Dendritic effect of ligand-coated nanoparticles: enhanced apoptotic activity of silica-berberine nanoconjugates

The potential of the nutraceutical berberine in the treatment of hepatocellular carcinoma and other liver diseases such as NAFLD and NASH

Hepatocellular carcinoma (HCC) is a common cancer which unfortunately has poor outcomes. Common anti-cancer treatments such as chemotherapy and targeted therapy have not increased patient survival significantly. A common treatment for HCC patients is transplantation, however, it has limitations and complications. Novel approaches are necessary to more effectively treat HCC patients. Berberine (BBR) is a nutraceutical derived from various fruits and trees, which has been used for centuries in traditional medicine to treat various diseases such as diabetes and inflammation. More recently, the anti-proliferation effects of BBR have been investigated in the treatment of patients with various cancers, especially colorectal cancer, and in non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH). In this review, we will focus on studies with BBR in liver diseases.

In vitro toxicity of naringin and berberine alone, and encapsulated within PMMA nanoparticles

Phytochemical compounds, such as naringin and berberine, have been used for many years due to their antioxidant activities, and consequently, beneficial health effects. In this study, it was aimed to evaluate the antioxidant properties of naringin, berberine and poly(methylmethacrylate) (PMMA) nanoparticles (NPs) encapsulated with naringin or berberine and their possible cytotoxic, genotoxic, and apoptotic effects on mouse fibroblast (NIH/3 T3) and colon cancer (Caco-2) cells. According to the results of the study, it was found that the 2,2-diphenyl-1-picrylhydrazyl (DPPH) inhibition antioxidant activity of naringin, berberine, and naringin or berberine encapsulated PMMA NPs, was significantly increased at higher tested concentrations due to the antioxidant effects of naringin, berberine and naringin or berberine encapsulated PMMA NPs. As a result of the cytotoxicity assay, after 24-, 48- and 72-h of exposure, all of the studied compounds caused cytotoxic effects in both cell lines. Genotoxic effects of studied compounds were not registered at lower tested concentrations. Based on these data, polymeric nanoparticles encapsulated with naringin or berberine may contribute to new treatment approaches for cancer, but further in vivo and in vitro research is required.

Silica-Based Nanoframeworks Involved Hepatocellular Carcinoma Theranostic

Silica-based nanoframeworks have been extensively studied for diagnosing and treating hepatocellular carcinoma (HCC). Several reviews have summarized the advantages and disadvantages of these nanoframeworks and their use as drug-delivery carriers. Encouragingly, these nanoframeworks, especially those with metal elements or small molecular drugs doping into the skeleton structure or modifying onto the surface of nanoparticles, could be multifunctional components participating in HCC diagnosis and treatment rather than functioning only as drug-delivery carriers. Therefore, in this work, we described the research progress of silica-based nanoframeworks involved in HCC diagnosis (plasma biomarker detection, magnetic resonance imaging, positron emission tomography, photoacoustic imaging, fluorescent imaging, ultrasonography, etc.) and treatment (chemotherapy, ferroptotic therapy, radiotherapy, phototherapy, sonodynamic therapy, immunotherapy, etc.) to clarify their roles in HCC theranostics. Further, the future expectations and challenges associated with silica-based nanoframeworks were highlighted. We believe that this review will provide a comprehensive understanding for researchers to design novel, functional silica-based nanoframeworks that can effectively overcome HCC.

A simple and efficient metal free, additive, or base free dehydrogenation of tetrahydroisoquinolines using oxygen as a clean oxidant

Metal free dehydrogenation of various substituted tetrahydroisoquinolines via a simple and convenient metal free, atom economical route for the synthesis of corresponding isoquinolines under oxygen atmosphere in N-methyl-2-pyrollidone (NMP) is described. Metal free dehydrogenation was carried out without the use of additive or base. A scope of the methodology was demonstrated for a number of aryl and heteroaryl substitutions present at C1 position and ester moiety at C3 position and was found to be good substrates. Substituted isoquinolines (3a–3h) and their esters (3i–3m) were synthesized in very good to excellent yields.

