, and digestive system malfunctions. However, the detailed mechanistic pharmacological effect of Melaleuca rugulosa (Link) Craven leaves in the management of liver inflammation has not been yet addressed.

AIM OF THE STUDY

The present study aimed to evaluate the anti-inflammatory, antioxidant, and antiapoptotic capacities of the aqueous methanol extract of M. rugulosa leaves in relevance to their flavonoid content using an appropriate in vivo model.

MATERIALS AND METHODS

The aqueous methanol extract of M. rugulosa leaves was administered to the rats at three non-toxic doses (250, 500, and 1000 mg/kg) for seven days prior to the initiation of liver-injury induced by paracetamol (3 g/kg). Liver enzymes including alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) were evaluated in serum samples. The oxidative stress markers including reduced glutathione (GSH), malondialdehyde (MDA), and nitric oxide (NO) levels as well as the inflammatory markers such as tumour necrosis factor-alpha (TNF-α) and nuclear factor-kappa B (NF-κB), were assessed in liver homogenate. The results were supported by histopathological and immuno-histochemical studies. The phytochemical investigation of the flavonoid-rich fraction of the aqueous methanol extract was accomplished using different chromatographic and spectroscopic techniques.

RESULTS

The aqueous methanol extract of M. rugulosa leaves showed a powerful hepatoprotective activity evidenced by the significant reduction of MDA and NO levels, as well as increasing GSH and catalase activity. Moreover, the extract exhibited anti-inflammatory and antiapoptotic activities witnessed by decreasing TNF-α, NF-κB, iNOS, p-JNK, caspase-3, BAX, and increasing Bcl-2 levels. Moreover, the pretreatment of rats with all doses of M. rugulosa leaves extract showed a significant decrease in liver weight/body weight (LW/BW) ratio, and total bilirubin induced by paracetamol. On the other hand, the chromatographic separation of the flavonoid-rich fraction afforded twenty known flavonoids namely; iso-orientin (1), orientin (2), isovitexin (3), vitexin (4), quercetin-3-O-β-D-glucuronid methyl ether (5), quercetin-3-O-β-D-mannuronpyranoside (6), isoquercetin (7), quercitrin (8), kaempferol-3-O-β-D-mannuronopyranoside (9), kaempferol-7-O-methyl ether-3-O-β-D-glucopyranoside (10), guaijaverin (11), avicularin (12), kaempferide-3-O-β-D-glucopyranoside (13), astragalin (14), afzelin (15), luteolin (16), apigenin (17), quercetin (18), kaempferol (19), and catechin (20).

CONCLUSION

The aqueous methanol extract of M. rugulosa leaves showed potential hepatoprotective, antioxidant, and anti-inflammatory activities against paracetamol-induced liver inflammation which is correlated at least in part to its considerable phenolic content.

Herbal nanomedicines: Recent advancements, challenges, opportunities and regulatory overview

BACKGROUND

Herbal Nano Medicines (HNMs) are nano-sized medicine containing herbal drugs as extracts, enriched fractions or biomarker constituents. HNMs have certain advantages because of their increased bioavailability and reduced toxicities. There are very few literature reports that address the common challenges of herbal nanoformulations, such as selecting the type/class of nanoformulation for an extract or a phytochemical, selection and optimisation of preparation method and physicochemical parameters. Although researchers have shown more interest in this field in the last decade, there is still an urgent need for systematic analysis of HNMs.

PURPOSE

This review aims to provide the recent advancement in various herbal nanomedicines like polymeric herbal nanoparticles, solid lipid nanoparticles, phytosomes, nano-micelles, self-nano emulsifying drug delivery system, nanofibers, liposomes, dendrimers, ethosomes, nanoemulsion, nanosuspension, and carbon nanotube; their evaluation parameters, challenges, and opportunities. Additionally, regulatory aspects and future perspectives of herbal nanomedicines are also being covered to some extent.

METHODS

The scientific data provided in this review article are retrieved by a thorough analysis of numerous research and review articles, textbooks, and patents searched using the electronic search tools like Sci-Finder, ScienceDirect, PubMed, Elsevier, Google Scholar, ACS, Medline Plus and Web of Science.

RESULTS

In this review, the authors suggested the suitability of nanoformulation for a particular type of extracts or enriched fraction of phytoconstituents based on their solubility and permeability profile (similar to the BCS class of drugs). This review focuses on different strategies for optimising preparation methods for various HNMs to ensure reproducibility in context with all the physicochemical parameters like particle size, surface area, zeta potential, polydispersity index, entrapment efficiency, drug loading, and drug release, along with the consistent therapeutic index.

CONCLUSION

A combination of herbal medicine with nanotechnology can be an essential tool for the advancement of herbal medicine research with enhanced bioavailability and fewer toxicities. Despite the challenges related to traditional medicine's safe and effective use, there is huge scope for nanotechnology-based herbal medicines. Overall, it is well stabilized that herbal nanomedicines are safer, have higher bioavailability, and have enhanced therapeutic value than conventional herbal and synthetic drugs.

