فهرست مطالب سمانه چهارمیری دوخواهرانی

Inocutis levis is a polypore basidiomycete from the Hymenochaetaceae family. Members of this family have well-known medicinal properties. Recently, anti-diabetic and anti-hypercholesterolemic effects of I. levis have been reported. This study aimed to evaluate antibacterial activities and antioxidant properties of the extracts of I. levis.

After the sampling and fungus identification, the methanolic, ethanolic, and aqueous extracts of the dried fruiting bodies of I. levis were prepared. The antioxidant activities were determined by DPPH method, and antibacterial activities by microdilution method against some gram-positive and gram-negative bacteria. Furthermore, the identification and quantification of phenolic and flavonoid compounds of the extracts were investigated by spectrophotometers and HPLC.

The results showed that the methanolic extract had the highest DPPH scavenging activity, with an IC50 value of 555 µg/ml. The ethanolic and methanolic extracts showed the same antibacterial effects, and Streptococcus mutansATCC35665 was more sensitive than other bacteria, with the MIC and MBC values of 12.5 and 25 mg/ml, respectively. Total phenolic (34.15mg gallic acid) and total flavonoid contents (5.4mg quercetin) per 1 gram dry methanolic extract were higher than other extracts. Furthermore, in the HPLC analysis, ascorbic acid, resorcinol, caffeic acid, catechin and, vanillic acid were determined.

This is the first study presenting the antibacterial and antioxidant properties of I. levis. The results can be considered for future studies in the design of new antibiotics and antioxidant compounds from natural resources applying native fungi.

Background and Dental caries is a pathological infectious disease. It begins with the formation of dental plaques which is a structurally and functionally organized biofilm. Streptococcus mutans is the most important bacterium in the formation of dental plaque and dental caries. This study aimed at evaluating the antibacterial and antibiofilm activity of Quercus infectoria galls against Streptococcus mutans. The bacterial strain used in this study was Streptococcus mutans (ATCC: 25923). Extracts were prepared by Soxehlet apparatus and maceration. They were then dissolved in sterile distilled water to a final concentration of 0.16 to 10.00 mg/ml. The antimicrobial activities of the extracts were determined using well diffusion method. The antibiofilm activities of the extracts were examined in a microdilution assay using TTC. Statistical analysis was performed in SPSS V.18. The methanol, ethanol, and acetone extracts of Quercus infectoria galls showed strong inhibitory effects against Streptococcus mutans. The MIC values of extracts were similar and ranged from 160µg/ml to 320µg/ml, whereas the MBC values ranged from 320µg/ml to 640µg/ml. Aqueous extracts of oak galls did not show antimicrobial activity. The extracts of Quercus infectoria galls strongly inhibited the formation of Streptococcus mutans biofilms at concentrations higher than 19.5µg/ml. The extracts of Quercus infectoria galls displayed similarities in their antibacterial activity against Streptococcus mutans. Also, they were found effective in preventing biofilm formation of Streptococcus mutans. The galls of Quercus infectoria are considered potentially good sources of antimicrobial agent.

Nowadays، bacterial infections and antibiotic resistance of their etiologic agents are among the most important challenges facing the health systems. Therefore the application of antimicrobial agents with natural origin has been deeply studied recently. The aim of this study is to evaluate antibacterial effects of aqueous extracts of Ghalghaf and Mazuj galls on gram-negative bacteria. The antibacterial activity of aqueous extract of two galls on the bacterial strains from clinical samples with multi-drug resistance (Pseudomonas aeruginosa، Acinetobacter baumannii، Escherichia coli) and reference bacterial strains were determined using agar dilution and agar diffusion methods. The aqueous extracts of both galls showed antibacterial activity against all studied bacterial strains. Inhibition zone diameter for aqueous extracts of Ghalghaf and Mazuj are in the ranges of 8-20 and 8-26 mm respectively. The size of the inhibition zone diameter was directly proportional to the concentration of extracts (p< 0. 05). The lowest amount of MIC related to aqueous extract of mazuj gall (0. 128 mg / ml). This study showed that two galls of Mazuj and Ghalghaf are contained of antibacterial compounds that could be used against multi-drug-resistant gram negative bacteria. Therefore the antibacterial activity of other extracts of these galls and pharmacologic studies are necessary.