Hamideh Parhiz

Antioxidant and Anti-Inflammatory Properties of the Citrus Flavonoids Hesperidin and Hesperetin: An Updated Review of their Molecular Mechanisms and Experimental Models

Inflammation and oxidative stress are two major causes of various life‐threatening diseases. Hesperidin (Hsd) and its aglycone, hesperetin (Hst), are two flavonoids from citrus species that have numerous biological properties, particularly antioxidant and anti‐inflammatory. New findings showed that the antioxidant activity of Hsd/Hst was not only limited to its radical scavenging activity, but it augmented the antioxidant cellular defenses via the ERK/Nrf2 signaling pathway as well. Various in vitro and in vivo studies have been conducted to evaluate Hsd, its metabolites, or its synthetic derivatives at reducing inflammatory targets including NF‐κB, iNOS, and COX‐2, and the markers of chronic inflammation. In this review, new findings regarding the molecular targets of Hsd and Hst in the reduction of oxidative stress are discussed. Also, in the anti‐inflammatory section, we provide a summary of significant investigations concerning the mechanisms of action based on the studied inflammation models. Copyright

Molecular mechanisms behind the biological effects of hesperidin and hesperetin for the prevention of cancer and cardiovascular diseases.

Hesperidin (Hsd) and its aglycone, hesperetin (Hst), are two flavonoids from citrus species that have various biological properties, particularly those for the prevention of cancer and cardiovascular diseases. Studies have shown both anti-cancer and cancer chemopreventive effects for Hsd and Hst. Cancer chemopreventive properties of Hsd and Hst are mainly associated with their antioxidant, radical scavenging and anti-inflammatory activities. In addition, Hsd and Hst interfere at different stages of cancer. Unlike conventional anti-cancer drugs, Hsd and Hst inhibit tumor growth by targeting multiple cellular protein targets at the same time, including caspases, Bcl-2 (B-cell lymphoma 2) and Bax (Bcl-2 associated X protein) for the induction of apoptosis, and COX-2 (cyclooxygenase-2), MMP-2 (matrix metalloproteinase-2) and MMP-9 for the inhibition of angiogenesis and metastasis. The results of the recent basic and clinical studies revealed the beneficial effects for Hst, Hsd and their derivatives in the treatment of heart failure and cardiac remodeling, myocardial ischemia and infarction, and hypertension. In addition, the valuable effects of Hst and Hsd in the treatment of diabetes and dyslipidemia with their anti-platelet and anticoagulant effects make them good candidates in the treatment of various cardiovascular diseases. In this review, new findings regarding the molecular targets of Hsd and Hst, animal studies and clinical trials are discussed.

Neuropharmacological properties and pharmacokinetics of the citrus flavonoids hesperidin and hesperetin — A mini-review

Hesperidin (Hsd) and its aglycone, hesperetin (Hst), are two flavonoids from citrus species that have various biological properties. Over the past decade, a large number of papers have been published regarding the biological activities of these compounds and their molecular mechanisms. In this paper, we reviewed the neuropharmacology of Hsd and Hst as a recently emerged topic that has not been addressed in the past. Some of molecular targets and signaling pathways for neuropharmacological effects of Hst and Hsd, including antidepressant, neuroprotective and the effects of Hsd/Hst on memory, have also been included in the review. We also discussed the mechanisms of actions for antidepressant activities of Hsd and Hst. In addition, pharmacokinetics of Hsd and Hst, their interaction with some drugs such as atenolol, diltiazem, felodipine and verapamil, as well as related underlying mechanisms have been discussed.

Protective effects of flavonoids against microbes and toxins: The cases of hesperidin and hesperetin.