Recapitulation of Evidence of Phytochemical, Pharmacokinetic and Biomedical Application of Silybin

Silymarin is a standardized extract obtained from seeds of Silybum marianum (SM) belonging to the family Asteraceae. It is a flavonolignan complex and consists of various compounds like silybin A silybin B, isosilybin A, isosilybin B, silydianin, silychristin and isosilychristin. Silybin is the major active component present in 60-70% of the silymarin extract. It has been used traditionally for the treatment of various liver disorders like cirrhosis, jaundice, and hepatitis. Silymarin possesses antioxidant and anti-inflammatory properties and is responsible for its antitumor activity. Other than hepatoprotective effect SM also possesses renoprotective, anti-diabetic, neuroprotective, hypolipidemic, anti-atherosclerosis and cardioprotective effects. Rather antimicrobial property of silymarin was observed against specific microbes, fungi, and viruses. This manuscript covered recent preclinical and clinical evidence of specific components silybin, responsible for its efficacy and about clinical studies has been conducted so far, which proven it's safety and offers mild effect like nausea, diarrhea and bloating. This review specifically focused on recent updates on its active components therapeutic applications against complicated ailments not covered in earlier reports.

Silymarin (milk thistle extract) as a therapeutic agent in gastrointestinal cancer

Silymarin contains a group of closely-related flavonolignan compounds including silibinin, and is extracted from Silybum marianum species, also called milk thistle. Silymarin has been shown to protect the liver in both experimental models and clinical studies. The chemopreventive activity of silymarin has shown some efficacy against cancer both in vitro and in vivo. Silymarin can modulate apoptosis in vitro and survival in vivo, by interfering with the expression of cell cycle regulators and apoptosis-associated proteins. In addition to its anti-metastatic activity, silymarin has also been reported to exhibit anti-inflammatory activity. The chemoprotective effects of silymarin and silibinin (its major constituent) suggest they could be applied to reduce the side effects and increase the anti-cancer effects of chemotherapy and radiotherapy in various cancer types, especially in gastrointestinal cancers. This review examines the recent studies and summarizes the mechanistic pathways and down-stream targets of silymarin in the therapy of gastrointestinal cancer.

Colloidal and vesicular delivery system for herbal bioactive constituents

OBJECTIVES

The main objective of the present review is to explore and examine the effectiveness of currently developed novel techniques to resolve the issues which are associated with the herbal constituents/extract.

METHODS

A systematic thorough search and collection of reviewed information from Science direct, PubMed and Google Scholar databases based on various sets of key phrases have been performed. All the findings from these data have been studied and briefed based on their relevant and irrelevant information.

RESULT

Herbal drugs are gaining more popularity in the modern world due to their applications in curing various ailments with minimum toxic effects, side effect or adverse effect. However, various challenges exist with herbal extracts/plant actives such as poor solubility (water/lipid), poor permeation, lack of targeting specificity, instability in highly acidic pH, and liver metabolism, etc. Nowadays with the expansion in the technology, novel drug delivery system provides avenues and newer opportunity towards the delivery of herbal drugs with improved physical chemical properties, pharmacokinetic and pharmacodynamic. Developing nano-strategies like Polymeric nanoparticles, Liposomes, Niosomes, Microspheres, Phytosomes, Nanoemulsion and Self Nano Emulsifying Drug Delivery System, etc. imparts benefits for delivery of phyto formulation and herbal bioactives. Nano formulation of phytoconstituents/ herbal extract could lead to enhancement of aqueous solubility, dissolution, bioavailability, stability, reduce toxicity, permeation, sustained delivery, protection from enzymatic degradation, etc. CONCLUSION: Based on the above findings, the conclusion can be drawn that the nano sized novel drug delivery systems of herbal and herbal bioactives have a potential future for upgrading the pharmacological action and defeating or overcoming the issues related with these constituents. The aims of the present review was to summarize and critically analyze the recent development of nano sized strategies for promising phytochemicals delivery systems along with their therapeutic applications supported by experimental evidence and discussing the opportunities for further aspects.

Enhanced Bioavailability and Efficacy of Silymarin Solid Dispersion in Rats with Acetaminophen-Induced Hepatotoxicity

We evaluated the bioavailability, liver distribution, and efficacy of silymarin-D-α-tocopherol polyethylene glycol 1000 succinate (TPGS) solid dispersion (silymarin-SD) in rats with acetaminophen-induced hepatotoxicity (APAP) compared with silymarin alone. The solubility of silybin, the major and active component of silymarin, in the silymarin-SD group increased 23-fold compared with the silymarin group. The absorptive permeability of silybin increased by 4.6-fold and its efflux ratio decreased from 5.5 to 0.6 in the presence of TPGS. The results suggested that TPGS functioned as a solubilizing agent and permeation enhancer by inhibiting efflux pump. Thus, silybin concentrations in plasma and liver were increased in the silymarin-SD group and liver distribution increased 3.4-fold after repeated oral administration of silymarin-SD (20 mg/kg as silybin) for five consecutive days compared with that of silymarin alone (20 mg/kg as silybin). Based on higher liver silybin concentrations in the silymarin-SD group, the therapeutic effects of silymarin-SD in hepatotoxic rats were evaluated and compared with silymarin administration only. Elevated alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase levels were significantly decreased by silymarin-SD, silymarin, and TPGS treatments, but these decreases were much higher in silymarin-SD animals than in those treated with silymarin or TPGS. In conclusion, silymarin-SD (20 mg/kg as silybin, three times per day for 5 days) exhibited hepatoprotective properties toward hepatotoxic rats and these properties were superior to silymarin alone, which may be attributed to increased solubility, enhanced intestinal permeability, and increased liver distribution of the silymarin-SD formulation.

