In order to survive in a hostile habitat, plants have to manage the available resources to reach a delicate balance between development and defense processes, setting up what plant scientists call a trade-off. Most of these processes are basically responses to stimuli sensed by plant cell receptors and are influenced by the environmental features, which can incredibly modify such responses and even cause changes upon both molecular and phenotypic level. Therefore, significant differences can be detected between plants of the same species living in different environments. The comprehension of plant growth-defense trade-offs from the molecular basis to the phenotypic expression is one of the fundamentals for developing sustainable agriculture, so with this review we intend to contribute to the increasing of knowledge on this topic, which have a great importance for future development of agricultural crop production.
1 January 2018 in Evidence-Based Complementary and Alternative Medicine
Currently, the most effective treatment for recurrent urinary tract infections in women is antibiotics. However, the limitation for this treatment is the duration and dosage of antibiotics and the resistance that bacteria develop after a long period of administration. With the aim of identifying mainly novel natural agents with antibacterial activity, the present study was undertaken to investigate the biological and phytochemical properties of extracts from the leaves Taraxacum officinale. The structural identification of compounds present in hexane (Hex) and ethyl acetate (AcOEt) extracts was performed by mass spectrometry (GC‐MS) spectroscopic techniques and nuclear magnetic resonance (NMR) with the major compounds corresponding to different sesquiterpene lactones (α‐santonin, glabellin, arborescin, and estafiatin), monoterpene (9,10‐dimethyltricycle [4.2.1.1 (2,5)]decane‐9,10‐diol), phytosterol (Stigmasta‐5,22‐dien‐3β‐ol acetate), terpenes (lupeol acetate, pregn‐5‐en‐20‐one‐3β‐acetyloxy‐17‐hydroxy, 2‐hydroxy‐4‐methoxy benzaldehyde), and coumarin (benzofuranone 5,6,7,7‐a‐tetraaldehyde‐4,4,7a‐trimethyl). The results obtained show that the Hex extract was highly active against Staphylococcus aureus showing a MIC of 200 μg/mL and moderately active against Escherichia coli and Klebsiella pneumoniae with MIC values of 400 μg/mL and 800 μg/mL for the other Gram‐negative strains tested with Proteus mirabilis as uropathogens in vitro. Therefore, the effective dandelion extracts could be used in the development of future products with industrial application.
Fungal diseases, both pre- and post-harvest, are currently difficult to control—increased antifungal resistances have further stimulated the search for natural alternatives. The objective of the present research work was to evaluate the antifungal activities of Mentha pulegium essential oil (EO) and its major constituents. The EO was obtained from hydro distillation of fresh leaves, and composition was determined using gas chromatography/mass spectrometry (GC/MS). The main components were identified as pulegone (29.33%), menthol (28.79%), menthone (20.48%), and isopulegol (9.75%). EO and isopulegol exhibited the highest antifungal activity, with half maximal effective concentrations (EC50) inhibiting mycelial activity of Monilinia fructicola at 24.6 µg/mL and 20.8 µg/mL, respectively, and against Botrytis cinerea, at 301.45 µg/mL and 333.84 µg/mL, respectively. These findings could lay the foundation for developing antifungal agents of agricultural value.
Gray mold disease, which is caused by Botrytis cinerea Pers ex. Fr., results in serious economic losses to Lycopersicum esculentum (tomato) crop productivity. In this study, we explored the possibility that mixtures of essential oils (EOs) and their respective hydrolates (HYSs) could be used to control this disease. Thus, EOs and HYSs were obtained from Origanum vulgare, Thymus vulgaris, Citrus limon, and Citrus sinensis by hydrodistillation. In vitro antifungal activities were evaluated, and EC50 values of 15.9 and 19.8 µg/mL were obtained for EOs of thyme and oregano, respectively. These activities are due mainly to volatile compounds, thymol and carvacrol. Results from in vivo assays show that although most tomatoes were infested five days after inoculation, the damage was considerably reduced by the application of an EO/HYS mixture of thyme. The disease incidence indexes of B. cinerea tomato rot, percentage and severity, measured four days after inoculation, were reduced by 70% and 76%, respectively, as compared with the inoculum control. These results suggest that a combination of HYSs and EOs enhances antifungal activity, and that optimization of relative concentrations, volumes, and the nature of the compounds, could design a formulation able to control B. cinerea inoculum on tomato fruits.
15 January 2012 in World Journal of Microbiology and Biotechnology