antioxidant

In many parts of the world, medicinal plants have been used as an alternative medicine to promote human health and longevity since ancient times. Microbes residing within plant tissues are known as endophytes. The compounds produced by these microbes have the potential to be employed in modern medicine, agriculture, and other industries. Endophytic bacteria isolated from medicinal plants are valuable sources of novel bioactive compounds with diverse activities, including antimicrobial, anticancer, and antiviral properties. This study aimed to isolate, identify, and screen endophyte bacteria with antimicrobial activity against plant pathogenic bacteria. Aromatic plants such as Satureja khuzestanica are utilized in traditional medicine due to their secondary metabolites, but data regarding its naturally occurring bacterial endophytes is limited.

In the current study, 17 strains of bacterial endophytes were isolated in a Tryptic Soy Agar medium from the medicinal plant Satureja khuzestanica. Based on sequencing the 16S rRNA encoding gene, researchers isolated bacterial strains from the Bacillus, Streptomyces, and Pseudomonas genera with the highest activity against plant pathogenic bacteria. Under standard conditions, these endophytic bacteria’s bioactive secondary metabolites were extracted with ethyl acetate and analyzed using Gas Chromatography-Mass Spectrometry (GC-MS). The mass spectra of the compounds were compared to the National Institute of Standards and Technology (NIST) library’s database. Moreover, microbroth dilution techniques were used to determine the minimum inhibitory concentration (MIC) values for five different bacteria species.

The GC-MS analysis revealed the presence of a number of compounds, including dibutyl phthalate (DBP), eicosane, octadecanoic acid, hexadecanoic acid, and hexadecane 1,4- dicyclohexylbutane. Four of the selected bacterial endophytes exhibited antimicrobial activity against three plant pathogens: Ralstonia solanacearum, Pectobacterium carotovorum subsp., carotovorum, and Clavibacter insidiosus. Data analysis revealed significant differences in antimicrobial activity, with the minimum inhibitor concentration ranging from 0.312 mg/ml to 2. 5 mg/ml. Furthermore, we identified bioactive secondary metabolites with reported biological activities in antimicrobial, anti-inflammatory, and antioxidant properties with biotechnological applications in medicine, agriculture, and other industries based on an endophytic crude extract data analysis.

Our findings shed new light on the antimicrobial properties of naturally occurring bacterial endophytes in S. khuzestanica.

Tuta absoluta Meyrick (Lep.: Gelechidae) has recently caused significant damages to tomato production in greenhouses and fields, necessitating sustainable and efficient management. Garlic has antimicrobial and antioxidant properties due to the presence of various compounds such as mono, di, and trisulfides. Meanwhile, diallyl sulfide and diallyl disulfide have demonstrated effective insecticidal activity against various insects. Due to their rapid decomposition and almost specific lethality, natural compounds may be a viable alternative to chemical compounds in the control of tomato leafminer. The purpose of this study was to determine the effect of diallyl sulfide and diallyl disulfide LC30 and LC50 concentrations on the antioxidant system and energy allocation of tomato leafminer.

The leaf disc method was used to conduct the larval bioassay. Initially, preliminary testing was performed to determine the final concentrations of 0.0625, 0.125, 0.5, 1, and 2%. Each leaf was submerged in the toxic solution for ten seconds before being transferred to 8 cm Petri dishes. Then, second instar larvae (seven to ten days old) were placed on the leaves and allowed to feed on both control and treated leaves. After 24 hours, larval mortality was counted, and POLO-Plus software was used to calculate lethal concentrations. The second instar larvae were initially immersed separately at LC30 and LC50 concentrations of each component to evaluate the antioxidant system and energy allocation. The control larvae were fed only solvent and each treatment used 60-second instar larva separately. After 24 hours, the treated and control larvae were divided into three groups of 10, and each group was homogenized in distilled water. Samples were centrifuged at 20,000 ×g at 4 ° C for 20 min, and supernatants were used to determine the activity of catalase, superoxide dismutase, peroxidase, glucose-6-phosphate dehydrogenase, and malondialdehyde concentration, as well as energy consumption.