Fabrication, characterization and biological evaluation of silymarin nanoparticles against carbon tetrachloride-induced oxidative stress and genotoxicity in rats

This study aimed to synthesize silymarin nanoparticles (SILNPs) using chitosan nanoparticles as a delivery system and to evaluate their protective effects against CCl₄ in rats. Eight groups of male Sprague-Dawley rats were treated for three weeks included the control group, CCl₄-treated group (100 mg/kg b.w twice a week); SIL-treated group (50 mg/lg b.w); the groups treated daily with low dose (LD) or high dose (HD) of SILNPs (25, 50 mg/kg b.w) and the groups treated with CCl₄ plus SIL, SILNPs (LD) or SILNPs (HD). Blood and tissue samples were collected for different assays. The synthesized SILNPs showed a smooth rounded shape with average particle size of 100 ± 2.8 nm. SILNPs contain the same compounds found in raw SIL and the in vitro release of SILNPs continues till 24 h. The in vivo study revealed that SIL and SILNPs at the low or high dose induced a significant improvement in the hematological parameters, liver and kidney function, lipid profile, serum cytokines, gene expression DNA fragmentation and histology of liver and kidney tissue resulted from CCl₄. It could be concluded that SILNPs can be applied in oral delivery formulations with a potential application value for liver disease therapy.

Long-Acting Paliperidone Parenteral Formulations Based on Polycaprolactone Nanoparticles; the Influence of Stabilizer and Chitosan on In Vitro Release, Protein Adsorption, and Cytotoxicity

Long-acting preparations containing the antipsychotic paliperidone for intramuscular injection has drawn considerable attention to achieve harmless long-term treatment. This study aimed to develop paliperidone loaded polycaprolactone (PCL) nanoparticles and investigate the influence of PCL/drug ratio, stabilizer type, and chitosan coating on physicochemical properties, protein adsorption, and cellular toxicity. Results showed that chitosan coating produced enlarged particle sizes, shifted the surface charges from negative into positive and did not influence encapsulation efficiencies. Chitosan coating relatively sustained the drug release especially in pluronic stabilized formulations. Pluronic F127 based formulations exhibited the least protein adsorption (384.3 μg/mL). Chitosan coating of Tween 80 and polyvinyl alcohol stabilized formulations significantly (p < 0.05) increased protein adsorption. Cellular viability was concentration-dependent and negatively affected by stabilizers. All formulations did not show cellular death at 1.56 μg/mL. Inflammatory responses and oxidative stress were less affected by Tween 80 compared with other stabilizers. Chitosan minimized all aspects of cellular toxicity. Collectively, stabilizer type and chitosan coating play critical roles in developing safe and effective long-acting PCL nanoparticles intended for parenteral drug delivery. The coated formulations containing Tween 80 and Pluronic F127 as stabilizers are warranted a future in vivo study to delineate its safety and efficacy profiles.

Design of bile-based vesicles (BBVs) for hepatocytes specific delivery of Daclatasvir: Comparison of ex-vivo transenterocytic transport, in-vitro protein adsorption resistance and HepG2 cellular uptake of charged and β-sitosterol decorated vesicles

Daclatasvir is a new direct acting antiviral used in treatment of Hepatitis C virus, in an attempt to increase its hepatocytes specificity and uptake. It was encapsulated within bile based vesicles (BBVs) containing egg phosphatidyl choline, cholesterol and sodium deoxycholate fabricated by thin-film hydration method. A D-optimal mixture design was applied to study the effect of formulation variables on vesicular characteristics. The dependent variables picked were the particle size, polydispersity index, zeta potential and entrapment efficiency. The optimized bile based vesicles were subjected for further modifications to prepare miniaturized anionic (ABBVs), cationic (CBBVs) and Sito-G decorated BBVs (Sito-GBBVs) to be capable to penetrate liver fenestrae (<200 nm). The aim of the current work is to compare the potential of the ABBVs, CBBVs and Sito-GBBVs loaded with Daclatasvir for stability in simulated biological fluids, ex-vivo intestinal transenterocytic transport, HepG2 cellular uptake and resistance to blood protein adsorption. The miniaturized ABBVs, CBBVs and Sito-GBBVs showed acceptable stability in simulated biological fluids. CBBVs had the highest transenterocytic transport through intestinal membrane. The internalization of CBBVs into HepG2 cells was about 2.1 folds that of ABBVs and 1.45 folds that of Sito-GBBVs. ABBVs and Sito-GBBVs showed superior resistance to opsonization compared to CBBVs which showed significant increase in particle size (p˃0.05) due to protein adsorption. The miniaturized Sito-GBBVs constitute a promising strategy to overcome key biological barriers facing hepatocytes specific delivery of Daclatasvir.

Bioavailability Enhancement of Poorly Soluble Drugs: The Holy Grail in Pharma Industry

Background:

Bioavailability, one of the prime pharmacokinetic properties of a drug, is defined as the fraction of an administered dose of unchanged drug that reaches the systemic circulation and is used to describe the systemic availability of a drug. Bioavailability assessment is imperative in order to demonstrate whether the drug attains the desirable systemic exposure for effective therapy. In recent years, bioavailability has become the subject of importance in drug discovery and development studies.