Many plants produce flavonoids as secondary metabolites. These organic compounds may be involved in the defense against plant-threatening factors, such as microbes and toxins. Certain flavonoids protect their origin source against plant pathogens, but they also exhibit potential healthy properties in human organisms. Hesperidin (Hsd) and its aglycone, hesperetin (Hst), are two flavonoids from the Citrus species that exhibit various biological properties, including antioxidant, antiinflammatory and anticancer effects. Recent studies indicated that Hst and Hsd possess antimicrobial activity. Although the exact mechanisms behind their antimicrobial properties are not fully understood, several mechanisms such as the activation of the host immune system, bacterial membrane disruption, and interference with microbial enzymes, have been proposed. Hsd and Hst may also have protective effects against toxicity induced by various agents. These natural substances may contribute to the protection of cells and tissues through their antioxidant and radical scavenging activities. This review discusses the protective activities of Hsd and Hst against microbes and several toxicities induced by oxidants, chemicals, toxins, chemotherapy and radiotherapy agents, which were reported in vitro and in vivo. Furthermore, the probable mechanisms behind these activities are discussed.

From rationally designed polymeric and peptidic systems to sophisticated gene delivery nano-vectors

Lack of safe, efficient and controllable methods for delivering therapeutic genes appears to be the most important factor preventing human gene therapy. Safety issues encountered with viral vectors have prompted substantial attention to in vivo investigations with non-viral vectors throughout the past decade. However, developing non-viral vectors with effectiveness comparable to viral ones has been a challenge. The strategy of designing multifunctional synthetic carriers targeting several extracellular and intracellular barriers in the gene transfer pathway has emerged as a promising approach to improving the efficacy of gene delivery systems. This review will explain how sophisticated synthetic vectors can be created by combining conventional polycationic vectors such as polyethylenimine and basic amino acid peptides with additional polymers and peptides that are designed to overcome potential barriers to the gene delivery process.

Arginine-rich hydrophobic polyethylenimine: Potent agent with simple components for nucleic acid delivery

Conjugation of various arginine-rich peptide sequences to vectors based on 10 kDa polyethylenimine (PEI) and its hydrophobic derivative (hexanoate-PEI) was investigated as a strategy for improving pDNA and siRNA transfection activities. Six different arginine-histidine (RH) sequences and two arginine-serine (RS) sequences with a range of R/H ratios were designed and coupled to PEI and hexanoate-PEI. All arginine-rich peptide derivatives of PEI significantly enhanced luciferase gene expression compared to PEI 10 kDa alone. Hexanoate-PEI derivatives exhibited higher transfection activity than underivatized PEI vectors. Improved transfection activity may have resulted at least in part from use of higher vector/DNA ratios made possible by reduced cytotoxicity of vectors, and to use of vectors with higher molecular weights. Vectors that were the most efficient in pDNA delivery and transfection were also the most effective in siRNA delivery and protein expression knock down.

Heterocyclic amine-modified polyethylenimine as gene carriers for transfection of mammalian cells

Branched polyethylenimine (PEI) is extensively used as a polycationic non-viral vector for gene delivery. Polyplexes formed with PEI are believed to be released from endocytotic vesicles by the osmotic burst mechanism in the rate-limiting step in transfection. Increasing the buffering capacity of PEI derivatives in the endosomal pH range of 4.5-7.5 should enhance transfection efficiency. In this study, PEI was derivatized by covalently attaching heterocyclic amine moieties (piperazine, pyridine and imidazole rings with pKa values from 5.23 to 6.04) through amide bonds. PEI derivatives with 50% of the primary amines on PEI exhibited increased buffering capacity, increased transfection activity and decreased cytotoxicity in murine neuroblastoma (Neuro-2a) cells. The relative effectiveness in enhancing transfection efficiency was piperazine>pyridine>histidine, but each type of amine was the most effective under a particular set of conditions. Modified vectors could significantly improve transfection efficiency in murine mesenchymal stem cells. PEI25 derivatized at 50% with histidine administered as polyplexes in the tail veins of mice resulted in remarkably enhanced luciferase gene expression in the expected organ distribution and much lower toxicity than underivatized PEI25.