Synthesis and investigation of quadruplex-DNA-binding, 9-O-substituted berberine derivatives

A small series of five novel berberine derivatives was synthesized by the Cu-catalyzed click reaction of 9-propargyladenine with 9-O-(azidoalkyl)berberine derivatives. The association of the resulting berberine-adenine conjugates with representative quadruplex-forming oligonucleotides 22AG dA(G3TTA)3G3 and a2 d(ACAG4TGTG4)2 was examined with photometric and fluorimetric titrations, thermal DNA denaturation analysis, and CD spectroscopy. The results from the spectrometric titrations indicated the formation of 2:1 or 1:1 complexes (ligand:G4-DNA) with log K b values of 10-11 (2:1) and 5-6 (1:1), which are typical for berberine derivatives. Notably, a clear relationship between the binding affinity of the ligands with the length of the alkyl linker chain, n, was not observed. However, depending on the structure, the ligands exhibited different effects when bound to the G4-DNA, such as fluorescent light-up effects and formation of ICD bands, which are mostly pronounced with a linker length of n = 4 (with a2) and n = 5 (with 22AG), thus indicating that each ligand-G4-DNA complex has a specific structure with respect to relative alignment and conformational flexibility of the ligand in the binding site. It was shown exemplarily with one representative ligand from the series that such berberine-adenine conjugates exhibit a selective binding, specifically a selectivity to quadruplex DNA in competition with duplex DNA, and a preferential thermal stabilization of the G4-DNA forms 22AG and KRAS. Notably, the experimental data do not provide evidence for a significant effect of the adenine unit on the binding affinity of the ligands, for example, by additional association with the loops, presumably because the adenine residue is sterically shielded by the neighboring triazole unit.

Dendrimers as efficient nanocarriers for the protection and delivery of bioactive phytochemicals

The genesis of dendrimers can be considered as a revolution in nano-scaled bioactive delivery systems. These structures possess a unique potential in encapsulating/entrapping bioactive ingredients due to their tree-like nature. Therefore, they could swiftly obtain a valuable statue in nutraceutical, pharmaceutical and medical sciences. Phytochemicals, as a large proportion of bioactives, have been studied and used by scholars in several fields of pharmacology, medical, food, and cosmetic for many years. But, the solubility, stability, and bioavailability issues have always been recognized as limiting factors in their application. Therefore, the main aim of this study is representing the use of dendrimers as novel nanocarriers for phytochemical bioactive compounds to deal with these problems. Hence, after a brief review of phytochemical ingredients, the text is commenced with a detailed explanation of dendrimers, including definitions, types, generations, synthesizing methods, and safety issues; then is continued with demonstration of their applications in encapsulation of phytochemical bioactive compounds and their active/passive delivery by dendrimers. Dendrimers provide a vast and appropriate surface to entrap the targeted phytochemical bioactive ingredients. Several parameters can affect the yield of nanoencapsulation by dendrimers, including their generation, type of end groups, surface charge, core structure, pH, and ambient factors. Another important issue of dendrimers is related to their toxicity. Cationic dendrimers, particularly PAMAM can be toxic to body cells through attaching to the cell membranes and disturbing their functions. However, a number of solutions have been suggested to decrease their toxicity.

The Degradation Products of Ascorbic Acid Inhibit Amyloid Fibrillation of Insulin and Destabilize Preformed Fibrils

Ascorbic acid (AsA) is an important antioxidant and enzyme cofactor in many biochemical processes. Most biological activities of AsA are closely related to its redox properties. Recent investigations have demonstrated that AsA is associated with amyloid-related diseases and can inhibit amyloid aggregation of polypeptides. In the present study, we determined the kinetics of AsA degradation and investigated the anti-amyloidogenic activities of AsA and its degradation products by utilizing insulin as a model polypeptide. The results showed that the half-life of AsA varied with the pH of the medium and the incubation temperature. The degradation products of AsA inhibited insulin fibrillation, with an activity positively correlated to the degree of AsA degradation. The degradation species, compared with intact AsA, also showed a stronger disruptive effect on mature amyloid fibrils and significantly decreased fibrillar cytotoxicity. Dehydroascorbic acid and diketogulonic acid, two key intermediates in AsA degradation, had similar anti-amyloidogenic activity toward the degradation species of AsA. The results of this work indicate that degradation of natural antioxidants must be considered when evaluating their anti-amyloidogenic effects. These insights into the action of AsA may also provide a novel route to understand its physiological/pharmacological roles in amyloid-related diseases.