Methods:

A systematic literature review in the field of bioavailability and the approaches towards its enhancement have been comprehensively done, purely focusing upon recent papers. The data mining was performed using databases like PubMed, Science Direct and general Google searches and the collected data was exhaustively studied and summarized in a generalized manner.

Results:

The main prospect of this review was to generate a comprehensive one-stop summary of the numerous available approaches and their pharmaceutical applications in improving the stability concerns, physicochemical and mechanical properties of the poorly water-soluble drugs which directly or indirectly augment their bioavailability.

Conclusion:

The use of novel methods, including but not limited to, nano-based formulations, bio-enhancers, solid dispersions, lipid-and polymer-based formulations which provide a wide range of applications not only increases the solubility and permeability of the poorly bioavailable drugs but also improves their stability, and targeting efficacy. Although, these methods have drastically changed the pharmaceutical industry demand for the newer potential methods with better outcomes in the field of pharmaceutical science to formulate various dosage forms with adequate systemic availability and improved patient compliance, further research is required.

Delivery of phytochemicals by liposome cargos: recent progress, challenges and opportunities

Bio-availability is a major concern in delivery of dietary phytochemicals for better bio-efficacy. The reduced bio-availability of food bioactive compounds is evident due to degradation during human digestion process which involves liberation, absorption, distribution, metabolism and elimination. The bio-efficacy of any nutrient can be increased by increasing bio-availability. Different technologies are available for engineered efficient delivery systems; still many challenges remain with advancement of delivery systems. The ease of preparedness and adaptability of liposomes has resulted in wide-range of applicability and acceptability in scientific field, especially as delivery vehicles. In view, of properties like biocompatibility and biodegradability, liposomes have been modified with different usable methodologies for delivery of phytochemicals. The aim of this review is to abridge liposomes, methods of preparation, their application as delivery cargo in dietary phytochemicals, result of using different preparation techniques on properties.

Formulation Strategies for Enhancing the Bioavailability of Silymarin: The State of the Art

Silymarin, a mixture of flavonolignan and flavonoid polyphenolic compounds extractable from milk thistle (Silybum marianum) seeds, has anti-oxidant, anti-inflammatory, anti-cancer and anti-viral activities potentially useful in the treatment of several liver disorders, such as chronic liver diseases, cirrhosis and hepatocellular carcinoma. Equally promising are the effects of silymarin in protecting the brain from the inflammatory and oxidative stress effects by which metabolic syndrome contributes to neurodegenerative diseases. However, although clinical trials have proved that silymarin is safe at high doses (>1500 mg/day) in humans, it suffers limiting factors such as low solubility in water (<50 μg/mL), low bioavailability and poor intestinal absorption. To improve its bioavailability and provide a prolonged silymarin release at the site of absorption, the use of nanotechnological strategies appears to be a promising method to potentiate the therapeutic action and promote sustained release of the active herbal extract. The purpose of this study is to review the different nanostructured systems available in literature as delivery strategies to improve the absorption and bioavailability of silymarin.

Enhancement of Silymarin Anti-fibrotic Effects by Complexation With Hydroxypropyl (HPBCD) and Randomly Methylated (RAMEB) β-Cyclodextrins in a Mouse Model of Liver Fibrosis

Silymarin (Sy) shows limited water solubility and poor oral bioavailability. Water-soluble hydroxypropyl (HPBCD) and randomly methylated (RAMEB) β-cyclodextrins were designed to enhance anti-fibrotic efficiency of silymarin in CCl₄-induced liver fibrosis in mice. Experimental fibrosis was induced by intraperitoneal injection with 2 ml/kg CCl₄ (20% v/v) twice a week, for 7 weeks. Mice were orally treated with 50 mg/kg of Sy-HPBCD, Sy-RAMEB and free silymarin. For assessment of the spontaneous reversion of fibrosis, CCl₄ treated animals were investigated after 2 weeks of recovery time. The CCl₄ administration increased hepatic oxidative stress, augmented the expression of transforming growth factor-β1 (TGF-β1) and Smad 2/3, and decreased Smad 7 expression. Furthermore, increased α-smooth muscle actin (α-SMA) expression indicated activation of hepatic stellate cells (HSCs), while up-regulation of collagen I (Col I) and matrix metalloproteinases (MMPs) expression led to an altered extracellular matrix enriched in collagen, confirmed as well by trichrome staining and electron microscopy analysis. Treatment with Sy-HPBCD and Sy-RAMEB significantly reduced liver injury, attenuating oxidative stress, restoring antioxidant balance in the hepatic tissue, and significantly decreasing collagen deposits in the liver. The levels of pro-fibrogenic markers' expression were also significantly down-regulated, whereas in the group for spontaneous regression of fibrosis, they remained significantly higher, even at 2 weeks after CCl₄ administration was discontinued. The recovery was significantly lower for free silymarin group compared to silymarin/β cyclodextrins co-treatments. Sy-HPBCD was found to be the most potent anti-fibrotic complex. We demonstrated that Sy-HPBCD and Sy-RAMEB complexes decreased extracellular matrix accumulation by inhibiting HSC activation and diminished the oxidative damage. This might occur via the inhibition of TGF-β1/Smad signal transduction and MMP/tissue inhibitor of MMPs (TIMP) rebalance, by blocking the synthesis of Col I and decreasing collagen deposition. These results suggest that complexation of silymarin with HPBCD or RAMEB represent viable options for the its oral delivery, of the flavonoid as a potential therapeutic entity candidate, with applications in the treatment of liver fibrosis.