Catalase activity was significantly higher in treated larvae than in control larvae, with the highest activity observed following LC50 treatment with diallyl disulfide. Except for the concentration of diallyl sulfide LC30, the treated larvae had increased peroxidase activity compared to the control. The diallyl disulfide LC50 concentration demonstrated the highest activity. Although larvae treated with diallyl disulfide at the LC50 concentration had the highest superoxide dismutase activity, there was no significant difference in the LC30 concentrations of the two compounds compared to control larvae. The highest glucose-6-phosphate dehydrogenase activity was observed in larvae treated with both compounds at LC50 concentrations; however, the lowest was observed in larvae treated with both components at LC30 concentrations. Finally, the malondialdehyde concentration was significantly higher in the treated larvae than in the control larvae. The amount of energy allocated to tomato leafminer treated with diallyl sulfide and diallyl disulfide was significantly lower than the control. Finally, the lowest value was observed in larvae treated with diallyl disulfide at its LC50 concentration, but there was no significant difference between the other treatments.

The two compounds, diallyl disulfide and diallyl sulfide, increased the antioxidant enzyme activities in tomato leafminer larvae through fat peroxidation and oxidative stress. In treated larvae, the amount of energy required for metabolic activity increased while the amount of energy available to the body decreased significantly. As a result, it is concluded that these two ingredients, garlic essential oil and tomato leafminer mortality, would effectively cause physiological disturbances, most notably in the antioxidant system and energy allocation. Based on the findings, field experiments are necessary to determine the environmental toxicity of these compounds and their importance in reducing crop damage compared to control. Additionally, the efficacy and combination of these compounds can be compared to other field control methods that aim to maintain a healthy crop with minimal pest damage.

Introduction Allelopathy means any process involving the secondary metabolites (allelochemicals) produced by plants, algae, bacteria, and fungi (excluding animals) that influences the growth and development of agricultural and biological systems, with positive or negative effects. Plants produce secondary metabolites and in certain circumstances, these can act as phytotoxins, inhibiting or promoting some biochemical or physiological processes in the other plants or organisms. Toxicity of allelochemical compounds include effects on growth, chlorophyll content, photosynthesis, transpiration, stomatal conductance, relative growth rate, and oxygen uptake in many crops. Furthermore, the influence of allelochemicals on alpha amylase, oxidase, sucrose synthase activity and malon dialdehyde concentration were analysed. The role of numerous plant secondary metabolites is still unclear, and this raises curiosity for both plant physiologist and ecologists. Inhibitory effects on germination and establishments of crops caused by residues of either crops or weeds have lead to investigation of the release of toxic compounds from such residues. This present study was designed to evaluate the allelopathic potential of milk thistle for controlling common cocklebur in vegetables.
Materials and Methods In order to investigate the effect of milk thistle aqueous extract on growth and enzyme activities of common cocklebur seedlings, two separate experiments were carried out in randomized complete design and randomized complete block designs with five and four replications, respectively, in spring 2012 in seed technology laboratory and greenhouse of Azad University, Shoushtar branch, Shoushtar, Iran. Milk thistle aqueous extract concentrations were involved (0, 5, 10 and 15% (v/v)) in petridish and (0, 10, 20 and 30% (v/v)) as spraying on common cocklebur seedlings under greenhouse conditions. Whole plants of milk thistle were gathered from medicine plant farm of Azad University. Then, their flowers were cut and their shoots were dried in 60 °C and grinded. For preparing aqueous extract 100 g powder of milk thistle dissolved in 1000 ml distilled water and maintained at 20 °C. The solution was filtered and cleared. The aqueous extract was considered as stock and other aqueous extracts were prepared from it. After application extract concentration in petridish and pot, seedling fresh weight, activity of sucrose synthase, alpha amylase, catalase enzymes and malon dealdehyde concentration of common cocklebur were measured. Statistical calculations were accomplished through the SPSS software and graphs were drawn by the Excel software.
Results and Discussion Results showed that fresh weight of common cocklebur seedlings were affected by milk thistle extract. Milk thistle extract reduced alpha amylase enzyme activity and seedling growth of common cocklebur. In addition, increase in aqueous extract of milk thistle resulted in reduction and increase in catalase and malon dialdehyde concentration in cocklebur seedling; respectively. The minimum alpha amylase enzyme activity (2.1 nM/g seed/min) and seedling fresh weight (0.32 g) were observed in 15% aqueous extract. Malon dialdehyde concentration of cocklebur seedlings was 0.4 (nM/g FW) in 15% aqueous extract of milk thistle. Catalase enzyme activity was the lowest (1.4 nM H2O2/mg Protein/min) and the greatest (27 protein absorption/60s) in 15% aqueous extract of milk thistle. In greenhouse experiment, also, with increasing aqueous extract of milk thistle was reduced seedling fresh weight, catalase and sucrose synthase enzyme activities. Catalase and sucrose enzyme activities were 1.8 (nM H2O2/mg Protein/min) and 2 (nM/ mg protein/min) at 30% aqueous extract of milk thistle. Futhermore, increase in aqueous extract of milk thistle resulting in increase cell memberane destruction and malon dialdehyde concentration in cocklebur seedling tissue. The lowest (0.0029 nM/g FW) and greatest (0.93 nM/g FW) malon dialdehyde concentration was at 30% aqueous extract.
Conclusions In this study, with increasing the amount of milk thistle extract, values of measured traits including fresh weight, sucrose synthase and catalase enzymes of cocklebur seedlings compared to control treatment (distilled water) have a decreasing trend, but malon dialdehyde concentration of cocklebur seedlings had increased compared to the control. The destruction of cell membranes under the influence of cocklebur allelopathic compounds can be one reason for the reduced growth of weed seedlings. Reduced sucrose synthase activity, led to reduced production of sucrose that was associated with reduced seedling growth. The present study confirmed that milk thistle can be used as an allelopathic plant for weed suppression in agroecosystems through its release of allelochemicals. Knowledge about the challenges related to the demonstration of allelopathy, as an ecological significant mechanism, is important in the assessment of ecological effects of allelopathic plants.

