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Piper divaricatum essential oil (PDEO), extracted from plants of the Brazilian Amazon, was investigated for the first time as a novel green or eco-friendly inhibitor for steel corrosion in 1 M HCl at 25 °C. Our electrochemical studies demonstrate that for different PDEO concentrations, lower E corr and i ) were attributed as a favorable process, i.e., an indicative of physisorption and chemisorption between the PDEO components and the steel surface. Our results reveal that the PDEO has a promising character for anticorrosive steel applications and metal coating in industries.corr values were obtained. The influence of the oil concentration on corrosion inhibition, 0.5-4 g/L, was determined for 1 and 7 days of immersion. The corrosion rate (CR) and inhibition efficiency (IE) were determined by mass loss. The steel surface in the presence and absence of oil was investigated by scanning electron microscopy (SEM). The main PDEO compounds, determined by gas chromatography-mass spectrometry (GC-MS), were methyleugenol (20.68%) and eugenol (15.42%). The CR and IE for 2 g/L PDEO exhibited an optimal value of 4.31 mm/year and 98.3% for 7 days of immersion, respectively. The surface with 2 g/L oil for 7 days exhibited a less rough morphology, which was attributed to the corrosion inhibitory effect of PDEO. In addition, the PDEO adsorption process on the steel surface obeyed the Langmuir isotherm model. Negative values found for free standard energy ( < 0 kJ·mol -1 ) were attributed as a favorable process, i.e., an indicative of physisorption and chemisorption between the PDEO components and the steel surface. Our results reveal that the PDEO has a promising character for anticorrosive steel applications and metal coating in industries., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

In the present study, the essential oil (EO) of Annona exsucca DC. or Rollinia exsucca was extracted by hydrodistillation, and the identification and quantification of volatile compounds were performed by GC-MS and GC-FID. A. exsucca leaves were collected from the Magalhães Barata, northeast of the State of Pará (Brazil) in March and September of 2019. Moreover, we used computational approaches to evaluate possible biological targets for the major compounds of the EO. In the sample obtained in March, 50 compounds were identified, with hydrocarbon sesquiterpenes being the predominant ones with the content of 80.52%. In the sample collected in September, 58 compounds were identified, and the chemical class of hydrocarbon monoterpenes and sesquiterpenes were the dominant ones with contents of 43.36 and 31.29%, respectively. Computational methods demonstrated that some major compounds have potential biological activity against some strains of pathogenic bacteria, as well as against molecular targets involved in cancer development.

Medicinal and aromatic plants present important active compounds that have potential for use in food, pharmaceutical, and agriculture industries. In this sense, the present work aimed to conduct a literature review on the potential applications of essential oils from Lamiaceae species. Antioxidant, anti-inflammatory, and antimicrobial activities were evaluated. The importance of this study is demonstrated as a way to theoretically provide information on the use of different plants belonging to the Lamiaceae family, especially with regard to the physical, chemical, and biological properties of its essential oils., Competing Interests: The authors declare that there are no conflicts of interest., (Copyright © 2021 Luiz Renan Ramos da Silva et al.)