Application of Spray Drying Particle Engineering to a High-Functionality/Low-Solubility Milk Thistle Extract: Powders Production and Characterization

Many natural compounds having antioxidant and anti-inflammatory activity are a potential target for new therapies against chronic inflammatory syndromes. The oral administration of functional herbal supplements may become a prevention strategy or therapy adjuvant for susceptible patients. A case study is our milk thistle (Silybum marianum) extract rich in silymarin complex. A water-soluble microencapsulated powder system was developed by a spray drying technique to improve the poor silymarin bioactivity after oral administration. Sodium carboxymethylcellulose (NaCMC) was employed as coating/swelling polymer matrix and sodium lauryl sulfate (SLS) as the surfactant (1:1:0.05 w/w/w). A H₂O/EtOH/acetone (50/15/35 v/v/v) solvent system was used as liquid feed. The microsystems were capable of improving the in vitro dissolution and permeation rates, suggesting an enhancement of bioactivity after oral administration. The microsystems protect the antioxidant activity of silymarin after harsh storage conditions period and do not affect the anti-inflammatory properties of the raw extract (efficient already at lower concentrations of 0.312 mg/mL) to reduce dendritic cells (DCs) inflammatory cytokine secretion after lipopolysaccharide administration. This approach allows managing particle size, surface properties and release of bioactive agents improving the bioactivity of a herbal supplement and is also possibly applicable to many other similar natural products.

Self-assembly and directed assembly of lipid nanocarriers for prevention of liver fibrosis in obese rats: a comparison with the therapy of bariatric surgery

Aim: Whether the obesity prevention by chemicals or surgeries in already obese patients is the better choice remains controversial. We aimed to compare the effect of orally silibinin-loaded nanocarriers and Roux-en-Y gastric bypass surgery on hepatic fibrosis in high-fat feeding-induced obese rats. Methodology: The developed nanocarriers included self-emulsifying drug delivery system (SNEDDS) and nanostructured lipid carriers (NLC). Results: A significant decrease in collagen production and lipid droplet formation was observed upon nanosystem and bariatric surgery than the rats treated with silibinin control suspension. Stage 3 fibrosis was present in 33% of the obese rats. This percentage could be minimized to 0% by SNEDDS and NLC. Following oral administration, SNEDDS and NLC resulted in 3.5- and 2.9-fold increase, respectively, in bioavailability compared with the reference suspension. Conclusion: Nanomedicine prevention provided a comparable efficiency to ameliorate liver steatosis as Roux-en-Y gastric bypass due to the improvement of silibinin dissolution and gastrointestinal permeation.

Effects of Silymarin-Loaded Nanoparticles on HT-29 Human Colon Cancer Cells

Background and objective: Previous studies have demonstrated the anti-cancer effects of silymarin (SLM). However, the low bioavailability of SLM has restricted its use. This study investigated the toxic effect of nanostructured SLM encapsulated in micelles (Nano-SLM) on the growth of the HT-29 human colon cancer cell line. Materials and methods: HT-29 cells were treated with 25 μM/mL of SLM or Nano-SLM for 48 h. MTT and colony formation assays were used to assess the cytotoxicity and proliferation of HT-29 cells, respectively. The cells were stained with annexin V/PI for assessment of apoptosis. Results: MTT assays revealed that Nano-SLM treatment was able to exert a more pronounced toxic effect on the HT-29 cells as compared to free SLM treatment (p < 0.01). In the Nano-SLM-treated cells, colony numbers were significantly reduced in comparison to the free SLM-treated cells (p < 0.01). Apoptotic and necrotic indexes of Nano-SLM-treated HT-29 cells were also significantly increased in comparison to those of the free SLM-treated cells (p < 0.01). The viability, proliferation and apoptosis of healthy cells (NIH-3T3 cells) were not changed in response to Nano-SLM or SLM. Conclusions: Our results indicate that Nano-SLM enhances the anti-cancer effects of SLM against human colon cancer cells.

In vitro assessment of nutraceutical compounds and novel nutraceutical formulations in a liver-steatosis-based model

Background

Steatosis is a chronic liver disease that depends on the accumulation of intracellular fatty acids. Currently, no drug treatment has been licensed for steatosis; thus, only nutritional guidelines are indicated to reduce its progression. The aim of this study is to combine different nutraceutical compounds in order to evaluate their synergistic effects on a steatosis in vitro model compared to their separate use. In particular, three different formulations based on silymarin, curcumin, vitamin E, docosahexaenoic acid (DHA), choline, and phosphatidylcholine were assayed.

Methods

Human hepatocellular carcinoma cells (HepG2 cell line) were treated with a mixture of fatty acids in order to induce an in vitro model of steatosic cells, and then the amount of intracellular fat was evaluated by Oil Red O staining. The peroxisome proliferator-activated receptors α and γ (PPARα and γ) expression, closely correlated to lipid metabolism, was evaluated. The efficiency of these receptors was evaluated through the study of LPL mRNA expression, a marker involved in the lipolysis mechanism. Superoxide dismutase (SOD-2) and malondialdehydes (MDA) in lipid peroxidation were assayed as specific biomarkers of oxidative stress. In addition, experiments were performed using human liver cells stressed to obtain a steatosis model. In particular, the content of the intracellular fat was assayed using Oil Red O staining, the activation of PPARα and γ was evaluated through western blotting analyses, and the LPL mRNA expression level was analyzed through qRT-PCR.

