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Introduction: Nowadays, the attention of researchers has been focused on natural medicine in order to avoid the detrimental side effects of chemical drugs. In this study we assessed the effect of root extract of Tagetes minuta against HSV-1 and HSV-2. Materials and Methods: This research is an experimental study. Root extract of Tagetes minuta was obtained with 70% ethanol by maceration. Vero cells were grown in DMEM containing 5% fetal bovine serum. Serial dilutions of extracted suspension (1/10, 1/20, 1/40, 1/80, 1/160) were incubated by the exact titer of viruses and monitored for antiviral activity of extract. Data was analyzed using Doncan test. Results: Root extract obtained from Tagetes minuta significantly has antiviral activity against HSV-1 and HSV-2. This extract has more effect on HSV-2 than HSV-1. This study indicates that antiviral activity of the extract varies between different concentrations and the optimum antiviral activity on both viruses was obtained using 1/10 concentration. Conclusion:The results of this investigation showed that root extract of Tagetes minuta have good antiviral potenoial against HSV-1 and HSV-2, a good source of drug for treatment of diseases due to HSV-1 and HSV-2.

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Introduction: Extracts of leaves from Camellia sinensis L contains polyphenolic components with antimicrobial activity. In this investigation biofilm inhibitory effects of black and green tea extracts were defined for five members of enterobacteriacea family including: Enteropathogenic Escherichia coli, Shigella flexneri, Proteus mirabilis, Klebsiella pneumoniae and Salmonella enterica serovar Typhimurium. Because tea is the most widely drunk beverage in Iran, therefore investigation of its effects on enterobacterial biofilm formation and colonization is very important. Materials and Methods: In this experimental study after extraction of samples with Soxhlet extractor in water/ methanol solution, further extraction took place in Ethyl acetate phase. The extracts preserved in 4oC refrigerator after sterilization by 0.44 µ filters. Well diffusion (Kirby Bauer) and broth dilution methods were used for evaluation of minimum inhibitory concentration of biofilm formation in black and green tea extracts treated cultures. Evaluation of biofilm formation was assayed by observation of colony forming unit of cultured bacteria per milliliter by sampling from Erlenmeyer flask wall scratching onto Tripticase soy agar medium and comparing the results with controls. Analysis of data was done using analysis of variance. Results: Biofilm inhibitory effects of black tea were greater than green tea. The concentration of 4.5 mg/ml of black tea and 5mg/ml of green tea had bactericidal effects against examined bacteria. On Mueller Hinton agar, Proteus mirabilis was more sensitive to black tea EPEC was more sensitive to green tea and Klebsiella pneumoniae showed more resistance to both extracts. Conclusion: Due to the fact that gastrointestinal tract is directly affected with consumed beverage, the high concentration of tea entered in lumen can reduce the number of enterobacteriaceae and can reduce their carcinogenic amine products. Thus it plays an important role in inhibition of gastrointestinal lymphoma and colon carcinoma. Also application of tea polyphenols as a food preservative can be useful.

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Background: Dental plaque is composed of bacterial derived extracellular polysacharide known as glucan which is synthesized by Streptococcus mutans. Natural substances that could inhibit the plaque formation of the bacteria have a significant importance. This investigation has evaluated the honey beeswax extract effect on the Gft production, the key enzyme of S. mutans colonization factor for the first time. Methods and Materials: In this experimental study extraction of the sample conducted with ethyl acetate and methanol solutions in the Clevenger extractor. The ethyl acetate soluble fraction was separated in the first step and after the evaporation of the first solute, the 70% methanol as inactive solvent was added and the water mixture was used as a second solution, then materials were separated with dH2O. Minimum inhibitory concentration (MIC) of the honey beeswax extract was assessed by Broth diffusion method. Examination of cell adherence (Biofilm Inhibitory Concentration, BIC) was calculated by colony counts from surface scratching of glass slides in the bacterial media that supplied with 1% sucrose. Glucosyltransferase expression was detected by 15% SDS poly acrylamide gel electrophoresis. Results: Concentration of 1mg/ml of ethyl acetate honey beeswax extract was inhibited completely biofilm and it was prevented the production of glucosyltransferase enzyme. The concentration of formation 6 mg/ml of the extract had bacteriostatic effect and 30 mg/ml concentration of this extract had bactericidal for S. mutans (P<0.01). Conclusion: The sub- bacterial concentrotion honey beeswax extract was able to block the major enzyme that contributes to S. mutans biofilm formation.

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Background: Staphylococcus aureus is a gram-positive bacterium that has remained a persistent pathogen, causing infections such as endocarditis and toxic shock syndrome in humans. The accessory gene regulator (agr) system of Staphylococcus aureus is responsible for controlling the expression of many genes that code virulence factors and hemolysis.This study was carried out to determine the S.aureus agr group based on their source of isolation and any relation between agr specificity groups, pigmentation and hemolysis .

Materials and Methods: DNA of 194 S. aureus isolates were extracted by lysozym-phenol chloroform method, included 85clinical samples, 58 samples which isolated from nose of health care workers and 51 cases obtained from food product in Gorgan, North of Iran. PCR-based assays were used to evaluate agr locus nucleotide polymorphism for the identification of agr specificity group. Pigmentation on nutrient agar medium and hemolysis on sheep Blood agar medium were assessed.

Results: The majority of isolates belonged to agr group I (43.3%), followed by agr group III (28.87%), agr group II (22.68%), and agr group IV (5.15%). The isolates belonged to agr group IV have greater ability to produce hemolysin (60%) whereas isolates belonged to agr group III have greater ability to produce pigment (60.5%).

Conclusion: agr group I was predominant among health care worker and food product specimens in Gorgan, North of Iran but in strains isolated from patient, agr group III was predominant. Investigation of the possible role of agr group III in Staphylococcus aureus infection in the next studies is recommended.

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