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There is no report on the antimicrobial effects of evening primrose (Oenothera biennis L.) and borage (Echium amoenum Fisch. & C.A.Mey.). In this research, the seeds of these plants were milled and extracted by chloroform:methanol (2:1). Then, the solvents were evaporated under reduced pressure and temperature to extract the oils. Antimicrobial effects of various concentrations of the oils (10- 1000 mg/l) were assessed against Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Candida albicans and Aspergillus niger. Minimum inhibition concentration of the oils for each strain was measured using Mueller Hinton Broth and Sabouraud Dextrose Broth. The results showed that evening primrose oil increased the growth of C. albicans and A. niger, while it suppressed the growth of S. aureus, S. epidermidis and P. aeruginosa even at the minimum concentration level (1mg/l). Borage oil was found to promote the growth of A. niger and S. epidermidis, but at concentration levels equal to or higher than 1mg/l it inhibited the growth of P. aeruginosa and C. albicans. However, at no concentration level, was it observed to leave any effect on S. aureus. It was also shown that some medical properties of evening primrose and borage could be attributed to antimicrobial effects of their oils. 

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Exopolymers (EPS) are high-molecular-weight polymers secreted by some micro-organisms and have several applications in food, pharmaceutical, packaging and agricultural industries, as well as medicine. Actinobacteria are valuable bacteria in biotechnology and many commercial drugs such as antibiotics, antioxidants and immune-suppressant agents are derived from Actinobacteria. Recently, their other capabilities such as exopolymer production have been taken into consideration. Due to the high potential of actinobacteria in producing various compounds and increased prevalence of infections by antibiotic-resistant pathogens, the aim of the present study was to evaluate the potential of isolated Actinobacteria from various locations of Iran to produce EPS with antimicrobial activity. Appropriate dilutions of the samples were, therefore, cultured in ISP2 medium after treatment. The isolates were primarily identified by morphological tests. Then, their ability to produce EPS was investigated in BHI medium with 5% sucrose. The exopolymers of the most efficient strain were analyzed by UV-visible spectroscopy and FT-IR. Finally, the most efficient isolate was molecularly identified. Of the 120 isolates, 38 were able to produce EPS, and six had significant capability of producing EPS (10-14 g/L) and showed antibiotic activity against Staphylococcus aureus, Bacillus subtilis and Aspergillus niger. The EPS of the strain So49 had high absorbance in 190-230 nm, but did not have absorbance in 260-280 nm. Therefore, it does not have any protein impurity. The EPS has hydroxyl and carboxyl functional groups, according to FT-IR analysis. 16S rRNA gene analysis showed that the most efficient isolate had 99.68% similarity to Promicromonospora xylanilytica.