Zahra Sabahi

Conjugation of poly(amidoamine) dendrimers with various acrylates for improved delivery of plasmid encoding interleukin-12 gene

In this study, a small library of polyamidoamine (PAMAM) derivatives was prepared through the conjugation of its amines with various acrylates containing 5–21 carbon chain lengths at two different conjugation degrees, and the ability of the nano-sized PAMAM-based complexes to transfer the plasmid encoding interleukin-12 (IL-12) gene into the cells was studied. As the wide clinical application of the recombinant IL-12 protein has been limited due to several deaths reported following the systemic administration of the protein, local expression of the IL-12 gene inside the tumor target has been considered as an effective alternative strategy. The idea subjacent to this type of modification was to enhance transfection efficiency by the synergistic effects of endosome buffering via the PAMAM amines and the interaction with biological membranes caused by the hydrophobic moieties grafted on the PAMAM structure. Acrylate conjugation of primary amines on PAMAM structure enhanced transfection efficiency, with the highest level of IL-12 expression occurring with the conjugates containing five to nine carbon chains on their periphery at the grafting degree of 10%. The results obtained in this study suggest that combining the cationic nature of PAMAM along with modulating the hydrophobicity of the dendrimer to achieve an appropriate hydrophobic-hydrophilic balance yields the optimal carriers for non-viral gene delivery.

Comparison of the effectiveness of polyethylenimine, polyamidoamine and chitosan in transferring plasmid encoding interleukin-12 gene into hepatocytes

AbstractInterleukin-12 (IL-12) has been proposed for cancer immunotherapy due to its versatile antitumor and antiangiogenesis effects. Although cancer immunotherapy through systemic administration of IL-12 has shown antitumor effects in tumor-bearing mice, broad application of recombinant IL-12 protein has been limited by its cytotoxicity. Therefore, the use of various polycationic polymers such as polyethylenimine (PEI), polyamidoamine (PAMAM) and chitosan has been considered as an effective strategy to transfer plasmid encoding IL-12 gene into cells. In this investigation, polyplexes (polymer/pDNA complexes) were prepared using PEI, PAMAM and chitosan at different N/P ratios and their ability in transferring plasmid encoding IL-12 gene was evaluated. Furthermore, these polyplexes were characterized and compared with regarding their cytotoxicity, DNA condensation ability, particle size, zeta potential, buffering capacity and pDNA protection against enzyme degradation. The results revealed that the polyplexes formulated with 25 kDa PEI and chitosan had the highest transfection efficiencies. The highest level of IL-12 gene expression was achieved by the nanoparticles prepared by 25 kDa PEI where they could increase the level of gene expression up to 12 times compared to that of naked plasmid encoding IL-12 gene. These results suggest that 25 kDa PEI and chitosan are the best candidates for adding targeting ligands into their structures in order to create a liver targeting gene delivery system.

Chemical Composition and Antimicrobial Activities of the Essential Oil From Salvia mirzayanii Leaves

Resistance of many pathogens to available drugs is a global challenge and is leading to growing interest in natural alternative products. In this study, chemical composition and in vitro antibacterial and antifungal activities of the essential oil from Salvia mirzayanii were investigated. The chemical constituents of essential oil from S mirzayanii were analyzed by gas chromatography–mass spectrometry. The antimicrobial activity was determined by broth microdilution. The main identified compounds were 1,8-cineole (41.2 ± 1.3%), linalool acetate (11.0 ± 0.5%), and α-terpinyl acetate (6.0 ± 0.4%) (mL of essential oil/g of plant material). The MIC95 were 0.03 to 0.5 µL/mL and 16 to 128 µL/mL for gram-positive and gram-negative bacteria, respectively. These results indicated that Salvia mirzayanii essential oil significantly inhibited the growth of standard and clinically isolated tested yeasts by MIC50 0.03 to 1 µL/mL. Potent antibacterial and antifungal activities of Salvia mirzayanii essential oil may be considered in future study, particularly against antibiotic-resistant cases.

Insight into DNA protection ability of medicinal herbs and potential mechanisms in hydrogen peroxide damages model

DNA damage is one of the most important consequences of oxidative stress in the cells. If DNA repair is unable to modify these inducible DNA damages, genomic instability may lead to mutation, cancer, aging and many other diseases. Single cell gel electrophoresis or comet assay is a common and versatile method to quantify these types of DNA damages. DNA damages induced by hydrogen peroxide (H2O2) are one of the proper models for measurement of protective ability of different compounds. So the main aim of this review is to provide an overview about protection ability of medicinal plants and their potential mechanism against H2O2 induced DNA damages. In this review, relevant researches on the effect of medicinal plants on DNA damages induced by H2O2 and possible molecular mechanisms are discussed. It seems that, medicinal plants are considered as therapeutic key factors to protect DNA from consequences caused by oxidative stress. Sufficient in vitro evidences introduce them as DNA protective agents through different mechanisms including antioxidant activity and some other cellular mechanisms. Moreover, in order to correlate the antigenotoxicity effects with their potential antioxidant property, most of medicinal plants were evaluated in term of antioxidant activity using standard methods. This review highlights the preventive effects of herbal medicine against oxidative DNA damages as well as provides rational possibility to engage them in animal studies and future clinical investigations.

Different methods evaluation of antioxidant properties of Myrtus communis extract and its fractions

Myrtus communis L. is a plant traditionally used as an antiseptic and disinfectant drug. In this research, the antioxidant activity of Myrtus communis was assayed by evaluating radical scavenging activity, reducing power, FRAP method and determination of phenolic compounds. The methanolic extract of leaves of Myrtus communis was fractionated by using petroleum ether, chloroform, ethyl acetate and buthanol. In reducing power, different concentrations of samples were mixed with phosphate buffer, ferrocyanate, TCA and ferric chloride. Different concentrations of samples were mixed with DPPH and after 30 min the absorbances were measured. For determination of phenolic content, 500 µl of sample was mixed with Folin-Ciocalteu and sodium carbonate. For determination of flavonoids, 500 µl of sample was mixed with 2 ml of distilled water, NaNO2 and NaOH. In reducing power method, chloroform fraction showed the highest reducing capacity. In the DPPH radical scavenging method, the highest antioxidant capacity was found in buthanol fraction (IC50=84.42±1.8 µg/ml). In FRAP method, the highest antioxidant capacity was found in crude extract (5.4±0.3 mg/ml) and buthanol fractions (5.51±0.4 mg/ml), respectively. The highest amount of phenolic compounds was detected in ethyl acetate fraction of Myrtus communis (17.5±0.001 µg/g). The highest amount of flavonoids was found in crude extract of Myrtus communis (171.9±7.3 µg/ml). Overall, we can suggest that the leaves of Myrtus communis can be used as antioxidant and as a food additives to avoid oxidative degradation of foods.