Results

All formulations proved effective on lipid content reduction of about 35%. The oxidative stress damage was reduced by all the substances separately and even more efficiently by the same in formulation (i.e. Formulation 1 and Formulation 3, which reduced the SOD-2 expression and induced the PPARs activation). Lipid peroxidation, was reduced about 2 fold by foormulation2 and up to 5 fold by the others compared to the cells pretreated with H₂O₂.Formulation 1, was more effective on PPARγ expression (2.5 fold increase) respect to the other compounds on FA treated hepathocytes. Beside, LPL was activated also by Formulation 3 and resulted in a 5 to 9 fold-increase respect to FA treated control.

Conclusions

Our results proved that the formulations tested could be considered suitable support to face steatosis disease beside the mandatory dietetic regimen.

Inducing Controlled Release and Increased Tumor-Targeted Delivery of Chlorambucil via Albumin/Liposome Hybrid Nanoparticles

Liposomes possess good biocompatibility and excellent tumor-targeting capacity. However, the rapid premature release of lipophilic drugs from the lipid bilayer of liposomes has negative effect on the tumor-targeted drug delivery of liposomes. In this study, a lipophilic antitumor drug-chlorambucil (CHL)-was encapsulated into the aqueous interior of liposomes with the aid of albumin to obtain the CHL-loaded liposomes/albumin hybrid nanoparticles (CHL-Hybrids). The in vitro accumulative release rate of CHL from CHL-Hybrids was less than 50% within 48 h, while the accumulative CHL release was more than 80% for CHL-loaded liposomes (CHL-Lip). After intravenous injection into rats, the half-life (t _1/2β = 5.68 h) and maximum blood concentration (C _max = 4.58 μg/mL) of CHL-Hybrids were respectively 1.1 times and 3.5 times higher than that of CHL-Lip. In addition, CHL-Hybrids had better tumor-targeting capacity for it significantly increased the drug accumulation in B16F10 tumors, which contributed to the significantly control of tumor growth compared with CHL-Lip. Furthermore, CHL-Hybrid-treated B16F10 melanoma-bearing mice displayed the longest median survival time of 30.0 days among all the treated groups. Our results illustrated that the proposed hybrids drug delivery system would be a promising strategy to maintain the controlled release of lipophilic antitumor drugs from liposomes and simultaneously facilitate the tumor-targeted drug delivery.

Liposomes as colloidal nanovehicles: on the road to success in intravenous drug delivery

The advancement of research in colloidal systems has led to the increased application of this technology in more effective and targeted drug delivery. Nanotechnology enables control over functionality parameters and allows innovations in biodegradable, biocompatible, and stimuli-responsive delivery systems. The first closed bilayer phospholipid system, the liposome system, has been making steady progress over five decades of extensive research and has been efficient in achieving many desirable parameters such as remote drug loading, size-controlling measures, longer circulation half-lives, and triggered release. Liposome-mediated drug delivery has been successful in overcoming obstacles to cellular and tissue uptake of drugs with improved biodistribution in vitro and in vivo. These colloidal nanovehicles have moved on from a mere concept to clinical applications in various drug delivery systems for antifungal, antibiotic, and anticancer drugs.

Critical Analysis on Characterization, Systemic Effect, and Therapeutic Potential of Beta-Sitosterol: A Plant-Derived Orphan Phytosterol

Beta-sitosterol (BS) is a phytosterol, widely distributed throughout the plant kingdom and known to be involved in the stabilization of cell membranes. To compile the sources, physical and chemical properties, spectral and chromatographic analytical methods, synthesis, systemic effects, pharmacokinetics, therapeutic potentials, toxicity, drug delivery and finally, to suggest future research with BS, classical as well as on-line literature were studied. Classical literature includes classical books on ethnomedicine and phytochemistry, and the electronic search included Pubmed, SciFinder, Scopus, the Web of Science, Google Scholar, and others. BS could be obtained from different plants, but the total biosynthetic pathway, as well as its exact physiological and structural function in plants, have not been fully understood. Different pharmacological effects have been studied, but most of the mechanisms of action have not been studied in detail. Clinical trials with BS have shown beneficial effects in different diseases, but long-term study results are not available. These have contributed to its current status as an "orphan phytosterol". Therefore, extensive research regarding its effect at cellular and molecular level in humans as well as addressing the claims made by commercial manufacturers such as the cholesterol lowering ability, immunological activity etc. are highly recommended.

