فهرست مطالب negin jafarian

 Natural preservatives extracted from herbs are important sources for bioactive compounds that can be used in protection of food products. Essential oils are aromatic oily liquids, obtained from plant material like flowers, buds, seeds, leaves, and roots. Unfortunately, most natural compounds are biologically instable, poorly soluble in water and they distribute poorly to target sites. Currently, some novel methods have been introduced in order to improve their stability and their bioavailability, among which is the use of liposomal encapsulation. Microencapsulation reduces reactivity with the environment (water, oxygen, light), decreases the evaporation or the transfer rate to the outside environment, promotes handling ability, masks taste and enhances dilution to achieve a uniform distribution in the final product when used in very small amounts. Essential oils, as natural extracted compounds extracted from plants, are unstable compounds with low water solubility and unable to achieve target cells. Essential oils encapsulation by nanoliposomes is a novel method for increasing their biological activity and protecting them from destructive factors. The aim of this study was production and optimization of nanoliposomes containing Z. teniur essential oil and investigating their antibacterial effects against pathogens (Staphylococcus aureus and Escherichia coli).
 
 Lipid film hydration method was used to produce nanoliposomes containing Z. teniur essential oil. Soy phosphatidylcholine and cholesterol were the main wall materials and chloroform was used as the mixing solvent . The particle size of nanoliposomes and their zeta-potential were investigated using laser diffraction method. In order to determine the minimum inhibitory concentration and the minimum bactericidal concentration of Z. teniur essential oil against examined bacteria, serial dilution method was used. Also, antioxidant activity of free and nano-encapsulated essential oil of Z. teniur was determined by DPPH method.
 
 According to the results, highest encapsulation efficiency achieved by using 80:20 ratio of soy phosphatidylcholine to cholesterol in nanoliposomes’ wall structures. In general, by increasing the ratio of phosphatidylcholine to cholesterol, encapsulation efficiency was improved. Zeta-potential of nanoliposomes was equal to -5.3 mv and mean particle sizes were in the range of 94.7-119.9 nm. Results indicated that essential oil ejection from nanoliposomes has direct relation to the time of storage and after 30 hours, ejection rate will increase considerably. Ejection rate was higher in phosphate buffer pH=7.4 in comparison with phosphate buffer pH=5.4. Minimum inhibitory concentration and minimum bactericidal concentration of free essential oil against Escherichia coli was 100 and 175 (µl/ml) respectively. Although, Minimum inhibitory concentration and minimum bactericidal concentration of nanoliposomes containing Z. teniur essential oil were equal to 75 and 150 (µl/ml) respectively. Also, results shown that , minimum inhibitory concentration and minimum bactericidal concentration of encapsulated Z. teniur essential oil against Staphylococcus aureus were lower in comparison with free form of Z. teniur essential oil. Staphylococcus aureus (as Gram-positive bacteria) was more susceptible than Escherichia coli (as Gram-negative bacteria).
 
 Encapsulation of Z. teniur essential oil by nanoliposomes led to improve antibacterial effects of essential oil against Staphylococcus aureus and Escherichia coli. Also, investigating of antioxidant activity showed that encapsulated Z. teniur essential oil in nanoliposomes was more effective than free form of Z. teniur essential oil in scavenging of DPPH free radicals. Using nanoliposome encapsulation technology can be an effective way for increasing the efficiency of natural antibacterial compounds and essential oils encapsulated in nanoliposomes are suitable alternatives for synthetic preservatives used in food industry nowadays. The use of liposomes containing Z. teniur essential oil can provide the necessary protection against growth of spoilage and pathogenic microorganisms such as Staphylococcus aureus and Escherichia coli in food products.

The prevalence of diabetes – especially diabetes type II- is increasing steadily; according to WHO reports it will increase to 366 million people by the year 2030. Microvascular complications including Proliferative diabetic retinopathy (PDR) and end stage renal disease (ESRD) are increased in patients with diabetes mellitus. Case-control association studies have demonstrated that rs1617640 SNP in the promoter of erythropoietin (EPO) gene is significantly associated with PDR and ESRD. In the mentioned SNP, TT genotype is considered as risk genotype which means that EPO concentration in human vitreous body in these people shall be higher. People with TT genotype are much more at risk of retinopathies. In this study we investigated the existence of rs1617640 EPO gene polymorphism among 150 healthy subjects and 150 subjects with diabetes type II who referred to Yazd central laboratory. Then the association of rs1617640 SNP with complications among diabetic patients were examined by ARMS-PCR method. The results were analyzed using GraphPad software (version 5.00). Prevalence of genotype GG was 8% in patients and 1.3% in the control group. GT was 51.3% in patients, and 86.7% in the control group, and finally TT was observed in 40.7% in patients, and 12% of control group. The TT genotype was 37.6% in patients with retinopathy and 42.6% in non-retinopathy patients. Our study demonstrates that the prevalence of rs1617640 SNP has significant difference between diabetic patients and control group; whereas there was not any significant relationship between this polymorphism and the complications of diabetes in patients. Together our study reveals that rs1617640 SNP may be associated with susceptibility to diabetes type II; however it seems that this polymorphism is not significantly related to the diabetic complications in Yazd.