Molecular dynamics techniques are increasingly being used for material science studies, being a theoretical approach based on molecular mechanics studies. GROMACS is a free software that allows the development of simulations of various types of molecules, from biological molecules to inorganic structures associated with the area of materials, requiring the system parameterization according to the force fields used in the simulation. ClayFF is a force field used for crystalline clay structures and has been applied in several articles published in scientific journals. The objective of this work was to present a didactic approach to the implementation of ClayFF in GROMACS and the force field was used to simulate a kaolinite structure as an example, demonstrating the implementation for students and researchers in the field.

Os óleos essenciais das folhas, ramos finos, galhos, cascas do caule e frutos de Croton palanostigma foram analisados por CG e CG-EM. Os componentes principais determinados no óleo das folhas foram linalol (25,4%), (E)-cariofileno (21,0%), metileugenol (17,2%) e β-elemeno (6,0%); no óleo dos ramos finos foram α-pineno (41,4%), limoneno (29,0%), sabineno (11,5%) e β-pineno (5,7%); no óleo dos galhos foram metileugenol (24,1%), (E)-metilisoeugenol (15,3%), α-pineno (11,2%) e (E)-cariofileno (8,5%); no óleo das cascas do caule foram a-pineno (31,6%), metileugenol (25,6%) e (E)-metilisoeugenol (23,7%); e no óleo dos frutos foram linalol (42,7%), metileugenol (16,3%) e β-elemeno (6,4%). Análise estatística mostrou que as folhas e os frutos apresentam significante similaridade entre si, assim como os galhos e as cascas do caule. Adicionalmente, o óleo obtido das cascas do caule possui elevada atividade larvicida sobre Artemia salina (CL50, 3,71 ± 0,01 mg mL-1).

The essential oils of leaves, twigs, branches, trunk bark and fruits of Croton palanostigma were analyzed by GC and GC-MS. The main compounds found in the oil of the leaves were linalool (25.4%), (E)-caryophyllene (21.0%), methyleugenol (17.2%) and β-elemene (6.0%); in the oil of the twigs were α-pinene (41.4%), limonene (29.0%), sabinene (11.5%) and β-pinene (5.7%); in the oil of the branches were methyleugenol (24.1%), (E)-methylisoeugenol (15.3%), α-pinene (11.2%) and (E)-caryophyllene (8.5%); in the oil of the trunk bark were a-pinene (31.6%), methyleugenol (25.6%) and (E)-methylisoeugenol (23.7%); and in the oil of the fruits were linalool (42.7%), methyleugenol (16.3%) and β-elemene (6.4%). Statistical analysis showed that the leaves and fruit, and the branches and trunk bark, have significant similarities between them. In addition, the trunk bark oil has high brine shrimp larvicidal activity (LC50, 3.71 ± 0.01 mg mL-1).