A new drug nanocrystal self-stabilized Pickering emulsion for oral delivery of silybin

A new silybin nanocrystal self-stabilized Pickering emulsion (SN-SSPE) has been developed using a high pressure homogenization method to improve the oral bioavailability of silybin. Influences of homogenization pressure and drug content on the formation of SN-SSPE were studied. The morphology, structure and size of Pickering emulsion droplets were characterized using a scanning electron micrograph, confocal laser scanning microscopy and atomic force microscopy. The stability, in vitro release and in vivo oral bioavailability of SN-SSPE were investigated. Results indicated that the particle size of silybin nanocrystals (SN-NC) decreased when homogenization pressure increased until 100MPa. When the content of silybin reached 300mg or above, a stable Pickering emulsion of silybin could be formed by sufficient SN-NC covering surfaces of oil droplets completely and thus self-stabilizing the Pickering emulsion. The emulsion droplet of SN-SSPE with the size of 27.3±3.1μm showed a core-shell structure consisting of a core of oil and a shell of SN-NC. SN-SSPE has shown high stability over 40days. The in vitro release rate of SN-SSPE was faster than silybin coarse powder and similar to silybin nanocrystalline suspension (SN-NCS). The peak concentration of silybin of SN-SSPE following intragastric administration in rats was increased by 2.5-fold and 3.6-fold compared with SN-NCS and silybin coarse powder, respectively. The AUC of SN-SSPE was increased by 1.6-fold and 4.0-fold compared with SN-NCS and silybin coarse powder, respectively. All these results showed that the Pickering emulsion of silybin could be stabilized by nanocrystals of silybin itself and increased the oral bioavailability of silybin. The drug nanocrystalline self-stabilized Pickering emulsion was a promising oral drug delivery system for poorly soluble drugs.

Juglone Thermosensitive Liposomes: Preparation, Characterization, in vitro Release and Hyperthermia Cell Evaluation

In this research, thermosensitive liposomes (t-L) containing juglone were prepared with 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and cholesterol by aether injection method. Morphological characteristics, encapsulation efficiency (EE), particle size, zeta potential, in vitro release, and cell viability of t-L were investigated and compared with those of conventional liposomes (c-L). Results indicated that t-L are multilamellar vesicles with lower negative charge, larger particle diameter, and higher EE than c-L. Moreover, in vitro juglone release from t-L was temperature dependent. Up to 60 % of the loaded juglone was released from t-L in 20 min when environmental temperature was increased from 37 °C to 42 °C; by contrast, >60 % of the drug remained inside for 24 h at 37 °C. Furthermore, MTT assay results revealed that t-L significantly increased the inhibitory effect on HepG2 cell growth and proliferation when these cells were exposed to hyperthermia; therefore, t-L could be applied for targeted therapy.

Silymarin-Loaded Nanoparticles Based on Stearic Acid-Modified Bletilla striata Polysaccharide for Hepatic Targeting

Silymarin has been widely used as a hepatoprotective drug in the treatment of various liver diseases, yet its effectiveness is affected by its poor water solubility and low bioavailability after oral administration, and there is a need for the development of intravenous products, especially for liver-targeting purposes. In this study, silymarin was encapsulated in self-assembled nanoparticles of Bletilla striata polysaccharide (BSP) conjugates modified with stearic acid and the physicochemical properties of the obtained nanoparticles were characterized. The silymarin-loaded micelles appeared as spherical particles with a mean diameter of 200 nm under TEM. The encapsulation of drug molecules was confirmed by DSC thermograms and XRD diffractograms, respectively. The nanoparticles exhibited a sustained-release profile for nearly 1 week with no obvious initial burst. Compared to drug solutions, the drug-loaded nanoparticles showed a lower viability and higher uptake intensity on HepG2 cell lines. After intravenous administration of nanoparticle formulation for 30 min to mice, the liver became the most significant organ enriched with the fluorescent probe. These results suggest that BSP derivative nanoparticles possess hepatic targeting capability and are promising nanocarriers for delivering silymarin to the liver.

A New Type of Liquid Silymarin Proliposome Containing Bile Salts: Its Preparation and Improved Hepatoprotective Effects

Silymarin, a known extract, is used in the treatment of liver diseases with various origins, but its current administration form cannot target the liver because of its poor oral bioavailability. A new type of oral silymarin proliposome aimed at improving silymarin's poor bioavailability and hepatoprotective effects, is introduced in this work. Silymarin-loaded liquid proliposome were prepared using a simple dissolving process. The morphology, particle size, zeta potential, and entrapment efficiency of the silymarin liposomes were analysed. The everted gut sac transport model was used to measure the intestinal transport of liposomes. The liposomal hepatoprotective activity was evaluated in three types of experimental hepatitis animal models. After staining with haematoxylin and eosin, the livers were microscopically examined to analyse any pathological changes. The prepared silymarin proliposome formed silymarin liposomes with a multilayer liposome structure and improved intestinal transport. In an injured liver, the silymarin liposomes produced a stronger hepatoprotective effect through a significant decrease in both the aminotransferase and MDA levels and a significant increase in the SOD and GSH-PX levels compared to orally administered silymarin tablets. This effect was also confirmed histopathologically. In a word, incorporation of silymarin into a liposomal carrier system increased intestinal absorption and showed better hepatoprotective effects compared to silymarin tablets.