Gene delivery efficiency and cytotoxicity of heterocyclic amine-modified PAMAM and PPI dendrimers.

Poly-(amidoamine) (PAMAM) and poly-(propylenimine) (PPI) are the two most widely investigated dendrimers for drug and gene delivery. In order to enhance DNA transfection activity of these dendrimers, generation 3 and 4 PAMAM and generation 4 and 5 PPI were modified by partial substitution of surface primary amines with histidine, pyridine, and piperazine, which have buffering capacity properties. It was shown that higher dendrimer generations and higher grafting percentages (30% and 50% of primary amines) were associated with higher transfection activity. Pyridine was the most effective substituent for PPI, while piperazine-modified PAMAM dendrimers showed the best transfection efficiency among PAMAM-based vectors in murine neuroblastoma (Neuro-2a) cells. None of the modified carriers showed remarkable cytotoxicity in vitro. Pretreatment of cells with bafilomycin A indicated that endosomal buffering capacity is the main mechanism of endosomal escape. In conclusion, PAMAM and PPI may exhibit different gene delivery efficiency and cytotoxicity profiles with the same chemical modifications. These modified dendrimers could be considered as efficient and safe gene carriers in neuroblastoma cells in vitro.

P53-Derived peptides conjugation to PEI: an approach to producing versatile and highly efficient targeted gene delivery carriers into cancer cells.

ABSTRACT Objectives: Targeted delivery of cytotoxic drugs or therapeutic antisense RNAs into specific cells is a major bottleneck in cancer therapy. To overcome this problem and improve the specificity for cancer cells, we describe a new-targeted delivery system using p53-derived peptides, namely PNC 27 and PNC 28. These peptides target HDM-2 on the surface of cancer cells. HDM-2 is overexpressed on the surface of cancerous cells, but not present on the untransformed cells. Methods: To determine HDM-2-expressing cells, we used immunocytochemistry and flow cytometry analysis on nine cell lines including MCF-7 and NIH-3t3. Conjugation of peptides to vectors was confirmed using reverse-phase high-pressure liquid chromatography (RP-HPLC). Physicochemical properties of vector/DNA complexes including particle size, surface charge and DNA condensation ability were determined. In transfection studies, three plasmids were used including luciferase, pEGFP and shRNA plasmid against Bcl-XL mRNA. The level of Bcl-XL expression was determined by real-time PCR and western blot techniques. Results: The results of gene delivery and shRNA-based gene silencing studies indicated that conjugation of PNC peptides could enhance gene delivery efficiently with high-targeted activity exclusively into cancer cells. Conclusion: Our results strongly indicated that this targeting system could be utilized as an efficient targeting method for most cancer cells.

Molecular weight-dependent genetic information transfer with disulfide-linked polyethylenimine-based nonviral vectors

One strategy for improving gene vector properties of polyethylenimine is to facilitate individual transfection mechanism steps. This study investigates (i) improving transfection efficiency by attaching peptide nuclear localization signals (nuclear localization signals: SV40 large T antigen nuclear localization signal or C-terminus of histone H1) to polyethylenimine (10 kDa) and (ii) using disulfide linkages, which are expected to be stable during polyplex formation, but cleaved inside cells giving improved gene release. Nuclear localization signal-containing polyplexes exhibited low cytotoxicity, whereas transfection efficiency with high molecular weight plasmid DNA increased up to 3.6 times that of underivatized polyethylenimine in Neuro2A cells at higher molar ratio of polyethylenimine-nitrogen to DNA-phosphate (N/P) ratios. However, with luciferase-specific low molecular weight small interfering RNA in Neuro2A/EGFPLuc cells, nuclear localization signal-containing polyplexes with disulfide linkages caused substantial cytotoxicity at N/P ratios >15 and no consistent significant reduction in luciferase expression. Possible explanations for molecular weight-dependent differences in genetic information transfer by polyplexes containing disulfide-linked nuclear localization signals are discussed.