Bermudagrass control in sugarcane in Brazil.

Abstract: Aims: Evaluation of the chemicals in controlling bermudagrass weed and effects on sugarcane selectivity. Study Design: Chamber growth studies: completely randomized design with nine treatments with five replicates. Field studies: Randomized block design with nine treatments with five replicates Place and Duration of Study: Instituto Agronômico, Centro de Cana, São Paulo State, Brazil, between February/2018 and December/2019. Methodology: Bermudagrass chemical control was studied in growth chamber in pots. In the first stage, imazapyr, clomazone, indaziflam, sulfentrazone and the control treatment were studied. In the second stage, imazapyr, clomazone, indaziflam were applied and a treatment with no herbicides was maintained. After 75 days of imazapyr application and 38 days of clomazone and indaziflam, clomazone + indaziflam and clomazone + sulfentrazone were applied, in addition to the control treatment. Sugar cane selectivity study was carried out in the field. Before sugarcane planting, imazapyr, clomazone, indaziflam were applied. After planting, clomazone + indaziflam and clomazone + sulfentrazone were applied, in addition to the control treatment. Results: Clomazone at 1050.0 g ha-1 applied as pre plant at 38 days before planting followed by clomazone at 1050.0 g ha-1 plus sulfentrazone at 650.0 g ha-1 applied 2 days after sugar cane planting was the best treatment for bermudagrass control and yield of the crop. Other viable options for control involved clomazone plus sulfentrazone used after imazapyr or indaziflam

Seletividade e controle de grama-seda em aplicações sequenciais de herbicidas em cana-planta.

A grama-seda (Cynodon dactylon) infesta os canaviais, tem suas plantas perenizadas em curto espaço de tempo e consequentemente tornam-se tolerantes aos herbicidas. Para elucidar estratégias de controle objetivou-se avaliar aplicações sequenciais de herbicidas sobre a eficácia de controle da grama-seda e a seletividade sobre a cana-de-açúcar. O experimento de eficácia de controle foi conduzido em vasos de plástico (18 L) preenchidos com solo de textura arenosa e plantados com ramos de C. dactylon. As parcelas foram distribuídas em delineamento inteiramente casualizado e em sala de crescimento, regulada para atender as condições de verão do clima Cwa (Koppen). O experimento de seletividade foi conduzido em cana-planta com parcelas de 7,5 m x 25m e delineamento em blocos casualizados. Ambos os experimentos foram constituídos por 9 tratamentos em cinco repetições, sendo compostos pela aplicação de clomazone + sulfentrazone ou clomazone + indaziflam, cada um precedidos da ausência de herbicidas, imazapyr (aplicado 75 dias antes), clomazone ou indaziflam (aplicados 38 dias antes) e o tratamento testemunha. No experimento de eficácia avaliou-se a porcentagem de controle e a matéria seca das plantas aos 60 dias após a última aplicação e no experimento de seletividade a altura, estande, produtividade dos colmos e perfil isoenzimático da ?-esterase aos 315 dias após plantio da cultura. A aplicação de clomazone + sulfentrazone após 38 dias de pousio do clomazone diminuíram a matéria seca de Cynodon dactylon e não prejudicaram a altura, estande e produtividade dos colmos aos 315 dias após plantio

Antileishmanial Activity of 4,8-Dimethoxynaphthalenyl Chalcones on Leishmania amazonensis

Leishmaniasis is a neglected tropical disease caused by Leishmania species. Available therapeutic options have several limitations. The drive to develop new, more potent, and selective antileishmanial agents is thus a major goal. Herein we report the synthesis and the biological activity evaluation against promastigote and amastigote forms of Leishmania amazonensis of nine 4,8-dimethoxynaphthalenyl chalcones. Compound ((E)-1-(4,8-dimethoxynaphthalen-1-yl)-3-(4-nitrophenyl)prop-2-en-1-one), 4f, was the most promising with an IC50 = 3.3 ± 0.34 μM (promastigotes), a low cytotoxicity profile (CC50 = 372.9 ± 0.04 μM), and a high selectivity index (SI = 112.6). Furthermore, 4f induced several morphological and ultrastructural changes in the free promastigote forms, loss of plasma membrane integrity, and increased reactive oxygen species (ROS). An in silico analysis of drug-likeness and ADME parameters suggested high oral bioavailability and intestinal absorption. Compound 4f reduced the number of infected macrophages and the number of amastigotes per macrophage, with an IC50 value of 18.5 ± 1.19 μM. Molecular docking studies with targets, ARG and TR, showed that compound 4f had more hydrogen bond interactions with the ARG enzyme, indicating a more stable protein-ligand binding. These results suggest that 4,8-dimethoxynaphthalenyl chalcones are worthy of further study as potential antileishmanial drugs