Copper-Catalyzed Benign and Efficient Oxidation of Tetrahydroisoquinolines and Dihydroisoquinolines Using Air as a Clean Oxidant

A green chemical method for mild oxidation of 1,2,3,4-tetrahydroisoquinolines (THIQs) and 3,4-dihydroisoquinolines (DHIQs) has been developed using air (O₂) as a clean oxidant. DHIQs and THIQs could be efficiently oxidized to isoquinolines in dimethyl sulfoxide at 25 °C under an open air atmosphere with CuBr₂ (20 mol %) as the catalyst; different bases [NaOEt and/or 1,8-diazabicyclo[5,4,0]undec-7-ene] were used for the reaction according to the patterns of substituents (R¹, R²).

Berberine-loaded Janus nanocarriers for magnetic field-enhanced therapy against hepatocellular carcinoma

Berberine, an bioactive isoquinolin alkaloid from traditional Chinese herbs, is considered to be a promising agent based on its remarkable activity against hepatocellular carcinoma. However, the clinical application of this nature compound had been hampered owing to its properties such as poor aqueous solubility, low gastrointestinal absorption, and reduced bioavailability. Therefore, we developed Janus magnetic mesoporous silica nanoparticles (Fe₃ O₄ -mSiO₂ NPs) consisting of a Fe₃ O₄ head for magnetic targeting and a mesoporous SiO₂ body for berberine delivery. A pH-sensitive group was introduced on the surface of mesoporous silica for berberine loading to develop a tumor microenvironment-responsive nanocarrier, which exhibited uniform morphology, good superparamagnetic properties, high drug-loading amounts, superior endocytic ability, and low cytotoxicity. Berberine-loaded Fe₃ O₄ -mSiO₂ NPs exerted extraordinarily high specificity for hepatocellular carcinoma cells, which was due to the pH-responsive berberine release, as well as higher endocytosis capacity in hepatocellular carcinoma cells rather than normal liver cells. More importantly, an external magnetic field could significantly improve antitumor activity of Ber-loaded Fe₃ O₄ -mSiO₂ NPs through enhancing berberine internalization. Taken together, our results suggest that Janus nanocarriers driven by the magnetic field may provide an effective and safe way to facilitate clinical use of berberine against hepatocellular carcinoma.

Antioxidant capacity and kinetics of dendritic hindered phenols using DPPH assay

Dendritic hindered phenols were synthesised using 3-(3,5-di-tert-butyl-4-hydroxy-phenyl)-propionic acid and dendritic poly(amido-amine) (PAMAM) as materials. The structures of the dendritic hindered phenols were characterised by infrared spectroscopy (FTIR), 1H-nuclear magnetic resonance spectroscopy (1H NMR) and liquid chromatography–mass spectrometry (LC-MS). The scavenging capacity and kinetics of the dendritic hindered phenols were investigated using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. These dendritic hindered phenols have excellent scavenging capacity, being superior to antioxidants 1010 and 1098 with the same number of phenol hydroxyl groups. The scavenging capacity of the first-generation dendritic hindered phenol (1.0G dendritic phenol) was superior to that of the second-generation dendritic hindered phenol (2.0G dendritic phenol). The kinetic behaviour of the hindered phenols in scavenging the DPPH radical was a first-order reaction. The scavenging rate constants ( k1) of the dendritic phenols with DPPH radical were higher than that of antioxidants 1010 and 1098, while the k1 value of 1.0 G dendritic phenol was superior to that of 2.0 G dendritic phenol under the same test conditions. The scavenging activation energy ( Ea) of 1.0 dendritic phenol with four phenolic groups and two tertiary amine groups was the lowest, while that of antioxidant 1010 with a higher molecular weight and four phenolic groups was the greatest.

New 13-pyridinealkyl berberine analogues intercalate to DNA and induce apoptosis in HepG2 and MCF-7 cells through ROS mediated p53 dependent pathway: biophysical, biochemical and molecular modeling studies

A new series of 13-pyridinealkyl berberine analogues was synthesized and their DNA binding efficacy studied by employing spectroscopic, calorimetric and molecular modeling techniques.

A novel fluorescent nano-chemosensor for Al(III) ions using a new macrocyclic receptor

A novel macrocyclic chemosensor (L) has been synthesized and characterized by common spectroscopic methods. Spectral properties of fluorescent macrocycle L were studied either as solution in ethanol or as insoluble nanoparticles in aqueous buffer solution. The nano-chemosensors with size about 35nm were prepared by nanoprecipitation method. The influence of metal cations such as Na(+), K(+), Cs(+), Mg(2+), Ba(2+), Al(3+), Pb(2+), Cr(3+), Mn(2+), Fe(3+), Fe(2+), Co(2+), Ni(2+), Cu(2+), Zn(2+), Cd(2+), Hg(2+) and Ag(+) on the spectroscopic properties of nano-chemosensor (L) in aqueous buffer solution were investigated by means of emission spectrophotometry. The macrocycle was found to be as an effective fluorescence sensor for Al(3+) ions.

