Introduction: The use of antimicrobial properties of medicinal plants can solve common problems in the use of antibiotics. The aim of this study was to evaluate the antibacterial properties of the Mentha longifolia essence on bacteria isolated from hospital infections.
 
Materials & methods: In this experimental study the Mentha longifolia essence was extracted using Clevenger device and its antimicrobial activity agar disk diffusion method for determination of bacterial sensitivity and dilution method for determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) was used separately.
 
Findings: The results of bacterial sensitivity test in the case of the standard antibiotics of tetracycline, amikacine, and also disks impregnated with Mentha longifolia essence showed that the diameter of the zone of inhibition caused by the compound being tested on four strains of isolates was far larger and this difference about Escherichia coli and Klebsiella isolates was significant (p<0.05). Also the results of MIC and MBC tests indicated that the inhibition of bacterial growth by Mentha longifolia essence had a direct relationship with the amount of available Mentha longifolia essence in the dilution and increasing of Mentha longifolia essence in each dilution reduced the number of cultured bacterial colonies and no bacterial growth was observed in the dilution equivalent to MBC of Mentha longifolia essence.
 
Discussion & conclusions: The results suggest that Mentha longifolia essence can be used as a source of cheap and accessible replacing chemical drugs to treat some bacterial infections.
 

Introduction: Having high antioxidant capacity and an important role in the health, the flavonoids and phenolic compounds increase antioxidant defense against antioxidative stress. White tea is among herbs attracting attention recently due to high antioxidant capacity. The present study aimed at surveying the effect of white tea on oxidative stress resulted of Arsenic.
 
Materials & methods: In the present study 32 male rats were used in four groups of eight animals. The first group composed of healthy animals (control group) which received distilled water along with standard dietary via gavage, the second one was treated with Arsenic (50 ppm in drinking water), the third group was treated with white tea extract (1.5%) via gavage and the fourth one received aqueous white tea extract (1.5%) plus Arsenic (50 ppm in drinking water) via gavage. Upon the end of the treatment period (28 days) the rats were anesthetized using ether and then autopsy was conducted to measure the levels of Catalase Antioxidant Enzymes (CAT), Glutathione Peroxidase (GPx), Super Oxide Dismutase (SOD), Total Antioxidant Capacity (TAC), and Malondialdehyde (MDA) of liver.
 
Findings: The aqueous extract of white tea caused a meaningful increase of CAT , GPx, and SOD activities as well as a meaningful decrease of MDA . It also increased the TAC (P<0.05). On the other hand, administrating the Sodium Arsenic caused a meaningful decrease of    CAT , GPx, and SOD as well as a meaningful increase of MDA . It also increased the TAC (P<0.05). Administrating the aqueous extract of white tea plus Sodium Arsenic caused a meaningful increase of SOD AND GPx activities (P<0.05).
 
Discussion & conclusions: The results demonstrated that administration of white tea causes to increase the antioxidant enzymes activity as well as to strengthen the antioxidant defense and to decrease the stress oxidative resulted of Arsenic, besides. In the present the administration of Sodium Arsenite caused decreased antioxidant enzymes activity and increased MDA.