Recent trends in the development of nanophytobioactive compounds and delivery systems for their possible role in reducing oxidative stress in Parkinson's disease models

Oxidative stress plays a very critical role in neurodegenerative diseases, such as Parkinson's disease (PD), which is the second most common neurodegenerative disease among elderly people worldwide. Increasing evidence has suggested that phytobioactive compounds show enhanced benefits in cell and animal models of PD. Curcumin, resveratrol, ginsenosides, quercetin, and catechin are phyto-derived bioactive compounds with important roles in the prevention and treatment of PD. However, in vivo studies suggest that their concentrations are very low to cross blood-brain barrier thereby it limits bioavailability, stability, and dissolution at target sites in the brain. To overcome these problems, nanophytomedicine with the controlled size of 1-100 nm is used to maximize efficiency in the treatment of PD. Nanosizing of phytobioactive compounds enhances the permeability into the brain with maximized efficiency and stability. Several nanodelivery techniques, including solid lipid nanoparticles, nanostructured lipid carriers, nanoliposomes, and nanoniosomes can be used for controlled delivery of nanobioactive compounds to brain. Nanocompounds, such as ginsenosides (19.9 nm) synthesized using a nanoemulsion technique, showed enhanced bioavailability in the rat brain. Here, we discuss the most recent trends and applications in PD, including 1) the role of phytobioactive compounds in reducing oxidative stress and their bioavailability; 2) the role of nanotechnology in reducing oxidative stress during PD; 3) nanodelivery systems; and 4) various nanophytobioactive compounds and their role in PD.

Beta-Sitosterol: A Promising but Orphan Nutraceutical to Fight Against Cancer

All the currently available cancer therapeutic options are expensive but none of them are safe. However, traditional plant-derived medicines or compounds are relatively safe. One widely known such compound is beta-sitosterol (BS), a plant derived nutrient with anticancer properties against breast cancer, prostate cancer, colon cancer, lung cancer, stomach cancer, ovarian cancer, and leukemia. Studies have shown that BS interfere with multiple cell signaling pathways, including cell cycle, apoptosis, proliferation, survival, invasion, angiogenesis, metastasis and inflammation. Most of the studies are incomplete partly due to the fact that BS is relatively less potent. But the fact that it is generally considered as nontoxic, the opposite of all currently available cancer chemo-therapeutics, is missed by almost all research communities. To offset the lower efficacy of BS, designing BS delivery for "cancer cell specific" therapy hold huge potential. Delivery of BS through liposome is one of such demonstrations that has shown to be highly promising. But further research did not progress neither in the field of drug delivery of BS nor in the field on how BS mediated anticancer activities could be improved, thus making BS an orphan nutraceutical. Therefore, extensive research with BS as potent anticancer nutraceutical is highly recommended.

Hepatoprotective Effect of Silymarin (Silybum marianum) on Hepatotoxicity Induced by Acetaminophen in Spontaneously Hypertensive Rats

This study was aimed to investigate the effect of Silymarin (SLM) on the hypertension state and the liver function changes induced by acetaminophen (APAP) in spontaneously hypertensive rat (SHR). Animals normotensive (N) or hypertensive (SHR) were treated or not with APAP (3 g/kg, oral) or previously treated with SLM. Twelve hours after APAP administration, plasmatic levels of liver function markers: alanine aminotransferase (ALT), aspartate aminotransferase (AST), glucose (GLU), gamma glutamyl transferase (γ-GT), and alkaline phosphatase (ALP) of all groups, were determined. Liver injury was assessed using histological studies. Samples of their livers were then used to determine the myeloperoxidase (MPO) activity and nitric oxide (NO) production and were also sectioned for histological analysis. No differences were observed for ALT, γ-GT, and GLU levels between SHR and normotensive rats groups. However, AST and ALP levels were increased in hypertensive animals. APAP treatment promoted an increase in ALT and AST in both SHR and N. However, only for SHR, γ-GT levels were increased. The inflammatory response evaluated by MPO activity and NO production showed that SHR was more susceptible to APAP effect, by increasing leucocyte infiltration. Silymarin treatment (Legalon) restored the hepatocyte functional and histopathological alterations induced by APAP in normotensive and hypertensive animals.

A safe and efficient hepatocyte-selective carrier system based on myristoylated preS1/21-47 domain of hepatitis B virus

A safe and efficient liver targeted PEGylated liposome (PEG-Lip) based on N-terminal myristoylated preS1/21-47 (preS1/21-47(myr)) of hepatitis B virus was successfully developed. The study aimed to elucidate the cellular uptake mechanism of preS1/21-47(myr) modified PEG-Lip (preS1/21-47(myr)-PEG-Lip) in hepatogenic cells and the distribution behavior of preS1/21-47(myr)-PEG-Lip in Vr:CD1 (ICR) mice. The cellular uptake results showed that preS1/21-47(myr)-PEG-Lip was effectively taken up by hepatogenic cells (including primary hepatocytes and liver tumor cells) through a receptor-mediated endocytosis pathway compared with non-hepatogenic cells. After systemic administration to H22 hepatoma-bearing mice, preS1/21-47(myr)-PEG-Lip showed significant liver-specific delivery and an increase in the distribution of preS1/21-47(myr)-PEG-Lip in hepatic tumor. Furthermore, the antitumor effect of preS1/21-47(myr)-PEG-Lip loaded with paclitaxel (PTX) was remarkably stronger than that of PTX injection and PTX loaded liposomes (including common liposomes and PEG-Lip). In safety evaluation, no acute systemic toxicity and immunotoxicity were observed after intravenous injection of preS1/21-47(myr)-PEG-Lip. No liver toxicity was observed despite the dramatic increase of preS1/21-47(myr)-PEG-Lip in liver. Taken together, preS1/21-47(myr)-PEG-Lip represents a promising carrier system for targeted liver disease therapy and imaging.