Silica nanoparticles for cell imaging and intracellular sensing

There is increasing interest in the use of nanoparticles (NPs) for biomedical applications. In particular, nanobiophotonic approaches using fluorescence offers the potential of high sensitivity and selectivity in applications such as cell imaging and intracellular sensing. In this review, we focus primarily on the use of fluorescent silica NPs for these applications and, in so doing, aim to enhance and complement the key recent review articles on these topics. We summarize the main synthetic approaches, namely the Stöber and microemulsion processes, and, in this context, we deal with issues in relation to both covalent and physical incorporation of different types of dyes in the particles. The important issue of NP functionalization for conjugation to biomolecules is discussed and strategies published in the recent literature are highlighted and evaluated. We cite recent examples of the use of fluorescent silica NPs for cell imaging in the areas of cancer, stem cell and infectious disease research, and we review the current literature on the use of silica NPs for intracellular sensing of oxygen, pH and ionic species. We include a short final section which seeks to identify the main challenges and obstacles in relation to the potential widespread use of these particles for in vivo diagnostics and therapeutics.

Photophysical and calorimetric studies on the binding of 9-O-substituted analogs of the plant alkaloid berberine to double stranded poly(A)

This interaction of four novel 9-O-substituted analogs of the plant alkaloid berberine with double stranded poly(A) was studied using a variety of biophysical techniques. Remarkably higher binding of two 9-O-ω-amino alkyl ether analogs compared to the two 9-O-N-aryl/arylalkyl amino carbonyl methyl berberine analogs was observed. Quantum efficiency values suggested that energy was transferred from the adenine base pairs to the analogs on binding. Ferrocyanide quenching and viscosity studies revealed the binding mode to be intercalative for these analogs. Circular dichroism studies showed that these analogs induced significant conformational changes in the secondary structure of ds poly(A). Energetics of the binding suggested that 9-O-N-aryl/arylalkyl amino carbonyl methyl berberines bound very weakly to ds poly(A). The binding of 9-O-ω-amino alkyl ether analogs was entropy dominated with a smaller but favorable enthalpic contribution to the Gibbs energy. Increasing the temperature resulted in weaker binding; the enthalpic contribution increased and the entropic contribution decreased. A small negative heat capacity change with significant enthalpy-entropy compensation established the involvement of multiple weak noncovalent interactions in the binding process.

Interaction of 9-O-(ω-amino) alkyl ether berberine analogs with poly(dT)·poly(dA)*poly(dT) triplex and poly(dA)·poly(dT) duplex: a comparative study

Isoquinoline alkaloids and their analogs represent an important class of molecules for their broad range of clinical and pharmacological utility. These compounds are of current interest owing to their low toxicity and excellent chemo preventive properties. These alkaloids can play important role in stabilising the nucleic acid triple helices. The present study has focused on the interaction of five 9-O-(ω-amino) alkyl ether berberine analogs with the DNA triplex poly(dT)·poly(dA)*poly(dT) and the parent duplex poly(dA)·poly(dT) studied using various biophysical techniques. Scatchard analysis of the spectral data indicated that the analogs bind both to the duplex and triplex in a non-cooperative manner in contrast to the cooperative binding of berberine to the DNA triplex. Strong intercalative binding to the DNA triplex structure was revealed from ferrocyanide quenching, fluorescence polarization and viscosity results. Thermal melting studies demonstrated higher stabilization of the Hoogsteen base paired third strand of the DNA triplex compared to the Watson-Crick strand. Circular dichroism studies suggested a stronger perturbation of the DNA triplex conformation by the alkaloid analogs compared to the duplex. The binding was entropy-driven in each case and the entropy contribution to free energy increased as the length of the alkyl side chain increased. The analogs exhibited stronger binding affinity to the triple helical structure compared to the parent double helical structure.

Biophysical characterization of the strong stabilization of the RNA triplex poly(U)•poly(A)*poly(U) by 9-O-(ω-amino) alkyl ether berberine analogs

BACKGROUND

Binding of two 9-O-(ω-amino) alkyl ether berberine analogs BC1 and BC2 to the RNA triplex poly(U)(•)poly(A)(*)poly(U) was studied by various biophysical techniques.

