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Tomato is one of the valuable crop plant that is used as a model plant. Salicylic acid leads to the synthesis and accumulation of secondary metabolites such as phenol, flavonoids, lignin and anthocyanin by changing the activity of the key enzymes involved in their biosynthesis pathway. For study of the effect of SA on secondary metabolites and its biosynthesis pathway, the current experiment carried out using 0, 000.1, 00.1, 0.01, 0.1 and 0.5 mM Salicylic acid in MS medium under in vitro culture condition. After four weeks, seedlings removed from culture container and were analyzed. Results showed that with increasing of salicylic acid concentration dry and fresh weight of roots and shoot as well as the amount of chlorophyll a and b were increased significantly compared with control plants but they were decreased significantly in some concentrations. The total phenol compounds, flavonoids and anthocyanin, as well as PAL, TAL and Peroxidase activity were also gradually increased by increasing of salicylic acid concentration. The maximum level of these parameters were observed at 0/01 mM salicylic acid. The results suggested that, salicylic acid improved plant growth in optimum levels and decreased pigments and plant weight in toxic levels. Phenolic compounds and biosynthesis enzymes were increased by inductive role of SA against ROS production and oxidative stress.

Background and purpose: The medlar (Mespilus germanica L., Rosaceae) is an edible fruit and modern medicine has recognized its healing properties in treatment of some diseases. There is no scientific data in literature about its activity against some bacteria. In this study, antibacterial activity of hydro-acetonic extract of medlar¢s leaf was evaluated against some bacteria. Materials and methods: In this experimental study, the leaves were collected from Sari, Iran. Materials were dried at room temperature and coarsely ground before extraction. The extraction was performed at room temperature by maceration method using acetone (70%) as solvent. Total phenols and tannins were determined by Folin-ciocalteu method and antibacterial effects were studied. Minimal Inhibitory Concentration (MIC) and Minimal Bactricidal Concentration (MBC) were calculated by Broth Dilution Test. Results: The yield of extraction was 20%. Total phenolic and tannins contents were 90±10 GAE (based on standard curve) and 10±4 /g extract, respectively. The extract showed best inhibitory and bactericidal activities against Klebsiella pneumoniae (MIC= 3.333 ± 0.0233 and MBC= 5.833 ± 0.065). The lowest MIC was observed against Vibrio Cholera (6.667±0.048) and the lowest MBC was seen against E. coli and Shigella dysentiea (9.167±0.042). Conclusion: M. germanica leaf extract showed good antibacterial activities. So, this plant is potentially effective in controlling dysentery.

The effect of UV-C irradiation, either alone or in combination with other treatments, on the biosynthesis of secondary compounds in plants has been recently become a matter of interest. In this study, the influence of UV-C light on some phytochemical traits and activity of enzymes involved in phenolic metabolism in grape was investigated. At first, the berries of table grape cv. Sultana were subjected to UV-C irradiation in different doses of 0 (control), 0.8, 1.2, and 4.2 kJm-2, then they were kept at 15°C for 6 days. UV-C low doses induced total phenol in the berry skin. The lowest flavonoid content was observed in berries subjected to the highest dose of UV-C (4.2 kJm-2) on the first day, whereas those irradiated by the low dose of UV-C (0.8 kJm-2) had the most flavonoid content after 5 days (0.45 mg Rutin/g FW). Also, UV-C application improved antioxidant capacity of treated samples in comparison with control. It should be noted that UV-C irradiation had no effect on total tannin content of the berry skin. However, the effect of UV-C radiation on phenylalanine amonialyase (PAL) activity was remarkable during storage. The UV-C restricted the POD activity up to the middle of storage. However, in terms of polyphenol oxidase (PPO), this behavior was dosagedependent. The results showed that UV-C application at the low doses is an appropriate way to increase phenolic content and antioxidant capacity of table grapes cv. Sultana during limited storage time. [ABSTRACT FROM AUTHOR]

Due to the adverse side effects of synthetic antioxidants, the search for natural and safe antioxidants has become crucial. In this study, the total phenolic compound contents and antioxidants activity of persimmon skin was investigated. The extraction was carried out by means of maceration method using ethanol and methanol solvents with ratio of 1 part persimmon skin to 5 parts of solvents. Afterwards, the total phenolic compounds and antioxidants activity was measured. According to the results, ethanolic and methanolic extracts contained 255.6 and 214.15 mg gallic acid per 100 g of persimmon skin, respectively. Moreover, ethanolic extracts showed a higher activity for scavenging free radicals compared to methanolic extracts.

Antioxidants have a wide range of application in food industry. Beside by attention to rising in universal attitude to use from natural antioxidants, at this study antioxidant extracts of barberry fruits extracted by subcritical water at 120 - 180 °C and 10 - 50 Bar and radical scavenging power, reduction power, stability power of edible oil matrix and amount of Total Phenolic Compounds (TPC) of extracts investigated in Folin method. Results showed that amount of Total Phenolic Compounds changed from 2073.81 until 2553.79 mg Gallic acid per 100 grams of Dry Material (mg G.A/100 g D.M) that maximum of Total Phenolic Compounds, observed at 160 °C and decreased with rising temperature, whereas radical scavenging power and stability power in edible oil of extracts increase with temperature. Optimization of extraction process did at different temperatures and pressures condition for receive to maximum amount of Total Phenolic Compounds, stability power, reduction and radical scavenging. [ABSTRACT FROM AUTHOR]