RESUMO
The synthesis and phytotoxic activity of a series of tyrosol 1,2,3-triazole derivatives are reported herein. Target compounds were synthesized through the copper(I)-catalyzed azide-alkyne cycloaddition reaction (CuAAC), known as click reaction, and these were tested for phytotoxic activity on leaves of wild poinsettia (Euphorbia heterophylla), fleabane (Conyza sumatrensis), and tropical spiderwort (Commelina benghalensis). These are three highly noxious agricultural weeds that challenge available weed control methods, including the use of chemical herbicides. Twenty-five compounds were synthesized and tested. None of the compounds showed phytotoxic activity against C. benghalensis and C. sumatrensis, but almost all of them produced yellowing, bleaching, and necrosis on leaves of E. heterophylla. Two of the tyrosol 1,2,3-triazole derivatives produced more extensive lesions than those produced by the commercial herbicide diquat, used as a positive control (p ≤ 0.05). When applied on leaves of E. heterophylla, these compounds interfered with the stomatal conductance, net photosynthesis, internal carbon concentration, transpiration rate, water-use efficiency, and chlorophyll A and B contents. The interference of such compounds on such photosynthesis-related variables indicates that tyrosol 1,2,3-triazole derivatives may be capable of lowering the competitiveness of E. heterophylla and acting as additional tools for managing this competitive weed in agricultural lands.
Assuntos
Euphorbia , Álcool Feniletílico , Clorofila A , Euphorbia/química , Álcool Feniletílico/análogos & derivados , Triazóis/química , Triazóis/toxicidadeRESUMO
Africanized and wild bees are sensitive to synthetic insecticides, but may not be sensitive to botanical extracts. In this work, we evaluated the toxicity of botanical extracts with homemade preparations used in agroecological crops and their constituents on the bees Apis mellifera and Partamona helleri. Toxicity bioassays of adult bees were done by means of oral exposure and ingestion, using the insecticide imidacloprid as a positive control. Dietary consumption, respiration rate and bee flight were evaluated as sublethal parameters. Although some extracts were toxic to bees, survival was always higher compared to the results obtained with the imidacloprid, which was lethal to 100% of bees. In dietary consumption, P. helleri consumed less (5 mg/bee) in 3 h than A. mellifera (11 mg/bee), and P. helleri consumed less (7 mg/bee) in 24 h than A. mellifera (22 mg/bee). There was no difference in consumption of food containing plant extracts or food containing water only. We did not detect any adverse effects of the botanical extracts on bee respiration rates or flight. The major constituent of N. tabacum is nicotine (8.4-15.1%), in A. americana it is ß-caryophyllene (11.3%), and in A. colubrina, lupeol (12.2%). Imidacloprid and nicotine were more toxic to bees (LC50 ≤ 1.3 and LC50 ≤ 44.3). Botanical extracts were selective to A. mellifera and the native bee P. helleri, and therefore, have the potential for ecofriendly pest control.
Assuntos
Abelhas/fisiologia , Inseticidas/toxicidade , Extratos Vegetais/toxicidade , Animais , Dieta , Dose Letal Mediana , Neonicotinoides , NitrocompostosRESUMO
The authors present a case of a hemorrhagic adrenal cyst, one of the tumors known in literature as incidentalomas, emphasizing the clinical characteristics, since adrenal cysts or pseudocysts are generally rare and observed by chance during imaging procedures. Traditionally they are classified as pseudocysts, endothelial, epithelial or parasitic cysts. Laparoscopic adrenalectomy has been considered the treatment of choice for benign, functioning or non-functioning adrenal lesions. Small cystic adrenal tumors can be managed conservatively by laparoscopic decortication or marsupialization, but larger cysts should be treated by total or partial adrenalectomy.