METHODOLOGY/PRINCIPAL FINDINGS

Berberine analogs bind to the RNA triplex non-cooperatively. The affinity of binding was remarkably high by about 5 and 15 times, respectively, for BC1 and BC2 compared to berberine. The site size for the binding was around 4.3 for all. Based on ferrocyanide quenching, fluorescence polarization, quantum yield values and viscosity results a strong intercalative binding of BC1 and BC2 to the RNA triplex has been demonstrated. BC1 and BC2 stabilized the Hoogsteen base paired third strand by about 18.1 and 20.5 °C compared to a 17.5 °C stabilization by berberine. The binding was entropy driven compared to the enthalpy driven binding of berbeine, most likely due to additional contacts within the grooves of the triplex and disruption of the water structure by the alkyl side chain.

CONCLUSIONS/SIGNIFICANCE

Remarkably higher binding affinity and stabilization effect of the RNA triplex by the amino alkyl berberine analogs was achieved compared to berberine. The length of the alkyl side chain influence in the triplex stabilization phenomena.

Berberine modulates AP-1 activity to suppress HPV transcription and downstream signaling to induce growth arrest and apoptosis in cervical cancer cells

BACKGROUND

Specific types of high risk Human papillomaviruses (HR-HPVs) particularly, HPV types 16 and 18 cause cervical cancer and while the two recently developed vaccines against these HPV types are prophylactic in nature, therapeutic options for treatment and management of already existing HPV infection are not available as yet. Because transcription factor, Activator Protein-1 (AP-1) plays a central role in HPV-mediated cervical carcinogenesis, we explored the possibility of its therapeutic targeting by berberine, a natural alkaloid derived from a medicinal plant species, Berberis which has been shown to possess anti-inflammatory and anti-cancer properties with no known toxicity; however, the effect of berberine against HPV has not been elucidated.

RESULTS

We studied the effect of berberine on HPV16-positive cervical cancer cell line, SiHa and HPV18-positive cervical cancer cell line, HeLa using electrophoretic mobility gel shift assays, western and northern blotting which showed that berberine could selectively inhibit constitutively activated AP-1 in a dose- and time-dependent manner and downregulates HPV oncogenes expression. Inhibition of AP-1 was also accompanied by changes in the composition of their DNA-binding complex. Berberine specifically downregulated expression of oncogenic c-Fos which was also absent in the AP-1 binding complex. Treatment with berberine resulted in repression of E6 and E7 levels and concomitant increase in p53 and Rb expression in both cell types. Berberine also suppressed expression of telomerase protein, hTERT, which translated into growth inhibition of cervical cancer cells. Interestingly, a higher concentration of berberine was found to reduce the cell viability through mitochondria-mediated pathway and induce apoptosis by activating caspase-3.

CONCLUSION

These results indicate that berberine can effectively target both the host and viral factors responsible for development of cervical cancer through inhibition of AP-1 and blocking viral oncoproteins E6 and E7 expression. Inhibition of AP-1 activity by berberine may be one of the mechanisms responsible for the anti-HPV effect of berberine. We propose that berberine is a potentially promising compound for the treatment of cervical cancer infected with HPV.

Synthesis and antioxidant properties of dendritic polyphenols

Three dendritic polyphenols (generation 1) were synthesized: a syringaldehyde-based dendrimer (1), a vanillin-based dendrimer (2), and an iodinated vanillin-based dendrimer (3). They all showed strong antioxidant activity according to the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical assay. The syringaldehyde dendrimer was twice and 10 times stronger than quercetin and Trolox, respectively. The vanillin-based dendrimer and its more hydrophobic iodinated derivative were also more potent antioxidants than quercetin and Trolox. The DPPH order of potency was 1>2, 3>quercetin>Trolox. All three dendrimers also protected human LDL from free radical attack in a dose-dependent manner. Their order of free radical scavenging was 1>3>2>quercetin>Trolox. The increased hydrophobic nature of the iodinated derivative may have contributed to its better LDL protection than 2. Protection of linoleic acid oxidation was studied by the beta-carotene-linoleate assay. Dendrimer 1 was clearly superior to the other antioxidants in protecting the fatty acid. In case of DNA protection against free radical damage, the order of activity was 1>quercetin>2>3, Trolox. Pro-oxidant effect on copper-induced DNA oxidation showed the following order: quercetin, Trolox>1>2>3. Results of the study show that dendritic antioxidants, even at the generation 1 level, provide promising antioxidant properties for their potential use as drug candidates for diseases associated with oxidative stress.