The red flour beetles Tribolium castaneum is one of the most important pests of stored products, to control this pests plant extracts are suitable components as alternate for chemical pesticides. On the other hand herbs as natural resources that are antioxidant properties, The attention of researchers for use in the food and biological systems are located. In this research theefficiency of Pimpinella anisum extract on biological activity of anise Tribolium castaneum and its antioxidant functional is evaluated. In this study, the effect of seed extract of anisum on nutritional indices of adults T.castaneum, in 3 concentrations 50, 75 and 100 µl and respiratory toxicity effects of extracts ( 50, 89, 158, 281, 500 µl of extract per liter of air) was in vitro (29 ± 1°C and 65 ± 5% R.H.). Also the antioxidant effects of P.anisum was investigated by two methods, radical scavenging, DPPH (2, 2-diphenyl-1-picrylhydrazyl) method and reducing power of iron method. Nutrition a lindices showed that the highest and lowest concentration, respectively, has 86/94% and 68/82% inhibition of feeding. The highest mortality concentration was 500 µl/L of air at 24 hours. The required concentration to 50% mortality of population (LC50) at 24 hours after treatment was 215/19 µl/L of air. In DPPH test, the 50% inhibitory concentration of leaf extract was higher than seed extract, the same result was obtained from the power reducing of iron test.

The larvae of silkworm, Bombyx mori L., were used to determine the activities of catalase (CAT), peroxidase (POD), glutathione-s-transferase (GST) and some macromolecules such as; protein and triglyceride after treatment at 24°C and 39°C. The larvae of fifth instars were treated at 39 ° C for 8 h. The humidity of experiment was set at 55% at 24˚C and increased to 75% at 39˚C. The hemolymph and fat body were removed after four days. Some economic indices were assessed like weight of one male cocoon shell, percentage of male cocoon shell, weight of male cocoon, weight of one female cocoon shell, percentage of female cocoon shell, weight of female cocoon and their mortalities. Results indicated that the higher temperature reduced all the economic indices and the amount of macromolecules. The heat also increased the activities of antioxidant enzymes. The comparison between the antioxidant enzymes and economic indices indicated that Chinese hybrid 67 is more tolerant to temperature.